254 
[Assembly 
It is thought probable that the ores may prove more abundant, and 
richer in lead, when the workings shall have reached the slate rocks 
that underlie the grit, but as the vein does not dip at a much greater 
angle than the strata, it is not probable that these rocks would be reached 
in this mine, without penetrating to at least the level of the valley, or 
500 to 700 feet below the present workings. 
The lead ore of this mine contains some silver, but I have not ascer- 
tained the proportion. I cupelled a few grains of the lead obtained 
from some of the ore. A small but distinct globule of silver remained. 
Prof. Beck, of the mineralogical and chemical department of the Geo- 
logical Survey, has since cupelled some of the ore and obtained silver.* 
Whether it exists in such quantity as to make its separation a matter of 
importance is not ascertained. 
Pyritous grit. 
In some places, the upper strata of the Shawangunk grit, are more 
or less loaded with pyrites. Occasionally this mineral forms a large 
portion of the rock, constituting the gaiigue, in which the pebbles and 
finer grains of silicious matter are embedded. Boulders of this variety 
of the grit rock were observed scattered over the country in the 
counties of Orange and Ulster, southeast of the Shawaiigunk moun- 
tains, and boulders of precisely similar appearance and com.position 
were seen on Long-Island near Sand's-Point, and in other places. 
A locality of this pyritous grit was examined south of Rochester, 
Ulster county, where the rock contained pyrites, and had been reputed 
to be a silver mine. A small excavation had been made. The only 
use to which it could be applied would be the manufacture of copperas; 
but it is not sufficiently abundant there to warrant any expenditure. 
This locality is near the base of the Shawangunk mountain, and one 
fourth of a mile south of the Mule kill, in the township of Rochester. 
Red rock of the Shaioangunk group. 
A stratum of red rock has been mentioned as lying on the top of the 
Shawangunk grit. It is observed covering it in several places, but it 
is usually thin, and varies in texture from a compact hard red grit, to 
a red crumbling shale. The former may be seen in crossing the moun- 
tain between Bloomingburgh and Wurtsboro, about one fourth of the 
* Vide Assembly Document No. 275, for 1839, p. 51. 
