316 Geotogy of Lewis County. [June, 



them, are nearly horizontal; Taut in a few places they are consid- 

 erably inclined, apparently from the upheaval of the subjacent 

 primitive. One of these upheavals may be observed about three- 

 fourths of a mile northeast of Martinsburgh village, where the 

 strata lie in an anticlinal position, sloping to the south, west, and 

 north, from a hill of moderate elevation. The primitive rock 

 occurs near the foot of the terrace, only a short distance from the 

 hill, presenting the rounded summits usual in this region; and, 

 although the fact cannot be demonstrated, yet we may fairly infer 

 that such an elevation of the gneiss exists beneath the hill in 

 question, which has given the strata their present inclination. 



Another locality occurs about one mile northeast of the village 

 of Lowville, where the Eirdseye dips at an angle of about twenty 

 degrees to the south-west; and at the base of the hill the primi- 

 tive appears in an upheaved mass, sufficiently indicating the cause 

 of the disturbance in the stratified rocks above it. 



The terrace, which is composed of the rocks here described, 

 extends without interruption through the county, gradually be- 

 coming depressed towards the north, and having an average 

 breadth of half a mile. 



The Trenton Limestone is the next rock in the ascending series, 

 reposing directly upon the thick bedded mass which forms the 

 surface of the first terrace of limestone. In no place, however, 

 has the junction between the two rocks been observed, except at 

 the village of Lowville, in the stream at that place. At other 

 localities, where one would expect to find the two formations in 

 contact, the rock is concealed by deposits of drift. 



The Trenton rock is well exposed along almost every one of 

 the streams that flow down from the west, which have in some 

 places worn chasms of great depth in it, and present cascades of 

 singular grandeur and beauty. One of the most interesting of 

 these occurs on Deer river, about half a mile below the village of 

 Copenhagen, where the stream is precipitated down a very steeply 

 inclined surface, to the depth of about two hundred and seventy 

 feet. The ravine which the river has here worn in the rock, of- 

 fers one of the most suitable localities for the study of this forma- 

 tion and the collection of its characteristic fossils. 



The Trenton limestone forms the bed of the stream, for several 

 miles below the falls, and the whole thickness of the rock, as ex- 

 posed at this place, cannot be much less than three hundred and 

 fifty feet. 



The texture of this rock at its different depths varies but little, 

 being composed of thin shaly strata, alternating with films of 

 slate, and thicker and more compact layers of grey limestone, suf- 

 ficiently firm to be used for building, for which purpose the form- 

 ation, as a whole, cannot be considered suitable. 



