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JOURNAL |
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ERRATA Vol. 14, 1924
Page 55: The papers by C. E. Van Orstrand and by A. L. Day and E. T. Allen were given at the 370th meeting, not at the 371st as stated in the Proceedings.
Page 78, line 11: For Dr. HILLEBRAND read Dr. H. S. WasHINGTON.
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Page 399, in the formula, line 13 from bottom: For 1-+ cos a read 1—cos a.
Vou. 14 January 4, 1924 No. 1
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JOURNAL
OF THE WASHINGTON ACADEMY OF SCIENCES
Vou. 14 JANUARY 4, 1924 Now
THE FOSSIL SWAMP DEPOSIT AT THE WALKER HOTEL SITE, CONNECTICUT AVENUE AND DE SALES STREET, WASHINGTON, D. C.
FORMATIONS EXPOSED IN THE EXCAVATION Cuester K. WENTWORTH, GEOLOGICAL SURVEY INTRODUCTION
Early in August, 1922, S. E. Godden, publicity manager of the Allen E. Walker Organization, called the attention of the United States Geological Survey to the stumps of trees and other vegetableremains that were being brought to light in the excavation for the foundation and basement of the new Walker Hotel, located at Connecticut avenue and DeSales street, N. W., Washington, D. C. DeSales Street is an east-west street, only one block long, about half way between L and M streets and between Seventeenth street and Connecticut avenue. The excavation is about 450 feet long and 150 feet wide.
The writer, who at the time was engaged in a critical study of terrace phenomena in the vicinity of Washington, under the auspices of the Geological Survey, examined the section at intervals of two or three days as the work progressed, until the 15th of September, when he left the city. The following paper is based in part on the writer’s personal observations and in part on notes later furnished to him by Messrs. L. W. Stephenson and Laurence La Forge, during the con- tinued progress of the work. Samples of the different formations were collected, but these have not as yet been critically studied in the laboratory.
1 Papers presented at the 176th meeting of the Washington Academy of Sciences held jointly with the Geological Society of Washington, the Biological Society of Washington, and the Botanical Society of Washington, the evening of Wednesday, March 14, 1923.
1
2 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 1
The writer is indebted to Mr. Godden, to F. F. Gillen, engineer in charge of the excavation, and to several of the workmen for courtesies and assistance rendered during his examination of the section.
The present surface of the ground at the block bounded by Seven- teenth and Connecticut avenue and DeSales street and L street has an altitude of 50 to 57 feet above sea level: The depth of the excavation for the foundation of the hotel was 35 to 40 feet, making the range of altitude of the bottom of the cut 15 to 22 feet above sea level.
THE SECTION
Five different formations were exposed in the section afforded by the excavation, the thicknesses and general relations of which are shown in the generalized columnar section (Fig. 1). These formations from above downward were as follows:
(1) Artificial fill.
(2) Pleistocene loam, sandy clay, sand, and gravel. (3) Pleistocene swamp silt or muck.
(4) Cretaceous sand and gravel.
(5) Pre-Cambrian schist.
DESCRIPTION OF FORMATIONS
Artificial fill. This material consists of a mixture of loam, clay, and sand, and varies in thickness from nothing at the northeast corner of the excavation to a maximum of 13 feet near the middle of the west side, the difference in thickness being due to the irregular configuration of the original surface on which the material was dumped. The material is likewise somewhat variable in composition and has little regularity of structure. Overlapping of different phases indicates the shifting of sources of the material dumped and of the directions of accumulation. Various materials of human source, while not quanti- tatively of great importance, are sufficiently abundant to indicate deposition of the material contemporaneously with the activities of - civilized man. The shapes and conditions of fragments of these materials together with the crude non-stratified character of the deposit show conclusively that it is artificial fill. Bits of coal, brick, tile and other pottery, tin cans, oyster shells, and occasional frag- ments of glass, leather, and metals are the most abundant relics found in this formation. A brick pavement, said to have been part of the cellar floor of the old convent which stood at the west end of the hotel site, and an old stone wall, extending two or three feet below the base of the fill, were exposed along the west side of the excavation.
JAN. 4, 1924 WALKER HOTEL DEPOSIT 3
Brick sidewalk at present street grade.
Unassorted mixture of gravel, loam, and clay. Contains a variety of articles of human source, such as bricks, tile, coal, cinders, glass, tin cans, and metal and leather fragments. 0 ft. to 13 ft.
ES = WN Os ly s ey eS x x
-Peat—a thin layer of carbonaceous material at the contact between the fill and the underlying sandy loam. 0 in. to 0.5 in.
Light gray loam, sandy clay, sand, and gravel, in places slightly mottled with buff. The material is poorly assorted and includes
ly bands and lenses of pebbly sand. Wicomico < formation. 5 ft. to 15 ft.
Se
K§
2s
ws B Light brown highly carbonaceous silt or q swamp muck, containing tree stumps and
wood fragments; turns black when exposed to air. 6 ft. to 9 ft.
Clay, sand, and gravel. Ranges from sandy clay above to coarse gravel at the base; finer material is a rich micaceous, little assorted gray-green geest from the underlying schist; the pebbles of the gravel are composed of a great variety of rocks from many parts of the Potomac basin, and the gravel is far less dominantly quartzose than the Pleistocene gravels of this region. The deposit is a basal phase of the Patuxent formation. 7 ft. to 12 ft.
LOWER CRETACEOUS
Schist, considerably weathered but still compact. —
Fig. 1. Generalized columnar section of formations exposed in the excavation.
<t JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, no. 1
Pleistocene loam, sandy clay, and gravel. At the top of this layer is a thin carbonaceous or peaty band containing small fragments of vegetable material. This band is an inch or less in thickness and is absent in some places; it is underlain by a soil zone 6 to 12 inches thick.
The main body of this layer below the soil zone includes gray to buff sandy clay and loam, and subordinate sand and gravel beds alternating with little order with respect to the top or the base of the section. The bedding, so far as observed by the writer, was of the cut- and-fill type, with stringers and zones of pebbles such as are common in the Pleistocene terrace deposits. The pebbles are dominantly of quartzite and vein quartz with a small amount of chert. The sand is almost wholly composed of quartz grains; ilmenite is present to the extent of perhaps one per cent, with muscovite and other minerals in much less abundance. The base of the formation grades into the swamp muck below, the contact being uneven, due apparently to differential leaching or perhaps to uneven deposition.
Though considerable search was made on several occasions by the writer and others, no brick, coal, cinders or other trash was found in this layer and there was no indication whatever that it was formed artificially or even contemporaneously with human occupation of the region.
Pleistocene swamp muck. The material next below the Pleistocene clay, sand, and gravel is of exceptional interest because of the unusual amount of fossil wood it contains, and is the subject of the great attention which the Walker Hotel section has commanded among scientists and residents of the city generally. The muck is 6 to 9 feet thick and underlies the entire hotel] site. When first uncovered it is a light brown, highly carbonaceous clay containing in places con- siderable sand and many mica flakes from underlying formations. Within a minute or two after exposure to the air the material turns very dark, almost black.
The wood is present in the form of many huge stumps, upright and in place, and broken fragments of limbs and roots. The largest stump measured by the writer was about 8 feet in diameter but others con- siderably larger are reported. Most of the wood is cypress and appears to differ, in no essential respect from the common bald cypress, Taxodium distichum. In addition to the cypress wood, which in- cludes stumps, roots, knees, and a few logs, numerous seeds and leaves of cypress were found. The seeds of other plants also occur, but these are less common than the cypress. Little alteration of the wood has taken place. It is water-soaked when first dug out and checks on
JAN. 4, 1924 WALKER HOTEL DEPOSIT 5
drying, becoming a little harder and firmer, but not “hard as iron” as has been reported. Like the green wood of recent cypress this fossil wood becomes very light in weight when dried. The stumps are rudely truncated at the top in an irregular but not splintery fashion. This abrupt upper termination appears to be due to subaerial rotting at or near the surface of continuous soil moisture, such as affects posts and poles erected by man. Likewise the scarcity of great trunks seems to be explicable by the rotting which usually takes place before burial is accomplished. Apparently only the smaller limbs, the stumps, and portions of a few larger trunks were buried or sub- merged in time to be preserved. No one has observed an authentic ancient axe mark on any of the stumps, and there is nothing in their appearance to warrant the popular opinion that the trees were cut down by man.
As the swamp deposit is 6 to 9 feet thick there is room for at least three stumps, one above the other, and as the individual trees must have lived 200 years or more, the time required for the deposition of the swamp muck must have been at least 600 years and may have been a thousand years.
Fossil remains of microscopic fresh water plant organisms, known as diatoms, are present in great numbers in the muck and they repre- sent many different species.
Lower Cretaceous sand and gravel, Patuxent formation. Beneath the swamp muck is micaceous clay silt, which grades downward to sand and gravel. This formation is penetrated in its upper part by the roots and rootlets extending downward from the tree stumps pre- served in the overlying formation; some of the roots extend 3 or 4 feet below the base of the swamp deposit. The finer portions of the Patuxent formation are almost wholly derived with little sorting from the weathered detritus of the underlying schist. The sands consist of angular grains of quartz, mica, garnet, tourmaline, hornblende, epidote, titanite, ilmenite, and other minerals, rudely assorted as to size, but clearly the product of very limited transportion, probably a few rods at most.
The gravel likewise contains angular blocks of the schist, though these are fragile and could not have been carried far. On the other hand, the bulk of the pebbles and boulders of the gravel, some of which range up to two feet or more in diameter, are of rocks foreign to the immediate vicinity.
G. W. Stose and Miss A. I. Jonas have very kindly made annotated identifications of the pebbles of a collection from this formation. On
6 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 1
the basis of these identifications the following composition was deter- mined by the writer for 423 pebbles of diameters ranging from 8 to 16 millimeters:
NUN CU STA Zoi 050 aa ea ee i tes ee ear gs prea ea ae
ATIDCTSESC IMSL. 22) nih ee eee i EAR ig RE 79 Chere olackyand! ory.) Sig ae pl lh ede A 5 63 Cambrian ‘quartzite ss ik I tN Oy Me 64 Chionticivcin (quartz Gitte doe, TO ee GS. otk Se. Boe 37 Epidotic greenstone, amygdaloidal................... 23 IGMaSsic Sand Stoner. aie Bey yeh ak eee bas fy een ae 13 Gray. W everton Quarizibe. sees. se ohio os Se ene 13 DVissahickomeschist. yee ae tes one a tysteis ate Cae 11 Garnetiterous and othemeramtes.» 202. Son oe oe 5 Sericitice quartzite! ..22 220. - eC. OTA. Tiers Slee Ce 1 Hematitie Weverton sandstone. 7.0... 2.) 2 Ee 2 Pre-Cambrianuapo-thyonike tank het fob. 80.8 cele a oper 3
) BG er Vi Saba wt SS = SH Sa 2 me 423
It is apparent from this list that the sources of the pebbles of the gravel are widespread over the Potomac basin and that transportation must have been comparatively rapid and weathering relatively slight during the epoch of its origin.
Pre-Cambrian schist. This ancient rock is a highly metamorphosed rock of gray-green color and schistose structure. It was clearly eroded to a relatively plane surface before the deposition of the overlying gravel but not all the weathered rock was removed at that time. At the surface, which was the only part seen by the writer, it is moderately compact and serves as an adequate basement for the heavy concrete walls and foundation, though it can be picked and wedged loose with a pick or hammer.
AGE RELATIONS OF THE FORMATIONS
The uppermost of the five formations is generally recognized by all observers to be of artificial origin and of very recent date. The persistent correlation of the tree stumps of the major swamp layer with the trees and swamp conditions which are remembered by some of the older inhabitants leads to the interpretation of the clay, sand, and gravel of the second formation as likewise artificial or at least of an origin contemporaneous with the growth of the modern city. The writer is convinced that this correlation and the consequent interpreta- tion are wholly erroneous. He considers that the recent surface with
WALKER HOTEL DEPOSIT
JAN. 4, 1924
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8 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 1
Fig. 3. One of the larger cypress stumps still in place but exposed and portions of it cut away in the process of digging. Sheet piling and one of the loading buckets are also prominent in the picture.
Fig. 4. One of the large cypress stumps from the Walker Hotel excavation, after it had been uncovered and lifted to the surface. By courtesy of the Walker Hotel! Organization
JAN. 4, 1924 WALKER HOTEL DEPOSIT 9
Fig. 5. Portion of a stump and roots still in place in the swamp muck on the north side of the excavation.
Fig. 6. View showing the edge of the swamp deposit into which the steam shovel is cutting. The form of a mud covered cypress stump upright and in place in the muck is indistinctly shown just to the right of the overturned bucket.
10 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 1
its vegetable mantle is represented by the thin peaty layer immediately below the fill, and that the clay, sand, and gravel, which is clean and devoid of artifacts, is of Pleistocene age.
The formation which lies immediately under the artificial fill is believed to have been formed during the latter half of the Pleistocene period, that is, during the latter half of the great ice age, an opinion based on the topographic position of the formation and its relation to the terraces that have been differentiated in this region. The terrace on which the portion of the city from K street northward to Sixteenth
Vig. 7. Photograph showing the character of the Patuxent gravel. This was a source of considerable water which kept the lower part of the cut constantly wet and during the off duty periods washed the gravel and kept it clean and bright, greatly facilitating its examination for various kinds of rocks and shapes of pebbles.
and U streets is built has long been known as the Wicomico terrace, and the loam, sand, and gravel underlying the terrace surface has been known as the Wicomico formation. The swamp deposit must neces- sarily have been formed at least a little earlier than the Pleistocene terrace deposit that overlies it, but there is no reason to believe that it is very much older. The swamp deposit is therefore referred to the early part of the Wicomico stage of the Pleistocene epoch.
The question is frequently asked, ‘“‘How long in years has it been since the fossil trees found in this swamp deposit were living trees?” This can not be answered definitely. If the swamp deposit was formed during the latter half of the ice age, it must have been many thousands of years ago. In the first press notice that was given out by the writer, the figures 20,000 or 30,000 years were mentioned. The biological evidence, however, as presented in the papers which follow this one, indicate that the climatic conditions during the formation of the swamp deposit were milder than at present. This suggests that the deposit was formed during one of the interglacial stages. If it was
JAN. 4, 1923 WALKER HOTEL DEPOSIT 11
formed during the last interglacial stage, the Peorian, which im- mediately preceded the last glacial stage, the Wisconsin, a conservative estimate of the age of the swamp would be 100,000 years, and it may be much older.
The gravel and sand deposit below the swamp layer is confidently assigned to the Patuxent formation (Lower Cretaceous) on the ground of its topographic position and lithologic character. However, no fossils have been found to corroborate this correlation. The deposit lies against the eroded edge of the Piedmont Plateau and is exposed with this relation at many places in the vicinity.
The unconformity which separates the Patuxent formation from the overlying swamp deposit represents an exceedingly long interval of time, including the Upper Cretaceous epoch, the Tertiary period, and the early part of the Quaternary period. No strata are preserved in this section which were laid down during this long interval. The unconformity which separates the Patuxent formation from the under- lying basement schist represents a period of time of even greater duration than does the unconformity at the top of the Patuxent, for it includes all of Paleozoic and most of Mesozoic time.
Though in this section there is presented an unusually interesting record of the conditions and history of past ages, there is no suggestion that any part of this history was unusual or exceptional at the time. The geologist knows that slowly and surely the products of nature are wrought, and that only in the fore-shortening of such a record as the one in question does one process seem to succeed another in an abrupt manner. There is to him no problem as to “What disaster over- whelmed the vast forest and crumpled it into a solid mass of crushed wood, shearing off these big trees as a man might cut grass with a scythe?” a question recently asked by a writer in Popular Mechan- ics with reference to this excavation. He can only hope that less and less as years go by will these relics of catastrophism persist in the popular mind.
12 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 1
ORGANIC REMAINS, OTHER THAN DIATOMS, FROM THE EXCAVATION
EpwarpD WILBER Berry, THE JoHNS Hopkins UNIVERSITY
The present imperfect contribution is, so far as I know, the first illustrated account of fruits and seeds from an American Pleistocene deposit—a much neglected field of research in this country, but one that has been cultivated with great distinction in northern and central Europe. .
As at the inauguration of work of this kind in Europe, I have felt the need of adequate collections of comparative material. Herbaria are almost useless, and carpological collections like those of the seed division of the Bureau of Plant Industry or that of the Biological Survey, built up with other ends in view, are not altogether satis- factory. J take much pleasure, however, in expressing my apprecia- tion of assistance from Edgar Brown of the former and W. L. McAtee of the latter bureau, and to E. P. Felt of Albany for his determination of Retinodiplosis.
The determined fossils obtained by washing a large amount of the argillaceous peaty material, carefully sorting it under water, and then drying and impregnating it with paraffin has involved an enormous amount of labor—a few ounces of prepared specimens being the result of the washing of 100 pounds of the material. ,
I cannot say that the results are decisively significant. The species identified represent with scarcely an exception such an assemblage as might be obtained in southern Maryland or Virginia at the present time. A substantially similar representation is to be found in the present flora of the District of Columbia, but the latter area does not include all of the species found among the fossils, and although the majority of the fossil forms do still inhabit the District several would not be likely to be present at the Walker site even though the latter had remained uninhabited.
There are recorded 28 more or less definitely named species of plants, as well as several undetermined and immature forms. Several species of galls were isolated. Of these two are figured and identified. One of these is present in great abundance. No beetle or other similar insect remains, such as are usually to be found in such deposits, were encountered, but bits of chitin and insect egg cases were present, as was also what appeared to be rodent dung.
The plants represent 19 families and include 1 gymnosperm, 8 monocotyledons, and 19 dicotyledons. Thirteen are positively deter- mined specifically and all of these represent still existing species; 5
~
JAN. 4, 1924 WALKER HOTEL DEPOSIT 13
additional are given tentative specific names; and the balance are merely identified generically. By far the most abundant remains were those of the bald cypress, grape, elderberry, Rubus, and sedges. As regards variety, the sedges furnish the most abundant element, six species representing the genera Carex, Scirpus, Cladium, and Dulichium being present—Carex and especially Dulichium in great abundance; and there are in addition various unidentified remains of sedges repre- senting Carex, Scirpus, and possibly Cyperus.
By far the most abundant single species represented was the bald cypress. All of the trunks, many of large size, seen in the excavation were of that species, and were present at successive levels; the peaty clays were also filled with their root systems and knees. In the washed and sorted material also the cypress was overwhelmingly represented, chiefly by seeds, there being relatively few cone scales. Pointing in the same direction was the abundance of cypress cone galls of the genus Retinodiplosis, and those of the cypress leaf gall of the genus Itonida.
Some critics, opposed to the antiquity of the deposit, have made much of the absence of prostrate logs. I have seen at least a score of similar Pleistocene swamp deposits, as well as many subfossil and recent ones, and prostrate logs are as rare in these as in the Walker deposit. They are not absent in the last and the reason for their rarity is clearly indicated by the accompanying photograph of such a log collected by Dr. Stephenson and photographed by Mr. Brown (Plate 3, fig. 1). It will be noted that this is part of a large log, the sub- merged portion of which was preserved, although the part exposed to the air had decayed before the growth of the deposit buried it. For other records of prostrate logs seen in the Walker deposits I am indebted to Dr. David White.
In trying to picture the environment as indicated by the planté alone, and for the moment ignoring the strictly geologic and physio- graphic data, it may be noted that the following, represented by fossils in this deposit, are found at the present time in swamps or marshes, or in standing and slow-moving water: Taxodium, Sparganium, Naias, Carex, Scirpus, Cladium, Dulichium, Polygonum, Castalia, Cerato- phyllum, Ranunculus, Vitis, Ampelopsis, Cornus, Leucothoé, Sambucus, and Viburnum. :
This list includes not only the majority of the species represented but nearly all that it has been possible to name specifically. Not only is this the case, but all but two of the remaining forms are species of
14 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. I
low woods and thickets, namely: Chenopodium, Rubus, Prunus, Acalypha, Galwum, and Ilex.
Only two of the fossils may be definitely assigned to various situa- tions. These are Phytolacca decandra and Viburnum prunifolium and both might normally be found associated with the foregoing. The plants therefore may be said to point overwhelmingly to a slow stream with seasonal or permanent ponds along its course bordered by low woods and thickets, with occasional glades. The geologic occurrence and the presence of numerous huge cypress butts prove | a prior’ what has just been deduced from the seeds and fruits identified.
The species represented, as is true of aquatic and water-side plants to a greater degree than to plants of other situations, are for the most part long-lived and widely distributed species. The Ceratophyllum is found practically throughout North America; several occur in Europe or Asia, a further indication of antiquity; and the majority are found to range from southern Canada or New England to Florida.
Those not found in the existing flora of the District are: Taxodium distichum, Navias marina, Scirpus lacustris, Cladium sp., Ampelopsis sp., and Chenopodium hybridum (?).
Others which are extremely rare or altogether absent on the Pied- mont and which are Coastal Plain species in this latitude are Ilex opaca, Rubus hispidus, Carex intumescens, and Leucothoé racemosa.
The bald cypress is preeminently a Coastal Plain species toward its present northern limits; in fact the so-called Fall Line is of considerable importance as a floral boundary in this region, as was clearly shown by Shreve in his Plant Life of Maryland.
