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clearly Eocene by Knowlton. This view was Professor Schuchert has gained wide repunot seriously opposed until the flora, first tation for his broad studies in paleogeography. found in the Fort Union, was traced down His mature opinion was no doubt expressed through the Lance almost to its base. The in his “ Text-book of Geology," (1915, p. 581) Aora thereby lost much of its interest to verte

where he says: brate and invertebrate paleontologists, but not

It is, therefore, the principles of diastrophism to paleobotanists or geologists.

and paleogeography that will eventually correctly The Fort Union beds have a mammalian

define the periods or systems, fauna of small forms considered to prove the Eocene

age of the strata containing them It may seem at first thought that this prinuntil allied types were found in the Lance ciple guided Professor Schuchert in his opinassociated with dinosaurs and other

ion that two paleogeographic maps presented

supposed Cretaceous forms. The significance of by Stanton are a most striking summation of the poor little mammals has seemed to dis- the problem in hand ...." That judgment appear, from certain standpoints, but not seems, to the writer, far from the truth. from all. The Ceratops fauna of the Lance

One of these maps (after Schuchert) repreis closely similar to that of the Denver beds,

sents the Pierre Cretaceous ocean as extendcorrelated by the Geological Survey, together

ing from the Gulf of Mexico through the with other Colorado and New Mexico forma- Rocky Mountain region far toward the Arctic, tions, with the early Eocene beds of the Gulf

with a land barrier reaching from the east region.

at least to the boundary of Colorado and New The Cannonball shales demonstrate the

Mexico. This barrier may have extended temporary return of marine waters from an

further. The other map shows the supposed unknown and as yet undiscussed region to early Eocene limits of the Gulf sea and the the Dakota district, after an absence which

geographic position of the Cannonball area. was of considerable duration. Where was

What is needed is a paleogeographic map, or this sea meanwhile? The known Cannonball several of them, to express a reasonable fauna consists of two sharks, several corals hypothesis of the course of retreat of the sea and foraminifera, all of which range into the

as the land barrier rose and apparently cut Tertiary, and 60 molluscan species. The off entirely a restricted northern ocean from molluscan group, according to Stanton, has the Gulf sea, perhaps before Fox Hills time. “ the general aspect of a Tertiary fauna," Somewhere there was an open sea, insisted on but he considers 24 species to be identical by Dr. Stanton, cut off from the Atlanticwith forms in the Fox Hills or Pierre Gulf ocean, in which the Fox Hills fauna was formations of the Cretaceous nearby, while

modified to that found in the Cannonball. not one is identical with any known form in Unfortunately Dr. Stanton does not discuss the lowest Eocene of the Gulf region and 35 the origin, the position, the extent, or the are new species.

climatic and other conditions of the open sea Dr. Stanton has given, in the excellent pub

in which this modification took place. He lication reviewed by Professor Schuchert, a

considers that the Fox Hills is the approxicareful description of the Cannonball fauna mate equivalent of the upper part of the and discussed its relationships to Cretaceous Exogyra costata zone, which is near the upper and Gulf Eocene faunas. Elsewhere he has limit of the Cretaceous in the Atlantic-Gulf discussed the age of the Lance on general region. He nevertheless recognizes considergrounds but he has always given the greatest able differences” in the faunas, which he weight to the character of the invertebrate attributes to lithologic facies, geographic fauna, as is natural considering his special separation, and possibly to climate. point of view.

It seems to a geologist necessary for the invertebrate paleontologist to give some at- Fort Union flora is attested by its affiliation tention to the possibility that a northern with many European Eocene deposits of isolated sea existed into early Eocene time definite, acknowledged position, as Ardtun in and that its conditions produced a modifica- Mull, Gelinden in Belgium, and Sezanne in tion of the Cretaceous molluscan fauna nat- the Paris Basin, as well as the Eocene urally different from that arising during the in Greenland and Alaska. This affiliation same time in the Gulf region. Does not the amounts to many identical and closely related Cannonball fauna show what modification had species, as well as identical and related genera. been reached at a time which, under the exist- Several Fort Union species are believed to be ing conditions, must be placed in the general still living, a condition not known for any time scale by utilizing, instead of ignoring, earlier American deposit. the other facts of the Lance and Fort Union The flora of the Lance formation is also a formations, and also the concordant knowl- rich one, comprising about 125 forms, some edge of Rocky Mountain history?

