324 
[Assembly 
The next rock in succession is the calciferous sandrock of Prof. 
Eaton, as its name indicates ; it is a sandstone, having carbonate of 
lime in sufficient quantity to effervesce with acids. It is well deve- 
loped at Chamont, and furnishes excellent blocks which are transported 
to Oswego for the public works. The upper portion may be the Mo- 
hawk limestone. It is a very durable rock, stands the weather re- 
markably, and is truly one of the most valuable building materials in 
the State. Where the series of rocks are complete, the next one in 
succession is the Birdseye. In relation to this, I am not fully satisfied 
whether it appears in Jefferson county or not. There is a limestone 
however which I have called the Birdseye between French creek and 
Depeauville. It is quite compact, breaks with a fracture somewhat con- 
choidal, but is destitute of animal remains. My doubts on this subject 
arise from not being able to refer to the specimens of this rock which 
I collected for illustration. In the rock which occurs between the two 
places just named, we have the first of the water limes. Before expo- 
sure to atmospheric agents, this rock differs very little in appearance 
from the Birdseye ; only it is not so compact and in some parts, is sandy 
and friable. On weathering, however, it turns yellowish and appears 
in contrast to the adjacent rock. It is entirely destitute of fossils of 
any kind. But the effect of the weather upon it, together with the 
presence of sulphate of strontian and calcareous spar, are characters 
sufficiently definite to distinguish it from other rocks in the vicinity. I 
have called this the water lime rock of Depeauville ; or Depeauville 
water lime, as it was at this place it was first prepared for use. 
There is a difference of opinion as it regards its value for water lime ; 
I conceive this to arise from a want of a proper selection from the rock 
for burning. Those portions which are sandy, contain evidently too 
much silex for mortar. Whenever, therefore, such portions have been 
used, there has been a disappointment. 
This rock has not been analyzed, but it probably contains silex, a 
little alumine and oxide of iron, in addition to the carbonate of lime. 
If I am right in the opinion just expressed, the Depeauville water lime 
occurs in beds, or overlies the Birdseye. Its beds are rarely more than 
10 feet thick at those places where it is quarried. The Birdseye ex- 
tends north to La Fargeville, preserving much the same character as in 
other places. It also at this last place contains a few important fossils 
which have not been examined. At this place too, the rock exhibits 
