MISSISSIPPIAN. 417 



Ft. in. Feet. 



3. Sunbury shale, total thickness 3 



Black fissile carbonaceous shales. 



2. Bedford-Berea, total thickness IJ 



Argillaceous shales with phosphatic nodules 2 



Black fissile carbonaceous shales 3 



Dark argillaceous shales, with some carbonaceous material 6 



Gray calcareous and argillaceous shales, slightly fossiliferous 2 



Yellowish calcareous and argillaceous shales, the upper part very fossiliferous. . . 5 



1. Ohio shale 94^ 



Black fissile carbonaceous shales, with an occasional softer argillaceous layer. 

 Practically all exposed to the highway. 



In the Irvine section the Bedford and Berea are stated to be represented by 

 IJ feet of fossiliferous shale and the Sunbury by but 3 feet of black carbonaceous 

 shale. Morse and Foerste conclude : 



The Bedford and Berea formations thin rapidly southwestward from the Ohio River and 

 this horizon, even after it has been reduced to a thickness of only a few inches, can be traced to 

 near the crossing of the Cincinnati geanticline by the Waverly series. 



The Sunbiiry shale, on the contrary, suffers but little decline, at least until Indian Fields is 

 reached. 



The Ohio black shale of the Kentucky reports or the Chattanooga shale of United States 

 reports, south of Petersville, is not of Devonian age alone but of Devonian and Carboniferous — 

 that is, is composed of both the Ohio and Sunbury shales and a thin zone representing the 

 Bedford and Berea. 



The sandstones which are extensively quarried about RockviUe station belong to the 

 Buena Vista member of the Cuyahoga formation rather than to the Berea grit. 



The Buena Vista sandstones begin to disappear from Olympian Springs southwestward 

 except a single layer which, if not always the same, at least occupied the position of the lowest 

 and which persists as far south as Stanton if not to Irvine. 



Tne Linietta clays belong to the lower part of the Cuyahoga formation. 



The so-called Waverly of at least the Richmond folio includes only the upper part of the 

 Waverly, begioning with the base of. the Cuyahoga. 



J-K 17-18. PENNSYLVANIA, MARYLAND, WEST VIRGINIA, AND VIRGINIA. 



The area considered under the above heading covers that restricted part of the 

 ancient bay of New York and Pennsylvania .which was occupied by the sea at inter- 

 vals during the Mississippian epoch and within which were laid down the coarse 

 clastic sediments of the Pocono, at the base of the series, and subsequently the shaly, 

 sandy Mauch Chunk formation. The Pocono is commonly a sandstone which 

 includes also strata of conglomerate shale, and thin coal beds. Its thickness is 

 1,800 feet in West Virginia and 2,000 feet in a section on the Susquehanna. It thins 

 out to the north and south, to 500 feet in the Wyoming anthracite field, Pennsylvania, 

 and to 100 feet or less in West Virginia. In western Pennsylvania, Ohio, Kentucky, 

 and Tennessee its equivalents are shales and sandstones whose precise stratigraphic 

 and faunal relations are still matters of doubt; but they, together with the Pocono, 

 are referred in general terms to the position of the Kinderhook, Burlington, and 

 .Keokuk of the Mississippi River section."* 



The lower part of the Pocono is regarded as Devonian by Stevenson. 



The Mauch Chunk formation is dominantly a red sandy shale, which in Penn- 

 sylvania is chiefly a subaerial flood-plain deposit, according to Barrell.^'' 



48011°— 12 27 



