Devonian Era in the Ohio Basin. — Claypolc. 85 
In order to attain the utmost certainty and exactness on the 
points involved the greatest caution and the most searching 
criticism of the arguments are necessary, and no one would 
more readily admit this than their author himself. And, in the 
further treatment of the'subject, the present writer does not 
claim the position of a critic of professor Williams, but merely 
that of a fellow-worker in the same field, where the only pur- 
pose of all is the discovery and establishment of the exact 
truth. 
With this view the following points seem worthy of con- 
sideration, of which some may be construed a^ in favor of and 
some in opposition to professor William's theory. The latter 
may be only difficulties which further study will remove. 
1. In writing of the northeastern uplift, of which mention 
has been made in a preceding section of this paper, professor 
Williams remarks:* 
"This Leptoccelia fauna extended northeastward as far as Acadia. 
There was evidently a barrier already separating the European sea 
from that of the Appalachian area and the connection with the South 
American faunas was by the southwest. It was as early as the age of 
the Oriskany that the separation of the typical southern from the typi- 
cal northern faunas took place." 
The present writer has assigned the separation of the Appal- 
achian area from the northeastern and probably from the Euro- 
pean region ro a somewnat later date, probably during or at the 
end of the Corniferous period. That some elevation in some 
part of eastern and northeastern land took place in the Oriskany 
period is rendered certain by the existence of the sandstone. 
But the continuance, though in a lessened degree, of the pre- 
vious strong Silurian-European aspect of the fauna is most eas- 
ily explained by admitting the persistence of the old channel or 
channels of whose existence in earlier days little doubt has been 
entertained. 
Moreover this i- the readiest way also of explaining the oc- 
currence of Oriskany fossils such as Rensselaeria ovoides, at 
Gaspe. It would also be difficult, on the supposition that the 
channel was closed in the Oriskany period, to account for the 
presence of a typical Appalachian Corniferous fauna far up in 
* Loc. Cit., pp. 165, 10s. 