Although it is not brought out with any great precision, a perusal of the ranges of the existing representatives of the fossils indicates that their general facies is southern rather than northern. The only form represented which might seem opposed to this interpretation rests on the validity of comparing the fossil Chenopodium with the existing Chenopodium hybridum. Nullifying this, as is pointed out under the discussion of that specimen, is the fact that almost any species of Chenopodium might, and occasionally does, have fruits as large as C. hybridum. I am therefore decidedly of the opinion that the fossil assemblage indicates slightly more genial climatic conditions than those which prevail at the present time in the District. It is conceivable that such an association might live in the District at the present time, but this southern facies and the distinctly Coastal Plain character of so many of the forms suggest that at the time they: lived - the Walker site was nearer sea level; or, stated another way, that
JAN. 4, 1924 WALKER HOTEL DEPOSIT 15
considerable areas of the present Coastal Plain were covered by the sea or penetrated by estuaries due to a much more extensive drowning of stream valleys than obtains at the present time.
With regard to the age of the deposit the decisive evidence must be that from the geological side. There were relatively few Pleistocene plants that are not still existing, and in a region such as this, situated in the middle Atlantic slope both at present and during the Pleistocene, the limits of range of the flora as a whole extend for long distances both to the northward and southward. In the absence of decisive elements the only estimate of age is that furnished by changes in range of the plants represented, and, as has been stated, these would be unlikely to be considerable in this situation (in respect to latitude, and situated in a relatively permanent river valley).
We have seen that these changes actually are slight, but that there have been some changes, and that certain species have withdrawn slightly to the southward, or more completely seaward in the present Coastal Plain, or both.
This points to a reasonable antiquity, as do the thickness of the deposit and the presence of large cypress butts at various levels. Adverse arguments based upon the freshness of preservation of the material are without the slightest force. I have seen fresher-looking wood from the Tertiary brown coal of Germany, where chemical tests reveal the presence of unaltered cellulose, and this is also said to be true for the inconceivably ancient Paleozoic coal in the province of Tula in Russia. I have collected equally modern-looking material from the Coastal Plain Upper Cretaceous. I see no reason for doubt- ing the Pleistocene age of the deposit, which is indeed confirmed by other lines of evidence, and also by the exact similarity between the Walker deposits and others in tidewater Maryland and Virginia wlnes the geological evidence is overwhelmingly positive.
At the same time I would deprecate the opinion of some students that this and similar deposits elsewhere along our Atlantic border are necessarily tens or hundreds of thousands of years old. I concede that such may be the case, but there is certainly no botanical evidence that the Walker plant bed is older than late Pleistocene.
GYMNOSPERMAE
TaxopiuM Disticuum (L.) L. C. Rich.(Pl. 1, f. 37-42; pl. 3).
It is probably impossible to differentiate Taxodium distichum from Taxo- dium imbricarivm by means of the seeds and cone-scales. The stumps, which with the root systems and knees make up the bulk of the fossil swamp deposit, appear to be those of the former rather than the latter species.
i6 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 1
The cone scales are not uncommon, but were apparently more perishable than the seeds, which are the most abundant objects present in the deposit. Both are characteristic. It is of interest that next in abundance are the galls of the midge, Retinodiplosis taxodiz, or its immediate ancestor.
The bald cypress has a most interesting history and its immediate ancestor attained a Holarctic distribution during the Tertiary. The present species makes its appearance in geological record in the Pliocene of Alabama, and it was very common in southeastern North America during the Pleistocene, at which time it extended its range both northward and inland beyond its modern limits. It has been recorded from the Pleistocene in New Jersey, Delaware, Maryland, Virginia, North Carolina, Georgia, Florida, and Alabama.
At the present time the bald cypress is confined to the Coastal Plain in this latitude, reaching its northern limits in southern Delaware and southern Maryland. It has not grown naturally in the District of Columbia in his- toric times. The Flora of the District (Washington, 1919) mentions it at Marshall Hall, Maryland, about 20 miles down the Potomac valley from the Walker Hotel site, but I have not observed it under unquestionable natural conditions nearer than southern Charles County, some miles distant.
That the Walker deposit was many years in formation is indicated by the section of a cypress log, between two and three feet in diameter, which is shown on Plate 3, figure 1. The lower third of this log, presumably buried in the more or less antiseptic swamp waters, was preserved, while the ex- posed two-thirds was subject to atmospheric conditions and hence decayed before the growth of the deposit was sufficient to entomb it. Cypress wood decays much more slowly than do most woods, and this possibly gives some measure of the rate of accumulation of the swamp deposit.
A section of one of the large pneumatophores or knees of the cypress, which are so common in the swamp deposit, is shown on Plate 3, figure 2. —
ANGIOSPERMAE MONOCOTYLEDONAE
SPARGANIUM EURYCARPUM Engelm. (PI. 1, f. 36)
This nut-like fruit, about which I entertained some doubt regarding its identity, has been positively determined for me by W. L. McAtee as identical with the recent fruits of this species.
The broad-fruited bur-reed, as it is called, is found in marshes and along streams from Newfoundland to Virginia and westward to British Columbia and California. It is the only identified form in the collection whose modern range is for the most part north of the Potomac River. It is frequent in swamps and along the marshy margins of streams in the District of Columbia at the present time.
1 See Berry, E. W.: Tree ancestors 56-67. 1923.
JAN. 4, 1924 WALKER HOTEL DEPOSIT 17
The genus goes back to Eocene, and possibly to Upper Cretaceous times. It is common in European Pleistocene deposits, but there is only one other American record, that of its occurrence in the Pleistocene of North Carolina.?
Nats sp. (Pl. 1, f. 1-3)
Several specimens in the collection represent this genus. It has not been possible to positively determine them specifically, although among existing species they are most similar to those of Nazas marina L. The pericarp is large, 2 to 4 mm. in length with a prominent, persistent style and a some- what rugose surface. Nazas marina is found in the existing flora of both North America and Europe in lakes and ponds. On the former continent it ranges from central New York to Florida, but it has not been recorded from the District of Columbia or Maryland. Three other forms of Nazas are present in the District, but the fossil appears to be distinct from these. The genus goes back to the Eocene; there are three extinct species in the Pliocene of Holland, and four species have been found in interglacial deposits in Germany. No others are known from the American Pleistocene.
Carex cf. cotuinsit Nutt. (Pl. 1, f. 4-8)
Achenes small, triangular-fusiform, widest medianly, and about equally nar-
rowed to the base and to the long, flexuous persistent style. This form is exceedingly common in the collection. It appears to represent Carex collinsii Nutt., a species of swamps, ranging from Rhode Island to Georgia, and apparently rare in the present flora of the District, from which there is but a single record. _ The genus is an old one and is supposed to date from the Upper Cre- taceous. Many species have been recorded from the Pleistocene of Europe. The American Pleistocene records include Scarboro, Ontario;? Greens Creek, Ontario;* Tennessee® and Florida.*®
CAREX cf. INTUMESCENS Rudge (PI. 1, f. 9-11)
Achenes triangular-fusiform, stout, with an expanded base, narrowing upward into a long, stout, flexuous style. Not uncommon in the collection but much less abundant than the preceding. Carices are determined with extreme difficulty and there are so many species that it is extremely hazar- dous to attempt the identification of fossil material. Nevertheless the present fossils are extremely close to Carex intumescens Rudge, which occurs in swamps and wet woods from Newfoundland to Manitoba, and southward to Florida and Louisiana. In the present flora of the District this species is apparently confined to low wet woods of the Coastal Plain.
2 Berry, E. W., Torreya 14: 160. 1914.
* Coleman, A. P., Journ. Geol. 3: 626. 1895.
4 Penhallow, D. P., Geol. Soc. Am. Bull. 1: 325. 1890. / 5 Berry, E. W., Torreya 22:11. 1922.
6 Berry, E. W., Florida Geol. Surv. 9th Ann. Rept. 22. 1917.
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Scrrpus cf. tacustris L. (PI. 1, f. 12)
Achene distinctly obovate in outline, plano-convex, mucronate. Bristles considerably longer than the achene. Several poor and one fairly satis- factory specimen were found, apparently representing Sczrpus lacustris L., a species that is widely distributed in ponds and swamps throughout North America, and present also in Europe. It is not recorded in the Flora of the District.
Species of Scirpus are common in the European Pleistocene, but no others are known from North American deposits of this age except Scirpus fluvia- tilis, which is recorded by Coleman’ from Scarboro, Ontario.
Scirpus cf. AMERICANUS Pers. (PI. 1, f. 13-15)
The fossil achenes are smooth, biconvex, obovate in outline, and promi- nently beaked. The bristles are not preserved. They appear to represent Scirpus americanus Pers., which, in the existing flora, is found in both brack- ish and fresh water swamps. It is widely distributed throughout North America, and is reported from South America. In the Flora of the Dis- trict it is reported as infrequent in open marshy situations on the flood plain of the Potomac River.
CLADIuM sp. (Pl. 1, f. 16)
A single achene in the swamp deposit is definitely referable to the genus Cladium, a genus with about 30 existing species, of which three are found in the United States—one eastern, one southern, and one on the Pacific coast. The fossil is much like the species of Cladiwm found in the early Pleistocene of Europe. It is close to the existing Cladiwm mariscoides (Muhl.) Torr., but may be distinct and represent an extinct species. The former is found in marshes from Nova Scotia to Florida but has not been recorded in the flora of the District. The genus is otherwise unknown in the Pleistocene of North America, although it is not uncommon in deposits of this age in Europe.
DULICHIUM ARUNDINACEUM (L.) Britton (Pl. 1, f. 17, 18)
The achenes of this species are among the commoner remains in the swamp deposit. This species, perhaps more commonly known as Dulichium spatha- ceum (L.) Pers., is a denizen of sluggish water bordering streams and ponds, and is found at the present time from Nova Scotia to Ontario and Minnesota, and southward to Florida and Texas. It is frequent in the District, es- pecially along the Potomac River flats. In former times, that is, during the Pleistocene, this species had a much more extended range, undoubted specimens having been found in the Pleistocene of Holland, Denmark, and Germany.’ The genus is monotypic in eastern North America at the pres- ent time, but four species have been described from the Pliocene of Holland.
7 Coleman, A. P., Geol. Soc. Am. Bull. 26: 247. 1915. 8 Stoller, J., Uber das foss. Vorkommen der Gattung Dulichium in Europa. Jahrb. k. Preuss. geol. Landes 30: 161. 1909 (1911).
JAN. 4, 1924 WALKER HOTEL DEPOSIT 19
DICOTYLEDONAE
PoOLYGONUM HYDROPIPEROIDES Michx. (PI. 1, f. 19-22)
Achenes not uncommon in the swamp deposit, about 0.104 inches in length. The illustrations fail to bring out their triangular cross-section. This species is found in swamps and wet places ranging from southern Canada to Florida and Mexico, and in California. In the Flora of the District of Columbia it is recorded, under the name of Persicaria hydropiperoides (Michx.) Small, from several stations along the Potomac, but is not com- mon.
Fossil forms of Polygonum have been recorded from the Pleistocene of Ontario,? Maryland,'® and Florida."
- POLYGONUM sp. (PI. 1, f. 23)
This may possibly be a variant of the preceding species, or it may repre- sent a second species of the genus. The fact that it is represented by the single specimen figured suggests that the first supposition is most likely the correct one.
CHENOPODIUM sp. (Pl. 1, f. 24)
This large seed of a Chenopodium is most like those of the existing Cheno- podium hybridum L., a form of woods and thickets found from Canada to New Mexico and in the eastern United States from New Jersey northward to Quebec. It is therefore extra-limital in the District, but this loses its significance when it is recalled that almost any of our chenopodiums might produce a few big seeds like the fossil, although most of the species recorded in the Flora of the District are naturalized weeds.
PHYTOLACCA DECANDRA L. (PI. 1, f. 26-28)
Characteristic seeds of this species are represented by several specimens in the collection. The pokeweed is found in various situations, usually in rich moist soil, from Maine and Ontario to Minnesota and southward to Florida and Texas. It has become naturalized in Europe. Its chief interest in the present connection is the fact that the balance of the genus is tropical and this species apparently represents a northward extension of range that took place at least as early as the late Pleistocene.
CasTaLia sp. (Pl. 1, f. 25)
These seeds, which have been identified for me by W. L. McAtee, are immature seeds of an undetermined species of water-lily. The only Castalia in the existing flora of the District is Castalia odorata (Dryand.).Woodv. & Wood, the common white water-lily, and the fossil may well represent that species. The genus has not been recorded hitherto in the North Ameri- can Pleistocene.
9 Coleman, A. P., Geol. Soc. Am. Bull. 26: 247. 1915.
19 Hollick, A., Maryland Geol. Surv. Plio-Pleistocene 231. 1996. i Berry, E. W., Journ. Geol. 25: 662. 1917.
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CERATOPHYLLUM DEMERSUM L. (PI. 1, f. 33-85)
The hornwort fruit, which is a nut or achene, shows considerable variation in its spinelike beak (the persistent style), and in the degree to which the margin is spined or tuberculated. Several supposed species have been based upon these variations of the fruit, the fossil resembling the variety echinatum A. Gray. Many botanists, however, believe these differentiations to be valueless.
The plant is a submerged aquatic of ponds and slow streams, and at the present time it is found throughout all of North America except the far north. The fossil fruits are characteristic, and I have figured one 4/5’s natural size, showing the beak, and two others enlarged, in which the beaks are broken away. The species is found in the District at the present time near the Potomac River from Plummers Island southward, but rarely fruit- ing, being generally propogated by buds. The genus is not otherwise known in the American Pleistocene.
RANUNCULUS sp. (Pl. 1, f. 29-31)
There are numerous specimens and some variety of achenes that can be rather confidently referred to this genus. They doubtless represent more than a single species, but I do not feel that they can be conclusively identified. The present flora of the District includes 12 species of Ranunculus. Several species have been recorded from Pleistocene deposits in Europe, where they seem to be determined with a great deal of confidence; but none are known from the American Pleistocene, although Ranunculus aquatilis L., has been found in what is called post-Pleistocene, at Hadley, Massachusetts.
Rusus spe(ely2) tf. 1)
These characteristic seeds of some species of Rubus are exceedingly com- mon in the swamp deposit. After an extended comparison with the seeds of recent species of raspberries and blackberries I have concluded that specific identification based on the seeds alone is unreliable, although several Euro- pean students of fossil seeds have apparently not found this to be the case.
There are six species of Rubus in the existing flora of the District, and the fossil probably represents the modern Rubus hispidus L. which occurs in low woods, especially in the Coastal Plain. A rubus stone has been recorded from the Pleistocene of Alabama.'® and a prickly twig from de- posits of this age in North Carolina.“
PRUNUS SEROTINA EHRH.? (Pl. 2, f. 2, 3)
These stones, of which several specimens have been found, are small, smooth, and nearly globose. They very probably represent a Pleistocene ancestral form of the black cherry, Prunus serotina Ehrh., although this identification
12 Emerson, B. K., U. S. Geol. Surv. Bull. 597: 148. 1917. 13 Berry, E. W., Torreya 14: 161. 1914. 14 Berry, E. W., Journ. Geol. 15: 344. 1907.
JAN. 4, 1924 WALKER HOTEL DEPOSIT 21
is not positive. This species, in the existing flora, is a denizen of rich woods and open places from southern Ontario to Florida, and westward to the eastern prairie states. It is frequent to the existing flora of the District. The presence of these stones in the swamp deposit might be explained as having been due to water transport after drying, but their presence is much more readily explained as having been due to the droppings of birds, which normally distribute them very widely.
The genus Prunus is supposed to date from the Upper Cretaceous, and stones have been found in the lower Eocene of the United States.!> Several species have been recorded from the Pleistocene of Europe, and in this country Pleistocene species are known from Ontario,!* from cave deposits in Pennsylvania,!’ and from post-glacial beds in Massachusetts.!8
ACALYPHA VIRGINICA L. (PI. 2, f. 10)
This large, mostly tropical and sub-tropical genus of herbs and shrubs extends northward as far as Ontario in the case of this single herbaceous species. Characteristic seeds are present in the swamp deposit. In the modern flora this species is an inhabitant of woods and thickets ranging from Ontario to Florida, and it is common in the existing flora of the Dis- trict. The genus is not known elsewhere in the fossil state.
Iuex opaca Ait. (Pl. 2, f. 4, 5)
The seeds of this species are not uncommon in the swamp deposit. In the existing flora it is found in low moist woods from southern New England to eastern Texas, and, except in the south Atlantic states, it is almost entirely confined to the Coastal Plain. Five species of Ilex have been recorded from the Pleistocene of North America, the present species occurring in beds of that age in North Carolina!® and Alabama.?°
ViTIs coRDIFOLIA Michx. (Pl. 2, f. 6-9)
Seeds of the chicken or frost grape are among the most abundant fossils in the swamp deposit, ranking next to the seeds of the bald cypress in abun- dance. They are frequently broken and are invariably hollow, as are most of the associated remains. They show considerable variation in size and form but are believed to represent a single species. The extremes of size are figured.
This species, which is also known as the possum and winter grape, is an inhabitant of low moist thickets and stream banks, and is found from New
15 Berry, E. W., U.S. Geol. Surv. Prof. Paper 91: 221, pl. 116, f.1. 1916.
16 Penhallow, D. P., Am. Nat. 41: 448. 1907; Coleman, A. P., Geol. Soc. Am. Bull. 26: 247. 1915.
17 Mercer, H. C., Journ. Acad. Nat. Sci. Phila. ser. 2,11: 281. 1899.
18 Emerson, B. K., U.S. Geol. Surv. Bull. 597: 148. 1917.
19 Berry, E. W., Journ. Geol. 15: 345. 1907.
20 Berry, E. W., Am. Nat. 41: 686, pl. 2, f. 1. 1907.
22 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 1
England westward to Nebraska, and southward to Florida and Texas. It is recorded as not uncommon in the flora of the District.
Grape seeds of various species, usually unidentified specifically, are common in the Pleistocene of the Atlantic Coastal Plain, and have been recorded from New Jersey,?! Maryland,™ Virginia,“ and North Carolina.”*
AmpELopsis (?) sp. (Pl. 2, f. 19)
A small berry-like, pedicellate fruit, apparently two-seeded, is tentatively referred to the genus Ampelopsis, and may be compared with the fruits of existing Ampelopsis cordata Michx., a species of swamps and river banks, found at the present time from southern Virginia to Florida, and westward to Illinois, Kansas, and Texas. The fossil is too small to represent a normal fruit of Ampelopsis arborea (L.) Rusby, which is a native of the District at the present time. Its identification is too uncertain to be considered as of special significance.
Cornus AMoMuUM Mill. (Pl. 2, f. 15-18)
The silky cornel, swamp dogwood, or kinnikinnik, is a shrub of low woods and stream banks, which, at the present time, ranges from New Brunswick and Ontario westward to Dakota and Nebraska, and southward to Florida and Texas. It is not at all uncommon in the modern flora of the District.
The stones of this species are not uncommon in the swamp deposit. They are usually somewhat compressed, pointed at both ends, unsymmetrical in outline, and irregularly ridged. Specimens are figured showing lateral and vertical views, as well as in section showing the two cells.
Stones belong to different species of the genus Cornus are not uncommon in the Pleistocene of Europe. In deposits of this age in North America the only previous record is in the Pleistocene of New Jersey.”°
LEUCOTHOH RACEMOSA (L.) A. Gray (PI. 2, f. 11-14)
This species, which is new to the Pleistocene of North America, is repre- sented in the swamp deposit by the single depressed-globose, 5-valved capsule figured, and by numerous detached loculicidal valves, some of which are figured from different angles.
The swamp leucothoé is usually found in swamps and moist thickets, although it may also occur in drier situations. It is found from Massa- chusetts to Florida and Louisiana at the present time, and is usually re- stricted to localities in the Coastal Plain. It is recorded, under the name of Eubotrys racemosa (L.) Nutt., as frequent, in the flora of the District of Columbia.
21 Berry, H. W., Torreya 10: 266. 1910.
2 Hollick, A., Maryland Geol. Surv. Pleistocene 235. 1906.
23 Berry, E. W., Torreya 6:89. 1906.
24 Berry, E. W., Journ. Geol. 15: 345. 1907.
25 Penhallow, D. P., Trans. Roy. Soc. Canada, ser. 2, sec.4:70. 1896.
JAN. 4, 1924 WALKER HOTEL DEPOSIT 23
GaLium sp. (Pl. 2, f. 20)
With the exception that the two specimens collected have an aperture at both poles, they are very similar to the fruits of various species of Galiwm. Since the embryo in Galium seeds is at the pole this region would probably be one to decay more rapidly, which might account for the double opening. Specific identification is impossible, but the specimens suggest the Holarctic recent species Galium triflorum Michx., which, in the existing flora of North America, is a woodland species, ranging from Nova Scotia to Alaska, and southward to California, Louisiana, and Alabama. It is common in damp woods in the existing flora of the District of Columbia, in which seven other species of Galium are also reported. Galiwm has-been recorded from the European Pleistocene, but has not been found heretofore in deposits of that age in America.
