Devonian Era in the Ohio Basin. — Clay pole. 315 
must involve the destruction of miles of the eastern shore .de- 
posits and their contained fossils as above assumed.* 
In the Black shale overlying the Corniferous-Hamilton, i.e. 
the Huron, — were found the earliest specimens of that remark- 
able fauna which has rendered the Ohio shale a classic ground. 
Dinichthys, laid open by Hertzer's fracture of one of the great 
concretionary masses, which characterize this stratum, at once 
attracted attention, and though a few other species have come 
to light, it is not a little singular that nearly all the great num- 
ber of specimens found should belong to the original species — 
V. hertzeri — evidently the tyrant of the western gulf: though 
this fact undoubtedly proves that other fishes shared the ground 
with the monster and supplied him with food. The great mass 
of this bed, 300 feet thick, is however, yet unexplored, so that it 
would be rash to assume the scarcity of fossils everywhere. 
Mr. Hertzer's researches were almost entirely limited to the 
district around Delaware. 
But in the vast wilderness of the Erie shale, overlying the 
Huron, not the faintest trace of a vertebrate fauna has yet been 
found in Ohio. Correlating this as the extension chiefly of the 
eastern Chemung in which a moderate number of fossil fishes 
have been found, ( see table) this absence is a little surprising. 
It is true that other fossils are very scarce, but the same may be 
said, of the black shales above and below and the lack is there- 
fore scarcely explained. There is no obvious cause to be as- 
signed for the apparent barrenness in fossil fishes of the Erie 
shale or middle mass of the Ohio great shale, and it is bett< r 
to expect that the}- will yet be found than to explain what may- 
after all be merely a difficulty due to our imperfect knowledge. 
The Cleveland shale, or the upper black portion of the great 
shale, was long considered equally barren. But within the past 
few years it has yielded to the labors of a tVu earnest collectors 
one of the richest and most remarkable fossil faunas that are 
known from any part of the world or from any geological hor- 
izon. Messrs. Wheat, Filey, and Terrell, almost as it seemed 
by accident, became aware that this stratum in the region 
around the city of Cleveland contained fragments of fishbone 
• The marginal portions of these strata were, of course, omitted from my 
map of the Corniferous sea, as its insertion would be purely theoretical, and 
the same is true of the maps of the other strata. ( Reference* is here made to 
maps published in the Amekican Geologist.). 
