late there has been a tendency to deny altogether the validity of the homotactic viewpoint.

The question is vital in a consideration of past evolution, distribution, climatic conditions and paleogeography. It is also almost infinitely complex, and there are various underlying conceptions such as the rate of spread of different classes of organisms and the degree of cosmopolitanism reached by marine organisms during times of land emergence and of terrestrial organisms during times of submergence when the obverse records are largely wanting, that have a very important bearing. If the conditions, both geographic and topographic, which are predicted for the various Appalachian troughs or basins during Paleozoic time, are correctly interpreted, as there seems to be no reason for doubting, we are introduced to an environment which is special in the sense that it is not duplicated at the present time anywhere on the earth's surface so far as I can see. This being true the generalizations derived from the study of the overlaps and the rapid floodings of these Appalachian basins must be applied with great caution to other sets of conditions such as determined the broad seas of Jurassic, Upper Cretaceous or Eogene times.

If our present Coastal Plain margin were to take another dip beneath the ocean, would it be possible for the paleontologist of a million years hence to establish the synchroneity of deposits formed at the same time along our middle Atlantic and Gulf coasts or to differentiate these chronologically from such late Pleistocene shell marls as those at Wailes Bluff at the mouth of the Potomac or Simmons Bluff in South Carolina? I think it would be feasible, and am inclined to disagree with the universality of the statement (Ulrich) that for stratigraphic purposes the coarseness of the distinguishable chronologic units obviates the necessity of attempting to deal with the theoretically true time involved in dispersal. This may be perfectly true, however, of some of the Paleozoic transgressions over the base-levelled Appalachian troughs and also when dealing with marginal invasions around the borders of a single oceanic basin where the faunas have had time to become generally distributed.

Our conclusions usually do not rest upon irrefutable logic, however, and it is most important to determine by closer analysis the interlacing waves and ripples of dis

persal of animals and plants that have been going on since the beginning of life-as well as the rapidity of radiation of different types of organisms. Paleogeography will be on a far less speculative footing when it rests on proof and not on authority.

I do not believe that we can safely generalize with our present stock of accumulated knowledge. Take a theoretical case of a transgression and assume that the rate of change of level amounted to a foot a century, which I suppose would be considered fairly rapid, and that the submergence amounted to 500 feet, the time involved. would be 50,000 years. The Upper Cretaceous transgression represented by the Dakota sandstone and Benton involved perhaps twice as great a change of level, and disregarding any halts or oscillations of the strand it would still mean that 100,000 years were involved in the operation. Inevitably there would be changes in salinity and climate which must be reflected in the faunas. It seems to me that we must either admit a certain measure of validity of homotaxis in all except special cases or assume that the breaks between faunally distinct formations represent very great lapses of time. On the other hand changes in faunal facies in passing from a formation like the Onondaga to the Hamilton mean merely a change in local environment such as is, I imagine, responsible for most examples of recurrent faunas, so-called.

The question is also influenced by what the term fauna denotes. Does it mean the whole biota or only certain forms considered as typical. Certainly I should expect Belemnitella to spread more rapidly than the contemporaneous Exogyra, or an Echinoid more rapidly than a Pentremite. The varying vitality or organisms under adverse conditions, either as mature animals or in the larval state, is also a factor of great importance. Larval oysters are very intolerant under adversity while other sedentary molluscs have a much more hardy progeny. Another factor in distribution is the relative length of the free swimming larval stage in sedentary forms. There are wide limits of usage as to what characterizes a fauna and what are its critical members. Shall we rely on its more abundant dominant species, on the percentage of species common to another fauna of known age, to the first or the last appearance of certain forms, or shall we place the greatest weight upon the rarer short lived

types? It seems to me that no single rule of general application can be laid down. There should be no dogmatism! In general the broadly conceived species which are abundant, are long ranging and of less value than the perhaps rarer more restricted types. One type of organism may be much more valuable than another. I should regard the active Zeugledon of the open sea as a much more critical indication of Upper Eocene age than a dozen species of Mollusca. Similarly I should regard the sea lizards of the Upper Cretaceous or fishes like Pycnodus as of much more diagnostic value than species of Exogyra or Inoceramus. The wider removed the areas to be correlated, the more important are the geographically wide ranging and geologically restricted forms and the greater the importance to be attached to their initial appearance.

