664 JESSE E. HYDE 



relatively thicker and the shales relatively thinner in the Berea, and 

 some, not all, of the sandstones of the Bedford are slightly cal- 

 careous, never enough so to be called an impure limestone. Further- 

 more, the same structure in the Berea sandstone generally in central 

 Ohio and at the only one of the localities seen by the writer, Litho- 

 polis, where the unconformity is present, shows that the Berea 

 above the unconformity in central Ohio is of much the same type 

 as, and is at least closely related to, the Berea of southern Ohio, 

 and presumably is not widely different from it in age. 



SUNBURY SHALE 



The Sunbury shale is a thin bed of black, fissile shale present 

 over the entire area here considered, either on outcrop or under 

 cover. Of it no more need be said in view of Prosser's excellent 

 description of its features,^ except that it with the subjacent Berea 

 has been invaluable as a base from which to pursue work in the 

 complex overlying formations. 



CUYAHOGA FORMATION 

 THE FACIES 



The Cuyahoga formation has for years been described as a shale 

 formation. It is true that sandstone members, sometimes of great 

 economic importance, have been known to occur in it at various 

 points, and thin sandstones in greater or less abundance have 

 always been recognized as a component throughout its thickness. 

 However, the descriptions which have appeared in print have gen- 

 erally been such as to give the impression that it is largely a body 

 of shales and not a great deal more complicated than the formations 

 below it. This is owing to the fact that portions of the massive 

 sandstone and conglomerate facies were not recognized as Cuya- 

 hoga but were considered a distinct horizon, the Black Hand 

 formation, or, under the name Logan conglomerate, were con- 

 sidered a part of the overlying Logan formation, while the remain- 

 ing portions of these same sandstones were practically unknown. 



The Cuyahoga formation may be made up very largely of shales 

 in one area but of sandstones or conglomerates in adjacent areas 



' Jour. Geol., X (1902), 262-312. 



