662 GEOLOGY OF OHIO. 
roads as to be inaccessible, though it cannot fail to be of value at some 
future time. 
The under clays of the unmistakable Sharon coal in Mahoning 
county, Massillon and Jackson, have nowhere been found valuable, so 
far as known. ‘The shales which overlie the Sharon coal in some places 
form in one instance the material upon which an immense manufacturing 
interest depends. The well-known Akron sewer-pipe is made entirely 
from these shales, which are not often used for such work. Their 
employment probably began in the use of the soft plastic clays of the 
out-crop, due to the decomposition of the shale. As these gradually 
failed, the less weathered material was called into use, until now the 
unaltered shale is the main reliance. It occurs in beds forty feet thick in 
some cases. It is cut by frequent joints, and is very easily mined. It 
lies just above the place of the Sharon coal. At Tallmadge this coal 
has been mined in close proximity to the shale pits. ‘The shales are in 
composition much like a silicious brick clay, having a large per cent. of 
iron which gives the cherry-red fracture found in all the Akron pipe. 
The potters’ clays of Springfield township, Summit county, are 
among the best natural beds of stone-ware clay in the State. They are 
referred a little doubtfully to the horizon of coal No. 2, or the Quaker- 
town seam, as the Lower Mercer limestone is formed about fifty feet 
above them. The clay deposits are from 6 to 10 feet thick, overlain by 
shales and a hard sandrock, and underlain by shales and occasionally by 
an inch or two of coal. ‘The clays are of several grades of excellence ; 
the poorest or ‘‘ chuck” clay, which is commonly rejected, is found on 
the top of the bed. The beds are found close to the surface in the largest 
part of the territory. They are mined by long pits or trenches by 
which the whole area worked is taken clean, and the refuse is piled 
back. In one or two instances the clays are mined by drifting, which 
gives a much cleaner product than the customary way. The district in 
which these clays are found is small, all the workings being at one place, 
viz., North Springfield, Summit county, where there are twelve or 
fifteen banks. They supply all the Mogadore, Tallmadge, Cuyahoga 
Falls and Akron stone-ware potteries, which make at least twice as much 
stone-ware as any other district in Ohio. 
The clays underlying the other coals supposed to be the equivalent 
of the Quakertown coal, notably the large coal at Wellston, Jackson 
county, have never been reported as valuable. 