SAMBUCUS CANADENSIS L. (PI. 2, f. 21-24)
The one-seeded, rough-surfaced nutlets of this species are rather common in the swamp deposit. The elder, or as it is more commonly termed, the elder-berry, inhabits wet situations generally thickets, and at the present time ranges from Nova Scotia westward to Manitoba and Kansas, and southward to Florida and Texas. It is still abundant in the District of Columbia. The genus has not been known before in the American Pleistocene. ;
VIBURNUM NuDUM L. ? (PI. 2, f. 25)
The specimen is a stone apparently belonging to this species, which, in the existing flora, is a rather large shrub of swamps, ranging from Long Island to Florida, and westward to Kentucky and Louisiana. It is common in swampy and wet places in the present flora of the District. This species has been reported from the Pleistocene of North Carolina®® and Florida.?’
VIRURNUM sp. (Pl. 2, f. 30)
This flattened equilateral stone is typical of certain species of Viburnum and probably represents the modern species Viburnum prunifolium L., which, in the existing flora, is a shrub or small tree, ranging from Connecticut to Florida. If this is the correct affinity of the fossil it may be an example of a dry-soil element otherwise unrepresented in this deposit, although the black haw is not especially restricted in its habitat and is found in a variety of situations. It is common in the existing flora of the District. In the absence of certainty of identification it would be futile to discuss the mean- ing of its presence in the present assemblage. It has not before been found fossil, although the stones of several other species of Viburnum have been found in the Pleistocene of the United States.
26 Berry, E. W., Torreya 14: 160. 1914. 27 Berry, E. W., Journ. Geol. 25: 662. 1917.
24 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VoL. 14, No. 1
Additional plant remains which are shown on the accompanying plates, and which are not positively determined, comprise the following:
1. A characteristic prickle, evidently of some species of Rubus or Rosa GRE 27):
2. Fruits that appear to represent some undetermined species of the family Ranunculaceae (PI. 2, f. 26).
3. Immature fruits of the genus Ranunculus (Pl. 1, f. 32; pl. 2, f. 28).
4, Immature fruits of sedges, probably representing the genera Carex and Scirpus (el 2) fs 3):
HEXAPODA-DIPTERA
RETINODIPLOSIS sp. (Pl. 2, f. 832-34)
These galls are very abundant in the swamp deposit. They are roughly spherical, thick walled, monothalamous, about 5 mm. in diameter. Dr. E. P. Felt, the well known authority on galls, has kindly examined them and states that they belong to the genus Retinodiplosis Kieff, of the family Itoni- didae—the gall midges.
Although possibly specifically distinct they are very close to the species Retinodiplosis taxodii Felt,?® whose galls are tightly packed in the cones of the cypress and probably represent modified or aborted seeds. Dr. Felt considers this cypress midge as decidedly more primitive than the other species of the genus occurring in the pines.
ITONIDA sp. (PI. 2, f. 29)
These galls are small, rotately 5-lobed and stalked. snl specimens have been found in the swamp deposit, but they are much less abundant than the Retinodiplosis galls. 'They were examined for me by W. L. McAtee who, however, is not responsible for the generic name. The genus Itonida belongs to the same family as Retinodiplosis, and is a more modern name © for the well known term Cecidomyia.
The fossil galls are very close to the galls of Itonzda anthici Felt,?® and very probably represent that species. The latter are flower-like, and are borne on the leaves of the bald cypress. For their general appearance in life the reader is referred to an illustration published by Dr. Felt.%°
28 Felt, H. P., Ent. News 27: 415-417. 1916. 29 Felt, E. P., Econ. Ent. Journ. 6: 278. 1913. ‘ON. Y. State Mus. Bull. pp. 231-232. 1920.
Journ. WasH. Acap. Scr., Vou. 14 PLATE 1
BERRY on ORGANIC REMAINS
Journ. WasH. Acap. Scr., Vou. 14 PLATE 2
BERRY on ORGANIC REMAINS
PLATE 3
1., Vou. 14
Sc
H. ACAD.
Ss
Journ. Wa
BERRY on ORGANIC REMAINS
JAN. 4, 1924 WALKER HOTEL DEPOSIT 25
PuaTE 1 Figs. 1-3. Naias sp. Figs. 4-8. Carez cf. collinsit Nutt. Figs. 9-11. Carex cf. intwmescens Rudge. Fig. 12. Scirpus ef. lacustris L. Figs. 13-15. Scirpus cf. americanus Pers. Fig. 16. Cladium sp. Figs. 17, 18. Dulichium arundinaceum (L.) Britton. Figs. 19-22. Polygonum hydropiperoides Michx. Fig. 23. Polygonum sp. Fig. 24. Chenopodium sp. Fig. 25. Castalia sp., immature. Figs. 26-28. Phytolacca decandra L. Figs. 29-31. Ranunculus sp. Fig. 32. Ranunculus sp., immature. Figs. 33-35. Ceratophyllum demersum L. Fig. 36. Sparganium eurycarpum Engelm. Figs. 37-42. Taxodium distichum (L.) Rich., cone scales and seeds. All of the figures on this plate are from untouched photographs and all are uniformly enlarged four times natural size except Figure 33 which is # natural size.
PLATE 2
Fig. 1. Rubus sp., eight stones.
Figs. 2, 3. Prunus serotina Ehrh. (?), 2 stones.
Figs. 4, 5. Ilex opaca Ait.
Figs. 6-9. Vitis cordifolia Michx. showing maximum and minimum sozed seeds.
Fig. 10. Acalypha virginica L.
Figs. 11-14. Leucothoéracemosa (L.) A. Gray. Fig. 11 shows a complete capsule, and Figs. 12-14 show detached valves, the usual method of occurrence.
Figs. 15-18. Cornus amomum Mill., various stones. Fig. 17 shows one in cross-section.
Fig. 19. Ampelopsis (?) sp.
Fig. 20. Galium sp.
Figs. 21-24. Sambucus canadensis L.
Fig. 25. Viburnum nudum L. (?)
Fig. 26. Fruit of some member of the Ranunculaceae.
Fig. 27. Thorn of Rubus or Rosa.
Fig. 28. Ranunculus sp., immature.
Fig. 29. Iionida sp., Gall of cypress leaf midge viewed from above.
Fig. 30. Viburnum sp., probably prunifolium L.
Fig. 31. Fruits of sedges, immature.
Figs. 32-34. Retinodiplosis sp., cypress cone galls.
All of the figures on this plate are from untouched photographs and all are uniformly enlarged four times natural size.
PLATE 3
Fig. 1. Cross-section of cypress log. Fig. 2. Longitudinal section of cypress knee.
26 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 1
DIATOM DEPOSIT FOUND IN THE EXCAVATION ALBERT Mann, Nationa Museum
In making the excavations under discussion it was found necessary to dig down to bed-rock, as building operations in the vicinity had shown the locality to be swampy and a stream to have had its bed nearby. The site had been filled in by the city. To reach a solid foundation digging was carried to a depth of 35 to 40 feet below the level of the adjacent streets. Close to the bottom of the excavation a swamp-like deposit was uncovered, in which were embedded the stumps of large bald cypress trees (Taxodium distichum) in a fair state of preservation. ‘The soil in which they had flourished was dark gray, almost black, and of a decidedly peaty texture, and was found to be richly mixed with the silica remains of fresh water diatoms. The material having been cleaned, the diatom flora proves so unique that a report seems to be called for.
In all, 78 species and notable varieties of diatoms have been detected in this deposit, which is rather more than the number of species usually found in fresh water localities in and about Washington at the present time. A large proportion of these are now locally unrepresented. In fact, so many are very rare and unique that one may be led to infer either that their life-period dates back very many years and that the deposit is a sub-fossil one, or that they flourished under quite different conditions from those of the present time. Their antiquity is further suggested by the fact that many of the specimens are in a decayed or “rotten”? condition, indicating that they have been subjected for a long time to some corrosive agency. ‘This is especially noticeable in those species that have thin and delicate ‘‘frustules,”’ the technical name given to the silica boxes or encasements that surround the life-substance of diatoms. Since silica, the material composing these diatom boxes, is affected only by hydrofluoric acid and by alkaline solutions, the corrosion here noted must have required a great many years. A weak solution of potash, soda, or lime, such as is generally found in alkaline soils, has only a very feeble and slow effect as a silica solvent. It may be added that there are rather an unusual number of distorted and misshapen diatoms present, and that this distortion is rather common where these microscopic plants are forced to grow in alkaline waters, especially if lime is present.
JAN. 4, 1924 WALKER HOTEL DEPOSIT 27
Another fact suggestive of the age of this deposit is that a number of uncommon species found here are characteristic of certain fossil diatom beds located in central Alabama, notably at Montgomery. In the Alabama State Geological Survey for 1894 is a report by K. N. Cunningham on the fossil diatoms of Montgomery, the geological age of which has been fixed as Pleistocene. Material from this precise spot is now not procurable, because the city has extended over the most of the diatom bed. But samples obtained from outcrops locted in the suburbs of the city have been examined and these agree in general with the Cunningham report. He lists 55 species, of which 44, or 80 per cent, have been found in the Connecticut avenue deposit. Of the 11 not found there nearly all are very minute forms, which may have escaped discovery in the examination of the local material. It should be noted that the close resemblance between these two deposits is seen not so much in the number of species common to both as in the rarity of many of the species common to both; and it must be recognized as a significant fact that the diatoms of the two beds—one Pleistocene fossil at Montgomery, Alabama, and the other here at Washington—are strikingly like each other and quite unlike the usual diatoms now found in a living state in the two localities.
To confirm this last point I have examined the diatom flora of a bald cypress swamp near Cape Henry, Virginia. <A few of the species found therein are present in the Connecticut avenue material; but they represent only such cosmopolitan species as inevitably are looked for in any fresh-water growths, fossil or recent, occurring in this part of the world. This correspondence therefore has little significance, especially as these recent cypress-swamp diatoms do not include a single one of the rare and unusual species found in the local material, in the Pleistocene material from Montgomery, and in some supposedly fossil material from Crane Pond, Massachusetts, the peculiarities of which will be hereafter noted. In other words, the diatoms of the local swamp are strikingly like those of the two fossil deposits and strikingly unlike those of the near-by bald cypress swamp now growing under practically identical conditions.
The remarkable similarity between a diatom flora found at Crane Pond, Massachusetts and this local flora is worthy of further attention. At the time that material was distributed to diatom students, it was understood to have been obtained from a stratum 13 feet below the mud surface of the bottom of the pond, although I am unable to find any reference in diatom literature to confirm this. At any rate, no
28 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 1
considerable number of the Crane Pond species have been met with elsewhere until they appear in this Connecticut avenue excavation In other words, most of the species common to Crane Pond and to the Connecticut avenue deposit are rare, and even when discovered at other localities are always commented upon as unusual. Thus, a few are recorded from French’s Pond, Albany, Maine; from Wolfboro, on Lake Winnepesaukee, New Hampshire; from Waltham, Massachu- setts; and, strangest of all, from the Demerara River in British Guiana. But the parallel existing between any of these is far less striking than that between Crane Pond and this local deposit.
Of the 78 species and well-marked varieties found in the local deposit 64, or over 80 per cent, belong also to the Crane Pond diatom flora. In the appended list the species common to both localities are marked with an asterisk. The parallel here shown is so close that it is fair to assume that the two floras would be found to be even more, rather than less, alike if an exhaustive study supplied us with com- plete lists from both places.
One of the rare species frequent in the Connecticut avenue material brings out an interesting fact. It is called Navicula Schinz Br. It was first discovered in two fresh water lakes in West Africa, Olu- konda and Ombika, and was subsequently discovered in the fossil material at Montgomery, Alabama. To rediscover this very rare diatom so far away from its first place of discovery is interesting, and to find that 1t seems to have developed nowhere in this country except in the Pleistocene deposit at Montgomery and in this bald cypress swamp in Washington is even more so. It certainly strengthens the belief that this local swamp dates back in its origin a great many years.
It may be well to summarize the three points of special interest in this study: (1) There is a great dissimilarity between the present- day local diatom flora, including that of near-by bald cypress swamps, and the diatom flora of the Connecticut avenue deposit; (2) there is a striking similarity between the diatoms of the local deposit and those found in the supposedly fossil material from Crane Pond, Massachusetts, and in the fossil bed at Montgomery, Alabama (3) there is an indication of the antiquity of this deposit shown by the decayed condition of many of the specimens, suggestive of long sub- jection to the corrosive effect of alkaline waters. The writer’s knowl- edge of Geology is too superficial to warrant any conclusion as to the precise age of this deposit, based on a study of its diatoms. Butit can —
JAN. 4, 1924 WALKER HOTEL DEPOSIT 29
be safely stated that in view of this study the burden of proof must rest on anyone who claims that this swamp is one of recent origin.
LIST OF SPECIES!
AmpHoRA Proteus Greg.* Sch. At. pl. 27, f. 4, 7.
CocconEIs PLACENTULA E.* Sch. At. pl. 192, f. 45.
CocconEIs PLACENTULA var.*
CYMATOPLEURA ELLIPTICA (Breb.) W. 8. V. H. Syn. pl. 53, f. 1-4. CymMBeLLA Americana A. §.* Sch. At. pl. 9, f. 15, 20.
CYMBELLA AMERICANA var. aAcuTA* Sch. At. pl. 71, f. 75-78.
This is one of the forms which is also reported from the Demerara River, British Guiana. No other locality is given, but it occurs here and in Crane Pond.
CYMBELLA EHRENBERGII K.* V. H. Syn. pl. 2, f. 1.
CYMBELLA GASTROIDES K.* V. H. Syn. pl. 2, f. 8.
CYMBELLA LANCEOLATA E.* V.H. Syn. pl. 2, f. 7.
CyYMBELLA LUNULA (E.) Rab.* Sch. At. pl. 71, f. 33; V. H. Syn. pl. 3, f. 164A. EpitHeMia Arcus (E.) K. V. H. Syn. pl. 31, f. 141.
EpITHeMIA ARGUS var. AMPHICEPHALA Grun.* V. H. Syn. pl. 31, f. 19. EPITHEMIA GIBBA (E.) K.* V.H. Syn. pl. 32, f. 6.
EPITHEMIA GIBBA var. VENTRICOSA Grun.* V.H. Syn. pl. 32, f. 4, 6. EPITHEMIA TURGIDA (E.) K.* V. H. Syn. pl. 31, f. 1, 2.
Eunotia Formica E. V. H. Syn. pl. 34, f. 1.
EUNOTIA GRACILIS (E.) Rab.* V.H. Syn. pl. 33, f. 1, 2.
EuNnoTia MINOR (K.) Rab.* V.H. Syn. pl. 33, f. 20, 21.
EuUNOTIA MONODON E.* V.H. Syn. pl. 33, f. 3.
EUNOTIA PECTINALIS (K.) Rab.* type. V.H. Syn. pl. 33, f. 16.
EUNOTIA PECTINALIS var. UNDULATA Ralfs.* V.H. Syn. pl. 33, f. 17.
Not only the type form of this species is found here but a curious variety called var. undulata. It was named “Himantidium undulatum” in 8. B. D. 2: 12, pl. 33, f. 281a,? and an excellent figure of the precise form common to both the Crane Pond and the Connecticut avenue
1 The references included are to satisfactory illustrations in diatom literature. The abbreviations used are as follows:
Authors: Ag. = Agardh; A. 8. = Adolph Schmidt; Br. = Brun; Cl. = Cleve; E. = Ehrenberg; Greg. = Gregory; Grun. = Grunow; Hantz. = Hantzsch; H. Heid. = H. Heiden; K. = Kutzing; Rab. = Rabenhorst; W. S. = William Smith; V. H. = Van Heurck.
Books: Cl. Nav. Diat. = Cureve: Naviculoid diatoms.
Cl. & Grun. Arct. Diat. = CLeve & Grunow: Arctic diatoms. Espec. Nouv. = Brun: Especes nouvelles.
H. L. 8. Types = H. L. Smiru: Diatomacearum species typicae. Mic. Jour. = Monthly Microscopical Journal, London.
Per. Mono. = H. Peracatio: Monographie du genre Pleurosigma. 8. B. D. = Wititam Smita: British diatoms.
Sch. At. = Schmidt’s Atlas der Diatomaceen-Kunde.
VY. H. Syn. = Van Hevrck: Synopsis des diatomees de Belgique. W.&C.N.&R. Diat. = Watker & Coase: New and rare diatoms.
30 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 1
deposits is given in Lewis, White Mt. Diat. pl. 2, f. 18a. The similarity between these two diatom floras is especially emphasized by this form, because the peculiarities of modification are therein duplicated to the minutest detail.
Eunotia rospusta (B.) Ralfs.* V. H. Syn. pl. 33, f. 12.
GOMPHONEMA ACUMINATUM E..* VY. H. Syn. pl. 23, f. 15, 16.
GOMPHONEMA GRACILE EK.* Sch. At. pl. 236, f. 16.
GOMPHONEMA GRACILE var. LANCEOLATA HE. Sch. At. pl. 236, f. 26.
GOMPHONEMA SUBTILE E. Sch. At. pl. 286, f. 10; V. H. Syn. pl. 23, f. 18.
Mertosira DISTANS (H..) K.* V. H. Syn. pl. 86, f. 21, 28.
MeE.Losira LAEVIS (H.) Grun. V. H. Syn. pl. 88, f. 191, misnamed in Sch.
At. pl. 182, f. 836 M. Roeseana Rab.
NAVICULA ACROSPHABRIA var. LAEVIS Breb. Sch. At. pl. 43, f. 18. NAVICULA AFFINIS E. var.* Sch. At. pl. 49, f. 1.
Navicuta AMERICANA E.* V.H. Syn. pl. 12, f. 37.
NavicuLA AMERICANA narrow var. Sch. At. pl. 312, f. 14.
NAVICULA AMPHIRHYNCHUS E.* Sch. At. pl. 49, f. 27-29.
NAVICULA APPENDICULATA (Ag.) K.* V.H. Syn. pl. 6, f. 18, 19. NAVICULA BacttLuM E.* V.H. Syn. pl: 13, f. 8; Cl. & Grun. Arctiipls 2.
f. 50.
Navicula bihastata Mann, nom. nov.* PI. 4, f. 2; see also Cl. Nav. Diat.
DES. DLs Ueifinu cle
This has been called Pinnularia trigonocephala by Cleve (Nav. Diat. 2:88, pl. 1, f. 21), where there is a good illustration. The restoration
of the indistinct genus Pinnularia not being advisable, and Navicula trigonocephala being preempted by Ralfs, I find it necessary to assign
to ita new name. ‘This is quite a rare species. NavicuLa CARDINALICULUS (Cl.) Mann, Cl. Nav. Diat. 2:79, pl. 1, f. 12a.
Cleve says that this is found in Crane Pond, Massachusetts; French’s Pond, Albany, Maine; and Houghton, Michigan.
Navicula cuneicephala Mann, nom. noy.* Pl. 4, f. 5; see also Sch. At.
{Din Hore ify JUS).
My form agrees closely with the illustration in Schmidt’s Atlas; but, as in the case of N. bzhastata, I cannot use the specific name already given because of N. integra W. S.
NAVICULA CUSPIDATA K.* V.H. Syn. ol. 12, f. 4.
All the specimens of this species found at Crane Pond and in the local deposit are peculiar in being narrowed at either end into an elon- gated tip. The type form, which is common throughout this part of the world at the present time, is much more truly spindle-shaped.
NAvIcULA DAcTyLus (E.) K.*. V. Syn. pl. 5, 7; 12) Sche Ata pli 2eaeaoe
NAVICULA ELLIPTICA K.* H. L. Sm. Types pl. 271.
NAVICULA ExIGUA Greg.* V.H. Syn. pl. 8, f. 32; Mic. Journ. 1854: pl. 4, es
It is possible this species is a variety of N. Gastrwm.
NAVICULA FLEXUOSA Cl.* Nav. Diat. 2:93, pl. 1, f. 23.
This species was found originally in Crane Pond, and forms found here and in that material are identical. It is possible that this species is invalid and should be looked upon as a variety of N. Dactylus.
NAVICULA GIBBA (H.) var.* Sch. At. pl. 45, f. 48. NAVICULA INSTABILIS A. 8.* Sch. At. pl. 43, f. 86.
JAN. 4, 1924 WALKER HOTEL DEPOSIT 31
Navicuna instaBinis A. 8. var.* Sch. At. pl. 43, f. 37. There are two well-marked forms of this species, corresponding to the figures given. Navicuta Iripis E. var.* Sch At. pl..49, f. 2, 4. Navicuta LecuMen (E.) A. 8.* Sch. At. pl. 44, f. 44-47. NavicuLa Ltimosa K.* V.H. Syn. pl. 12; f. 18-21. Perhaps a variety of N. gibberula K. Navicuta magor K. Typical.* Sch. At. pl. 42, f. 8. NAVICULA MESOLEPTA var. STAURONEIFORMIS (H.) Grun.* Sch. At. pl. 44, . 52, 58. eR NOBrEIS) (E.)K.* Sch. Ati pl. 43.) f.0. NAVICULA PERIPUNCTATA Br.* Expec. Nouv. p. 37, pl. 16, f. 11; also Sch.
At. pl. 311, f. 5-7, misnamed.
Schmidt, in the reference above given, confuses this with the very different NV. Formica E. So far as I know, this delicate species has never been found, except at Crane Pond, until discovered here.
Navicuna propucta W.S.* 8S. B. D. pl. 17, f. 144; Sch. At. pl. 49, f. 38. NavicuLaA PRopucTA var.* Sch. At. pl. 49, f. 40, unnamed. NAVICULA RUPESTRIS (Hantz) A. 8.* Sch. At. pl. 45, f. 438.
