0(5 
GEOLOGY OF THE THIRD DISTRICT. 
the dam, a more sandy and rather lighter colored mass is seen, holding a higher position, 
evidently the terminal part of the division in that region. This portion abounds in the Alter¬ 
nate strophomena, none of which, in any of the localities where the whole could be seen, was 
found below that position. The same ferruginous stains also mark the upper portion when 
greatly altered. 
The first locality in the Mohawk valley where the sandstone shale of Pulaski appears, is at 
Talcott’s and Comstock’s quarries about two miles to the south of Rome. About ten feet of 
the mass is exposed, the larger portion of which is good building stone, and is quarried for 
Rome. It is far more sandy than' any of its other localities, and its color is a light grey. 
It is not in regular or straight layers ; the divisions are caused by shale of the usual bluish color, 
either uniformly spread over the surface of the sandstone, but in patches of no great extent, 
or irregularly intermixed with it, and sometimes so thin as to be a mere coating. The fossils 
so characteristic of the division at Pulaski and other localities north and west of the Mohawk, 
are here extremely abundant; such as the Carinate pterinea, the different species of Cypricar- 
dites, the Alternate strophomena, the Ornated cyrtolite, and other testaceous fossils and some 
fucoids to be noticed in the Report of the fossils of the State. 
The Alternate strophomena occupies, as at Pulaski, the highest part of the mass. It is 
in very thin layers of sandstone, and with the same altered character as at the former place. 
Fragments of this division of the group are numerous in the enclosures of the field, for some 
distance from the quarries. 
To the west of Rome, extending north through Lewis county, the.Pulaski shale covers a 
large portion of the west side of the range of the Hudson-rivcr group, varying in breadth from 
four to six and more miles. Throughout its whole range its fragments are numerous, and 
usually show one or more specimens of its peculiar fossils. Among the many localities where 
the division may be seen to advantage, is the creek at Taberg village, and at the point of rocks 
on Fish creek, about seven miles above the village. At the latter place, it forms a bluff about 
twenty feet high, where two streams meet at an acute angle, and it is also found in the bed of 
the creek. Its range is rather to the east of the north branch of the Mohawk river, forming 
a low bank at Preston’s saw-mill, and appearing also in a well at Tuttle’s farm, to the north¬ 
east of the mill. 
In Lewis county, no localities were observed of particular note; it ranges to the west of 
the lower slates, appearing in numerous places along their range, and approaching nearer and 
nearer, going north, to the line of the Utica slate. On Deer river, about three miles to the 
west of Copenhagen, the shale and sandstone appears at Adcock’s mill, and contains Tortoise 
orthis, Semioval strophomena, etc. Where the road crosses the river from Rodman to Low- 
ville, seven and a half miles from Copenhagen, the Pterinea and other fossils of Pulaski are 
seen near the bridge. 
The most numerous points where the Pulaski rocks are exposed, are in the northwest part 
of Oswego county, where it forms the surface rock, and where numerous creeks and other 
water courses traverse its layers, exposing their surface and edges. Among these are Dem¬ 
and Little Sandy creeks, the latter being a good point for examination, both at Washington- 
