LORAIN COUNTY. 211 
soapstone—with thin bands or flags of fine-grained sandstone. The 
maximum thickness of the Cuyahoga shale is something like 250 feet ; 
but as the upper portion has been removed from Lorain county, its thick- 
ness here may be estimated at 150 feet. This formation supplies com- 
paratively little that is of scientific interest or economical value. It 
rarely furnishes any good building stone, and is generally destitute of 
fossils. Its upper beds, however, yielded in Medina a very large num- 
ber of beautifully marked mollusks and crinoids, many of which are 
described and figured in our report. Fossils are also found in the bed of 
Black River, within the limits of this county. 
Berea Grit.—The Cuyahoga shale is underlain by the Berea sandstone, 
the most distinctly marked and economically important element in the 
geology of the county. Asit extends through a large part of Northern 
Ohio, and has been fully described in other portions of our report, no 
detailed notice of it will be required here. It contributes largely to the 
wealth and business of all the country it traverses, but its best and most 
valuable development occurs in Lorain county. Though varying con- 
siderably in thickness and character in different localities, the Berea 
grit is generally a rather fine-grained and homogeneous sandstone, lying 
in courses from a few inches to several feet in thickness, and varying in 
color from a light drab to a light blue or dove color. Its thickness ranges 
from fifty to seventy feet, and it forms a continuous line of outcrop, ex- 
cept where covered by superficial deposits. It enters the county from 
the east in the township of Avon, and its lower surface is exposed at the 
village of French Creek; thence it passes south-westerly to Elyria, 
where it forms the falls; thence sweeping around through Amherst to 
its most north-westerly outcrop in Brownhelm. As it lies so nearly ho ‘i- 
zontal, and has a thickness so considerable, the Berea grit is the surface 
rock over a very extensive area of the northern and central portions of 
the county, but it is generally overlain and c:ncealed by the Drift clay, 
even where it approaches very near the surface. As the Berea grit sup- 
plies perhaps the best building stone in the State, and one that is ex- 
ported to New York and Boston on the one hand and Chicago on the 
other, it has such value that its distribution, quality, and accessibility 
deserve to be carefully studied over all the region where it can be 
reached. I shall, therefore, refer to it again when I come to speak of the 
economic geology of the county. The exposures of the Berea grit which 
have hitherto attracted the most attention are those of the Amherst and 
Brownhelm ledges. These, as has been before stated, were undoubtedly 
once the shore cliffs of Lake Erie, when its waters stood much higher 
than now. They owe their prominence and relief, however, mainly to 
