184 
The Ohio Naturalist. 
[Yol. VII, No. 8, 
THE DEVONIAN LIMESTONES OF CENTRAL OHIO AND 
SOUTHERN INDIANA. 
Clinton R. Stauffer. 
A comparative study of the two regions, lying on opposite 
sides of the Cincinnati island, shows that there is a remarkable 
similarity between the Devonian limestones of central Ohio and 
southern Indiana. This is perhaps more evident from a litholog¬ 
ical point of view although the paleontology of the formations 
of the two places is very similar and the stratigraphic arrange¬ 
ment is identical. 
These deposits in Ohio have been divided into the Columbus 
and Delaware limestones. The Columbus presents two very 
different lithological phases which are persistent throughout the 
state. In southern Indiana Dr. Edward M. Kindle has recog¬ 
nized three distinct formations, the Geneva and Jeffersonville 
limestones and the Sellersburg beds, 1 the latter including the 
Silver Creek hydraulic limestone of some authors. 
The lower of these Indiana formations, stratigraphically, is 
the Geneva limestone which “is generally a massive light buff to 
chocolate brown saccharoidal magnesian limestone” in which 
“fossils are extremely rare at most locations and occur usually 
as casts when found.” 2 It thins out toward the Ohio river 
but may be seen in the vicinity of Charleston, along the hill above 
the “Lick” and at the road side east of town. 
In Ohio the lower thirty-five to forty feet of the Columbus 
limestone answers admirably to the above description. It is 
usuallv a porous brown limestone high in its- percentage of mag¬ 
nesium carbonate. The bedding is irregular and frequently 
almost wanting. Oblique jointing, although not necessarily 
characteristic, is common. It contains but few fossils all of 
which are usually but poorly preserved, existing mostly as 
moulds with occasional casts. Bituminous matter is also usually 
found, either as thin films between layers or within the rock 
itself causing an irregular banding. Pockets of calcite crystals 
are often found and occasionally some gray chert. 
The upper sixty-five or seventy feet of the Columbus lime¬ 
stone is usually a crystalline gray limestone high in its percentage 
of calcium carbonate. It contains great numbers of excellently 
preserved fossils and considerable gray chert which is also quite 
fossiliferous. The limestone occurs in even beds which vary from 
comparatively thin to massive layers. The lower part of this 
1. Twenty-fifth Annual Report of the Department of Geology and 
Natural Resources of Indiana. (1900), pp. 533-536. 
2. Ibid. pp. 535, 536. 
