CHAMPLAIN DIVISION. 
417 
approaching the calciferous slate. Some of it has a ribbon-like appearance^ the laminae of 
light and dark grey alternating in the layer. A locality, nearly similar, may be seen at Bell- 
vale, on the land of Mr. Wilson. At this place some of the layers contain but little lime, 
and approximate closely in appearance the calciferous sandrock of Prof. Eaton.”* 
Slaty Limestone. 
A slaty limestone is associated with the slate rocks, which, without close inspection, would 
be passed over as a slate. It is an argillaceous limestone, so marked in its characters, so 
constant in its appearance, and contains the impressions of what are supposed to have been 
a species of fucoid that has not been seen in any other rock in the series, that it is a great 
aid in tracing the strata. It enables us to demonstrate the breaking up of the strata. 
This peculiar rock has been found in the successive ranges of hills, and in the same order 
of superposition with all the strata in each, and dipping in the same direction. In some 
places this material may be usefully employed for hones. I have used it for setting a fine 
edge. It has been used as a flagging stone and coping stone, and is well adapted to these 
uses. It is easily split out in smooth slabs. It has been observed in a great number of 
places in Washington county in its southern part, from the western to near the eastern side. 
It may be seen well characterized at Centre falls on the Batten kill in Greenwich ; also near 
Battenville ; on the road from Cambridge to Union village ; on the road from Cambridge to 
Battenville ; on the road from Reed’s mineral spring to Argyle corners, at some quarries, and 
in other places ; near Cambridge centre; one mile west of Hebron ; four miles southwest of 
Hebron ; at Hartford lower village ; between North-Granville and Middle-Granville in several 
places, as at the falls, one mile above, one-fourth of a mile northeast, and at Middle- 
Granville. 
The rock, when long exposed, is grey on the exterior, and the fucoidal marks imperfect. 
I examined many specimens before I was fully convinced that the markings were from 
organic bodies.f The fresh fractures of the rocks shows a slight mottled appearance, as if 
the carbonaceous matter of the fucoid had penetrated into the mass below and above the place 
where the impression remains. 
This rock is almost uniformly found near the Calciferous sandstone, with a thickness of 
from forty to sixty feet of slate intervening. 
• Third Annual Geological Report of New-York, p. 150. 
t The Rev. Mr. Newton of Cambridge, who is an ardent admirer of geology as a science, and who is an active and useful 
laborer in geological instruction and observation, first called my attention to the fucoidal impressions in this calcareous slate near 
Cambridge, and I have to express my thanks for his kind cooperation in aiding my investigations in the south part of Washington 
county. 
Geol. 1st Dist. 
53 
