408 GEOLOGY OF THE SECOND DISTRICT. 



difference, though I am not able to state how extensive these differences are, and whether 

 they extend to the masses generally, or are merely local. The differences which I refer to, 

 consist in the dip of the rocks when stratified, and of the veins traversing them. Thus in 

 Canada the gneiss dips east, while in St. Lawrence and Jefferson county it is west or north- 

 west, leaving out of view local exceptions. The lead mine near Furnace falls dips south, 

 while the Rossie vein dips north. Such are a few particulars in which the geological pheno- 

 mena differ ; but as it regards composition, or the materials which enter into the formation of 

 the rocks, there are no essential differences. The trap dykes pursue courses varying but 

 little from an east and west course ; such is the fact in relation to the lead vein just referred to. 



The breadth of the sedimentary rocks on each side of the St. Lawrence is nearly equal ; 

 so that this river flows in a channel which seems to have been formed in the central part of 

 the beds ; not as usual near the edge of a formation, where the rocks are thinnest ; for there 

 can be no doubt that the route of this river was first determined by a fracture and slight uplift. 

 A light dip exists to the east on the east side, and upon the opposite side to the west. The 

 greatest depression is along the river, and at the termination of the calciferous and potsdam 

 sandstone. 



Other phenomena, which are strictly geological, correspond with those upon the east side 

 of the St. Lawrence. Thus the lakes are narrow, having their longer axis in a northeast and 

 southwest direction ; and like the rivers, their beds or channels appear to have been formed 

 partly by fractures in the rock, which were afterwards deepened by water moving with more 

 than ordinary force. We find, too, that they all belong as it were to one system ; that is, 

 they are parallel to each other. 



The breadth of the calciferous and potsdam sandstone on the St. Lawrence river is full 

 sixty miles, on a line passing east and west through Ogdensburgh and Prescott. On the 

 Canada side, tlie sedimentary rocks spread out much wider towards Bytown on the Ottawa. 

 The same fact may be stated in regard to their extension toward Hopkinton on the New- York 

 side, but here the form of the country is different. 



The preceding facts in relation to the geology of Canada are, I am sensible, exceedingly 

 meagre and barren of interest ; still they serve to supply a few items of geology, and give 

 some additional knowledge of the extension of the New-York rocks in an adjacent province. 



Gulfs of Loraine and Rodman. 



The term gulf is applied to several long, deep and narrow excavations in the rocks of Lo- 

 raine and Rodman. Tiiey are bounded by perpendicular walls of rock from top to bottom, 

 with but few places where the slopes are sufficiently safe for descent, or upon which it is 

 possible to ascend. Througli these long narrow deep passages the creeks of this region flow ; 

 in fact, they are but the channels which the creeks have worn for themselves in a shaly thin- 

 bedded rock, a large proportion of the layers of which are perishable from their composition 

 and structure. They terminate towards the west or southwest, just beyond the limits of the 



