266 



GEOLOGY OF THE SECOND DISTRICT. 



TRANSITION ROCKS OF ESSEX COUNTY. 



Potsdam Sandstone. 



Having treated in detail of the primary rocks of Essex county, I proceed to speak of the 

 sedimentary deposits. By reference to the map, it will be seen that they occupy merely a 

 narrow belt along the shore of Lake Champlain. The uplift which elevated the great mass of 

 primary, broke off from the main mass of the sedimentary rocks merely their western edge, 

 producing thereby a solution of continuity between tiiose upon the west, and those which 

 lie upon the east side of the lake. Tiicse masses spread out and occupy a much greater 

 space upon the Vermont than upon the New- York side ; still, the latter are well worthy of a 

 careful examination. 



