274 



GEOLOGY OF THE SECOND DISTRICT. 



water, the contact of the two rocks is seen, when it appears tliat the former rocli has been 

 elevated and pushed through the latter, which was witiiovtt doubt borne upwards. 



But a point of greater interest, though only the same fact is revealed, is a place about 

 forty rods south upon the lake, which may be visited in a skiff, where this uplift of the chazy 

 limestone is still more distinct, being raised forty or fifty feet. On the south, the Hudson 

 river shales are not only bent upwards, but, at a plane along the line of junction, are crushed. 

 The annexed cut is introduced to illustrate what probably took place at the time of the uplift. 



70. 



when the whole or entire mass of the trenton and Hudson river shales were uplifted and 

 borne aloft as is represented in the figure. 



The illustration at the head of this article (fig. 69), is a plan of the present appearances at 

 the junction of the two rocks ; the Hudson river shales upon the south, and the Chazy limestone 

 upon the north. The plane of junction of both rocks is strongly marked, and finely polished 

 by friction and pressure, to which they were subjected at the time of the uplift. Scarcely 

 an instance has been observed in the northern district, which is more illustrative of the me- 

 chanical displacement of rocks than at this place ; and it is remarkable on account of the 

 limited area to which the uplifting force was applied, for here it extends in width only a few 

 rods, and the fracture is sharp and well defined on both sides, lifting directly upwards a thick 

 mass, breaking through the upper rocks, and leaving them each side in their places, but heav- 

 ing the lower mass high above, and there suffering it to remain. Almost the whole effect is 

 spent in this uplift upon a space but a few rods in length, but not entirely ; for upon the shore 

 north of this mass, we find that an oscillatory movement has been communicated, which has 

 left the rocks as represented in fig. 71. We find the strata broken off at intervals of about 



