290 GEOLOGY OF OHIO. 
The blue color, close, crystalline texture, frequent argillaceous depos- 
its, and regularity of beds, as well as the occurrence of Hamilton fossils 
through the whole of the Upper Corniferous, as described in the reports 
on the counties of Sandusky and Seneca, and more especially of Pauld- 
ing and Defiance, are indications that the Hamilton characters pertain- 
ing to the formation are confined to the upper thirty-five feet. These 
characters are very well displayed in the quarries at Delaware, Marion, 
and Sandusky, while the characters of the Lower Corniferous, as the 
term has been used by the writer, are seen at the quarries at Delhi, in 
Delaware county, and at Marblehead, north of Sandusky Bay. It is also 
well exposed in the creek blufts at Bellepoint, in Delaware county, al- 
though at that place the beds exposed he below the Delhi beds. 
The upper surface of these beds can be seen on the Olentangy, near 
Norton, on the land of J. B. Wyatt, Mary Wyatt, and of John Brundage, 
where they have been opened for building stone. They are also quarried 
near Waldo, in Marion county, in a similar situation, in the bed of the 
Olentangy. The only other undoubted exposure of the very highest 
beds belonging to this formation that is known occurs near Delaware, 
likewise in the bed of the Olentangy. It is mentioned in the section of 
is supposed by Prof. Winchell to be the rock specifically referred to as the probable 
equivalent of the Hamilton. In this he is in error, as the bed referred to as a possi- 
‘ble representative of the Hamilton in Delaware county is one described by Mr. Hert- 
zer as a light-blue marly stratum, containing concretions with fish remains different 
from those of the overlying Huron. It would seem from Prof. Winchell’s report that 
he has not encountered this deposit. His Olentangy shale, without some evidence 
to the contrary, 1 should regard, as he does, as merely a subdivision of the Huron 
shale. 
2d. The Tully limestone ? of Prof. Winchell’s sections is certainly Hamilton, as I 
have obtained from it Tropidoleptis carinatus, Pterinea flabella, Nyassa arguta, Spirifera 
mucronata, ete. That it is the equivalent of the Tully limestone is not indicated by 
any evidence yet obtained. 
3d. The relations of the limestone called Hamilton by Prof. Winchell—the equiv- 
alent of the ‘“ Sandusky limestone” of our reports—which I have considered a por- 
tion of the Corniferous group, is discussed in the remarks on the Hamilton group, 
Vol. L, Part. I., pp. 144-149, and in the report on Erie county, which forms part of 
this volume. By reference to the passages referred to, I think it will be seen that the 
weight of evidence is decidedly in favor of its being of Corniferous age. 
The cherty layers which lie between the Huron shale and the quarry-stone at Del- 
‘aware are probably Hamilton, but the quarry-stone itself, though containing some 
fossils which are common to the Hamilton and the Corniferous, has never yielded me 
any exclusively Hamilton fossils. Qn the contrary, I have obtained from it quite a 
iunaber of Corniferous species—such as Spirifera gregaria, S. inacra, Strophodonta hemi- 
spherica, Peutamerus aratus, which are never known to ascend into the Hamilton. 
a. 8. Ne 
