EURYPTERIDS FROM THE NORMANSKILL SHALE OF NEW YORK
After the foregoing discussion of the Frankfort shale eurypterids had been prepared our attention was directed by Professor G. H. Chadwick to similar remains which he had observed in the sandstones of the Broom street quarry at Catskill, N. Y. The only fossils heretofore known from the so called "Hudson River beds" about Catskill are the Normanskill graptolites, indicating horizons of Upper Chazy age,[1] and the presence of eurypterid remains in this early stage was a matter of so much interest as to justify a careful examination of the locality.
The lithologic and faunal conditions at the Broom street quarry exposure were found to be a singularly complete duplication of those of the eurypterid-bearing exposures in the bluestone quarries at Schenectady. The Broom street quarry is also a bluestone quarry, the rock being mostly used in the crusher. The courses of "bluestone" (here an impure argillaceous sandstone) are very compact, from 3 to 30 feet thick between the intercalations of black shales. There is distinct evidence of shallowwater conditions, one bed being conglomeritic and largely composed of pebbles, many of which appear to be mud pebbles; another beautifully exhibiting very regular, widely separated wave marks with winnows of comminuted seaweeds and eurypterids in the troughs.
Quite as in the bluestone quarries of the Schenectady beds, the surfaces of some of the sandstones are densely covered with rather poorly preserved seaweeds and eurypterids. It was therefore natural to expect that here too the black intercalated shales would contain better material
- ↑ In the body of this work the species from the Schenectady beds have been referred to the "Schenectady facies" of the Frankfort beds. Investigations since carried on by the junior author in the thick formation of sandstones and shales in the lower Mohawk valley, hitherto referred by all authors to either the Hudson River shale or the Frankfort beds, have shown that the faunal differences which induced us to distinguish the beds as Schenectady facies are of such nature that the whole formation has to be placed within the middle and upper Trenton. It will therefore in a forthcoming bulletin be distinguished as the Schenectady formation.
