Geology and Mizeralocs, of a part of Massachusetts, &c. 19 
hills. It occurs also in New Ashford, Richmond, West 
Stockbridge, Egremont and Sheffield. It is more exten- 
sive along the ‘boundary line between the states of New- 
York and Vermont, associated with the limestone and mi- 
ca-slate, asin the county of Berkshire. The same stratum 
‘may be traced in a direct line from Williamstown over 
North West Hill, through Pownal and Bennington in Vt. 
On the west side of the Taconick range in the state of 
New York, this argillite is also abundant. See the ‘* Geo- 
logical and Agricultural Survey of Rensselaer County,” pa- 
ges 9 and 18,and Mr. Barnes’ “Section of the Canaan Moun- 
tain,” Vol. V. p. 11, of the American Journal of Science and 
Arts. This rock appears therefore to alternate with the 
western range of mica-slate, and talco-micaceous slate as- 
sociated with it. On the east side it can scarcely be con- 
sidered a continuous rock; at least it cannot be traced 
through the whole section. But on the west side, it ap- 
pears to be abundant and continuous, and to form a regular 
stratum. It extends farther south in this section than the 
county of Rensselaer, though I am not able to state its ex- 
tent at the south. : 
This argillite is found also in small quantities in the mica- 
slate in the eastern range of mountains. I have seen it in 
New Marlborough, and it is found in Plainfield, still farther 
east. 
This stratum of argillite has a shining aspect, and is very 
different from that along the Hudson river.* It is sometimes 
tortuous. In other parts its strata are easily divisible into 
large tables, forming roof slate. It is wrought extensively 
in Hoosack, Lebanon, and Hillsdale. 
the New Ed. Encyc. seems desirous of placing argillite as one rock by 
itself; but he acknowledges that organie remains have never been found 
in the older varieties of it, meaning the-argillite found in the rocks, gen- 
erally denominated primitive. With the same acknowledgment respect- 
ing some limestone, he appears toconsider it all as one formation. Surely 
this will reduce all rocks to one formation. 
* While Prof. Eaton is disposed to consider the argillite along the 
border of Massachusetts as transition, he says. however, that it is separated 
from that of the Hudson, ‘throughout the whole extent, by a continuous 
north and south range of well characterized metalliferous limestone ; and 
it agrees in ees with the European specimens of shining argillite.”” 
Geol. and Ag, Survey of Rensselaer County, page 10. 