Perhaps this is a variety of N. commutata Grun., as figured in Sch. At. pl. 45, f. 37.
Navicunua Scurnzi Br. PI. 4, f. 4; see also Sch. At. pl. 242, f. 9.
The presence of this diatom in this gathering, found originally in west Africa and subsequently in a fossil bed in Alabama, has been already discussed.
NAVICULA SILLIMANORUM -(E.) K.* Lewis, White Mt. Diat. pl. 2, f. 8;
W.&G.N. & R. Diat. pl. 2, f. 2.
NAvIcuLA suBAcuTA A. S.* Sch. At. pl. 42, f. 8, passing into the next. NAVICULA VIRIDIS (Nitz.) K. NavicuLa suscAPITaTA (Greg.) V. H. Sch. At. pl. 44, f. 58, 55; V. H. Syn.
pl. 6, f. 22.
NAVICULA SUBOVALIS (Cl.) Mann.* Nav. Diat. 1:96, pl. 1,f.27. Pl. 4, f. 4.
This diatom, called by Cleve Diploneis subovalis, was found in fresh water material from New Zealand. It closely resembles N. elliptica K. in shape and size, but has the markings of N. Smithiz Breb. I have found rare specimens of it in several fresh water gatherings; and as N. Smithii is a marine form, I have hitherto considered it as an adapta- tion of that species to fresh water conditions. It is interesting to note that it is a common form in Crane Pond.
NAvVIcuLA TABELLARIA (E.) K.* V.H. Syn. ol. 6, f. &. Navicula torta Mann, nom. nov.* PI. 4, f. 6.
This diatom is well illustrated by Cleve (Nav. Diat. 2: pl. 1, f. 22) but misnamed as a variety of N. major K. (N. major var. asymmetrica). It has nothing to do with N. major but more nearly resembles N. T'reve- lyana Donk., but it should be recognized as an independent species. It is quite constant, although found in such widely distributed localities as Canada, Waltham and Crane Pond, Massachusetts, and fossil de- posits at Montgomery, Alabama. ;
NAVICULA TRANSVERSA A. 8.* Sch. At. pl. 43, f. 56.
NAVIcULA TRINODIS W. 8S. Lewis, Diat.U. 8. Seaboard pl. 2, f. 6. ~ The local examples of this very small and oddly shaped diatom have more rounded ends than illustrations generally give, but there is no question of its belonging to this species.
32 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 1
NAVICULA vinipIs K.* Sch. At. pl. 42, f. 3.
Nivzscuia HeuFLeRiana Grun. V. H. Syn. pl. 68, f. 13, 14.
NITZSCHIA SPECTABILIS (E.) Ralfs.* V.H. Syn. pl. 67, f. 8(2).
Nirzscuia TRYBLIONELLA Hantz var. Levipensis (W. 8.) Grun. V. H.
Shits folks Ole tia tec
PLEUROSIGMA SpENcERID W. 8. Per. Mono. pl. 8, f. 20, 21. SrAURONEIS AcuTA W.8.* V.H. Syn. pl. 4, f. 3.
This and the other species here classified under this generic name are unquestionably members of the genus Navicula. The utterly untrust- worthy distinguishing mark, the stauros, appears so frequently in species that can not be classed in the same genus that any hope of a. definite description is impossible. The subject is discussed at length in my Report on the diatoms of the Albatross voyages. I use the above generic name here because it has strongly entrenched itself in literature and will aid in understanding the references given.
STAURONEIS ALABAMAE H. Heid.* Sch. At. pl. 242, f. 4, var. SrauRONEIS ANCEPS E.* Sch. At. pl. 242, f. 7, passing into the next. STAURONEIS PHOENICENTERON E.* VY. H. Syn. pl. 4, f. 2. Stauroneis Washingtonia Mann, sp. nov. PI. 4, f. 3 and 7.
Valve narrow-lanceolate, with nearly straight sides, tapering from the center to the rounded apices; stauros narrow but not linear, not spreading, reaching to the sides; longitudinal median area evident on each side of the strong raphe, the ends of which are well separated at the center; markings, rows of beaded lines, all strongly oblique, and unusually coarse for the size of the diatom.
Length, 0.163 to 0.194; width, 0.020 to 0.022; 11 to 12 lines in 0.01 mm.
This does not seem to occur in the Crane Pond material, nor is there any figure closely resembling it in diatom literature. A species some- what similar in shape is S. Spicula Dickie, a good figure of which is in V. H. Syn. pl, 4, f. 9. But that is a marine form, with very fine recti- linear markings, 28 to 29 in 0.01 mm., and with a delicate linear stauros. The lines of the present species are very coarse, even coarser than those of the much larger S. Phoenicenteron, which has 14 or more in 0.01 mm. It is common in the local deposit.
SURIRELLA ENGLERI O. Moller,* Sch. At. pl. 245, f. 13-18. SURIRELLA TENERA Greg.* Sch. At. pl. 23, f. 4-9. SURIRELLA TENERA wide var.* Sch. At. pl. 23, f. 17.
PLATE 4
Fig. 1, Navicula Schinzii Br.; 2, Navicula bihastata Mann, nom. nov.; 3, Stauroneis Washingtonia Mann, sp. noy.; 4, Navicula subovalis (Cl.) Mann; 5, Naviculacuneicephala Mann, nom. nov.; 6, Navicula torta Mann, nom. nov.; 7, Stauroneis Washingtonia Mann, sp. nov. (detail of fig. 3).
PLATE 4
Journ. Wash. AcaD. Scr., Vor. 14
qui
sy
Wi; WH
TU
\ MMM \ Ne
i 4
MANN on DIATOM
JAN. 4, 1924 WALKER HOTEL DEPOSIT 390
THE GEOGRAPHIC AND HISTORICAL EVIDENCE LAURENCE LAFoRGE, GEOLOGICAL SURVEY INTRODUCTION
The problems of the origin, structural relations, and age of the muck bed containing the cypress stumps are essentially geologic, are not. especially difficult, and require only ordinary geologic methods for their solution. The geologists who investigated the deposit recognized these facts and employed such methods, with the result that the - evidence so obtained was abundant, plain, and unmistakable and enabled them to establish beyond question and by geologic methods alone that the muck bed is of great antiquity, humanly speaking, and that its age must be reckoned in tens of thousands of years. All geologists who examined the locality were agreed in this conclusion. Nevertheless many other persons, not appreciating the nature of the geological evidence and the certainty of the conclusions derived from it, and impressed by the nearly perfect preservation of the wood of the ‘stumps, were skeptical of the age assigned by the geologists and pre- ferred to regard the deposit as not more than a few score of years old.
This conclusion appeared to them to be supported by the topography of the locality and by its recent history. From Sixteenth street westward to New Hampshire avenue, L street lies in a depression which, within the memory of many old residents of Washington, was deeper than now and was the lower valley of a small stream named Slash Run—a tributary of Rock Creek. The boys and young men of 60 or more years ago caught frogs and small fish in this stream, swam in its deeper pools, and hunted rabbits and wild fowl in the reeds and brush along its banks. When the streets of that part of the city were graded a trunk sewer was built to carry the water of Slash Run and its channel was filled in, as was the adjacent low ground, in some places to a depth of 10 or 12 feet. The square bounded by De Sales, Seven- teenth, and L streets and Connecticut avenue became the grounds of the Academy of the Visitation, and the building of the Academy was erected on the west end of the lot. Its north end, which was within the present hotel site, stood on filled ground over the former course of Slash Run. This building was razed several years ago and its cellar filled in.
In 1922, when the muck bed and cypress stumps were exposed in the excavation for the hotel and the geologists had announced their con- clusion regarding the age of the deposit, many persons, who remembered or had heard of Slash Run and that considerable filling
34 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 1
had been done along its former course, hastily concluded that the plant remains were merely those of trees and other vegetation that had grown there since the settlement of the city and had been buried but a few years. In support of this contention speeches were made in meetings of local societies and letters were written to local papers, ‘and at Jeast one article was written by a scientific man and published in a periodical of national circulation. The arguments of all who supported this view were deficient in that they were based on oral traditions, boyhood recollections, and similar hear-say evidence and not on authenticated documentary records. Many of the arguments were also quite irrelevant and most of them completely disregarded the facts that were plainly revealed in the excavation. Hence it seemed to be desirable, to convince others of the soundness of the geologic conclusions, for the geologists to reinforce the evidence from the facts displayed in the excavation with the available geographic and historical evidence. Such evidence, on investigation, proved to be as abundant, unequivocal, and convincing as the geologic evidence and to be in entire agreement with it.
HISTORICAL HVIDENCE
The historical evidence is largely negative, that is, it is not so much directly confirmatory of the conclusions of the geologists regarding the age of the deposit as it is opposed to the conclusions of those advocating the other view. There is much historical evidence about Slash Run, the topography of its valley, and the conditions along its course, but none of any swamp along it below Massachusetts avenue, although there may have been marshy ground along the left bank of the stream in the neighborhood of Sixteenth and L streets, and along the right bank at Connecticut avenue and again between Nineteenth and Twentieth streets. In this lower part of its course the stream was mainly clear and flowed over a sandy or gravelly bed between banks 5 to 8 feet high and a few yards apart. The swimming-holes remem- bered by so many persons were probably partly artificial, as one of the old residents of the city has stated that such holes were dug in the bed of the stream for the use of soldiers camped in the city during the Civil War.
The stumps found in the muck bed are those of bald cypress, and the great number of stumps and the abundance of cypress leaves and seeds in the muck leave no room for doubt that the bed is the remains of aformer cypress swamp. Bald cypress does not now grow naturally
JAN. 4, 1924 WALKER HOTEL DEPOSIT 35
in the District of Columbia nor within several miles of its boundaries and the nearest cypress swamp is in southern Maryland, about 100 miles south of Washington. There is no record of bald cypress having been found growing naturally in the District since the first visits by white men. It is not mentioned in the earliest check lists of the plants of the District, which were compiled more than a century ago, nor in any lists except those of very recent years which cover a con- siderable territory outside the District. Of those old residents of the city who remember playing along the banks of Slash Run in their youth, and some of whom insist that the stumps found in the excava- tion are those of trees growing there only 60 years ago, not one pro- fesses any recollection of a cypress swamp or of cypress trees or stumps in that locality. In a description, published in 1861, of the part of the city traversed by Slash Run, sweetgum, maple, and magnolia are enumerated as growing in or about the wetter places, but no mention is made of bald cypress. These facts alone ought to be sufficient evi- dence that the deposit is not the remains of a swamp that existed on the surface within the memory of men still living.
Furthermore, early records and descriptions of Washington contain several references to the finding of logs and pieces of trees, some of them nearly perfectly preserved, in digging cellars and wells during the settlement of the city, but there is no record of the species of the trees dug up and no indication that any of them were bald cypress. Such remains were found in several places and at various depths, even 48 feet below the surface, and as they were discovered before the streets had been graded and the contour of the surface changed by cutting and filling there can be no suspicion of their having been buried artificially. The records of these early discoveries dispose of the argument that such well preserved tree remains must necessarily have been buried artificially but a few years ago.
Finally, the muck bed found in the Walker Hotel excavation is by no means so unique as many people have supposed. What is pre- sumably the same bed was encountered, at the same depth, in excavating for the foundations of Stoneleigh Court, a large apartment house built a number of years ago on the east side of Connecticut avenue about 100 yards south of the Walker Hotel. Apparently the top of the same bed was exposed, though no stumps were reported, in digging the cellar of the Rauscher building, across Connecticut avenue from Stoneleigh Court. A similar bed must have been exposed somewhere in the city many years ago, as a brief account of the geology
36
JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 1
“Lafayette ale
0." oe
De Sales St, I
og
<——500 feet—__ - Scale-
Fig. 1. Generalized contour map of the lower part of Slash Run valley as it was when
the city of Washington was laid out.
(For explanation see body of text.)
JAN. 4, 1924 WALKER HOTEL DEPOSIT BV
of Washington, written before 1860, in describing the strata upon which the city is built, mentions beds of peat and other vegetal material, interstratified with beds of gravel, sand, and clay.
GEOGRAPHIC EVIDENCE
When the city of Washington was laid out the relief of the land now occupied by it was greater than at present and many features have since been obliterated by the grading of streets, cutting down of knolls, and filling up of ravines. No contour map of the original surface was made and the contours on the oldest existing contour ° map of the city proper, which was made in 1863, after the surface had been considerably modified, were drawn mainly with reference to established street grades and with little regard to the form of the surface inside the squares. However, early in the nineteenth century, after the streets had been surveyed and opened through the woods and brush, lines of leveling were run along the centers of all the streets and the altitudes of the street intersections and of other important points in the streets were determined, as a preliminary step to the establishment of grades. The altitudes were plotted on a large-scale street map which is preserved in the office of the District Engineer of Highways, and material is thus available for the construction of a contour map that will show approximately the relief of the original surface. Several published maps made from early surveys show accurately the former courses of the small streams, but no one seems to have thought it worth while to map the positions and outlines of the swamps.
Figure 1 is a map of the part of the city in which the Walker Hotel is situated, showing the former course of Slash Run and, by five-foot contours, approximately the original form of the surface in the lower part of Slash Run valley. The contours were drawn partly by Dr. N. H. Darton, of the Geological Survey, and partly by the author, from data taken from the old map showing the original altitudes, mentioned in the preceding paragraph. They are, of course, con- structed by interpolation, but are accurate for the points where they cross the streets, though necessarily only approximately located between the streets. The italic figures give the altitude of the con- tours above sea level, the underscored figures the altitude of the bed of Slash Run where it crossed the streets, and the figures in circles the present altitude of street intersections near the Bite of the hotel, which is the diagonally cross-lined space.
vou. 14, No. 1
JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES
38
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This map shows that in the vicinity of the hotel site there was a rather steep descent from Rhode Island avenue to the north bank of Slash Run and a more gentle rise from the south bank of the stream to I street, and that the stream flowed through the area now occupied by the hotel in a ravine in which there was no room for a swamp. It also shows that through most of its lower course the fall of the stream was too rapid for the formation of a swamp. In two places, however, one east of Seventeenth street and the other west of Nine- teenth street, where the valley was wider and one bank of the stream was lower than elsewhere, the stream may have flooded the valley bottom during freshets and may thus have formed somewhat marshy areas. Finally, comparison of the present altitudes of the street ‘intersections with the former altitude of the surface shows the amount by which the surface has been raised by filling. This ranges from nothing at the northeast corner of the hotel site to 12 feet at the north- west corner, but at one place in the channel of the stream the depth of fill shown in the excavation was about 15 or 16 feet.
The top of the stump bed is 16 to 20 feet below the present surface and as the depth of fill was nowhere greater than 12 feet, except in the stream channel and there only in deep holes, the stumps clearly can not be those of trees that were growing on the banks of the stream before the fill was made and within the memory of living persons. This is more clearly brought out by Figure 2, which shows two profiles, with a vertical exaggeration of 8 to 1, drawn along the centers of Connecticut avenue and Seventeenth street, respectively. The pro- files show the present grade and the original surface and thus the amount of cut or fill, the fill being indicated by a stippled pattern. They also show the position of the hotel excavation, projected into the planes of the profiles, the positions and thicknesses of the geologic formations exposed, and the approximate position of the crystalline rock surface. They present incontestable evidence of the correctness of the conclusion of the geologists that the stump bed represents an ancient swamp that existed in a former geologic epoch, that was not exposed at the surface during the early history of Washington as a city, and that had no relation to Slash Run.
PHYSIOGRAPHIC RELATIONS
The muck bed was found at nearly the same level in all parts of the hotel excavation and has been encountered at that level on the south side of I street, 100 yards south of the hotel. It therefore underlay
40 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 1.
parts of the surface that differed in altitude, before Slash Run was filled in, by at least 16 feet, and it must also underlie areas where there has been no fill. Hence it has no relation to the recent topog- raphy and must have occupied a hollow in a surface existing at some time during the Pleistocene epoch. As the average thickness of the bed is about 8 feet it must represent a swamp that was in existence for a long time. The swamp could have extended but a short distance northwest of the hotel site, as the muck bed was not encountered in excavating for the foundations of the Connecticut apartment house, at the southwest corner of Connecticut avenue and M street, where the crystalline rock surface was reached at no great depth. On the other hand it may have extended some distance southeastward, as there are indications of a shallow trough, trending in that direction, in the surface of the Cretaceous beds.
The cypress swamp must have been but little above the base level of drainage in the Potomac basin at that time. It probably occupied the lower valley of a tributary of the Potomac, perhaps the Rock Creek of that epoch, when the land stood 30 feet or so lower than now with regard to sea level, and when the uplift which caused the stream to excavate its valley had ceased and had been succeeded by a slow subsidence, which allowed the accumulation of 5 to 10 feet of swamp deposit. The subsidence then became more rapid and the swamp was buried by the beds of sandy clay and fine gravel con- stituting the Wicomico formation. After some later oscillations of level that did not materially affect the history of the Walker Hotel locality the Recent epoch was ushered in by an uplift of the land to a little more than its present height and the development of a new drainage on the emerged surface. Slash Run was formed and began to carve its valley, and it had almost but not quite uncovered the old stump bed when man interfered and put an end to its activities.
Buried muck and peat beds containing cypress stumps and wood have been found exposed in cliffs and river banks or have been pene- trated in wells at many places in the Coastal Plain from Maryland to Alabama. Nearly everywhere they are overlain by deposits of the Talbot formation of the Pleistocene age and are believed to have been formed in the early part of Talbot time, hence the bed in the Walker Hotel excavation was at first regarded as of Talbot age. Later study led to the view that the overlying sandy clay is part of the Wicomico formation. Furthermore, its altitude above present sea level and its relation to the topography of Pleistocene time make it improbable that the bed can be as young as Talbot. It is now regarded as having been formed in the early part of Wicomico time and hence of mid-
JAN. 4, 1924 WALKER HOTEL DEPOSIT 4]
Pleistocene age. Although the Pleistocene formations of the Chesa- peake Bay region have not yet been satisfactorily correlated with the drift sheets of the northern United States, there is little doubt that a deposit of early Wicomico age must be older than the Wisconsin drift, if not, indeed, older than the Illinoian drift. The best recent estimates of the date of beginning of the Wisconsin glacial epoch put it not later than 100,000 years ago and the date of beginning of the IIlinoian glacial epoch as at least 300,000 years ago. It seems fairly certain, therefore, that the muck bed and the cypress stumps can not well be less than 100,000 years old and that they may be much older.
SUMMARY.
The conclusions of the geologists as to the great age of the stump bed, based on the stratigraphic relations displayed in the excavation, have been confirmed in every respect by the testimony of the leaves, seeds, and diatom remains found in the muck, by the physiographic evidence of the conditions under which the cypress swamp was formed and existed, by the geographic evidence regarding the topography of the lower valley of Slash Run, and by the historical evidence from descriptions published years before the growth of the city had altered the conditions in the locality. It is, therefore, established that the stumps and the muck in which they are imbedded are the remains of a cypress swamp that was overwhelmed and buried by natural processes many thousand years ago and are not, as so many people have supposed, the remains of trees that grew on the banks of Slash Run less than 60 years ago and were cut down and covered by an artificial fill.
It should be said in closing that the geologists make no demur to the recollections of the old residents, but only to the conclusions based on those recollections. The geologists are well aware and admit without question that a stream formerly ran through the locality in a valley - that was deeper than it is now; that there may have been marshy spots here and there along its course; that large trees grew on its banks; and that the trees were cut down and the land was filled to some depth about 50 years ago. They insist, however, and have proved, that all this has nothing to do with the muck bed and cypress stumps discovered in the Walker Hotel excavation, at a depth several feet below the bottom of the former Slash Run valley, and that the stump bed is a much older deposit in no way related to the conditions along Slash Run that many people still remember.
42 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 1
Obituary
Mr. Erskine Dovueias WILLIAMSON, physicist in the Geophysical Lab- oratory of the Carnegie Institution of Washington, and one of the Editors of this Journal, died on Christmas afternoon at about three o’clock at the George Washington University Hospital.
Although only thirty-seven years of age at the time of his death, Mr. Williamson had won for himself an eminent position not only in the scientific life of Washington, but in a wide circle of mathematical physicists and physi- cal chemists in this country and abroad. He was born in Scotland on April 10, 1886, and was educated at the University of Edinburgh, where he took the degrees of Bachelor of Science in 1908 and Master of Arts in 1909. As one of the most promising pupils of Sir James Walker, he was appointed a re- search assistant under the Carnegie Trust of Scotland. His research work at Edinburgh became known in this country and he was offered an appoint- ment at the Geophysical Laboratory of the Carnegie Institution in 1914. Here, in company with John Johnston and L. H. Adams, he studied the prob- lems of the formation and consolidation of limestone. This work was fol- lowed up by research on the physical and chemical effects of very high pres- sures, in which he did pioneer work in the development of special apparatus and in the measurement of compressibilities of minerals and rocks.
During the War he did his part in aid of the cause of his native country, as well as of the United States, by going into one of the glass plants, in company with other members of the Laboratory force, and assisting in the rapid devel- opment of the manufacture of optical glass, a “key industry’’ in which this country rapidly shook itself free of its former dependence on Germany.
Mr. Williamsen’s ability as a mathematician was particularly highly valued at the Laboratory, and he made several valuable contributions to the practical problems of the annealing of glass, as well as to the theoretical and highly important question of the transmission of earthquake waves through the earth, and the deductions concerning the constitution of the earth’s interior, which can be drawn from these facts.