of which, however, are so fragmentary and

WHITMAN CROSS obscure as to be incapable of more than WASHINGTON, D. C.,

generic determination. After eliminating the

new forms and those that can not be specificTO THE EDITOR OF SCIENCE: In SCIENCE for ally named there are 87 species that are posiJanuary 14, 1921, Professor Schuchert, in re- tively identified, all but 15 of which (about viewing Dr. Stanton's recent paper on The

80 per cent.) are found in the Fort Union. fauna of the Cannonball marine member of It is unmistakably a Fort Union flora, and the Lance formation,” proceeds to answer this occurs through the whole vertical range of the query in a most emphatic and unreserved Lance formation, some of the most characteraffirmative. He assumes to speak with au- istic Fort Union plants being found within thority for geologists and vertebrate and in- four feet of the base of the beds. Of the vertebrate paleontologists, but he admits that entire known Lance-Fort Union flora less than the “ floral brethren” will, of course, continue 15 species have been reported from Cretaceous to dissent. The problem of establishing the beds anywhere, and this number will be reline between Cretaceous and Tertiary time in duced instead of enlarged by revision of the the Rocky Mountain province has been more floras involved. or less of a storm center for a number of Sedimentation was undoubtedly continuous years, but the question can only be settled through the Lance and Fort Union formawhen all the available lines of evidence have tions; in fact, it is impossible to draw any been evaluated and harmonized. Drawing satisfactory line between them. The highest this line at the top of the Fort Union will point at which dinosaurs occur is taken as profoundly affect other areas and other prob- the top of the Lance, but where these remains lems, many of which Professor Schuchert are absent it has no recognized or recognizable appears to have underestimated if not indeed top. If the Cannonball marine member of the overlooked.

Lance formation is Cretaceous then both The faith that is in the “ floral brethren" Lance and Fort Union are Cretaceous, for is strong! This evidence has been set forth there is no stopping point short of the top of at length on several occasions, but a brief the Fort Union. Professor Schuchert even recapitulation may not be without interest. holds that there “is here a continuous and Up to the present time, with one or two minor unbroken series of deposits from the Pierre exceptions, the Fort Union has been every- and Fox Hills into the top of the Fort Union, where accepted as of Eocene age. It has a and that the reported erosion contacts between very large flora of approximately 500 species. the several formations are due to nothing Aside from local stratigraphic and paleonto- more than changes from marine to brackish logic considerations, the Eocene age of the and fresh-water deposition, or to irregularities

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characteristic of continental sediments, the should always go together in the manner local breaks not representing a loss of geologic assumed. A simple explanation is supplied time of any marked historical value.”

on the weak-allelomorph view, for Ee is the The plants certainly do not uphold this weak allelomorph and the selective reduction contention, but they do indicate a very con- Ee-e is simply segregation in the ew - e siderable hiatus between the top of the compound. Linkage supplies the explanation acknowledged marine Cretaceous section and

on the modifier view, for the E is then a domithe inauguration of the Lance. The Laramie

nant minus modifier in the fourth chromois not known within this area, but can it be

some, and Ee e is simply Mee As far doubted that it was the interval during which

as can be judged from the short account given, in other areas beds of Laramie age were laid

all the observed ratios are in conformity with down and subsequently removed in whole or

either of these views. Thus, Dr. Little has not in part? That there was an important inter

proved by direct and available means that the val of some kind is also shown by the fact

case is actually one of non-disjunction, nor that it was sufficiently long for over 60 per

has he proved it negatively by excluding wellcent. of the marine Cannonball fauna to be

recognized alternative hypotheses which are derived through modification of the typical

equally valid and even more in harmony with Fox Hills fauna.

F. H. KNOWLTON
the facts of the case as stated.

C. B. BRIDGES
PROOF OF NON-DISJUNCTION FOR THE
FOURTH CHROMOSOME OF DROSO-

SURVEYING FROM THE AIR
PHILA MELANOGASTER
During the spring and summer of 1920 I

The article on “Surveying from the Air," secured genetic evidence that strains of D.

