OHIO. 



003 



nilVrous limestone. Tho beautiful crystals of 

 ; . ine, found on Strontion Island, occur in 

 tho water-liine. 



Passing from tho Silurian to tho Devonian 

 ii, it is found that upon tho Water-lime, 

 sometimes directly, sometimes separated by a 

 few feet of limestone, rests a thin sheet three 

 to five feet thick of sandstone. This holds 

 tin- place of tho Oriskany sandstone of New 

 York, mid probably represents that formation. 

 In West Virginia the Oriskany is a massive and 

 important group of rocks, but it rapidly thins 

 out westward, and in Ohio is tho least impor- 

 tant of the series, and it is even doubtful 

 wlu-ther it should bo enumerated as one of 

 its formations. 



Tho Corniferous limestone is a limestone 

 group, like the Water-lime and Niagara, highly 

 magnesian, often adolomite, and supplies a 

 large part of the quicklime and some of the 

 finest building-stones of the State. The Cor- 

 niforous limestone forms two lines of outcrop, 

 one east and the other west of the anticilinal, 

 also an island, twenty-five miles in length, near 

 Bcllofontarae. An interesting circumstance 

 connected with this formation is, that in Marion 

 and Delaware Counties it is partially composed 

 of rolled fragments of tho Water-lime, showing 

 a break between the Upper Silurian and Devo- 

 nian, just as has been indicated between the 

 Lower and Upper Silurian. The Hamilton for- 

 mation, so important in New York, in Ohio 

 consists of a thin sheet of marl and marly lime- 

 stone, never more than thirty feet in thickness, 

 resting on the Corniferous. It is, however, 

 clearly identified by the numerous Hamilton 

 fossils which it contains. 



The Huron shale is a name used to designate 

 tho great mass of black bituminous shale, 

 called by the older geologists the "Black 

 Slate." This formation is from 200 to 350 feet 

 in thickness, and its outcrop forms a broad 

 belt, running from the lake through the centre 

 of the State to the Ohio. It also underlies 

 several counties in the northwestern corner. 

 Though not absolutely homogeneous, the Hu- 

 ron shale is generally black, and contains ten 

 to twenty per cent, of combustible matter. 

 This carbonaceous mass, slowly decomposing, 

 as all organic matter will, gives rise to the gas 

 and petroleum which form such constant as- 

 sociates in the water which flows from it. The 

 fossils of the Black shale indicate that it repre- 

 sents the Genesee and a portion of the Portage 

 of New York. Aside from such of its fossils 

 us are found elsewhere, the Huron shale con- 

 tains some things which are very remarkable, 

 and such as have been met with only in Ohio. 

 These are jaws and bones of great ganoid fishes, 

 larger and more formidable than any of those 

 obtained from the Old Red sandstones of 

 Europe. Here, also, as in the Corniferous be- 

 low, we find floated fragments of trees, often 

 of large size, tho first evidence which we meet 

 with of a terrestrial vegetation. Several of 

 the formations last enumerated, viz., the 



Water- lime, Oriakany, Corniferous, and Hamil- 

 ti.n, thin out and disappear toward the south, 

 and in Highland and Adams Counties the Huron 

 shale is found resting directly upon the Niagara 

 limestone. The explanation of this is, that the 

 higher portion of the old ridge that has been 

 described, at Cincinnati and southward, formed 

 an island raised above the sea, in which were 

 deposited the later Silurian and earlier Devo- 

 nian formations. Hence the shores of this 

 island limited the reach of these deposits. In 

 tho epoch of the Huron shale, however, the 

 submergence of this island was more complete, 

 and hence this stratum is found stretching far 

 beyond the edges of the underlying rocks. 



The Erie shales, which come next, are tho 

 western prolongation of the Chemung, and, in 

 part, of the Portage rocks of New York. Like 

 all other strata composed of mechanical mate- 

 rials, sand, clay, etc., these shales thin out 

 westward, so that, while having a thickness of 

 several hundred feet on the Pennsylvania line, 

 they cease to be recognizable in the central 

 portion of the State of Ohio. 



Passing to the Carboniferous system, we come 

 to the Waverly group, called by th6 former 

 geological survey the Waverly sandstone. It 

 consists of a series of shales and sandstones, 

 from 850 to 600 feet in thickness, of which tho 

 outcrop forms abroad belt, extending from the 

 Pennsylvania line, near the lake-shore, around 

 to the Ohio, at the mouth of the Scioto. Tho 

 relations of this formation to the rocks above 

 and below have been actively discussed for 

 many years by geologists. By some, the Wa- 

 verly group was considered a representative of 

 the Portage and Chemung rocks of New York, 

 and part of the Devonian system, while others 

 have been led, by paleontological evidence, to 

 consider the formations carboniferous. This 

 mooted question the chief geologist claims to 

 have been definitely settled by the recent ex- 

 plorations, and that there is no longer room 

 for doubt that this is a portion of the Carbonif- 

 erous system, and the equivalent of the " Ves- 

 pertine" of Rogers in Pennsylvania, and of the 

 " Subcarboniferous sandstones" of Owen in. 

 Kentucky. The fossils of the Waverly are 

 very numerous and interesting ; they are almost 

 exclusively marine, and include many genera 

 and species of fishes, mollusks, and crinoids. 

 The Waverly sandstone is the repository of 

 some of the oil which emanates from the Hu- 

 ron shale below, and the wellg of Mecca, 

 Grafton, Liverpool, etc., are sunk in this for- 

 mation. For the want of a proper reservoir to 

 receive, and an impervious cover to retain this 

 oil, the qiiantity that has accumulated in any 

 locality is not large. The lower carboniferous 

 limestone is another of the several new ele- 

 ments which the present survey has con- 

 tributed to the geological column in Ohio. It 

 is the thin edge of the great carboniferous 

 limestone of Kentucky, discovered by Prof. 

 Andrews to extend much farther north than 

 was formerly supposed. It represents only tho 



