7S8 JESSE E. HYDE 



each exhibits the characteristics of its respective type Httle 

 changed. 



The Cuyahoga over the shale area is not as thick as in the Hock- 

 ing Valley facies. Between Chillicothe and Waverly it is about 

 300 feet thick and at Portsmouth about 300 or 320 feet. West of 

 the Scioto River near Portsmouth it falls to about 260 feet. 



Members. — ^Three members are distinguished. At the base is 

 the Henley shale member which apparently attains a thickness of 

 over 200 feet. This is succeeded by the Buena Vista sandstone 

 member. Since both are recognized in the Vanceburg sandstone 

 facies, their description is better reserved for that place. 



The name Portsmouth is applied to the upper shale member 

 from Portsmouth, where it is excellently exhibited on both sides 

 of the Scioto River, and on the Ohio River above the town. At 

 the *' Two-Mile Hill" at Portsmouth it is 253 feet thick, but this 

 decreases to the northward and westward. The Portsmouth 

 shale is the equivalent of the three upper members of the Vance- 

 burg facies. It is impossible, at present, to present correlations 

 between the members of the Scioto Valley shale facies and those 

 of the Hocking Valley conglomerate facies to the eastward. All 

 that can be suggested is that the Buena Vista sandstone is not the 

 equivalent of any one of the four members distinguished there ; its 

 horizon is probably near the middle of the deposits in the Hocking 

 Valley. Further, it appears that the upper part of the Ports- 

 mouth shales at Portsmouth — how much is not known, but perhaps 

 50 feet or more — is the stratigraphic equivalent of the lower part 

 of the Byer member of the Logan formation only six miles up the 

 Ohio River at Sciotoville. 



THE VANCEBURG SANDSTONE PACIES 



Extent and general nature. — This is confined to the western 

 parts of Scioto and Pike and the southwest corner of Ross counties, 

 with some extension into Adams County. The facies proper 

 lies well west of the Scioto River. The thickness of the Cuyahoga 

 appears to be about 250 feet, of which the lower 150 feet or more 

 are made up largely of sandstones, the upper 100 feet largely of 

 shale. 



