318 



GEOLOGY OF OHIO. 



color, and a grindstone grit. The dip of the rock is 5 ° north , and the quarry 

 is twenty feet below an opening in the same rock at Plymouth village. 

 The following illustration of the face of a broken rock of the lower strata, 

 which at the time of my visit was lying in its natural bed, indicates the 

 manner in which atmospheric agencies operating upon the cementing 

 mineral of the rock change its color, and show how these may have pro- 

 duced the remarkable and beautifully colored bands so conspicuous in the 

 quarry near Mansfield, and some other openings in the Center. 



The mass of the rock marked A A has the ordinary bluish color of much 

 of the Berea. The parts marked B B B are striped with black and yellow 

 in regular layers, the changes evidently tending to involve the whole, 

 and progressing more rapidly at the point C on account of a seam in the 

 rock which is permeable to water. 



This is the southern exposure in this neighborhood of unmistakable 

 Berea, and there is great difficulty in tracing its connection with the 

 outcrops of massive sandrock to the north-east, and in the central and 

 eastern parts of the county. The surface rises to the north-east, is gently 

 undulating, sometimes hilly, everywhere exhibiting a thick deposit of 

 Drift, which conceals all the rocks, until a little north of Rome, in 

 Blooming Grove township, on the banks of a small stream about fifteen 

 feet of rocks are exposed, consisting of soft argillaceous shales, with hard 

 blue tessellated bands which weather yellow, affording poor stone, but 

 furnishing the only supply in this neighborhood. These present some- 

 what the appearance of the Bedford shales belonging below the Berea, 

 while topographically they are by the barometer one hundred and sev- 

 enty feet above the Berea last described. In Weller township, one-half 

 mile north-west of Olivesburgh, a well was sunk passing through twenty- 

 one feet of unstratified clay Drift, then striking a hard fine-grained blue 

 sandstone, underlain with alternate bands of sandstone and argillaceous 

 shales. These were penetrated to the depth of nineteen feet, when a 

 small supply of water was obtained, and the explorations ceased. Four 

 miles west, at Big Hill, the same sandstone is quarried. South of this 

 and in the hills immediately north of Windsor station, in Weller town. 



