316 EDWARD M. KINDLE 
Wabash valley —The Devonian limestones of the Wabash area 
are differentiated both faunally and lithologically into two divisions, 
as in the southern part of the southern Indiana area. These two 
divisions are correlated respectively with the Sellersburg limestone 
and the Jeffersonville limestone. The Sellersburg formation of the 
Wabash area contains a Hamilton fauna. It varies from a bluish- 
drab limestone breaking with subconchoidal fracture to a dark 
Remeetere L/S (gi ea ee ae) IL 
SZ a a EN 
MeaG Oe 35 535 = 2 ]O YOOWSSsssSs5) 
ple Gal ; 
i 
Fic. 7.—Irregular contact line between the Devonian limestone (B) and the 
Silurian limestone (A) on the bank of the Wabash River, Georgetown, Ind. 
argillaceous limestone. Spirifer pennatus is the most abundant 
and generally distributed species. 
The formation corresponding to the Jeffersonville limestone 
at the Falls of the Ohio is a gray crystalline, thin to heavy bedded 
limestone. This limestone carries a fauna similar to that of the 
same formation in southern Indiana, and has as one of its most 
characteristic species Spirifer acuminatus. This limestone is 
unconformable with the Silurian limestone on which it rests. 
In the other areas in which the stratigraphic break at the base 
of the Onondaga and its western equivalents has been discussed 
