340 : GEOLOGY OF OHIO. 
evident that the latter, which is a conspicuous and well marked deposit 
in all the northeastern counties of the State, thins out in this direction, 
and like the Carboniferous Conglomerate, it was a shore deposit, the 
coarse materials being carried no great distance into the deep waters 
which then lay to the south. At the depth of about six hundred and 
seventy feet below the Sub-carboniferous conglomerate is the red or choco- 
late shale, the lowest member of the Waverly, and the first in this 
county which can be identified fully with any of the subdivisions that 
are so clearly defined in the valley of the Cuyahoga. This is apparently 
the equivalent of the Bedford shale, which in many places at the north 
is all or in part red shale. In Erie county this red shale reaches a thick- 
ness of some forty feet. The well-borings here show that it is very homo- 
geneous in structure, except that near the bottom there are interstrati- 
fied bands of argillaceous shale. | 
Below this chocolate shale are the Erie shales, which so far as their 
character can be determined by an inspection of the borings, present 
precisely the same characteristics as in the northwestern counties, where 
they are fully exposed. They consist of a mass of soft, blue argillaceous 
shale, with hard calcareo-silicious bands. | 
Below this Hrie lies the Huron or “ Black shale,” the thickness of 
which cannot be determined. It seems evident that along the western 
margin of the Sub-carboniferous rocks the lower members of this series. 
and the upper member of the Devonian are thinning out, and that their 
advance further west is not altogether the result of erosion, but that 
their extent in that direction was limited by the presence of dry land 
at the time of their deposit. 
Petroleum and Gas.—The report upon this county would be incomplete 
without an acknowledgment of the very important aid derived from the 
borings for oil on Owl Creek, and a brief account of this interesting 
work. Some ten years ago the attention of enterprising parties was 
called to the “oil signs” of the eastern part of Knox county. On the 
western margin of the coal field were indications of dislocation in the 
rock strata; gas springs were abundant, and from several places it is 
reported that oil in small quantities was obtained. A company was or- 
ganized, territory leased, and since that time something like $85,000 has 
been expended in explorations, mainly under the superintendence of 
Peter Neff, Esq., of Gambier. The registers of the wells, which have 
been kept with commendable care by Mr. Neff, show that there is a 
marked disturbance in the strata extending to the lower rocks reached, 
its apparent extent, however, being exaggerated by the causes mentioned 
on a preceding page. 
