102 TRANSATIONS OF THE [FeB. 23^ 



structure. Either the gneiss is younger than, and has been 

 introduced into, the limestone, or else it is a metamorphosed 

 plutonic rock, which formed the floor of the sea in which the 

 limestone was deposited. The absence of anything like an 

 irruptive contact between the two rocks at once excludes the 

 first sui^position, and therefore the gneiss has been called, 

 without hesitation, the older rock. The second supposition, 

 which has been already mentioned, is somewhat favored by the 

 structural relations of the rocks. Regai'ding the foliation as 

 a secondary feature resulting from pressure, it would natiirally 

 be parallel to the folds of the limestone, which are due to the 

 same cause. The foliation may date from the same period of 

 metamorphism as does the folding, or it may have been complete 

 before the deposition of the limestone. But even in the latter 

 event, it seems probable that the pressure of the second stage 

 of metamorphism would act in the same direction as that of the 

 first, thus leading to a general parallelism between the foliations 

 of the gneiss and the bedding of the limestone. 



This view of the gneiss as a metamorphosed pkitonic rock 

 seems to afford the simplest explanation of the facts thus far 

 observed, but it cannot be accepted even conditionally until 

 sustained by much more extended investigation. That some 

 j)ortions of the gneiss will j^rove to be of igneous, and other 

 portions of sedimentary, origin, is extremely probable. 



Schists. — Near the base of the limestone and imbedded with 

 it are some peculiar schistose rocks, which outcrop near the 

 gneiss, north and south of Gouverneur, and again in the village. 

 These schists are variable in color, usually dark, and weather 

 to a rusty color. They offer greater resistance to denuding 

 agents than does the surrounding limestone, and, therefore, 

 form low, steep ridges. Containing feldsj^ar, quartz, biotite, 

 hornblende, and augite, they somewhat resemble igneous rocks 

 in composition, but their field relations indicate that they are 

 of sedimentaiy origin, and have been subjected to metmorphism 

 sufficiently intense to produce complete recrystallization. 



Sandstone. — Overlying the limestone is a heavy mass of sand- 

 stone, often so much indurated as to be better called quartzite. 

 The color varies from yellow to red, and the grain from very fine 

 to that of coarse conglomerate. The rock outcrops in prominent 

 ridges on both sides of the river, three miles north of Gouverneur^ 

 and extends several miles east and west, but was not traced to 

 a limit in either direction. It is composed chiefly of quartz^ 



