whole are omitted. One great advantage which this book possesses over most of its kind lies in the fact that organs are taken up in such sequence that one specimen should suffice for the entire dissection.

R. W. H.

III. MISCELLANEOUS SCIENTIFIC INTELLIGENCE.

1. National Academy of Sciences.-The annual meeting of the National Academy of Sciences was held in Washington, April 15-18; it was largely attended and full of interest. Professor Alexander Agassiz, elected President of the Academy a year since, presided during the sessions. The following gentlemen were elected members: William W. Campbell of Mt. Hamilton, California, George E. Hale of Chicago, C. Hart Merriam of Washington, D. C., William Trelease of St. Louis, Missouri, Charles R. Van Hise of Madison, Wisconsin.

The titles of papers presented for reading are as follows:

HENRY F. OSBORN: Evolution of the Titanotheres III; models and restorations. Homoplasy and latent homology. A correction. Evidence that North America and Eurasia constituted a single zoological realm during the Mesozoic and Cenozoic, and that correlations can be established as a basis for uniformity of geological nomenclature.

ALPHEUS S. PACKARD: Monograph of the bombycine moths of America, including their transformation; with a revision of the known genera. Part III. Sphingicampidæ.

ALEXANDER AGASSIZ: On the coral reefs of the Maldives. On the theory of the formation of coral reefs.

J. MCK. CATTELL: Psychophysical fatigue.

EDWARD L. NICHOLS: On some optical properties of asphalt.

CHARLES S. PEIRCE: The classification of the sciences. The postulates of geometry. The color system.

WILLIAM SELLERS: The compulsory introduction of the French Metrical System into the United States.

ASAPH HALL: The disintegration of comets.

IRA IBSEN STERNER: A new computation of the coefficients of precession and nutation.

E. C. PICKERING: The distribution of the stars. The variability in light of Eros.

H. P. BOWDITCH: The physiological station on Monte Rosa.

JAMES M. CRAFTS: On catalysis.

T. W. RICHARDS: The atomic weight of cæsium. The significance of changing atomic volume.

EDWARD W. MORLEY: Determination of the weight of the vapor of mercury at temperatures below 100.

ARTHUR SEARLE: Biography of Professor William A. Rogers.

HENRY L. ABBOT: Biographical memoir of General J. G. Barnard.

JOHN S. BILLINGS: Biographical memoir of General Francis A. Walker.

C. A. WHITE: Biographical memoir of J. S. Newberry.

S. C. CHANDLER: The present aspect of our knowledge as to the constant of aberration.

2. American Association for the Advancement of Science.The fifty-first meeting of the American Association for the Advancement of Science will be held at Pittsburg, Pa., June 28th to July 3d. In connection with this meeting Dr. I. C. White proposes to guide a party for a week in the study of the Coal

Measures, and Mr. M. R. Campbell will conduct an excursion to the abandoned channels of the Monongahela River.

3. National Bureau of Standards.-In Circular of Information, No. 1, S. W. STRATTON, Director of the National Bureau of Standards, announces the organization of the bureau and explains the work which it is prepared to do at the present time.

4. The Centenary of Hugh Miller. It is proposed to commemorate the 100th anniversary of the distinguished Scotch geologist, Hugh Miller, who was born at Cromarty, on the 10th of October, 1802. The committee having the matter in charge hope to secure funds sufficient to justify the foundation of a Hugh Miller Institute. Subscriptions may be sent to John M. Clarke, State Hall, Albany, N. Y.

5. Ostwald's Klassiker der Exakten Wissenschaften. Leipzig, 1900-1901 (Wilhelm Engelmann).-The following are recent additions to this valuable series:

Nr. 119. Versuch über die Hygrometrie (II. Heft 1783); von Horace Bènèdicte de Saussure. Pp. 170.

Nr. 120. Die Anatomie der Pflanzen (I. und II. Theil): von Marcellus Malpighi (London 1675 and 1679). Pp 163.

Nr. 121. Versuche über Pflanzenhybriden (zwei Abhandlungen 1865 und 1867); von Gregor Mendel. Pp. 62.

Nr. 122. Sechs Beweise des Fundamental theorems über quadratische Reste; von Carl Friedrich Gauss. Pp. 111.

Nr. 123. Einige geometrische Betrachtungen (1826); von Jacob Steiner. Pp.

125.

6. British Association Meeting at Glasgow, 1901. Discussion on the Teaching of Mathematics, edited by JOHN PERRY. (The Macmillan Co.) Pp. 101.-An exhaustive report of a full and thorough discussion contributed to by thirty-two of the most able and experienced educators of England. Any teacher of mathematics who feels himself in danger of dry rot should secure the book.

The two points brought out with special emphasis and unanimity are that the elementary notions of the Calculus and Analytical Geometry should be taught to school boys as early as formal Geometry and that England must get rid of the study of Euclid.

W. B.

7. The Basis of Social Relations; by DANIEL G. BRINTON, A.M., M.D., LL.D., Sc.D. Edited by LIVINGSTON FARRAND. New York: G. P. Putnam's Sons. Pp. 204.-At his death (1899) Dr. Brinton had this work approximately complete, and the editor has made only slight changes in it. The doctrine of the psychological unity of man is plainly stated and the variations resulting from physiological and pathological causes is explained in some detail (pp. 23-123). Part II deals with the Natural History of the Ethnic Mind and contains chapters on the Somatic Environment, the Social Environment, and the Geographic Environment. The book commends itself to the general reader and has an added interest in the fact that it is the last word of one of America's most distinguished ethnologists.