Progress depends on research, as even an outcrop chaser in Oklahoma would probably admit, but research is about as much abused a term as culture. Research to the neophyte at the university, particularly in current biologic and psychologic investigation, consists in "having a problem" and I often wish that the Board of Health classed "having a problem" along with other communicable diseases and would quarantine its victims.

True research does not depend on subject matter but on method and the invidious distinction and discussions of pure and applied science would have no point were it not for the pragmatic individuals, false and mercenary ideals and superficial Burbank methods that characterize so much of applied science.

I should wish to depreciate the tendency, rampant throughout the world, and accelerated by war conditions, to seek a justification for research as a means toward some economic end. If the elucidation of earth history and the origin and evolution of life on the globe are not of prime importance as ends in themselves; if the whence and the why and the whither are not supreme, then indeed has our lot fallen among evil days.

Research is, I suspect, a dangerous subject for discussion before a body of men the majority of whom are connected with a great Federal Bureau. There are so many very necessary and commendable public services crying for accomplishment, and there is so much justification for the pious wish to give the people what they think they

want, that it is not to be expected that the pragmatist and the idealist will contentedly lie down together like the proverbial lion and lamb, or that the Survey will ever lack for critics or defenders. Without posing as either may I not venture to hope that research will constantly increase in both quality and amount, and that the day will speedily arrive when a first rate paleontologist can command as large an income in the successful practice of his profession as he can in an administrative position.

I have, I fully realize, inflicted upon you to-night a few rather poorly articulated and in some cases trite illustrations. A large subject hastily presented always leads to half truths, unless elaborated in much greater detail, and I can only hope that those who follow me in the series will display a greater competence than I have done.

Johns Hopkins University,

Baltimore, Maryland.

ART. II.-Comanchean Formations underlying Florida; by E. H. SELLARDS.

During the latter part of 1917 the Florida Geological Survey received through the courtesy of Mr. H. B. Goodrich, a very important set of well samples from a deep well then recently completed by the Dundee Petroleum Company in Sumter County, Florida. Early in 1918 a few of the samples from this well, in which foraminifera were abundant, were forwarded by the writer to Dr. T. W. Vaughan of the United States Geological Survey by whom they were referred to Dr. Joseph A. Cushman. The foraminifera of these samples indicated, according to Dr. Cushman, the presence of Comanchean formations in this well. Subsequently Dr. Cushman undertook for the State Survey a study of the cuttings from some fifteen wells in Florida, and has now published the results of his study. The location of the wells from which samples were obtained is indicated on the accompanying sketch map (fig. 1).

In nine of the wells Comanchean fossils were recognized. These are numbers 2, 3, 4, 5, 7, 8, 11, and 15 as shown on the map. Numbers 6, 9, and 10, in which Comanchean fossils were not found, are shallow wells, from 113 to 190 feet in depth, terminating in the Eocene formations. Well number 12, at the north side of Lake Okeechobee, was represented by samples to the depth of only 500 feet; number 13, at Boca Grande, is represented by but one sample in which no characteristic fossils were found; number 14, at Ft. Myers, from which no Comanchean fossils were obtained, is represented by a series of samples submitted by the driller as representing the formations to the depth of 950 feet. Examining the results as a whole it is seen that fossils of the Comanchean formations were recognized in all wells of considerable depth from near Tallahassee in West Florida to Cocoa and Tiger Bay somewhat south of the center of peninsular Florida. In southern Florida these formations, although present as indicated by the well on the Florida Keys (well No. 15), lie at a much greater depth than in Central Florida.

Owing to the relatively small number of samples Fla. Geol. Survey, 12th Ann. Rpt., 1919.