ROCK FORMATIONS OF THE WESTERN STATES. 
503 
of Delthyris, several of Atrypa, a Productus, and crinoidal joints in great numbers. A lime¬ 
stone holding this position among the coal beds is a very interesting circumstance, when taken 
in consideration with the absence of any limestone representing the Carboniferous of Europe. 
One species of the Delthyris , also, is very similar, if not identical with Sowerby’s figure of 
Spirifera attenuata; and the other fossils have all the aspect of those figured by Sowerby 
and Phillips from the Carboniferous limestone of England. A similar rock appears in the 
southern part of the State, where I obtained some of the same as fossils at Greentown. It also 
appears in several places in the vicinity of Canton. 
Passing to the south and west along the road to Columbus, we soon leave the Coal forma¬ 
tion, and come upon the groups below. These present few important features, except a 
gradual thinning in that direction, and the almost entire absence of fossils. The Chemung 
becomes scarcely'distinguishable from the Portage group, and both are known in the Ohio 
reports as the Waverly sandstone series. From beneath these, pass out all that remains of 
the Hamilton group and Marcellus shales, the whole known as the black bituminous shales 
of the Ohio reports, and possessing, as a whole, the character of the Marcellus shale of 
New-York. I was not so fortunate as to meet with fossils in any part of this mass examined, 
though they do occur in some places. This rock was traced nearly to Columbus ; and a short 
distance to the west of that place, the Corniferous limestone of New-York appears, presenting 
its characteristic fossils. This mass is the upper part of the Cliff limestone formation of Dr 
Locke, the name by which it is generally known in Ohio.* The localities where I saw this 
rock exhibited less hornstone than is usual in New-York, but the position and fossil charac¬ 
ters were unequivocal. 
After ascertaining the existence of the Corniferous limestone, and the middle and lower 
members of the Cliff limestone, for some distance west of Columbus, an offset was made 
into the coal region of the southern counties, and the line of observation again taken up on 
the Ohio river at Portsmouth. 
In following down the river, the limestones appear rising from beneath the shales, as re¬ 
presented in the section. Numerous localities are presented in the river bank and ravines, 
where the blue limestone exists in great force ; the most interesting, before reaching Cincin¬ 
nati, are in Adarns county, Ohio, and Maysville, Kentucky. An examination of the fossils 
at Maysville convinced me of the identity of the Blue limestone of Ohio, and the Hudson- 
river group of New-York. The evidences of this identity are the following: The mass con¬ 
sists of green shale or marl, alternating with courses of bluish crystalline limestone of a peculiar 
aspect, resembling that associated with the Clinton group of New-York, particularly the 
portion containing Pentamerus ohlongus. Thin layers of grey sandstone occur, sometimes 
separate, and at others attached to the limestone in wedge-form masses, and always containing 
a species of fucoid, which I had learned to consider a characteristic fossil in New-York. 
See Report on the Geology of the southwestern counties of Ohio, by Dr. John Locke. Ohio Geological Reports, 183S. 