December 17, 1920, is a summary of the work melanogaster haploid for the fourth chromo- of the Coast and Geodetic Survey along the some had been produced by non-disjunction,

lines of aerial photography, and of necessity and in November cytological verification was

does not go into the requisite detail regarding obtained. The fact that non-disjunction of

the reasons for making the following statethe fourth chromosome is known to occur is

ment: perhaps the strongest reason for believeing These experiments proved very conclusively that that the aberrations observed by Dr. Little photographs from the air, using present-day equipmay be the consequences of non-disjunction. ment, are of little practical value to the hydroThe direct evidence presented by Dr. Little by

grapher. no means proves such to be the case, which is This statement has been noted by Mr. Willis unfortunate, considering the ample means in T. Lee, of the U. S. Geological Survey in D. melanogaster for checking up this hy- SCIENCE, February 18, 1921, who cites Comptes pothesis by means of other fourth-chromo- Rendus Tome 169, October 27, 1919, in which some mutants (bent, shaven) and especially by mention is made of experiments near Brest direct cytological examination. Probably Dr. where successful photographs were obtained Little will include such evidence in his forth- of the bottom at a maximum depth of 17 coming detailed report. For the present, his meters. published evidence is in better conformity During the experiments at Key West, the with the assumption of a less extreme eyeless results of which were the only ones then allelomorph, or of a dominant fourth-chroino- known to me, occasional successful photosome minus”

modifier. On the non-dis- graphs of the bottom were obtained in depths junctional view selective reduction of the of 35 feet and less. No attempt was made to three fourth chromosomes present is required, photograph at greater depths. When the conbut there is no obvious reason why E and e clusion regarding the “ practical value” of the 1 SCIENCE, 53: 167.

photographs was arrived at, all factors re

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garding their use for hydrographic purposes coast where enough land stations would apwere considered. Obviously, a comparison pear for control, but these areas are generally was made with the present-day methods of in bays or rivers where water is not clear hydrographic surveying.

enough for good photographic work. Buoys It may be argued that aerial photography or rafts may be used as control points, but is more rapid, because a photograph of more the cost and labor of handling them would than one square mile is made in a fraction of be excessive. A raft about 10 feet in diameter a second, and a strip 70 miles long and over would be needed in order to be legible on a a mile wide can be photographed in an hour. 1:10,000 scale photograph. The problem of There are several problems to be overcome by handling a large number of these floating both the aviator and the hydrographer before signals would require a good sized vessel and this can be done. Weather conditions along the sea coast are not as suitable for aerial The uncertainty of results is another factor. photography as might be expected. Let us The French have solved some of the problems see how the photographs as made by the by using the stereoscope, so that the confuFrench would apply to our waters. These sion, brought about by vari-colored bottom of photographs were made under the following uniform depth, is partly eliminated. Some conditions: Focal plane horizontal; altitude, shoals will show clearly, while others close by 2,600 meters; at time of low water; the sun do not appear in the photograph, probably due high above the horizon; calm sea. Along the to a difference in color or lighting. The coast of the United States, a calm day is gen- photographs will not record all shoals as seen erally hazy, so much so that it is impossible by the aviator. It is often necessary to fly to make photographs from an altitude of even over the same area repeatedly in order to ob4,000 feet without special treatment of plates tain good results. or films. We are aware of recent experiments Unless ideal conditions prevail, the cost of regarding the penetration of haze, but at the

an aerial survey with present-day equipment, time the Key West experiments were made, will far exceed that of a wire drag survey, little was known of this new process. Further and will not give as certain results. We bedevelopments may make it possible to pene- liove that aerial photo-hydrography is of some trate haze at altitudes of 2,600 meters. But

use in a few limited locations, and there are disregarding haze, those days that are calm

possibilities of future development, but at the and cloudless are infrequent. It is difficult

present date, revision work by photographs on to obtain data regarding meteorological con- land holds forth greater promise, and is one ditions as affecting aerial photography along

in which more certain results can be obtained. the coast, but from available data, it is ven

