LORAIN COUNTY. 215 



given the name of Dinichthys Terrelli, the maxillaries terminate below 

 in a sharp, knife-like edge, which plays upon a similar edge on the man. 

 dible, and the whole dentition constitutes a cutting or slicing apparatus 

 of great power. So far as at present known, all the bones of Dinichthys 

 found at Sheffield belong to this species, while all those found at Dela- 

 ware appertain to D. Hertzeri. A fine spine of Otenacanthus (_Ct. vetustus) 

 was also found at Sheffield by Mr. J. W. Hulbert, of Elyria ; and this is 

 described in Vol. I., Part II., p. 326, pi. 35, fig. 3. Mr. Terrell obtained, in 

 addition to'the fossils mentioned, several bones of small and, as yet, un- 

 described fishes, some cones, apparently belonging to Lepidodendron, and 

 an undescribed species of Goniatites, all from the Huron shale at Sheffield. 

 Broad, flag-like impressions of plants are very common in the formation 

 here as well as elsewhere. These are undoubtedly the remains of sea- 

 weeds, and it is probable that the carbonaceous matter the shale contains 

 was derived from this source. 



The succession of the rocks exposed in the central and northern por- 

 tions of the county will be seen at a glance by reference to the section 

 given below, which begins at the surface of the Berea grit, 15 feet below 

 the Lake Shore Railroad at Elyria, and reaches to the lake level at the 

 mouth of Black River. 



Section of the Rocks in the Valley of Black River. 



1. Berea grit, thickness 40 to 70 feet. 



2. Red shale, " 30 to 60 " 



3. Gray shale, " 10 " 



4. Gray limestone, thickness 5 to 8 inches. 



5. Calcareous shale, " 1 foot. 



6. Black bituminous shale, thickness ... 27 feet. •> 



7. Gray shale, thickness 7 " [-Cleveland shale. 



8. Black shale, like No. 6, thickness 50 " ' 



9. Gray shale, to Lake, " 40 " Erie shale. 



A well bored for oil in the valley of Black River, at Elyria, and begun 

 a few feet below the base of the Berea grit, is said, by a near resident and 

 stockholder, to have been carried to the depth of 1,000 feet, " 600 feet of 

 which was in shale, the remainder in limestone and sandstone." If this 

 boring can be relied upon, the interval between the Berea grit and the 

 Corniferous limestone is here only about 600 feet, while at Peninsula, in 

 the valley of the Cuyahoga, wells beginning at the same horizon were 

 bored to the depth of 1,000, and in one case 1,400 feet, and, as reported, 

 "all in shale;" and at Cleveland a well, begun more than 200 feet below 

 the Berea grit, was sunk 1,000 feet in gray and black shales without 

 reaching the limestone. 



■ Bedford shale. 



