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. As it 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 laflges. 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 o 



