248 Notice of the Ancram Lead Mie. 
the argillite begins to disappear, and Limestone interme- 
: : : 
iate between the granular and compact takes its place. 
As we proceed west it becomes finer grained and 1s evi- 
Some of the slate is glazed like that at Troy, N. Y. and 
ituminous shale. It is often regularly 
good samples of roof-slate. This 
but a small part of the hill. As we 
netrate the rock it becomes of a grayish white color, has 
a conchoidal fracture, and effervesces in acids. The sh 
and Limestone appear to be passing into each other, and 
the lime and alumine are in very nearly equal proportions. 
It might perhaps be called an Argillo-Calcareous Slate. 
The vein of Galena intersects the rock nearly vertically. 
At the surface it was not very thick but increased as they 
descended. The mine was worked 4 or 5 years when if 
was abandoned about a year since, as it was said, on ac- 
count of the scarcity of the ore. Several excavations were 
make an angle of 60° with the principal seam by which the rock is divided.” 
The same remarks will apply to the argillite of this region, as well as that 
of Albany and Renselaer Cos, as noticed by Mr. Eaton in his Index to the 
Geology ofthe Northern States. p. 172. 
