44 J. J. STEVENSON CARBONIFEROUS OP APPALACHIAN BASIN 



West Virginia. The important locality is in the central region, within 

 West Virginia and Ohio, where are the great reds of the Conemaugh, 

 some of them extending downward into the Allegheny. 



Eed beds appear in the Pittsburg-Upper Sewickley interval within 

 the south central counties of Ohio, Monroe, Washington, Morgan, 

 Athens, and Gallia, as well as in Wood, Eitchie, Gilmer, Calhoun, and 

 more southern counties of West Virginia. Farther north the only oc- 

 currence of red is in Wetzel, where 5 feet are on the Pittsburg coal bed. 

 The greatest thickness is in Calhoun, Mason, