78 ANNUAL REPORT 
at places where limestone is also found near by. The Bedford shale 
extends from Lake Erie down to the Ohio river. Starting from Cleve- 
land, Independence (Cuyahoga county), the shale extends south through 
Crawford, Delaware, Franklin, Fairfield counties, and is found to crop 
out in large sections at Waverly and Piketon. 
Sections of this material in Franklin county run about as follows: 
Berea Obits Ak ak oe scien cse ems eee 0 to 30 feet. 
Chocolates Bediordsshales eee eee 10 to 40 feet. 
Green olive Bedtord shalere. seco 0 to 20 feet. 
Calcareous Shales——Where shales are in contact with limestone or 
highly calcareous materials we are apt to find them rather high in calcium 
carbonate, which might run so high as to convert the shale into a 
hydraulic cement material, as is the case at Defiance, where the natural 
cement stone has a distinct shale structure. Larger areas of calcareous 
shale in Ohio are not known to the writer. 
Carbomferous Shales.—Vhese differ from the other shales in the 
fact that they contain carbonaceous matter varying from one or two 
up to 12 or 14 per cent. The most prominent shale of this type is the 
Huron shale, of Devonian age, lying on top of the great limestone beds. 
In color the shale varies from a black to a dirty green. The black shale 
is very hard, tough and almost non-plastic and resembles roofing’ slate. 
Where it has been exposed to the weather it appears as a yellowish clay, 
full of thin flakes of harder material. These pieces are often rusty brown 
on the surface and still black in the core. The lower green layers of the 
shale are much softer and contain much less, frequently almost no carbon. 
A piece of the black shale thrown into the fire burns for a few: 
minutes. Its carbonaceous matter consists principally of bitumen, which 
volatilizes readily and burns like a rich gas. The amount of this material 
is from 2 to 6 per cent. : 
The iron in this shale owing to the large amount of carbon present 
is, of course, all in the lower state of oxization, being present as ferrous 
carbonate or ferrous sulphide. 
This fact in connection with the large amount of organic matter 
makes this kind of shale exceedingly difficult to handle for the clay 
worker, though not interfering with cement making. While the bitumen 
is a great tribulation to the brick maker it would work beneficially to 
the cement manufacturer, inasmuch as the carbon would help burn the 
cement mixture}; making a considerable saving in the fuel) expense, 
provided, of course, that the chemical composition of the shale otherwise 
is satisfactory. 
The following is an analysis* of the black Huron shale, sampled at 
Columbus: 
**Ohio Geological Survey,’ Vol. VII, Part I, p. 188. 
