II.—On a Case in which various massive Crystalline Rocks including Soda–Granite, Quartz–Diorite, Norite, Hornblendite, Pyroxenite, and different Chrysolitic Rocks, were made through Metamorphic Agencies in one Metamorphic Process

Abstract

The hornblendic and associated rocks referred to in the above title cover a large part of the township of Cortland—the north-western of Westchester County, New York—between Croton River on the south and the parallel of Peekskill on the north, an area of about 25 square miles. They differ widely from the ordinary rocks of the county, and may well be designated the Cortland series. In fact, a series so remarkable in constitution, so diversified in kinds, and so full of geological interest, is seldom found together within so small an area anywhere on the globe. They reach the banks of the Hudson just south of the Peekskill railroad station, and at several points beyond; yet considerable portions of the shore region are occupied by narrow strips of common kinds of mica schist and gneiss, and occasionally limestone.