92 GEOLOGY OF OHIO. 



In this list there are several which have peculiar interest and signifi- 

 cance, Syringothyris typa and Spiriferina solidirostris, for example, from the 

 fact that they are characteristic of the Lower Carboniferous rocks of other 

 States, while Orthis Michelini is common to the Carboniferous formation 

 all over our country and in Europe. 



South of the Western Reserve the Bedford shales are scarcely distin- 

 guishable, as in the central and southern portions of the State they as- 

 sume the prevailing character of the Waverly group, and blend with the 

 other portions of the series. At East Cleveland, Kingsbury's quarry, New- 

 burgh, etc., the lower portion of the Bedford shale is so highly charged 

 with silica as to become a fine-grained sandstone, which is extensively 

 used for building, flagging, etc., in Cleveland. This is, however, only a 

 local induration of the shale, and is not often met with elsewhere. 

 Though nearly or quite destitute of fossils, except some fucoidal impres- 

 sions, the blue sandstone of the East Cleveland quarries is highly 

 charged with a sulphide of iron ; and hence the rock is liable to stain 

 and exfoliate on exposure by the conversion of the pyrites into limonite. 

 It makes excellent flagging, however, and when sawed is much used for 

 that purpose. 



In all the quarries where this blue sandstone is worked the seams 

 between the layers, as well as the pores of the stone, are often found 

 filled with petroleum. This evidently proceeds from the underlying 

 black shale from which it emanates by spontaneous distillation. Simi- 

 lar emissions of oil give rise to a line of oil springs which mark the base 

 of the Bedford shale all along its line of outcrop. At Kingsbury's quarry, 

 near Cleveland, a fine thread of oil may be seen floating on the surface of 

 each little spring stream that issues from the crevices of the rock. I 

 have seen the flow kept up for years, and have regarded it as an inter- 

 esting illustration of the genesis of petroleum — from bituminous shale 

 by spontaneous distillation. 



Not unfrequently the East Cleveland stone, like that from Waverly, 

 shows stains of oil on exposure to the sun. 



4. Cleveland Shale. — The lowest member of the Waverly group in 

 northern Ohio is a black bituminous shale, which I have designated by 

 the name of the Cleveland shale, from the fact that it seems to have 

 attained its greatest development in the region about the mouth of the 

 Cuyahoga, and is there, perhaps, the most strongly marked element in 

 the Lower Carboniferous series. Its greatest thickness in Cuyahoga 

 county is 54 feet, and its best exposure is in the valley of Doane's Brook, 

 in East Cleveland, where it immediately underlies the Bedford shale, of 

 which the lower layers are there converted into massive, blue, fine- 



