180 
GEOLOGY OF THE SECOND DISTRICT. 
But few localities furnish fossils, and the only one of much importance in the Second 
district is at Chazy, Clinton county, where the upper part of the rock contains them in great 
numbers. They will be given when the geology of that county is taken up. 
The order in which the sedimentary rocks of Warren county occur is exhibited in the sec¬ 
tion which extends from Glen’s-Falls four and a half or live miles northeast, to the junction 
of the Potsdam sandstone with the Primary system. 
54 . 
In the vicinity of c, two or two and a half miles from the falls, the surface has been deeply 
abraded and worn, and upon it many primary boulders have been deposited ; beyond this is 
a great accumulation of sand and boulders, principally of Potsdam sandstone, which have been 
derived from the mass immediately beneath. In this respect, there is a great uniformity 
adjacent to all our primary ranges. Near the line of junction between the two systems of 
rocks, we find numerous boulders arranged somewhat in regular lines, together with rounded 
hills composed of sand and gravel. But to return to the consideration of the calciferous 
sandrock, I remark that its thickness cannot be well determined at the falls, inasmuch as it 
is not fully disclosed ; but judging from the presence of the more siliceous layers, it may be 
estimated at about seventy feet. 
This rock has been extensively quarried for the locks of the canal. It is found to be a 
durable material for this purpose. It has the advantage of other masses belonging to this 
group, in being a firm thick-bedded rock. It is very tough, and little liable to break; and 
such is its texture, that it may be quarried with gunpowder, or receive severe concussions by 
other means, without producing cracks or flaws. In consequence of its composition, being a 
mixture of earthy matter with carbonate of lime, it weathers unequally; the calcareous part 
being more rapidly acted upon, it leaves the siliceous portion standing out in a rough surface. 
It has in consequence an unseemly appearance before it is dressed. 
The mineral substances of this rock appear to be confined to a small quantity of sulphuret 
of zinc, the particles of which are but little larger than peas; they are disseminated in the 
rock, without showing any tendency to form veins. The locality is a mile or two northeast 
from Glen’s-Falls. 
