340 GEOLOGY OF THE SECOND DISTRICT. 



sion in a saving form. I have not yet seen a specimen of trap, or a trap dyke, in the towns 

 I have mentioned ; and yet the rocks bear more of a phUonic character, than in the north- 

 easterly part of St. Lawrence county. 



Primary Limestone. 



« 



The range which this rock pursues, is mucli, if not entirely, the same as that of the granite. 

 Beds and vein;*, or rather distinct ridges, are common in Hammond near Grasse lake, pursuing 

 a northeast direction. They are found under similar conditions in Gouverneur, Dekalb and 

 Hermon. With but few exceptions, the primary limestone occupies the lower grounds, and 

 is projected up in low ridges. It is always coarse and friable upon the outside, or in a state 

 of disintegration, and ready to crumble and break in the hand. 



The largest beds of this rock are in Fowler, Edwards, Rossie, Hammond and Gouver- 

 neur, and in all it may be said to possess the same characters. 



In the general account of the rocks of the Second district, the view which we are to take 

 of this rock is detailed at length. It was my object in those details to present the facts which 

 bear upon the two questions mainly of its stratification and origin. How far those views are 

 supported and sustained by facts, the reader is at liberty to judge for himself; but it seems 

 to be impossible to regard it in any other light than as an unstratified rock, and as of igneous 

 origin, or a plutonic rock — one analogous to granite. Additional facts bearing upon this 

 point might be gleaned from various sources ; but as the most important appear to be already 

 given, accompanied with illustrations, I deem it inexpedient to occupy farther time and space 

 upon this subject. There is, however, one locality, though removed from all travelled routes, 

 at which limestone lies between layers of gneiss. This is in Depeyster, or the western part 

 of Dekaib, at the Osborn lake. The mass lies in parallel planes, between strata of gneiss. 

 It is the coarse kind, and diifers in no respect from that associated with granite ; and thougli 

 the rock in which it lies is distinctly stratified, this mass of limestone is as far removed from 

 stratification as the beds of the same rock at Gouverneur. This limestone was exposed in 

 searching for lead, during the lead mania. I found it contained small particles of pyritous 

 copper, yet no lead, nor any mineral substance of value. 



Gneiss and Hornblende. 



The remarks which liave been made in regard to the passage of granite into gneiss, apply 

 with more force to the region of Gouverneur, Hammond and Edwards ; but towards the 

 northeast, they do not apply so well. It is here that hornblende, as a rock, becomes more 

 associated with gneiss, and forms with it the surface rock. 



A very large proportion of the county, however, is not in a condition to be examined with 

 satisfactory results ; and as is the case in Essex, more than one-half of the territory is a 

 wilderness, or covered with forests. Even in those towns whicli are considerably settled, 

 there are many obstacles to impede examination even on foot. This, with other reasons 