Mr. Williamson was active in the local scientific organizations, having been a member of committees in the American Chemical Society and the Philo- sophical Society of Washington, and one of the editors of the Journal of the AcaprEmy, of which he would have become Senior Editor in January. He was also a member of the American Physical Society and the Mathematical Society of Edinburgh.
The Editors wish to put on record their appreciation of his self-sacrificing devotion to the editorial work of the Journal, which he continued until forced by illness a few weeks ago to relinquish the duties, and of their own keen sense of loss in the sudden death of their colleague.
OUNCEMENT ¢ OF MEETINGS OF THE ACADEMY AND ; y ex AFFILIATED SOCIETIES : ; eee 5. The Biological Society. : . | | puedey, January 8. THE AcapEmy, at the Carnegie Institution. ee ee TT. Waynan - VauGHAN: Oceanography in its relation to es earth s sciences. Annual meeting. - | MA ic Be Co ome January 9. The Geological Society. eG ace toa pa Ren
day, January 10. The Chemical Society. DAN tA
u day, January 12. The Philosophical Society. | i fs : i ‘ ar : ue 1esd Jay, January 15. The Anthropological Society. pa aaa sdaj reer t 17. Tae ACADEMY. u Mea : 7. - 0 ef
street, Washington, DG. ites cece eek ye a eae So See ‘ ee cane in the sel as CuesterR K. ee eee .
Diatom deposit found in the excavation. ALBERT MANN..............c0000 S The geographic and historical evidence. LauRENCE LaForce.. Toles 8 gk eee
OBITUARY: 6 dosys vc vice be SERRE Fete Me Fake nek oh ee ee
OFFICERS OF THE ACADEMY
President: T. WAYLAND VauGHAN, U.S. Geological Survey. Corresponding Secretary: Francis B. StnsBex, Bureau of Standards. Recording Secretary: Wiut1aM R. Maxon, National Museum. _ Treasurer: R. L. Faris, Coast and Geodetic Survey. ne
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January 19, 1924 a yh No. 2
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ENTOMOLOGY.—A new Prorhinotermes from Panama. T. E. SnypDER, Bureau of Entomology.
J. Zetek and I. Molino of this Bureau, stationed at Ancon, Canal. Zone, have recently collected a species in the genus Prorhinotermes Silvestri, which proves to be new. This new termite (Prorhinotermes molinot Snyder) was found on Largo Remo Island, Canal Zone, on the Atlantic Coast. With the addition of this new species, the known termite fauna of Panama totals 30 species, representing 18 genera or sub-genera. The termites of Panama are of great biological interest; three families are well represented, but the Termitidae are the most numerous. Since the forming of Gatun Lake some species are appar- ently now confined to virgin islands in this lake.
Species of Prorhinotermes apparently are not subterranean in habit. In burrowing through wood the grain is followed; the hardest species of woods are riddled.
Prorhinotermes molinoi, new species.
Winged adult.— Head greyish-brown, darker than P. simplex Hagen; spectacle markings on epicranium, but slightly longer than broad, slightly broader posteriorly than anteriorly, with few scattered long hairs—3 transverse rows.
Fontanelle distinct, hyaline, sub-oval spot, on line at posterior of ocelli. Eyes black, nearly round, large, projecting, less than their diameter from lateral margin of head, a little less than twice their diameter from the posterior margin of the head. Ocelli hyaline, subelliptical, narrow, pointed at apex, nearly touching eyes, at oblique angle to eyes, nearly parallel to upper margin of antennal socket. Post-clypeus lighter colored than head, bilobed, projecting. Labrum lighter colored than head, arched, tongue-shaped, broader than long, broadest beyond central transverse line, with long hairs at apex.
Antennae yellow-brown, 17 or 18 segments, pubescent (long hairs); third segment is shorter and narrower than second or fourth segments; segments are wedge-shaped, but become broader and longer towards apex; last segment elongate and subelliptical.
43
44 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 2
Pronotum same color as head, broader than long, anterior margin slightly (concave) roundedly emarginate, sides roundedly taper to posterior margin, which is convex; with scattered long hairs on margins.
Legs yellow brown, fairly elongate, pubescent.
Wing scale plainly longer than the pronotum.
Wings hyaline, costal veins yellowish, base blackish, over twice as long as the abdomen. In forewing, there is no definite median vein, but the cubitus branches in the middle into two branches, the upper branch may be considered the median vein; it is above the cubitus, parallel to the subcostal vein, is unbranched, and nearly reaches the apex of the wing; the lower branch branches to the lower margin, there being from this and direct from the cubitus 17 branches or sub- branches to the lower margin of the wing. In hind wing, the median is more distinct, and runs parallel and close to the cubitus until near the apex of the wing, where it branches to the subcosta; the cubitus reaches the apex of the wing, and has 17 branches or subbranches to the lower margin (Figs. 1 and 2).
Abdomen dorsum same color as pronotum, ventrally lighter colored; with row of long hairs at base of each tergite. Cerci fairly elongate.
Measurements: Length of entire winged adult: 9.50 mm. Length of entire dealated adult: 5.0-5.5 mm. Length of head: 1.50 mm. Length of pronotum: 0.77 mm. Length of anterior wing: 7.50 mm. Length of hind tibia: 1.17 mm. Diameter of eye: 0.32 mm. Width of head: 1.40 mm. Width of pronotum: 1.10-1.20 mm. Width of anterior wing: 2.30 mm.
Prorhinotermes molinoi Snyder has a larger head than P. :nopinatus Silvestri of the Samoan Islands, and a larger pronotum and different wing venation than P. simplex Hagen of the West Indies and Southern Florida; it differs from P. oceanicus Wasmann of the Cocos Islands in that P. oceanicus has 22 segments to the antennae and differs in wing venation. Wasmann states in an appendix (p. 160)! that P. oceanicus is the winged adult of Leucotermes insularis Wasmann from the Cocos Islands. Holmgren,? however, considers oceanicus to be in the genus Prorhinotermes.
Soldier.—Head yellow-brown, slightly darker anteriorly, much broader posteriorly than anteriorly, with few scattered long hairs in several transverse rows; fontanelle hyaline spot (distinct) on line at center of eye spot. Eye spot hyaline, large, suboval. Labrum yellow-brown, elongate, rather narrow and rounded at tip, with long hairs at apex.
-Mandibles dark reddish-brown, heavier and broader even to apex (less taper) than in P. simplex Hagen.
11903. Wasmann, E. Uber einige Termiten von Oceanien. Zool. Jahrb. Band 17, Heft 1, Anhang 10: 139-164.
21910. Hotmeren, N. Termitienstudien. Kungl. Sv. Vet. Akad. Handling., Band 46, no. 6: 73, pl. 5, f. 11.
JAN. 19, 1924 SNYDER: NEW PRORHINOTERMES 45
Antennae yellow-brown (broken), pubescent; third segment sub- clavate, longer than fourth, but slightly shorter than second segment; segments wedge-shaped.
Maxillary palpi very long and slender; as long as mandibles.
Pronotum slightly darker than head, broader than long, broadest near anterior margin, slightly concave, sides roundedly taper to pos- terior margin, which is nearly a straight line.
Legs light yellow-brown, fairly elongate and slender, pubescent.
Abdomen yellow-brown, with row ‘of long hairs at base of each tergite.
Fig.2 hind wing
Measurements:
Length of entire soldier: 5.75-6.20 mm.
Length of head with mandibles: 2.90-3.00 mm.
Length of head without mandibles (to anterior): 1.90 mm. Length of left mandible: 1.15-1.20 mm.
Length of pronotum: 0.70—-0.80 mm.
Length of hind tibia: 1.20 mm.
Width of head (posteriorly where broadest): 1.60—-1.65 mm. Width of head (at anterior margin): 1.0-1.1 mm.
Width of pronotum: 1.20-1.30 mm.
Prorhinotermes molinoit Snyder has a larger head than P. inopinatus Silvestri and is longer than P. simplex Hagen.
Type locality. Largo Remo Island, Canal Zone, Panama, on the Atlantic Coast.
Described from a series of winged adults collected with soldiers and workers at the type locality by J. Zetek and I. Molino on August 31, 1923, in a hard, wet tree trunk on the ground. On the same day and on the same island winged adults, soldiers, and workers were found under the bark of a fallen coconut palm tree. I take pleasure in naming this termite after Dr. I. Molino, who has collected many interesting termites, and made valuable notes on their habits.
Type, winged, male adult.— Cat. No. 26756, U. 8S. N. M.; morpho- type, soldier.
46 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, NO. 2
BOTAN Y—The genus Oxyrhynchus Brandegee. CHARLES V. PIPER, Bureau of Plant Industry.
In December, 1920, there were received from Miss Mary E. Wood- bridge, State Department of Agriculture, Austin, ‘Texas, seeds of a bean taken from plants grown near Austin by H. H. Parker, who reports that his original seeds were found in a lot of castor beans which the label on the bag indicated were imported from India. The seeds could not be identified, and so some of them were sent to Sir David. Prain, at Kew, who forwarded a few to Colonel A. T. Gage, in Cal- cutta. Neither could identify the bean. Later, fairly complete. botanical material was received from Miss Woodbridge. It proves torepresent an undescribed species of the genus Oxyrhynchus Brandegee, which was based on a single species, O. volubilis Brandeg., collected by Purpus near Rascén, San Luis Potosi, Mexico. ‘The specimens are in young flower. :
The plant from Abaco and Cuba, described as Dolichos insularis Britton, also belongs to Oxyrhynchus.
On the basis of the more complete material the genus may be rede- scribed as follows:
OxYRHYNCHUS Brandegee (Leguminosae— Papilionacae— Phaseoleae— Phaseolinae)
Twining herbs, perennial; leaves trifoliolate; stipules striate; flowers in axillary narrow raceme-like thyrses; bracts subulate, striate; bracteoles ovate; calyx bilabiate, campanulate, the rounded lobes subequal; standard reniform, broader than long, deeply emarginate, with two reflexed auricles at base; wings free, as long as the keel; keel broadly faleate, with narrowed acute beak, the two petals partly united, minutely ciliate; stamens diadelphous, the filaments glabrous, : slightly enlarged at base; ovary linear, pubescent; style glabrous except near the apex, where bearded on each side with long hairs, and at tip, bearing similar hairs which partly surround the stigma; stigma ellipsoid-obovoid, attached on the dorsal side just below the middle; pods short-pedicelled, straight, cylindrical, beaked, terete or com- pressed, thin-walled, 2 or 3-seeded; seeds globose, each with a linear hilum extending over half the circumference of the seed, the hilum covered with a white caruncle; germination hypogeous.
Harms placed! Oxyrhynchus next to Rhynchosia, but it clearly be- longs close to Dolichos, Vigna, and Dysolobium, as Dr. Harms points out in a recent letter.
1 Die Nat. Phlanzenf. Erganzungsheft 3: 149.
gan. 19, 1924 PIPER: OXYRHYNCHUS 47
Apparently there are three species involved, certainly two, as the Austin plant is quite distinct from the others in its swollen pods. These species may be distinguished by the following key:
Pods turgid, circular in cross secuat leaflets thin; inner layer of pod felt-like..... Fa ott de NOT oO Gleenins: Pods compressed and 2-edged. Leaflets thin, tending to coriaceous, 4—6 cm. long, truncate at base; flowers 8 mm. long: inner layer of pod thin...... 2. O. volubilis. Leaflets thickish, membranous, 4-7 cm. long, the middle one often subcordate; flowers 10 mm. long; inner layer of pod felt-like. 3. O. insularis.
1. Oxyrhynchus alienus Piper, sp. nov.
Perennial; stems herbaceous, twining, slender, terete, sparsely strigillose, tall, growing 15 to 20 meters in a season; petioles about as long as the leaflets, very slender, sulcate above, strigillose especially at the enlarged base; stipules triangular-lanceolate, acute, striate, persistent, 2.5 mm. long; stipels subulate, 1 mm. long; petiolules somewhat fleshy, puberulent; leaflets membranous, ovate-triangular, the lateral ones oblique, nearly truncate at base, obtuse and apiculate at apex, 3-nerved at base, sparsely strigillose on both faces especially beneath, 6 to 8 em. long, 4 em. broad; peduncles terete, axillary, strigillose, the inflorescences exceeding the leaves; flowers about 6 in each of 10 to 20 lateral clusters in a narrow, rather dense, raceme- like thyrse, the pedicellar glands oblong and prominent; bracts subu- late, striate, fugacious, 3 mm. long; bracteoles ovate, thin, ciliate, 1 mm. long; pedicels short, puberulent; calyx purple, open campanu- late, 5 mm. long, 2-lipped, the subequal lobes as long as the teeth; upper lip 2-lobed, the lobes semicircular, minutely ciliate; lower lip 3-lobed, the broadly oblong lobes rounded at apex, minutely ciliate, the median one two-thirds as long as the others; corolla green, more or less tinged with dull purple; standard green, butterfly-shape, deeply notched, 10 mm. long, 15 mm. broad, slightly pubescent on the back especially near the base, bearing a deep depression below the middle, broadly cordate at base, the stipe only as long as the sinus, each basal lobe with a blunt inflexed auricle; wing dull violet, as long as the standard, oblong, obtuse, sparsely ciliate, a broad triangular tooth near the base on the upper edge, the stipe one-third as long as the blade, the edges somewhat inflexed; keel green with the beak violet, lunate, semicircular, rather broad, the two petals attached to below the middle, the beak rather acute; stamens included, dia- delphous; filaments filiform, glabrous; anthers innate; pollen yellow; ovary linear, pubescent; style curved, glabrous to near the tip, bear- ing long lateral hairs on each side just below the stigma; stigma terminal, dark green, obovoid, attached on the dorsal side below the middle, surrounded by long stiff hairs arising from the sides of the style tip a short distance below the stigma; pods inflated, oblong- cylindric, thin-walled, acutely short-beaked, densely covered with short somewhat ferruginous hairs, the two sutures prominent, a faint ridge on each valve very close to the ventral suture, 5 cm. long, 2 cm. broad, 2 or 3-seeded; pods lined inside with a thick soft felt-like layer
48 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 2
of white tissue; seeds spherical, dark brown, shiny, 10 to 12 mm. in diameter, the hilum linear, extending over half the circumference of the seed and covered with a dense white caruncle.
Orginally sent by Miss Mary E. Woodbridge, from plants grown by H. H. Parker, Austin, Texas, from seeds found in castor beans supposed to be from India. Type in the United States National Herbarium, nos. 1,111,336 and 1,111,337.
In October, 1923, when seen by the writer, the plant was just beginning to bloom. The roots are thickish, about the size of a lead pencil, but no nodules were found on the original plant nor on sev- eral seedlings examined. The herbage is not ill-tasting and probably would be palatable to cattle. The vine is quite attractive and when in bloom showy. It is well worthy of culture as an ornamental vine.
2. OXYRHYNCHUS VOLUBILIS Brandeg. Univ. Cal. Publ. Bot. 4:271. 1912.
In addition to the type specimens collected by Purpus and repre- sented in several herbaria, the plant was collected in mature fruit at Victoria, Tamaulipas, Mexico, November, 1830, by Berlandier (no. 3129), the specimen being in the Gray Herbarium. Another specimen from the same place was collected by Dr. E. Palmer (no. 265), February 1 to April 2, 1907, also in mature fruit. Dr. Palmer notes that it is called “frijol monilla,’’ and that the seeds are used as food and also by children in lieu of marbles. Both the Berlandier and Palmer specimens seem identical with the Purpus plant, and the two localities are not far apart. The mature pods are compressed, 6.5cm. long, 3 cm. broad, and 1 em. thick, each containing three nearly glo- bose seeds, 10 mm. long. Pringle’s 11333, collected near Monterey, Nuevo Leon, is in young flower.
3. OXYRHYNCHUS INSULARIS (Britton) Piper.
Dolichos insularis Brittton in Brit. & Millspaugh, Bahama Flora 195. 1920.
This plant is known from the following specimens:
Cusa: Cayo Ballenato Grande, Camaguey, Shafer 1026, March 22, 1909 (type); La Gloria, Camaguey, Shafer 255, February 3, 1909.
Axpaco: Old fields, Great Cistern, Brace 1757, Dec. 19, 1904.
gan. 19, 1924 PIPER: OXYRHYNCHUS 49
OXYRHYNCHUS ALIENUS PIPER
1. Branch of plant, X 4; 2. Inflorescence, X 4; 3. Front view of flower, X 3; 4. Separate petals of flower, X 3; 5. Keel, lateral view, X 3; 6. Calyx, stamens, and pistil, X 3; 7. Anthers, much enlarged; 8 and 9. Tip of style and stigma, much enlarged; 10. Pods and seeds, X }.
50 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 2
PROCEEDINGS OF THE ACADEMY AND AFFILIATED SOCIETIES
THE GEOLOGICAL SOCIETY
364TH MEETING
The 364th meeting of the Society was held in the Cosmos Club, Wednesday evening, November 23, 1921, President StosE presiding and 49 persons present. ;
Informal communications: Davip Wuitr exhibited an unusual specimen showing joint-plane induration in sandstone, reported by Dr. I. C. White from northeastern West Virginia.
Mr. White also spoke on shaft and gallery mining of oil sand at Pechelbronn and in the Irvine pool of Kentucky. Discussion by Messrs. StosrE, Utricu, Brooks, BassLerR, and REINHOLT.
Program: J. 8. BRown: Coastal ground water. The contamination of wells by sea water on sea coasts is a problem of economic impor- tance wherever the coastal population is dense and a large amount of ’ water must be supplied, and has received attention in many parts of the world. This paper is based on a field study on the coast of Connecticut and on a review of the widely scattered literature on the subject. Statements regarding contamination are based on a large number of analyses, in which the amount of chloride (Cl) is the most important criterion.
In Connecticut shallow wells, such as are dug in the drift for domes- tic supply, seldom are contaminated at distances of more than 100 feet and never more than 250 feet from the shore. This corresponds with observations in other regions where rainfall is normal or abundant.
The deeper, drilled wellls in Connecticut usually penetrate bedrock and range from 100 to 500 feet in depth. They are contaminated more frequently than are shallow wells. The probability of con- tamination also increases with the depth, and when once salt water is encountered, fresh water is not likely to be obtained below. How- ever, in places like the Atlantic Coastal Plain, where there are strati- fied ’ sedimentary rocks, impervious beds often seal out salt water so that fresh water may be obtained even on islands or beneath the sea.
Contamination in Connecticut probably does not extend more than 500 feet inland, even at depth, because of the poor circulation of ground water in the fissures of the deeper zones in bedrock. However, on a sandy coast practically pure sea water may occur beneath fresh water even several miles inland, as has been shown by investigations in the dune belt on the coast of Holland.
Most islands appear to contain bodies of fresh ground water, gener- ally only as a lens or thin sheet overlying salt water. The greater head of fresh water due to increment from rains enables it to displace a certain amount of salt water of greater density. On the basis of this equilibrium established between the fresh and salt water in porous materials such as sand, it is possible somietimes to predict the depth at which salt water will be found when the height of the water table above sea level is known.
JAN. 19, 1924 PROCEEDINGS: GEOLOGICAL SOCIETY dt
Heavy pumping of wells near the sea frequently exhausts the fresh water faster than it is supplied, and causes the wells to become salty. Even a large drainage basin underlain by good water-bearing material such as the stratified drift of Connecticut can not be expected to yield more than about 25 per cent of the amount of water it receives by precipitation.
The salinity in certain wells on small islands and promontories sometimes is much greater in summer than in winter. A number of factors seem to combine to produce this effect. Diffusion and per- colation are more rapid in summer. Evaporation is greater and transpiration by plants tends to reduce the quantity of water that. reaches the water table. As a result, the salinity curve of wells in such localities shows a relation to the yearly temperature curve. (Author’s abstract.)
E. O. Uuricu: Solution of some vexing problems in Appalachian. stratigraphy. . W. T. THomM, JR., Secretary.
365TH MEETING
The 365th meeting was held in the Cosmos Club, Wednesday even- ing, December 14, 1921, with 55 persons present. The Presidential Address was delivered by the retiring President, GEorGE W. STosE: Relation of faults to folds in the Appalachians.
W. T. Tuo, Secretary.
At the 29th Annual Meeting, held on the same evening, the following officers were elected for the ensuing year: President, Wm. C. ALDEN; Vice Presidents, G. F. Louauuin and L. W. STEPHENSON; Treasurer, G. R. MAnsFIEeLp; Secretaries, WM. T. THom, Jr., Kirk Bryan; Mem- bers-at-Large of the Council, J. B. RersipE, Jr., R. C. Weuus, M. I. GoutpMAN, E. T. WHerry, Miss A. I. Jonas.
LAURENCE LAForaGs, Secretary.
366TH MEETING
The 366th meeting was held in the Cosmos Club, Wednesday even- ing, January 11, 1922, President ALpeEN presiding and 45 persons present.
Program: Hersert E. Grecory: Geographic outline of the Southern. Pacific. Presented by T. WAYLAND VavaHss in the absence of Dr. Gregory.
T. WayLanp VAUGHAN: Correlation of the post-Cretaceous geological Jormations of the Pacific region.
H. 8. Wasuineton: Chemistry of ianaian Lavas.
367TH MEETING
The 367th meeting was held in the Cosmos Club, Wednesday even- ing, January 25, 1922, President ALDEN presiding and 48 persons present.