It may be of interest to quote a sentence tured that about one day a month would ful

from a letter dated January 10, 1921, from fill conditions as called for by the French,

Le Directeur du Service Hydrographique adand that is believed to be an optimistic esti

dressed to the Director of the Coast and Geomate.

detic Survey, in which the following stateRegarding control for the photographs, very

ment is made regarding aerial photography few places along our coast are as ideally fitted

along the coast of Syria in 1920. for control of aerial protographs as the area chosen near Brest. This locality is dotted

Les circonstances n'ont d'ailleurs pas permis de with numerous small islets, and ample control

l'employer systematiquement. (The circumstances could be obtained for each photograph. At

do not, however, permit of its systematic use). Key West, it was necessary to use boats as A careful analysis of the conclusion reached control points, so that the speed at which an in the article “ Surveying from the Air,” espearea was covered was limited to the speed of cially of the qualifying words

cially of the qualifying words “ using presentthe vessels. There are a few places along our day equipment," and "little practical value,"

will probably derive the result that the statoment is not as hastily worded as it was first thought to be.

E. LESTER JONES

SCIENTIFIC BOOKS Physics of the Air. By W. J. HUMPHREYS,

C.E., Ph.D., Professor U. S. Weather Bureau, Philadelphia. Published for the Franklin Institute by J. B. Lippincott Co., 1920.

Professor Humphreys states in his introduction that “it is obvious that an orderly assemblage of all those facts and theories that together might be called the Physics of the Air, would be exceedingly helpful to the student of atmospherics."

Of this there can be no doubt, and the author has rendered a great service by thus bringing together and making easily available material that otherwise would have remained scattered through technical magazines, official publications like the Monthly Weather Review and journals of organizations like the Royal Meteorological Society.

The volume had its inception in a series of lectures delivered by Dr. Humphreys at the San Diego Aviation School in 1914. These lectures revised and printed from month to month in the Journal of the Franklin Institute, 1917, 1918, 1919 and 1920, are now consolidated in one volume.

As late as 1917 our military authorities failed to appreciate the importance of a knowledge of aerography, that is, the structure of the atmosphere. In June of that year a high officer of the Signal Corps, at that time entrusted with aviation, wrote:

It has frequently happened in the past that men who might otherwise have made good pilots became so alarmed in advance over the subject of “holes in the airand so impressed with the terrible dangers of aerial navigation, that they never succeeded in gaining the necessary confidence to become good pilots, etc.

This was given as a valid reason for refusing to utilize recent advances in meteorology! And again :

So little time is available and so great the necessity for extreme haste in preparing aviators for service overseas that there is no opportunity to give more than the elements of meteorology in on or two lectures.

These views are referred to here, simply to show in some measure the amount of official inertia which had to be overcome. After many promising lives had been sacrificed, the need of the fullest knowledge possible was manifest; and before the war ended aerography had come into its own in both army and navy schools of instruction.

Professor Humphreys divides his treatise into four main parts; mechanics and thermodynamics; atmospheric electricity and auroras; atmospheric optics; and factors of climatic control. The author had the great advantage of access to the Weather Bureau Library, and critical readings by his colleagues. Furthermore, the text appeared in type before final publication. The work is unusually free from typographical errors.

There are a few slips, however. On page 49 the symbol for temperature of the isothermal region T might with advantage have been placed in front of the radical, or at least in some way separated more than at present. Again, it would be a gain if instead of saying that the temperature of a black radiator, in this case the earth, was 259° C. absolute, the author had used the more common form 259° A., adding if he thought it nécessary, in degrees C. It is desirable in a text-book to avoid confusion, by using consistent notation. The reviewer holds that it is not good form to speak of a given temperature as 259° C. absolute on one page and on the next page give a diagram expressing the same value in degrees Centigrade, that is, -14° C. One may expect to meet a slip from such loose practise and sure enough it

On pages 75 and 76 it is stated: The effective absolute temperature of the earth as a full radiator is approximately 260° C.

Rather a warm condition; but of course the author means that the effective temperature

a certain approximate absolute scale is

occurs.

on

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