lake, where the serpentine, associated with pyroxene, has been reported to contain Eozoon.

Farther reference was made to phenomena observed at an apatite mine near Côte St. Pierre and at limestone outcrops in that vicinity, in the dolomitic beds of Warren, New York and Westchester counties, N. Y., and in certain limestones of Orange Co., N. Y., and of northern New Jersey.

Specimens of the rocks and photographs taken in the field were exhibited to illustrate the observations made at most of these localities.

NOTE ON THE INTIMATE RELATIONS OF THE CHEMUNG GROUP AND WAVERLY SANDSTONE IN NORTHWESTERN PENNSYLVANIA AND SOUTHWESTERN NEW YORK. By Prof. JAMES HALL, State Geologist of N. Y., Albany, N. Y.

[ABSTRACT]

THE general relations of the Chemung and Waverly groups are very well understood by geologists at the present time, but I am not aware that the absolute limitations of these groups at their junction has been fully shown, either by their physical or palæontological characteristics.

Those who have studied the Chemung group in its palæontological aspect regard the presence of Spirifer disjuncta S. Verneuili, as marking its uppermost fossiliferous beds, and the presence of this fossil as reliable evidence of the age of the formation. All the investigations in southwestern New York, made by the writer, have hitherto failed to show the presence of the Waverly sandstone above the Chemung. Some of the conglomerates-as that of Panamahave sometimes been paralleled with the Waverly or Marshall group, and therefore regarded as of Carboniferous age. A more critical study of the fossils of these conglomerates has proved them to be of Chemung age, and their position in the upper member of that group.

In following the Chemung group in its exposures from Panama to the southwest, and beyond the limits of New York, we find the higher members to consist of a bluish shaly sandstone containing great numbers of separated valves of Spirifer disjuncta, which bear evidence of having been drifted and worn before em

bedding. Associated with these water-worn and separated valves of Spirifer are shells or casts of Ptychopteria not dissimilar from the species abundant in the conglomerate of Panama.

Succeeding these fossiliferous beds comes a gray or bluish gray fissile shale, which graduates into a stronger dark colored or nearly black shale above. This shale, as exposed in a railroad cutting, presents a thickness of about thirty feet, but as no rock could be found above it, its entire thickness is unknown. Throughout the whole thickness examined it is totally barren of fossils of any kind-so far as observed—and its relations to the beds below are apparently only those of superposition. A careful examination of the country for some miles to the south and southeast of the locality mentioned failed to show any succession of beds above the dark barren shales.

This knowledge of the upper fossiliferous member of the Chemung group, and its relation to the non fossiliferous beds above, has been possessed for many years, but we have had no positive knowledge of the character of the strata or of the direct succession above this horizon until the present time. During this season Mr. C. E. Beecher of the N. Y. State Museum of Natural History has made an examination of the strata in the neighborhood of Warren, Penn., and with the information thus obtained, together with previous knowledge, he and Mr. F. A. Randall have constructed the section here presented to the association.

The section exhibits about 1500 feet of the upper members of the Chemung group, terminated by the barren shales and flags which correspond to those already described, and lie above the Spirifer disjuncta beds.

The first fossiliferous beds above these barren measures contain Crinoids, Syringothyris and Productus, but no specimens of any form of Chemung Spirifera has been found.1

1 The accompanying generic list comprises the larger number of forms thus far known in this horizon. With our present knowledge it would be fair to assert that we have at Warren more than fifty genera and at least 200 species in the Waverly group between the Chemung barren measures and the Garland conglomerate.

In the succeeding beds, in the ascending order, the fauna assumes a more and more carboniferous aspect, leaving no doubt as to the proper reference of the beds of this horizon.

In the upper part of the conglomerate, and in the sandstones above it, the fossils are chiefly of land plants of the genera Lepidodendron, Sigillaria, Calamites, Halonia, etc., of large size and abundant in specimens.

The absence of the Catskill group or any beds which can be referred to that horizon is very significant.

Without any apparent want of conformity, the Waverly group follows the Chemung, but we know that at the point in the Section marked+"Place of Catskill" there is a hiatus which, in eastern New York and Pennsylvania, is marked by the presence of measures having a thickness of from 3000 to 5000 feet. Therefore we have a right to conclude that there has been a long interval in time between the final deposition of the barren Chemung shales and the fossiliferous Waverly sandstone, or that the deposition of the estuary Catskill sediments has been going on simultaneously with the open sea deposits of the Waverly formation.

The results of these investigations, and the study of the fossils of these formations, have shown that there exists no conspicuous physical line of demarcation between them, and that the only reliable means of distinguishing them, lie in the careful study of the palæontological features of the two groups.

The entire section is too large and elaborate to accompany the present paper, but the principal features representing the strata under discussion are here given.

2 It may be mentioned that fragments of the shells of Spirifera disjuncta, and some other fossils, have been found in these shales near Warren, Pennsylvania.

NOTE ON THE EURYPTERIDE OF THE DEVONIAN AND CARBONIFEROUS FORMATIONS OF PENNSYLVANIA; WITH A SUPPLEMENTARY NOTE ON STYLONURUS EXCELSIOR. By Prof. JAMES HALL, State Geologist of New York, Albany, N. Y.

THE presence of fossils of this family in the Devonian and Carboniferous formations of the United States, is of such rare occurrence that the fact is worthy of especial notice; and although the descriptions have already been published, the information may not improperly come before this association.

Although several species of this genus have been described from the Carboniferous rocks of Europe, the first published notice of Eurypterus from this system in America was given, under the name Erypterus (Anthraconectes) Mazonensis by Messrs. Meek and Worthen in 1868. In 1877 Mr. Charles E. Hall described a species from the lower Carboniferous rocks of Venango county, Pennsylvania, E. Pennsylvanicus, and another form from the coal measures of Cannelton, Pa., E. (Dolichopterus) Mansfieldi.

An examination of all the specimens proves these species to belong to the genus Eurypterus, presenting the generic form and structure, without any variation of sufficient significance to require sub-generic distinction. A critical examination and comparison of the specimens received from the geological survey of Pennsylvania has led me to the conclusion that three distinct species may be recognized from the coal measures, and a fourth species from the lower beds of the carboniferous system.

The single species from the Chemung group at Warren, Pennsylvania, is the only one yet known from the Devonian rocks of the country. This form is more compact, the swimming feet stronger, and the articulations less extended at their extremities, than those of the carboniferous horizon.

The geological range of the genus, so far as at present known, is from the Clinton group, where we have an unpublished species (E. prominens), to the Coal measures. Taking the Water-lime forms as typical of the genus, the only marked differences between these and the coal measure species are the comparatively greater elongation and more slender forms of the latter. The swimming feet and limbs, the operculum, and the mesial appendage, are similar in character. The segments of the body in the later forms