Program: Prof. P. P. Goupxorr: New aspects on the geology of the principal ore-bearing provinces of Siberia.
02 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 2
JOINT MEETING
A joint meeting of the Washington Academy of Sciences and the Geological Society of Washington was held in the assembly hall of the Cosmos Club, Thursday evening, February 2, 1922, President Humpureys of the Academy presiding, and 74 persons present.
Program: Prof. H. A. Brouwsr: The major tectonic features of the Dutch East Indies.
368TH MEETING
The 368th meeting was held in the Cosmos Club, Wednesday even- ing, February 20, 1922, President ALDEN presiding and 63 persons present.
Informal communication: Krrk Bryan—EHzamples of wind ero- ston in the Plateau country of Arizona.
AT C. E. S1IeBENTHAL: Fluorspar district of Jardin County, inots.
FRANK L. Hess: Uranium-bearing asphaltite sediments of Utah.
F H. D. Miser and C. 8. Ross: Diamond-bearing peridotite in Ar- kansas.
369TH MEETING
‘The 369th meeting was held in the Cosmos Club, Wednesday even- ing, March 8, 1922, President ALDEN presiding and 62 persons present.
Program: FRANK ReEEVES: A distant peripheral zone of thrust faulting in flat-lying beds around the Bearpaw Mountain intrusion, Montana.
The regionally flat-lying Cretaceous formations which encircle the Bearpaw Mountains in Montana are highly faulted. These faults apparently are confined to a peripheral zone approximately 20 miles - wide, which may be separated from the mountains by an unfaulted belt 8 to 10 miles wide. The larger faults are 10 to 20 miles long and have throws ranging from 1,200 to 1,500 feet. In a rough way they form ares of circles circumscribed about the mountains. The chief characteristics of these faults are that on the upthrown side along a belt one-half to 1 mile wide the strata are usually highly in- clined away from the fault, while on the downthrown side they he at their regionally horizontal position. Other interesting features are the occurrence of pivotal faults—i.e., faults in which the throw changes sides along the fault plane—and the presence of long, narrow, rectangular, and smaller triangular horsts.
As many of these faults pass laterally into steeply dipping limbs of anticlines and as parallel with them there are long, narrow unbroken anticlinal folds, some of which are overturned, it seems evident that the faulting and folding are contemporaneous, and consequently that all the faults are either thrust faults or faults of slight hade. The few fault planes observed by the speaker, who mapped a portion of the faulted belt on the southeastern side of the mountains in the summer of 1921, were inclined toward the upthrown side at angles from 45° to 70°. The pivotal faults can be considered as thrust faults produced by the faulting of anticlinal folds along their axes. At one end of such a fault one limb of the anticline is faulted down, on the other end the other limb is faulted down.
JAN. 19, 1924 PROCEEDINGS: GEOLOGICAL SOCIETY 53
Apparently these faults and folds were produced as a result of horizontal compression and as the deformed zone is so closely as- sociated with the Bearpaw Mountains, these compressive forces probably originated in crustal movements in the mountains. These mountains, however, being a circular area of uplift consisting of a cluster of extinct voleanos whose breccia tuffs and flows rest upon a slightly elevated floor of Cretaceous shale, offer no obvious explana- tion of the origin of these compressive forces.
It is here suggested that beneath these mountains, at a depth of a few thousand feet, there is a laccolith, and that the intrusion of this laccolith domed up the overlying beds to a height of about 3 miles, and that later, either as a result of a sag in the earth’s crust, induced by the weight of the laccolith, or by the escape of the magma upward through voleanic vents, the whole laccolith or the upper surface was lowered nearly 3 miles. (Such an elevation and subsidence would be necessary to produce a crustal shortening across the faulted zone of 2,500 feet, which is the amount estimated for the part of the faulted zone that was studied by the speaker.)
If this subsidence occurred, it is thought that the strata overlying the laccolith would be under great horizontal compression, for they would probably have been lengthened by the solidification of lava intruded into the tensional fissures caused by the uplifts, and could not settle back to a lower position without buckling. It is possible that the intrusion of igneous dikes and sills into the strata overlying the laeccolith would so metamorphose and reinforce the strata that they would not buckle in the center of the dome but would transmit the compressive stresses out to the less rigid strata surrounding the mountains, and produce there the peripheral zone of faults.
The presence of dikes, sills, and small voleanic necks cutting Cre- taceous rocks out as far from the mountains as the faulted zone sug- gests that the laccolith extended out under the faulted area in sill- like form. If it had such an extension and was not solidified when the collapse occurred, it would furnish a surfaee on which the domed beds could flatten without the development of a great amount of friction. In transmitting these compressive stresses the Eagle and Judith River sandstones, and probably the Madison limestone, if the laccolith were intruded below it, acted as competent beds. It is thought that the associated Claggett and Colorado shales under pressure would flow and give a vertical component to the horizontal compression stresses, which would explain why the strata are bowed up so sharply along the fault planes and why there are so many horsts. or upthrown blocks. This flow of shales can be observed in some places in the field where the 600 feet of Claggett shale has been en- tirely pinched out, leaving the Judith River formation resting upon the Eagle sandstones.
That other laccoliths in the same region have not had such a history may be due to the fact that as a result of deeper burial or greater viscosity there was no upward escape of magma, or more probably that because of the larger size of the Bearpaw laccolith it alone of al) the laccoliths in the western United States exceeded the load that the earth’s crust could support. In support of such an explanation it may be noted that the larger laccoliths of the world have centripetal dips. (Author’s abstract.)
54 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 2
W. D. Couns: Fallacies regarding mineral waters. It is generally admitted that a number of mineral waters have therapeutic properties. Some of the literature on the subject is thoroughly reliable, but erro- neous or misleading statements may be found in the writings of those not specialists in the subject. Such errors are particularly apparent in attempts to correlate the composition of the mineral matter dissolved in a water with the therapeutic properties of the water. These properties have been attributed to the presence of traces of lithium, bromide, iodide, radium, or like substances, because such traces have been shown in analyses of the waters, and because the substances themselves are known to produce certain physiological effects. Such an explanation ignores the fact that no one could drink in a day the quantity of water which would contain an ordinary thera- peutic dose of the unusual constituents. Furthermore, the water of many public supplies contains traces of these constituents so that such an explanation implies that millions of people are taking the medicine in every drink of water. It is not uncommon to describe the therapeutic action of ordinary substances such as calcium car- bonate and bicarbonate or sodium chloride in connection with analyses of waters which contain no more of these constituents than can be found in many public and private supplies. All the statements re- garding therapeutic action of the substances may be true, but the implied connection between the presence of these common constit- uents and curative properties of the waters is misleading. (Author’s abstract.)
P. V. Rounpy: Upward migration of oil along a fault plane in Okla- homa.
370TH MEETING
The 370th meeting of the Society was held in the Cosmos Club, Wednesday evening, March 22, 1922, Vice-President LOUHGLIN presiding and 52 persons present.
Program: J. 8. Dinter: The surface fusion of recent lavas. (Illus- trated.) In the remarkably progressive paper by Drs. Arthur L. Day and E. 8. Shepherd on Water and volcanic activity: the important part played by waterin voleanic eruptions was clearly demonstrated. | It was also shown by them that as a magma rose in a volcano in con- sequence of the gradual release of pressure, dissolved gases were set free in constantly increasing quantity as the surfce is approached, and, especially near the surface, reactions were set up among the gases that increased the temperature in some eases locally at least more than enough to offset the loss of heat by expansion and ex- posure. The lava lake of Kilauea, apparently, is regarded by Day and Shepherd, and also by Dr. E. T. Allen, as maintained in a molten condition by such reactions.
A remarkable case of the fusion of lava after it reached the surface occurred in Salvador in connection with an eruption of basalt from the crater of El Pinar, June 7, 1917. Specimens of the lava were sent by Dr. S. Calderén, of San Salvador, to the U. 8. Department of Agriculture. Dr. Calderén says, ‘‘The samples I am sending you were collected on the upper surface of the ground, in the pockets
1 Bull. Geol. Soc. Amer. 24: 573. 1913, reprinted in Ann. Rep. Smithsonian Inst. 1913 275.
JAN. 19, 1924 PROCEEDINGS: GEOLOGICAL SOCIETY 55
of scoria formed by the escape of gases, being found on all very steep slopes where the current of lava formed casades.” It appears that the lava flow in passing over the cascade was much broken and torn forming pockets into which the gases escaping from the lava collected and apparently mixed with the confined air. The reaction of the gases produced so much heat that the lava exposed on the inner sur- faces of the pockets was fused. The fused basalt formed icicle-shaped bodies hanging from the roof from which the molten basalt dropped off to the floor or ran down the sides of the pocket. Although the lava in this case is basalt and fuses more easily than most other lavas the amount fused in the pockets appears to have been relatively small.
A similar phenomenon has been observed in connection with a late eruption of Lassen Peak. The lava is not basalt but dacite. About the voleanic vent from which the dacite was erupted May 19, 1915, on the joint plane surfaces in the new lava there are local patches of once molten material which appear to have been formed during the great explosive eruption of May 22, by rising hot gases escaping from beneath the surface along fractures into small pockets at the surface.
371ST MEETING
The 37lst meeting was held in the Cosmos Club Wednesday even- ing, April 12, 1922, President ALDEN presiding and 53 persons present.
Program: M. N. BramMuetre: The origin of the chert in the One- ota Dolomite. The Oneota Dolomite of the basal Ordovician in Wis- consin contains much associated chert as nodules and lens-like masses parallel to the bedding-planes. This chert is a replacement of the earbonate rock, as shown by the exact similarity of micro-structure in the oolitic dolomite and oolitic chert, with a contact between the two showing all stages of the change, individual ooliths being partly of carbonate and partly of chert. Also, “cryptozoan’’ reefs, in which the chert occurs, show the organic micro-structure preserved by the replacing chert.
Evidence of the time of replacement is not conclusive. It seems to have been effected by marine waters as a syngenetic process; first, because the distribution is more suggestive of such a process, and secondly, because silicification was antecedent to dolomitization, as evidenced by the destruction of fossils by the latter process and their preservation where silicified before such dolomitization. Dolomiti- zation of formations similar to the Oneota Dolomite is generally ac- cepted as a syngenetic process effected by sea-waters. (Author’s abstract.) ; |
C. E. VAN OrstRAND: Deep earth temperatures. (Illustrated.)
ArtHurR L. Day and E. T. Auten: The hot springs of the Lassen National Park. (Illustrated.) These springs are regarded as vol- canic in origin. The heat is doubtless volcanic as well as the gases which issue from the springs. The same may be said of a portion of the water, but the conditions prevailing satisfy none of the criteria which have been proposed for “juvenile” springs; most of the water is therefore probably meteoric.
The substances dissolved and precipitated in the springs are inter- preted as decomposition products of the lavas of the region by free sulphuric acid which occurs in many of the waters. These substances
56 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 2
are opal, ‘‘kaolin,’’ alunite, pyrite, and the sulphates of the common
rock bases. The sulphuric acid is probably derived from the volcanic gases, hydrogen sulphide or sulphur.
Though most of the springs contain free acid a Bear are shghtly alkaline. The alkaline condition logically represents a later stage of chemical reaction between the rock and dilute acid. These springs do not necessarily belong to a subsequent period; they may rather be the product of conditions locally favorable to more complete chemi- eal action.
Hot acid springs of volcanic origin on chemical grounds are classified as a stage of voleanic activity that follows fumaroles and precedes alkaline springs. (Author’s abstract.)
R. 8. Bassuer: Oscillation of the Central Basin of Tennessee in Ordovician time and its economic bearing. (Illustrated.) The Carters, Lowville, and Kimmswick formations, of Black River age; the Curds- ville, Hermitage, Bigby, Cannon, and Catheys formations, of Mo- hawkian age; and the Leipers formation, of Cincinnatian age, all rather easily distinguished faunally and lithologically, prove, in the course of extensive mapping, to be developed quite unequally on different sides of the Nashville dome. For example, the Carters limestone is thickest on the western side, while the overlying Lowville limestone is thickest on the eastern side; the Kimmswick limestone outcrops only on the southern flank; and the next younger formation, the Curdsville limestone, is found alone on the northern side. The chief reason for these differences is believed to be due to oscillation of the Nashville dome, and the great development of phosphatic _ rock in the Hermitage, Bigby, Catheys, and Leipers formations is considered as likewise connected with the same phenomenon.
Davin G. THompson: Some features of desert playas. (Illustrated.) The Spanish word playa is used to-day in Spanish-American countries to designate beaches along lakes, seas, or large rivers. Most English- speaking geologists, however, use the term to designate nearly level areas of alluvium in the lowest parts of closed basins in arid or semi- arid regions, which at times may be covered with temporary lakes and which are generally devoid of vegetation. This paper is based on. . observations of some 30 playas in the Mohave Desert region, Cali- fornia.
Most playas can be separated into two groups, depending upon the position of the water table. In water-tight basins the water table will always be within a few feet of the surface, and ground water is carried upward by capillary movement and discharged by evapora- tion and transpiration. The playas in these basins are kept moist almost continually by the capillary discharge, and, lacking a better term, they are tentatively called wet playas. If part of the rim of the basin is not water tight, ground water may move freely from one basin to another, and in the higher basin the water table may lie at a considerable depth. Playas in such basins are moistened only occasionally by storm waters and are dry for most of the time. These playas are tentatively called dry playas.
The dry playa has a water table generally deeper than 8 feet; the surface is hard and smooth in the dry season, with or without mud cracks; and there is generally less than 2 per cent of alkali in the soil. The wet playa has a soft, rough, and perennially moist surface; mud
JAN. 19, 1924 PROCEEDINGS: GEOLOGICAL SOCIETY 57
cracks are generally absent; and alkali is present in the soil in amounts over 2 per cent and easily visible. These characteristic features seem to be directly related to the ground-water conditions in the enclosing basins. Observations of these surface features will generally enable the geologists to determine whether or not ground water is close to the surface.
Mechanical analyses were made of a number of samples, and a rough microscopic examination of them was made by Dr. M. I. Gold- man to determine whether the soil of playas of the wet type con- tained more sand than those of the dry type, as seemed to be true in the field. The results did not show any unusual abundance of sand in the soils from the wet playas. The samples from several wet playas, however, showed unusually high percentages of very fine clay. In three samples from dry playas the greater proportion of the fine material was between 0.02 and 0.005 mm. in diameter. In four samples where the water table is known to be or is believed to be close to the surface a very large proportion of the material was much finer, in two of the soils 45 and 66 per cent, respectively, of the entire sample being finer than 0.0005 mm. It is suggested that the greater per- centage of very fine material in the soils from the wet playas may be due to more effective chemical decomposition than where the water table is at some distance below the surface. Possibly some of the concentration of clayey material of the dry playa in the larger size is due to the fact that aggregates of the finer material have not been properly dispersed. (Auwthor’s abstract.)
372D MEETING
The 372d meeting was held in the Cosmos Club, Wednesday even- ing, April 26, 1922, President ALDEN presiding and 46 persons present.
Program: F. E. Marrues: The production of steps in canyons by selective glacial quarrying. (Illustrated.) A critical study of the features of the Yosemite Valley, the Evolution Valley, and other glaciated canyons in the Sierra Nevada discloses the fact that the cross cliffs in their stairwise ascending floors consist, as a rule, of sparsely jointed, prevailingly massive rocks, whereas the basined treads are developed in relatively well jointed rocks.
The intimate relations that thus are seen to exist between form and structure can scarcely be explained by any of the more generally current theories of glacial excavating. The two theories that have been applied to the interpretation of the development of the Yosemite Valley—the frost sapping theory of Willard D. Johnson and the gravitational corrasion theory of E. C. Andrews—both postulate rapid headward recession of cross cliffs under the influence of sapping “processes acting intensively at their bases. The treads of the stair- way are supposed to result from this recession, which, for reasons not adequately explained, is assumed to work horizontally, or nearly so. However, it is manifest that the cross cliffs in the Sierra canyons are developed under structural controls of a purely local nature, and therefore are not migrant but essentially stationary features.
It is believed that the evolution of steps in glaciated canyons is better explained by a theory of selective quarrying, according to which the ice would excavate most effectively where the rock is most thoroughly jointed and therefore most readily quarried away block
58 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 2
by block, and would excavate least effectively where the rock is massive and not susceptible of being quarried. In a canyon floor composed of alternating stretches of jointed and massive rock, there- fore, selective quarrying would in time produce a series of shallow basins separated by barriers of massive rock. However, the barriers are slowly planed down by grinding on their upstream sides and crests, and the basins are quarried out most energetically at their heads, where the glacier falls into them, and so, the asymmetry of both bar- riers and basins becomes progressively accentuated, and there re- sults a canyon profile resembling a stairway with basined treads.
Abundant proof of the local origin and essentially stationary charac- ter of the cross cliffs is afforded by their peculiarities of form, de- clivity, and orientation, which are in every case clearly determined by the structural peculiarities of the rock. Particularly instructive in this regard are the cross cliffs at the heads of the Yosemite and Evolu- tion valleys. They cut obliquely across the valleys, regardless of the direction of the motion of the ice, but strictly in accordance with the local structures.
ArtHuR Howick: A review of the fossil flora of the West Indies. Comparatively little is known and still less has been recorded in relation to the fossil flora of the West Indies. The bibliography is very scanty. Ward,? in his comprehensive paper on The geographical distribution of fossil plants, issued in 1889, gives a list of eight titles, and states that “‘the only one of the West Indies from which fossil plants have been reported is the island of Antigua.’”’ <A recent thorough search through all the available literature on the natural features of the region has resulted in the compilation of a list of only sixteen titles in which there were any descriptions of or references to fossil plants, and many of these include mere incidental references to the presence of fossil plant remains without any descriptive text or il- lustrations. The only islands in connection with which fossil plants are mentioned are Cuba, Jamaica, Haiti, Porto Rico, Antigua, Mar- tinique, and Trinidad. Collections made within the past three or four years are being studied, and the publication of the results will add considerably to the meagre information heretofore available. All of the specimens included in the several collections mentioned have been figured, and many of the descriptions have been written. It is expected that a contribution will be ready for publication in the near future which will include all that is known at date in regard to the fossil flora of the entire West Indies. (Author’s abstract.)
WENDELL P. Wooprine: Tectonic features of the Republic of Haits and their bearing on the geologic history of the West Indies. The West Indian region belongs to the zone of Alpine folding that outlines the track of the late Mesozoic and Tertiary equatorial geosyncline. In the Republic of Haiti there were three periods of folding, at the close of Cretaceous time, at the close of Eocene time, and at the close of Miocene time. The geographic and tectonic features of the entire central part of the Republic, of the northwestern peninsula, and in part of the southern peninsula are due to the folding and crumpling of the rocks at the close of Miocene time. In some parts of the Re- public the folding that began at the close of Miocene time has con-
* Ward, L. F., U. 8. Geol. Surv. 8th. Ann. Rep. 1866-872: 663-690. 1899.
JAN. 19, 1924 PROCEEDINGS: BIOLOGICAL SOCIETY 59
tinued to the present time. In these regions Pleistocene reef caps are symmetrically arched over the crests of ‘older arches. In the north-
western peninsula the Pleistocene reef caps have an altitude of 400 to 450 meters above sea level on the crest of the arch.
The most striking feature of the present morphology of the West Indies is the series of ares, which are convex northward and south- ward. The great submerged troughs, such as the Bartlett trough, Brownson trough, and Anegada trough, have been interpreted by Vaughan and Taber as down-faulted blocks bounded by normal faults. Accumulating evidence shows that these submerged troughs were deepened, if not formed, at the close of Miocene time and during Pliocene time. It would be difficult to account for the tension de- manded by the block-fault hypothesis at any time, but it would be particularly difficult to account for it at the same time when similar subaerial features were being formed in the Republic of Haiti by the folding and crumpling of the rocks. The Cul-de-Sac plain, Arti- bonite valley, and Central plain are deep subaerial troughs. All of these subaerial troughs are synclines and some of them are bounded by a zone of imbricate high-angle thrust faults. It seems more reason- able to believe that the submerged troughs are similar tectonic features. (Author’s abstract.)
Kirk Bryan, Secretary.
THE BIOLOGICAL SOCIETY 656TH MEETING
The 656th meeting was held in the lecture hall of the Cosmos Club November 10, 1923, at 8 p.m., with Vice-President Gidley in the chair and 103 persons present. The program was as follows:
W. B. Greetery. Chief, U. S. Forest Service: The relation of National Forest management to wild life.—The National Forests include a large part of the breeding grounds and range of American big game. A game census by Forest officers, though it has obvious limitations, gives a fair idea of the importance of this resource in its total of over 515,000 of the larger ruminants. No management of these areas is sound or far-sighted which does not recog- nize wild life as one of their major resources, to be fostered and wisely used exactly as timber and forage. The Forest Service is working toward an ultimate policy of real game management, whose main points are: replenish- ment or restocking of areas depleted of game; maintenance of a normal game population; rational methods of utilizing the natural increase of a normal game stock; total protection of rare or distinctive game animals;complete protection of wild life, except predatory species, on special areas.
The next step in advancing the interests of game as a primary resource of the National Forests should be the enactment of a general law authorizing the establishment of game and fish refuges by Executive Order, with State concurrence. (Author’s abstract.)
