CLINTON COUNTY. 
319 
which intervenes, never contains it. Orthoceratites are sometimes large and abundant. Very 
few, if any, of the Trenton fossils are ever found in it; hence it seems to be a mass more 
nearly allied to the limestones below, than to those above. 
Quarries of this marble might be opened at or near the landing at Chazy. The texture of 
this mass, if any thing, is finer than that upon the island, and might probably be worked to 
equal profit and advantage. 
Trenton Limestone. 
This rock, though well characterized in Clinton, abounds more in shaly layers than usual. 
It commences (taking the locality at Chazy as the type for description) with alternating 
layers of black limestone from two to four inches thick, and black shivery slate in almost the 
same proportion. The layers of limestone are somewhat thicker in a higher position; but, in 
general, such is the character of the whole mass, which is about four hundred feet thick at 
Chazy. Varying but little from the above, I found the same rock at and in the vicinity of 
Plattsburgh. The calcareous part is fine grained, and as beautiful as any of the black marbles, 
but it is very tough and difficult to break. 
In all respects excepting the amount of shale, the trenton limestone of Clinton maintains 
a uniformity of character, and in all respects agrees with the same rock at Trenton and 
Glen’s-Falls. The position it occupies geographically, is near the lake shore. At Chazy, it is 
farther west than at any other place from Whitehall to Champlain, and here it is only four 
miles. The probability is, that Lake Champlain now occupies the space which was once 
filled with this mass ; and that, being slaty and subject to disintegration, this rock has in a 
great measure been broken down and decomposed. On either side it remains, and also in the 
islands it forms the surface rock ; but the great mass, for one hundred and twenty miles in 
length, has disappeared. 
At Plattsburgh upon the shore of the lake, and at Cumberland head and the shores down 
to Rouse’s point, the trenton limestone is the surface rock. The upper part of the mass at 
Isle La Motte is also the same ; and we find it overlying the black marble, so justly cele¬ 
brated for mantel and other ornamental purposes. 
The fossils, wherever they occur, are similar to those at Trenton, as the Isotelus gigas, 
Calymene senaria, Orthis alternata, etc.; each of which abound at Plattsburgh and Chazy, 
Cumberland head. Grand Isle and Isle La Motte. For figures, see Jefferson county. 
The extent of this rock may be learned from the preceding localities, and the remarks already 
made. 
Utica Slate. 
This rock forms only a narrow belt in Clinton, and is confined wholly to the immediate vi¬ 
cinity of the lake : its exposures, too, are quite limited and unimportant. The only position in 
which it can be examined, is three or four miles southeast of Chazy, towards the lake. It 
presents nothing of sufficient interest to require even a passing notice. On Grand Isle, or 