THE

AMERICAN JOURNAL OF SCIENCE

[FOURTH SERIES.]

ART. XXXV.-Fossil Faunas and their use in correlating Geological Formations*; by HENRY S. WILLIAMS.

[By permission of the Director of the U. S. Geological Survey.]

IT has long been the practice of geologists to recognize fossils as the best available means of determining the systematic correlation of geological formations. And in making correlations by fossils it is probably true that the degree of likeness, expressed by numbers of identical species, is taken in general as the measure of the contemporaneity of the formations compared. As a means of gaining a rough approximation to contemporaneity this principle may be safely followed. The geological systems may thus be recognized in different parts of the world, and from comparisons of the faunas of the Paleozoic systems it has been estimated by the writer that a later and an earlier, and in some cases a middle division of the grand systems, can be distinguished throughout the known world by this method of interpretation of identity of species into contemporaneity. The plan of restricting uniformity of correlation, in an international scheme of classification, to systems and divisions of the systems to be indicated by the prefixes eo-, meso-, and neo- to the system name, is based upon this calculation.+

When, however, the attempt is made to correlate formations on a firm basis, and to trace or estimate the limits of local formations by means of fossils, some more accurate method than mere identity of species is demanded.

The reasons for this conclusion are various; among which is the fact that very many single species, whose range has been

* Read before the Connecticut Academy, Feb. 12, 1902.

Journal of Geology, vol. ii, p. 157; Comptes Rendus, Congrès Geol. Internat., vii, cl and cli; Comptes Rendus, viii, p. 202.

AM. JOUR. SCI.-FOURTH SERIES, VOL. XIII, No. 78.-JUNE, 1902.

established by thorough study of the successive formations in which they occur, range through a third and often a half of one of the standard geological systems.

With such a long range for the life period, it has been in some cases established that the variation between the earliest and latest known representatives of the species is not greater than the variation among representatives of the same species found buried together in the same stratum of rock. Having established such long range and such long persistence of specific characters, and associated with plasticity of the varietal characters for a few well studied species, it seems reasonable to infer that simple specific identity cannot be taken as proof of contemporaneity within narrower bounds than the life endurance of the species.

A second reason for not resting implicit confidence on this method of correlation is the frequently observed fact, that parts of the geological column of different sections, which upon satisfactory stratigraphic grounds are known to be stratigraphically equivalent, contain different fossils. If two such faunas were to be observed one above the other, the difference in fossils would be naturally interpreted as difference in time, while the fact of stratigraphic equivalency proves their contemporaneity. Since the non-identity of fossils is consistent with contemporaneity, the reverse is to be inferred, viz: that identity of fossils may be consistent with non-contemporaneity.

A third cbservation also may be cited against the principle: In a continuous section it is often the case that the topmost beds of one formation are followed abruptly, but without apparent unconformity, by the next following formation containing a majority of new species.

The abrupt change in the fossils, in such a case, cannot be taken as evidence of the total stopping of the old fauna or of the beginning of the new, but rather as the result of a shifting laterally of the conditions in which the faunas have lived, across the locality in which the sedimentation was made.

It is thus shown that a sufficient amount of doubt is thrown upon the reliability of simple identity of single fossils in determining equivalency of stratigraphic horizon (except in a broad sense) to call for a discussion of some more accurate method of correlation.

In the following pages is given a synopsis of the results of a prolonged series of investigations directed toward the discovery of the true time element in fossil faunas. It will be assumed that the reader is familiar with the distinction between a stratigraphic formation (which is a more or less uniform lithologic unit, and constitutes the thing which is represented

on a geologic map by a definite color, and is defined and discussed in literature under a definite name), and a fossil fauna (which is the aggregate of fossil remains representing once living animals which were associated together at the time of sedimentation of the formation in which they were buried). The geological column is made up of the successive formations, which would be exposed by a vertical section through any part of the earth's crust. In common usage the geological time-scale is constructed by applying chronologic terms, like age, period, epoch, etc., to the several formations of the geological column. The reference of each formation to its proper place in the scale, is established not by lithologic likeness but by faunal likeness. So far as common usage goes, the epochs or ages are the time equivalents of the formations and not of the faunas by which the time relations of the formations are established.

Further, it is a generally accepted belief that each geological formation occupies a definite place in such a theoretical time-scale. This belief carries with it the further conclusion that, if we determine the limits (below and above) of a given formation in the rocks of a particular locality, the recognition of the same formation in another section (fifty or a hundred miles distant, for instance) carries with it the inference that the second section of the formation represents the same interval of geological time.

These are ideas that constitute the working hypothesis of field geologists everywhere; and, although they may be applied as general, and not absolutely exact rules, they are used pretty commonly in what is called correlation. For instance, when the statement is made that the Independence Shales of Iowa. are, or are not, equivalent to the Hamilton Formation,*-the meaning is that the formation which outcrops at Independence, Iowa, and specifically is named the "Independence shale," was, or was not, formed by deposition at the same time in which the Hamilton formation was forming over the area now called New York State.

Now the fact basis of that affirmation is not the recognition of the same constitution or thickness of the rocks in the two regions, but it is an opinion based solely upon the evidence of fossils occurring in the rocks.

The assumption, at the basis of the opinion, is that the fauna present in the rocks of the Hamilton formation represents a period of time which is recorded by the deposits of sediments called Hamilton in New York, and therefore that the same species seen in different regions can be relied on as evidence of the same portion of time.

* Iowa Geol. Survey, vol. viii, p. 205, etc., 1897.