L. O. Howarp, Chief, Bureau of Entomology: A recent visit to certain European centers. The speaker described his visit to Europe during the past year and showed views of the buildings and some of the principal workers at the following institutions: the Liverpool School of Tropical Medicine, the London School of Tropical Medicine, and the Wellcome Research Labora-
60 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 2
tory. The buildings at Hyéres, maintained as a laboratory for work on insect parasites by the U. 8. Department of Agriculture were also shown. An interesting account was given of Dr. Howard’s visit to Dr. Grassi, the Italian worker on malaria, at Fumacino. The talk closed with pictures of the delegates to the International Conference of Phytopathologists and Economic Entomologists at Wageningen.
657TH MEETING
The 657th meeting was held at the Cosmos Club November 24, 1923, at 8 p.m., with Vice-President Oberholser in the chair and 44 persons present. The following persons were elected members of the Society: Edward Elhott, Mrs. Edward Elliott, Harry Harris, A. G. Johnson. .
Under Short Notes, E. A. GoLpMAN reported his observation of a Cali- fornia Condor at the west entrance of General Grant National Park, Tulare County, Calif., October 11, 1923.
L. O. Howarp spoke of an interesting lecture on metallic colors recently given at Ithaca by Prof. WILDER BaNcRoFT.
F. C. Lincoun reported that 500 returns of banded birds have been re- ceived up to October 1. Among the most interesting records are those of three Pintails banded in the Mississippi Valley and recovered in California, and of a Green-winged Teal banded in Louisiana and recovered in Cali- fornia.
The regular program was as follows:
C. W. Stites, Public Health Service: Underground movements of bacteria.
The investigations on which this paper is based have been reported on in Public Health Reports38:1350-1353. 1923, from which the following abstract is derived:
The pollution of the ground-water (or phreatic water) by privy wastes, and the possibility and method of extension of this pollution to wells, springs, and other water supplies, have been subjects of discussion, experiment, and public health legislation for many years and in various parts of the world. In connection with investigations by the United States Public Health Service, extensive and rigorously controlled experiments have been made which bear upon the subject at issue and especially upon the move-— ment of bacteria, of fecal origin, in the ground-water. These studies have involved the experimental pollution of the ground-water (namely, the water in the saturated zone, which supplies wells and springs), and have been correlated with the rise and fall of the ground-water table, the flow of ground- water, and the rainfall. Bacillus coli was taken as the bacterial test, and a dye (uranin) was utilized in tracing the movement of the water from the dosing trenches to the more than 400 experimental pipe wells which were arranged at intervals from the trenches and at various depths into ground- water.
The examination of thousands of water samples from the wells during a period of more than a year has resulted in very definite data which seem to express practically a natural law as applied to the movement of the bacteria in the field of fine sand in which the experiments were conducted. The results to date may be summarized as follows:
1. Pollution with fecal Bacillus coli has up to date been definitely and progressively followed in the ground-water for distances of 3 to 65 feet from the trench in which the pollution was placed; uranin has been recovered from these same wells and has spread to other wells at 70 to 117 feet: from the
Jan. 19, 1924 PROCEEDINGS: BIOLOGICAL SOCIETY 61
pollution trench. The soil in question is a fine sand with an effective size of 0.13 mm. 2. The pollution has traveled these distances within a period of 187 days, and only in the direction of the flow of the ground-water. 3. The pollution has traveled only in a thin sheet at the surface of the zone of saturation. 4. As the ground-water level falls, owing to dry weather, the pollution tends to remain in the sand above the new (lower) ground-water level, namely, in the new capillary fringe. 5. There is no evidence which would justify a conclusion at present that either the bacteria or the uranin is carried or moves to any appreciable distance in the capillary fringe itself. All present evidence is to the effect that when the ground-water level falls the pollution remains practically stranded in the capillary fringe or in the intermediate belt, according to the degree of fall of the ground-water. 6. A rainfall of 1 inch results in a rise of 5 to 6 inches in the ground-water table (in the particular experimental area in question); and if this rise is sufficient to reestablish the zone of saturation up at the level of the stranded pollu- tion, the bacteria and the uranin are again picked up and carried along farther in the direction of the ground-water flow until dry weather again intervenes to cause another fall of the ground-water level. 7. Thus the progressive (passive) movement and the stasis (stranding) of the pollution are intimately connected with, are dependent upon, and alternate with the rise and the fall of the ground-water level, and this latter factor is dependent upon the alternation of wet weather and dry weather. 8. In explaining these results, capillarity, filtration, and gravity seem to come up for special con- sideration. 9. The ultimate distance to which the pollution will be carried is dependent upon a number of complex and interlocking factors, namely, wet and dry weather, with resulting rise and fall of the ground-water; the length of each of these periods; the rate of the ground-water flow (depending upon the “‘head,” which, in turn, is dependent upon the rainfall); and, ob- viously, also the factor of the viability of the organisms under conditions of moisture, pH, food supply, ete. 10. The bearing of the foregoing results upon the intermittent pollution of wells, the location of water supplies, and the location of camps in peace or in war, will be evident to persons who are called upon for technical advice in these matters. 11. In protecting wells special attention should be given not only to surface protection as is now generally recognized but also to a new element, namely, the danger zone which exists from the highest water level to about a foot below the lowest water level. A leak in the pipe in this region is potentially very dangerous, and all wells unprotected in this danger zone are to be considered as poten tially unsafe.
This paper was discussed by Messrs. Bonp, GoLpMAN, and BalILey.
Frank Bonp, General Land Office: Reproduction in painting of the metallic feathers of birds, with exhibition of paintings of hummingbirds.
About fourteen years ago the speaker saw in the possession of W. L. Baily, of Ardmore, Pennsylvania, a book containing paintings of humming- birds made by Mr. Baily’s uncle fifty or sixty years before. The effort of this painter to reproduce in pictures the iridescence of the throat feathers of hummingbirds aroused the interest of the speaker, and urged him to make experiments with a view to reviving what was believed to be a lost art. After many months’ effort he succeeded in painting pictures in which the luster of the feathers was brilliantly reproduced, as follows:
By means of a process which usually employs gold or silver leaf in order to secure a brilliant reflecting surface, which is the necessary first step, thereafter followed with successive applications on the reflecting surface of
62 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 2
a protecting transparent medium, a transparent paste colored with such transparent or lantern slide colors as many be required, and thereafter tracing with transparent or opaque colors feather designs to reproduce characteristic plumage details with the luster desired, he has succeeded in representing with remarkable fidelity the sheen of the hummingbird’s plumage.
The collection of paintings exhibited by Mr. Bond represented the male of every United States species of hummingbird, except one, and of that no adult male has yet been collected.
In discussing the paper Dr. T. 58. PatMeER mentioned that the Mr. Baily, by whom the earlier paintings were made, had been in correspondence with John Gould, the celebrated British ornithologist, at the time of publication of Gould’s monograph on the Trochilidae, and had in fact offered to com- municate to Gould his secrets of painting,—an offer which was not accepted by Gould. The process invented by Mr. Bond has been patented, and may prove to be of commercial importance. (Author’s abstract.)
658TH MEETING
The 658th regular and 44th annual meeting of the Biological Society was held at the Cosmos Club December 8, 1923 at 8:15 p.m., with Vice- President E. A. Goldman in the chair and 16 persons present. The minutes of the previous annual meeting were read and approved.
The reports of the Recording Secretary, the Corresponding Secretary, the Committee on Publications, and the Treasurer were read and accepted.
The following officers were elected: President, J. W. Gidley; Vice-Presi- dents, S. A. Rohwer, H. C. Oberholser, E. A. Goldman, A. Wetmore; Re- cording Secretary, 8. F. Blake; Corresponding Secretary, T. E. Snyder; Treasurer, F. C. Lincoln; Members of the Council, C. E. Chambliss, H. C. Fuller, H. H. T. Jackson, W. R. Maxon, C. W. Stiles.
S. F. Buaxn, Recording Secretary.
SCIENTIFIC NOTES AND NEWS
The sixteenth annual meeting of the American Institute of Chemical Engi- neers was held in Washington December 5-7, 1923.
At the meeting of the Petrologists’ Club on Tuesday, December 4, 1923, the program was given by E. B. Sampson, who spoke on Determination of anisotropy in metallic minerals, and E. Wa SHANNON, on Mineralogy and petrography of intrusive Triassic diabase at Goose Creek, Virginia.
Dr. ArtHur L. Day, director of the Geophysical Laboratory, Carnegie Institution of Washington, gave the inaugural lecture of the 1923 series before the members of the Royal Canadian Institute in Toronto, November 17. His subject was Harthquakes and volcanic eruptions.
NN' OUNCEMENT OF MEETINGS OF THE ACADEMY AND ; ; AFFILIATED SOCIETIES | |
5 January 19. The Biological Society. Vii ‘ The Helminthological Society. ‘sche a ee Geological nels
CONTENTS
ORIGINAL ‘PAPERS
PROCEEDINGS
The Geological Buelety, us Tea Me nem Ok nl ed The Biological Societys... she enya ary mop lay ne sates ooo 5 Sis aeinleieiale ca ‘Scrantwie, Notes AND News. yi. i. gra ie oe sible ys, ole Joa aes
OFFICERS OF THE ACADEMY
President: Anruur L. Day, Geophysical Laboratory.
Corresponding Secretary: Francis B. Stuspzx, Bureau of Stance Recording Secretary: W. D. LamBeRt, Coast and Geodetic Survey.
Treasurer: R. L. Farts, Coast and Geodetic Sumer
— Von. 14 February 4, 1924 No. 3
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Vou. 14 FEBRUARY 4, 1924 No. 3
PHOTOGRAPHY .—Stereoscopic photography in geological field work. F. E. Wricut, Geophysical Laboratory, Carnegie Institution of Washington.
Photography has rendered valuable services to geology both by providing illustrations for geological literature and, to a much greater extent, by furnishing note-book reminders of geological field relations which were difficult to describe concisely. The geologist on his return home from the field is aided by the snapshots he has taken to revisualize the field relations and thus to interpret the recorded data. The photo- graphs are valuable to him in the degree they contribute to the re- visualization process. If a print is large and the view is well chosen with regard to a proper foreground, so that the perspective relations are emphasized and even overemphasized, the observer gathers at first glance the impression of space and of the relative positions of the several details in the picture. If, on the other hand, the print is small with but little contrast in light and shade to bring out the perspective, the picture fails to convey to the eye an adequate impression of space. It is “flat,” and is unsatisfactory both pictorially and for purposes of study. In some instances these defects can be remedied by making an enlarged print on contrast paper or by examining a small print on contrast paper through a magnifying glass.
Photography to the geologist is simply a means to an end, namely, to record certain spacial relations between details of geological interest in the field. He is not concerned primarily with the making of a photo- graph of artistic merit. His photograph should tell clearly the story of the field relations between certain geological features and everything must be subordinated to this story, otherwise the point may be lost. This means that the two factors, sharpness of detail and perspective
63
64 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOU. 14, No. 3
are essential; if, at the same time, a balanced rendering of the subject is possible, so much the better, but in no case should the correct render- ing of geological details be sacrificed to gain pictorial quality. Another factor, that of scale, is also essential. Not only should the relative positions, but also the relative sizes of the details be represented by the photograph. In the case of near objects, such as rock exposures in a quarry or a cliff, a scale of known dimensions, as a geological hammer, or a hat, may be purposely introduced into the picture; for larger objects the figure of a man, looking toward the geological object and not toward the camera, may serve as a suitable scale. For objects at a distance, as a mountain side, a foreground is necessary not only to give the impression of distance, but also to convey an idea of the size of the mountain. A view taken from an elevated position, looking out over a wide plain or a valley is always disappointing because it fails to fur- nish a scale by which to measure distances and does not convey the im- pression of limitless expanse, which the observer on the mountain peak felt while taking the photograph.
Sharpness of detail in depth is attained by means of a small lens aperture. Color values are rendered so that they agree fairly well with the visual impressions by the use of color sensitive plates or films and properly adjusted ray filters. Berspective is attained chiefly by means of the foreground which, if skilfully selected, leads the eye from near objects to the more distant objects of geological interest and thus creates the impression of space and perspective. It is a simple matter to test this conclusion by first covering the foreground in a good photo- graph of distant mountains or hills and then observing the increase in apparent distance and perspective as the foreground is uncovered.
In the field the geologist is more or less encumbered with field ap- paratus and necessarily adopts the simplest camera that will answer the purpose. This is commonly a roll film camera of postcard size and equipped with a lens of focal length about 7 inches. Photographs taken with a lens of this focal length appear more natural and the depth relations stand out more clearly if they are examined through a reading glass. The effect of the reading glass is not only to magnify the print from one and one-half to twofold, but also to shift the image to a position more nearly in accord with that obtaining in the field where the objects were viewed directly. The combination of these two factors produces the enhanced stereoscopic effect or perspective ob- tained by use of the reading glass.
FEB. 4, 1924 WRIGHT: STEREOSCOPIC PHOTOGRAPHY 65
In ease the geologist is in a position to carry a greater load, a larger eamera, 5 by 7, or even larger, with a series of lenses or lens combina- tions covering a wide range in focal lengths enables him to obtain results . not possible with the small hand camera. Even with the postcard size camera a small tripod well repays the extra trouble it may cause. By using a small lens aperture and a suitable ray filter, and by making a short time exposure with the camera mounted on a tripod, the geologist is more certain of uniformly good results than he can be with ordinary snapshots. Experience has shown that in the photography of geological subjects ample exposure (even slight over exposure) of the film and the use of adequate amounts of restrainer (potassium bromide) in the developer produces the best average results.
It is evident from the foregoing that geological photographs are essentially technical in character rather than pictorial; that the criteria for excellence in a geological photograph, are degree of sharpness, perspective, and scale; in other words, degree of exactness of repre- sentation of the field relations. If in addition pictorial quality is present in the photograph it may well serve for illustration purposes; pictures which tell a geological story and at the same time have artistic merit are rare. The geologist who introduces into his photographs as much of the pictorial element as the circumstances permit, but with due regard to accuracy in representation, is rewarded by genuine apprecia- tion of his efforts. This would be lacking were the pictorial element lacking.
The feeling of space or stereoscopic effect in a photograph depends on the emphasis given to the perspective, and this is in part attained by means of a proper foreground with strong contrasts; but in the field a foreground of this character may not be available, and the resulting photograph is flat and represents inadequately the spacial relations. At best the stereoscopic effect in a photograph lags greatly behind the picture in the field, and there seems to be no remedy for this unless the geologist is willing to take two photographs of the object from slightly different positions and view the prints through a stereoscope Adequate representation is attainable only by means of stereoscopic photographs which enable the geologist at home to study the field relations in detail with a degree of certainty not attainable in the single view photograph. The taking of the two photographs requires no new apparatus; the two photographs are made with the same camera, one after the othe_, at points separated by a distance dependent on the distance to the object to be photographed. It is surprising, in view of the ease with
66 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 3
which stereoscopic photographs can be taken with the ordinary hand camera and without a tripod, that this method is not in general use among geologists. This disregard of the stereoscopic method may be due to two factors, namely; the idea that a special stereoscopic camera is required; and the development of stereogrammetric methods for
Fig. 1. Diagram to illustrate the principle of stereoscopic resolving power in depth.
>
field surveying which require special apparatus and are not adapted to ordinary geological field work. The purpose of this note is to emphasize the value of stereoscopic photographs in geological field work and to indicate briefly certain practical details in connection with the taking of stereoscopic views with an ordinary film camera.
Stereoscopic vision. Our ability to recognize the relative distances to two points P; and P, (Fig. 1) depends on the sensitivity of the eyes to shght angular changes between the lines of sight of the two eyes and to a much less degree on the change in focus of each eye as the line of sight passes from P; to Ps. In Fig. 1 let ¢:, es represent the two eyes; P, and Ps, two object points located at distances D, and Dz respectively from the eyes. The angle between the lines of sight to P; is e:Pié, and to Pe, e:P2é2. The difference between the angles e:Pié2 and @:Prée
FEB. 4, 1924 WRIGHT: STEREOSCOPIC PHOTOGRAPHY 67
is the angular shift which takes place between the lines of sight to P, and P, respectively. It is evident from Fig. 1 that all points on the circle ee2.P, subtend at the eyes é:, é, the same angle e,P,e:; similarly all points on the circle e:e2.P2 subtend the angle e,;P2e.. If the inter- pupillary distance ee. be standard, namely 65 mm., the distance along the chord e,€: is so nearly equal to that along the circumference for circles 1 meter and over in diameter that the difference (0.046 mm. or less) is for practical purposes negligible. On this assumption we derive directly from Fig. 1 for the points P; and P,
Leia £0. 3 Cie D, D;
ay
wherein 6b = ee. and D, = D, + d. The angular difference in radians
is accordingly
he, me b-d Z b-d
D, Di+d D,(D;+4 d) pia +4) 1
yy =| a=
As a rule dis a very small quantity compared with D, and the equation may be written as a first approximation
Aa = ay — a = =, (1)
This equation indicates that for short distances to P, the change in angle for a given distance d is large; for greater distances to P the change in angle is much less for the same interval d as is shown by Table 1 computed on the basis of an interpupillary distance ee. = 65 mm.
TABLE 1—AncLes SuBTENDED AT THE Eyes (INTERPUPILLARY DISTANCE 65 MM.) BY THE LINES OF SIGHT TO AN OBsEcT Point AT A GIVEN Distance IN METERS
enmee 30 E2 IN ANGLE pp ia LINES DISTANCE TO P1 IN METERS ANGLE patho LINES ~- 0.25 14° 48.83’ hs) east ale? 0.50 FO LG Ge 30 o es 0.75 4 57.75 40 OW 5:58 1.00 3 43.38 50 On 447 2.00 1 51:72 100 Op? 28 3.00 1 14.48 200 (ermal ah 4.00 0 55.86 300 0 0.74 5.00 0 44.69 400 0 0.56 10.00 0. 22:34 500 0 0.45 1000 OF 90:22
.68 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 3
Experiments by Helmholtz and others on the ability of the eyes to distinguish the relative distances of objects from the observer have proved that on the average two points separated stereoscopically (in depth) by 30” of are and in exceptional cases by 10” or 12” or even less are recognized as situated in different planes. If therefore we assume a value
Aa = a, —a, = 0.0001 in radians or A a = 20.63”
equation (1) becomes g = 0:0001 - Di b
Stereoscopic views. In the stereoscopic photography of geological features the combination of camera lens and plate functions as the eye. The distance between the two camera positions corresponds to the inter- pupillary distance and equation (1) is directly. applicable, if the focal length of the camera lens is taken into account. The photographs thus taken are viewed with the aid of a stereoscope which may or may not be equipped with weakly magnifying lenses. The stereoscope is necessary because the eyes, as a result of long practice and habit, per- form a series of operations automatically in passing from one object to another; at the same time that the object is brought to focus the lines of sight are adjusted for the distance. In the case of two photographs placed at the distance of near vision the eyes tend, in focussing on the photographs, to converge the lines of sight to a single point of a single photograph, whereas to see stereoscopically it is essential that the right eye focus on the right hand photograph, the left eye on the left. This | it is possible to do with practice, but in general it is simpler and involves less eye strain to superimpose the two photographs by means of a stereoscope either of the reflecting mirror type (Wollaston or Helm- holtz) or of the lens refracting type (Brewster or Helmholtz) in which the photographs are viewed through weak lenses so placed that the distances to the images appear to be comparable to those of the original object. In the case of a lens stereoscope the image is also enlarged and the stereoscopic effect is thereby enhanced.
1H. v. Hetmuouirz, Physiologische Optik 814 et seq. 1896; O. Hecker, Zeitschr. Instrumentenkunde 2: 372. 1902; C. Punrricu, Zeitschr. Instrumentenkunde 21: 221, 1901; 22: 65, 1383, 178, 229. 1902; - 23: 43. 1903; 25: 233. 1905; J. W. Frencu, Trans. Opt. Soc. 24: 226. 1923.
FEB. 4, 1924 WRIGHT: STEREOSCOPIC PHOTOGRAPHY 69
As a first approximation we may consider that the stereoscopic effect increases directly with the degree of enlargement of the photograph; and this in turn increases with the focal length of the camera lens and with the magnification by the stereoscope. Equation (1) may accord- ingly be written
ee 2)
De ot
wherein f is the equivalent focal length of the camera lens, / the distance at which the photographs are viewed by the eye (commonly 10 inches or 25.0 em., the distance of near vision), V the magnifying power of the stereoscope which, as ordinarily defined, is the ratio of the apparent height of the image observed through the lens at a distance / (10 inches) to the height of the object itself. Assuming the value, a:—a: = 0.0001, the magnifying power of the stereoscope to be N = 2, the distance of near vision / = 10 inches, we may write equation (2) _ 0.0001-10 Dj; Dj 3)
_= 0.0005: 2 d-f ad-f
b
Thus if a lens of focal length f = 7 inches, the separation b of the two camera positions required for a depth resolution of 1 per cent of the distance, d = 0.01 D, is
_ 9.0005 - D:_ 9 9971 D, 0.01 %7
For d = 0.001, b = 0.071 D; for d = 0.005, b = 0.014 D. For a lens of focal length f = 20 inches we find for d = 0.01 D, 6 = 0.0025; for d = 0.001 D, b = 0.025 D; for d = 0.005 D, b = 0.005 D. Similarly, for an object at 2000 feet distance, the separation of camera positions with a lens of 12 inch focus required to enable the observer to recognize a depth difference of 2 feet (d = 0.001 D) in the stereoscope is 6 = 0.0005 - 20007 Aim 1 In general it may be stated that, with ordinary cameras having lenses of focal lengths between 5 inches and 20 inches, a camera sepra- tion of 3 to 5 per cent of the distance suffices for critical stereoscopic studies; commonly a camera separation of 1 to 2 per cent of the distance to the object suffices. The greater the camera separation (up to 10 per cent) the higher the resolving power in depth. <A separation b exceeding 10 per cent of D is likely to produce exaggerated perspective.
