212 GEOLOGY OF OHIO. 



the fact that the rock which composes them is more massive than that 

 which connects and surrounds them. Hence, in the erosion to which 

 this region has been exposed, these harder and more massive portions 

 have best resisted the denuding action, while the softer rocks have been 

 more deeply cut away. The light and uniform buff of the Amherst 

 stone is undoubtedly due to the *act that these elevated cliffs, being 

 freely drained, have been traversed by atmospheric waters, so that the 

 iron the rock contains has been thoroughly oxidized. In localitie 

 where the stone is beneath the water level, or is covered with a consider- 

 able thickness of clay, it will be found to Have a light blue color, as at 

 Berea. This is well illustrated by the recent workings of the Amherst 

 quarries, in which a stratum of very fine-grained, homogeneous blue 

 stone has been found beneath the lighter beds, and where the rock was 

 imperfectly drained. This variety is called Blue Amherst, and is very 

 handsome and highly esteemed. 



No fossils have been found in the Berea grit of Lorain county, so far as 

 I am informed. It has, however, yielded many interesting fossil fishes 

 at Chagrin Palls {Palseoniscus Brainerdi), and some fish spines (Ctenacan- 

 thus formosus) , and a large Lingula at Berea, so that something of the kind 

 may be looked for in the quarries of Lorain county. 



Bedford Shale. — Below the Berea grit comes in the Bedford shale, and 

 this is exposed in all places where the sandstone is cut through. In 

 Lorain county the upper part of the Bedford shale is generally red, and 

 this will serve as a convenient guide in future explorations made in 

 search of the Berea grit, it being understood that the only red shale in 

 the county lies immediately beneath the sandstone. This red shale is 

 well shown at the village of French Creek, in the gorge of Black River, 

 at Elyria, in the railroad cut between Elyria and Amherst, in the quar- 

 ries at Amherst, and in the cliffs bordering the Vermilion in Brown- 

 helm. The best exposures of the entire thickness of the Bedford shale 

 are on Black River, below Elyria, since the cliffs are chiefly composed of 

 it for two or three miles. Here it is seen that the upper portion is deep 

 red, the lower, bluish red and- gray. It will be also noticed here that the 

 upper surface of the shale is very irregular, showing that the currents of 

 water which transported the sand — now the Berea sandstone — cut away 

 the shale, then a red clay, in deep and broad channels. As these were 

 filled with sand, the under surface of the sandstone is very uneven and 

 its thickness variable. Several thin bands of impure limestone occur in 

 the Bedford shale in the banks of Black River, and these oentain a few 

 fossils, the most abundant being a lammellibranch mollusk, called Mac- 

 radon Hamiltonise, and a small Lingula not yet described. In one of 



