1847.] Geology of Lewis County. 325 



of the Mohawk, and those who have traveled across that part of 

 Herkimer county which is known as the " Grant," may form a 

 just idea of their appearance. 



Minor accumulations of drift materials arc of constant occur- 

 rence throughout the county, forming gentle swells and conical 

 hills of small extent. 



The surface of the rock is in numerous places worn smooth and 

 scratched, by the materials of which these hills are composed be- 

 ing transported over them; and the direction of these rocks indi- 

 cate the existence of a current from the north-west. 



Usually a surface presents scratches in two or three directions, 

 which uniformly coincide with the general direction of the valleys. 



The transported materials form in some places a soil of clay, 

 in others of sand, but usually its quality does not vary materially 

 from that underlaid by the rock. 



The erratic blocks of stone every where frequent, are composed 

 of gneiss, hypersthene, chloritic slates, mica slate, primitive lime- 

 stone, specular and magnetic iron ores,* coarse serpentine and 

 epidote in disseminated grains. 



The relative abundance of these rocks is in about the same or- 

 der as enumerated. Besides these the lower transition rocks 

 occur as boulders, being in certain localities extremely abundant. 

 Local derangements of strata occur occasionally, which are to be 

 ascribed to the drift period. About three miles south of Copen- 

 hagen on the Number Three road, the Utica slate is highly and 

 irregularly inclined, w-ith masses of en-atic rock thrust under the 

 strata. Large masses are occasionally found torn up and resting 

 upon their edges, appearing to be on the site in which they were 

 formed.f 



The erratic rocks wherever observed, have very uniformly their 

 angles rounded as if they had been rolled for a great distance, and 



* An amusing illustration of the folly of some mining speculations occurred 

 in Martinsburgh in 1837, about the time when the mania for mining was at 

 its height. A portion of a large boulder of specular iron ore had been un- 

 covered, being, as was supposed, the top of a mine of untold extent A com- 

 pany with a large capital was to be organized, and nothing was thought of 

 in the neighborhood but stocks, shares, dividends, and the prospective pos- 

 session of fortunes, until a further examination dissipated the day dreams of 

 the proprietors by revealing the true nature of the deposite. The ore was 

 said to contain copper, and no small percentage of Gold! 



t A very singular instance of these disturbances exists in Jefferson county 

 on the " Rutland Hollow" road, about half a mile from where it enters the 

 State road towards Watertown. Here there occurs two or three isolated 

 hills, thirty feet high, which are composed of Trenton rock, laying in every 

 possible position, with their edges thrust up by boulders of gneiss, and witli 

 every appearance of having been exposed to the most violent torrents of wa- 

 ter, or masses of moving ice. The strata beneath the disturbance arc hori- 

 zontal. 



Vol. v., No. 14. 23 