= 83.7 feet.
70 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 3
In the taking of stereoscopic views of geological features with a single camera the best results are obtained by holding the camera horizontal, by pointing it directly at the object, and by selecting, in a line approximately at right angles to the lines of sight, two positions from which the two views are taken, such that their distance apart is from 4 to 5 per cent of the distance to the object.
Eazpervmental tests. In order to test the validity of equation (2) and incidentally to test the stereoscopic sensitivity of the eyes, a framework was constructed which consists essentially of a thick cardboard top
lle ceri ys ammonia on?
Vig. 2. Stereoscopic photographs of test objects taken at a distance of 20 meters with a camera lens of 22.7 inches focal length; the distance between the two camera stations was 40 em.
and bottom each about 1 meter square, into which holes were drilled at different distances from the front edge. Through these holes cords were passed and through loops in the cords pencils were attached so that when mounted (Fig. 2) and viewed from a distance a number of vertical pencils appeared to be suspended in mid air against an illu- minated back ground of white cloth tacked to the rear side of the frame- work. This group of suspended pencils was then photographed at a distance of 20 meters, with the camera at different distances of separa- tion and with different lenses of focal lengths ranging from 7 inches to 69 inches. The minimum depth separation of the pencils was 4 cm. or 0.002 of the total distance. Prints of the photographs were then studied with the aid of a stereoscope equipped either with achromatic lenses of different focal lengths (E.F. = 80, 151, 190, and 241 mm.)
FEB. 4, 1924 WRIGHT: STEREOSCOPIC PHOTOGRAPHY 71
or with reflecting mirrors (Helmholtz arrangement). The separation of two adjacent lead pencils ranges from 4 cm. to 1 meter. As the observer passes from one part of the diagram to the other he records the relative positions in depth of the several pencils. The results which are listed in Table 2 are not very concordant. The degree of accuracy
TABLE 2—Tue Deptu SEPARATION IN CENTIMETERS EAstny DETECTED STEREO- SCOPICALLY, WITH THE AID OF A STEREOSCOPE OF MAGNIFYING PowERS RANGING FROM 1 To 3.81, ON PHOTOGRAPHS TAKEN OF THE TEST OpJEcTS (Fig. 2) at 20 Meters DISTANCE AND WITH DIFFERENT CAMERA LENSES AND DISTANCES BETWEEN THE CaMERA POSITIONS
MAGNIFICATION BY STEREOSCOPE
DISTANCE BETWEEN
CAMERA POSITIONS
E.F. oF CAMERA
spss 1 1.93 2.49 3.81
| Stereoscopic depth in em. resolved on photographic prints |
cm. cm. 12.0 10 - 64 32 28 28 20 48 24 20 16 30 16 16 2, 40 24 12 12 12 80 16 8 8 8 22.7 20 20 16 12 12 40 16 12 8 8 60 12 8 4 4 . 80 8 4 4 4 68.7 10 20 16 16 12 20 16 12 12 8 | 30 8 8 8 4 | 40 8 4 4 4
obtainable was found to be in part dependent on the quality of the photographic prints. The data were converted by means of equation (2) into angular values and these were then plotted on coordinate paper; the general trend of the values suffices to indicate that for the stereoscopic effect depicted in the photographs, the magnification factors introduced into the formula covering focal lengths of the cameralenses and magnifying power of the stereoscope are too large; in other words the stereoscopic effect under these conditions is increased with the magnifi- cation of the image but the degree of increase is appreciably less than that indicated by the formula. For the purposes for which the photo- graphs are to be used, equation (2) may be considered, however, to represent the situation with sufficient accuracy. More detailed work would be required to determine the exact form of the equation with a given type of photographic print.
Summary. In geological field work stereoscopic photographs taken , by the ordinary roll film camera are of value in assisting the geologist to
72 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 3
revisualize the relations studied in the field. Details which may have escaped his notice are brought out much more effectively than in the single photograph. The taking of stereoscopic photographs for this purpose does not require special apparatus. To obtain good stereo- scopic effects it is advisable to take two photographs, one after another and from different positions, of the geological features to be recorded, the distance between the two camera stations to be from 1 to 5 per cent of the distance of the object itself, the camera in each position to be pointed at the object and the lines joining the camera stations to be approximately normal to the lines of sight to the object. The stereo- scopic effect can be enhanced if enlarged prints of the negatives are made and a lens stereoscope of the ordinary type is used in the examination of the prints.
BOTANY.—Two new species of Jamesonia.! Witi1am R. Maxon, National Museum.
Recent large collections of ferns from the Andes of South America have contained numerous specimens of Jamesonia, necessitating a revision of the genus. Of several species regarded as undoubtedly new two are described herewith.
Jamesonia brunnea Maxon, sp. nov. .
Rhizome flexuose, wide-creeping, brown, terete, lignose, 3 to 4.5 mm. in diameter, densely clothed with oblique bright brown setae (2.5 to 3.5 mm. long). Fronds few, long-stalked, 55 to 70 em. long, distichous, 7 or 8 mm. apart, erect-arcuate; stipes 25 to 30 em. long, stout (1.5 to 2 mm. in diam- eter), subflexuose, brown, subangulate above, deciduously appressed- setose; blades linear, 25 to 30 em. long, slightly attenuate toward the base, the rachis stout, brown, strongly compressed, lightly bisuleate above, every- where densely and coarsely crispate-hirsute with broad flattish brown-ferru- ginous septate hairs, these never forming a tomentum; pinnae numerous, borne in two close rows on the upper side of the rachis, alternate, horizontal, usually arranged closely in a single scalariform series, stalked (1.5 to 2 mm.), broadly orbicular-ovate, roundedin the apical portion, truncate or very broadly cuneate at base, rigidly spongiose-coriaceous, strongly convex, broadly and deeply revolute, the slightly thinner margin freely ciliate (the cilia close, weak, flexuose, pale ferruginous, 1 mm. long); upper surface of pinnae strongly glandular-viscid, vernicose; lower surface glandular-pubescent and freely crispate-hirsute, chiefly along the veins, the shorter hairs erect and capitate, the long ones flexuose and septate like those of the rachis; larger pinnae 6 to 7 mm. long, 5 to 6 mm. broad; venation pinnate-flabellate, deeply immersed, barely evident above, coarsely corrugate beneath, 20 to 24 branches attaining the margin; sporangia not observed.
! Published by permission of the Secretary of the Smithsonian Institution.
FEB. 4, 1924 MAXON: NEW SPECIES OF JAMESONIA 73
Type in the U. 8. National Herbarium, no. 1,067,752, collected at the summit of Mount Guamani, Ecuador, altitude 4,000 meters, by Father L. Mille (no. 42).
In its large long-stipitate fronds and in its generally coarse aspect and habit of growth Jamesonza brunnea recalls J. verticalis; but the resemblance goes no farther, J. verticalzs having, for example, adnate pinnae, in which it is unique. J. brunnea is more nearly related to J. tolimensis (Hieron.) C. Chr., of Colombia, which agrees in haying the fronds long-stipitate and the pinnae truncate, ciliate, viscid-glandular above, and with a mixed glandu- lar and septate-hairy covering beneath. J. tolimensis is, however, a smaller plant and has the pinnae chartaceous, sessile, roundish-obovate to obovate- elliptical, and the margins lobulate-crenate to crenulate, and short-ciliate (the cilia 0.5 mm. long or less), in all of which characters it differs from J. brunnea.
There is no other described species with which J. brunnea need be com- pared. The ladder-like arrangement of the alternate pinnae in a single or nearly single series at the upper side of the arcuate rachis is not due to pressure in drying, being quite as conspicuous in leaves that are restored to normal condition by boiling.
Jamesonia ceracea Maxon, sp. nov.
Rhizome wanting. Fronds (mature) 10 to 20 em. long, nearly straight above the curved base; stipe 1 to 3 cm. long, 0.3 to 0.5 mm. in diameter, flexuose, strongly curved at summit, dark chestnut-brown, lustrous, minutely striate, deciduously and laxly setose, the hairs few, flattish, pale ferruginous, septate; blades 9 to 17 ecm. long, 2 to 3.5 mm. broad, narrowly linear, long- attenuate toward the apex, the tip also attenuate though indeterminate; rachis relatively stout, castaneous, wholly concealed beneath by a dense imbricate covering of spreading or recurved, buff or pale ferruginous, flat, septate hairs, these concealing only the bases of the pinnae, persistent; pinnae 75 to 115 pairs, short-petiolate (about 0.5mm.), alternate, mostly imbricate and horizontally deflexed in two contiguous rows upon the upper side of the rachis, those of the lower part spreading, more than their width apart, the lowermost ones distant; largest (middle) pinnae about 2.5 mm. long, 1.8 mm. broad, obliquely and broadly oblong from a subcordate inequilat- eral base, rigidly herbaceo-coriaceous, strongly convex, the deeply recurved margin nearly 0.5 mm. broad, crenately constricted, bordered abruptly by a broad whitish membranous true indusium, the aperture between the indusia 0.5 mm. broad or less; upper surface of pinnae grayish green, nearly glab- rous, bearing a few minute short appressed whitish glandlike hairs; lower surface densely and deeply covered by minute white ceriferous hairs, the loose ceraceous mass mostly concealed by the revolute margins and broad indusia, persistent; venation pinnate-flabellate, deeply impressed, the branches 5 or 6 in number; sporangia not detected.
Type in the U. 8. National Herbarium, no. 1,042,371, collected on steep p4ramo slope of Mount Chuscal, west of Zipaquira, Department of Cundi-
74 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 3
namarea, Colombia, altitude 3,100 to 3,200 meters, October 22, °1917, = Francis W. Pennell (no. 2607).
In size and general appearance Jamesonia ceracea is not very unlike small forms of J. imbricata (Cav.) Hook. & Grev., which it resembles also in having a relatively broad true indusium. It differs widely from that species in nearly all minute characters, however, and is the only member of the genus with ceraceous pinnae. The waxy indument of the under surfaces is not due to a juvenile condition or to extreme age, but is a definite morphological character. The loose waxy mass, which is persistent and is evident at all ages, is not quite amorphous, the presence of short, white, intermingled secreting hairs being readily demonstrable.
PROCEEDINGS OF THE ACADEMY AND AFFILIATED SOCIETIES |
THE BOTANICAL SOCIETY
167TH MEETING
The 167th meeting of the Botanical Society was held at the Cosmos Club April 3, 1923 with President L. C. Corbett in the chair and 32 persons present. N. Rex Hunt was elected to membership in the society.
Program: F. V. Covinie: Experiments in Rhododendron culture. (Il- lustrated). It has been recognized for some time that when rhododendrons have been taken from their natural habitat and planted around houses they frequently stagnate and die. This condition is caused by the change from an acid to an alkaline soil. Nurserymen claimed that rhododendrons could thrive in an ordinary fertile soil through the application of magnesium sulfate. It was decided to try magnesium sulfate and aluminum sulfate, also, in an experiment to bring about an acid reaction in an alkaline soil. A solution of magnesium sulfate stimulated the growth of seedlings of Rhododendron catawbiense to a slight degree, while a solution of aluminum , sulfate very greatly stimulated the growth of the plants. A full discussion of The effects of aluminum sulfate on Rhododendron seedlings is presented in a paper by Dr. Coville, published as Bulletin 1 of the American Horticulture Society.
Rupoutr Kuraz, Secretary of the Czechoslovak Legation: Seed control in Czechoslovakia. The growing of cereals and industrial plants for seed is a well established industry in Czechoslovakia. For the protection of the growers as well as the purchasers a seed control law was passed by the National Assembly on March 17, 1921, supplementary regulations going into effect June 15, 1921. Thelaw provides for official inspection, analysis, certification, and registration of original varieties developed by the growers and of seeds grown for them. Only those growers who have complied with the requirements of the law may use the designations ‘original variety,” “certified seed,’ ‘‘certified seedlings,’ and “registered variety.’”’? The Ministry of Agriculture, charged with enforcement of the law, appoints certifying commissions for the various districts, as well as the Central Certi- fying Commission, an advisory body with offices at Prague. The analysis of seeds and the control of the trade in seeds have been intrusted to four
FEB. 4, 1924 PROCEEDINGS: BOTANICAL SOCIETY 75
testing stations, or research institutes. A certifying commission has at least eight members and eight alternates, selected from among the expert officials of agricultural associations, instructors in agricultural colleges and other schools, and professional seed growers. Membership on the com- mission is purely honorary; the members receive no salaries and are com- pensated only for their actual expenses.
A. 8. Hirexcocr: The proposed tropical biological station in the Panama Canal Zone.
The Institute for Research in Tropical America, consisting of 5 museums, 6 universities, and 10 scientific societies, was organized in 1922 for the pur- pose of promoting research in tropical America. The Executive Committee decided to give prominence to research in Panama, because of the unusual biological conditions found here. The Isthmus is a bridge across which nearly all the migrations of land animals have taken place, and two great oceans are closer together here than in any other tropical region. More- over, the physical conditions on the two sides of the Isthmus are distinctly different, and there is a corresponding difference in the marine faunas. The Atlantic side is uniformly hot; the Pacific side is cooler because of the cold currents from the north and south. Into these conditions has been thrown a disturbing factor—the Panama Canal. What effect will this have on the biological conditions? |
The Institute will proceed with its program as soon as financial support is obtained. Itis hoped to utilize the laboratories of the institutions already established in Panama, and to codperate with all agencies interested in developing the resources of that region.
R. Kent Beatriz, Recording Secretary Pro Tem.
168TH MEETING
The 168th meeting was held at the Cosmos Club May 1, 1923, with Presi- dent L. C. Corbett in the chair and 65 persons present. H.C. Dient, F. P. ScHuatTrer, JAMES H. Beatriz, and F. L. Gout. were elected members of the society.
Brief notes: F. P. Mercaur outlined his prospective work in China as head of the Botany Department at the Fukien Christian University. This school has financial support from the Chinese Government.
C. R. Bat spoke of the presence in the city of the representatives of foreign mission fields as guests of the Department of Agriculture.
Program: W. J. Morse: The soybean, abroad and at home. Illustrated.) The rapid rise of the soybean, also called soya and soja bean, to a crop of special importance in the world’s commerce in the past few years is one of the important commercial events of recent times. It is a plant of ancient cultivation in China, Japan, and Chosen (Korea). The annals of Old China state that the soybean was an important food with the Chinese fully 5,000 years ago. When the ports of China were first opened to foreign commerce, the trade in beans and bean-products was found a long estab- lished and flourishing institution. In extent of uses and value the soybean is, at the present time, the most important legume grown in Asiatic coun- tries. In addition to its use as food in the Orient, large quantities are utilized by first extracting the oil and then using the cake for stock feed and as a fertilizer.
At the close of the eighteenth century the soybean found its way to Europe, its cultivation being recorded in England in 1790. It is mentioned in the
76 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 3
United States as early as 1804. For several decades, however, it was re- garded more as a botanical curiosity than as a plant of much economic im- portance. In 1875 Professor Haberlandt began an extensive series of experiments in Austria with the soybean, strongly urging its use as a food, both for man and beast. Although considerable interest was aroused during the experiments, the soybean failed to attain the success hoped by the author of the experiments.
Previous to the Russian-Japanese war, China and Japan were not only the greatest producers but also the greatest consumers of the soybean and its products. During the war the production of the crop was greatly in- creased throughout Manchuria. After the war, however, it became neces- sary to find new markets for the surplus beans and trial shipments were made to Europe. The first attempts to introduce the soybean and its products into European markets were generally unsuccessful owing to the inferior quality of the beans and cake, caused by poor shipping conditions. About 1908 a large trial shipment made to English oil mills was received in much better condition than the previous shipments, and the results obtained were so satisfactory that larger imports were made.
The success in the utilization of the soybean as an oil seed extended rapidly to the continental countries, and the importation of beans from Manchuria and Japan soon reached enormous proportions. The beans were utilized by extracting the oil that was found valuable for various industrial pur- poses, leaving the cake as a cattle food. As the value of the oil and cake came to be recognized, new uses and markets were found, and the trade assumed such large proportions that the soybean has become an important competitor of other oil seeds.
As previously stated, the soybean was introduced as early as 1804, but it is only within recent years that it has become a crop of much importance in the United States. The soybean, until the present season, has been grown primarily as a forage crop. The increased demand for seed, for food, and for planting has led to the development of a very profitable industry in many sections of the cotton and corn belts. The large yield of seed, the ease of growing and handling the crop, the value of the beans for both human and animal food, and the value of the oil and meal, all tend to give this crop a high potential importance and assure its greater agricultural development in America.
C. A. Reep: Glimpses of economic trees and plants of China. (Illustrated.) So great is the need due to the density of its population and so limited the means of distribution of its products that it would not be far wrong to put all plants of North China into one group, namely, an economic group. In such provinces as Shantung, where the population is in the neighborhood of 600 to the square mile, practically everything is economized with the ex- ception of labor. Every part of the cultivated plants is utilized in one or more ways. China is commonly regarded as being a treeless country, yet the city streets and their various compounds are adorned with such species as whaishu, (Sophora japonica), German acacias, willows, catalpas, pop- lars, ginkgos, jujubes, persimmons, pines of various species, cedars, arbor vitae, pistache, and even oaks, and other genera more or less familiar in this country. Not infrequently, large areas of house tops are hidden from view by foliage in the cities and towns. All brush of the mountains is used either in the manufacture of wicker-ware or for fuel, or other purposes. The sour fruits of the low-growing jujube are gathered for food, and the spiny
FEB. 4, 1924 PROCEEDINGS: BOTANICAL SOCIETY 77
branches used for obstructions either as simple fences or barricades on the tops of walls. For fuel, all lower branches of non-fruit producing trees are eut, and the trunks of trees having scaly bark are pared as closely as possible without serious injury. Field crops, such as corn, sorghum, soybeans, millet, ete., are either pulled up by the roots at harvest time or cut in the usual way, and later the roots are taken up and used for fuel. Apparently the soybean nodules on the roots are mainly responsible for the fertility of the soil.
Planted trees along railroad lines, about family cemeteries, or elsewhere in the landscape form some of the most familiar sights throughout the plains sections of Northeast China. Perhaps the most graceful in appearance are the various species of willow. The basket willow, with its side branches removed well up to near the tops of the trees, bears striking resemblance to the American elm. Probably the most highly prized species of tree is that of the white-barked pine, Pznus bungeana, which, when dormant, greatly resembles the American sycamore and the Oriental plane. This species is claimed to be exceedingly difficult to propagate and of slow growth, yet exceedingly longlived. For these reasons it was a great favorite with: the royalty of at least one dynasty, the Ming. Wherever members of that family established themselves, avenues of these trees were sure to be planted. Single specimen trees and occasional avenues still remain, and in one case a forest of several acres extent is still to be seen, although from 300 to 500 years have elapsed since they were planted, and in spite of the fact that the succeeding dynasty, the Manchu, apparently sought literally to uproot the trees as well as, figuratively, to uproot everything else pertaining to the Ming.
Among fruit-producing trees North China has a great range of species and varieties. Of these, in probable order of excellence, there are the per- simmon, pear, jujube, or chinese date, as it is called, and the hawthorne. Of chestnuts there is an equally choice range of strains. The same might be true of walnuts if the product were to be allowed to properly ripen before being harvested. The native apples are of low order; they could doubtless be improved upon by crossing with the wild types of lower New England; certainly this would make the quality no worse. Some of the peaches are very fine and can well. The Bartlett pear was introduced from America some 50 years ago by John L. Nevius, a Presbyterian missionary at Chefoo, who is also credited with having introduced many other American fruits. There is said to be a highly developed fruit industry on the north side of Shantung Peninsula in the neighborhood of Chefoo. Bartlett pears from that section were common on the hotel tables from Peking south to Shan- tung throughout what seemed to be a long season. The Concord grape appeared somewhat sparingly in an important fruit center, 100 miles to the northeast of Tientsin. However, European grapes lead American varieties in extent of planting, and in some sections they are of large im- portance. Other American products successfully established in China are the peanut, the sweet potato, and Indian corn. Most American vege- tables and fruits have their counterparts in China. The total number of Chinese varieties surpasses that of this country, yet with the exception of paitsi, egg plant, carrots, and a few others, these varieties show little evidence of having been bred up and improved systematically. Walnuts and chest- nuts are propagated by seedage only.
Roy G. Pizrce, Recording Secretary.
78 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 14, No. 3
SCIENTIFIC NOTES AND NEWS
Puinie §. Suir, of the Geological Survey, has returned to the Alaska Branch, and will undertake for that Branch and the Navy Department the examination of Naval Petroleum Reserve No. 4, Alaska. JuLian D. Sears has been designated Administrative Geologist to fill the position relinquished by Mr. Smith.
The 348th meeting of the Washington Section of the American Chemical Society, on December 13, 1923, was made a special meeting