STATE GEOLOGIST. 141 



I. I.OWKK SILURIAN SY! 



3. Hudson River Group, (observed,) 18 feet: 



A ^illace< us liii, Blled with fossils in the upper 



part, L5 feet: N. side Drummond's Island. 

 Bluish" crystalline lim I,) 8 feet. 



2 Trenton Group, 

 (e) Dark blue, Bubcrystalline limestone, with 3 dark- 



green sren 1 North side 



Drummond's and 

 (d) Dull gray limestone, bard, eilicious, 2 feet. Ibid, 

 (c) Blue, argillaceou no, ( .) feotj Ibid. 



(b) Lin* lark, bluish gray, with partings of green 



ile, 12 feet: Ibid. 

 (a) Limesione, gray, eilicious, resting on quartz, 2 feet: Sul- 

 pha; aorth of Drummond's. 

 1. Lai Istone, (Potsdam), at the Sault, 18 feet 



Tot. d thickness of the Palaeozoic rooks, 1,725 feet. 



Actual thickness probably 2,500 feet. 



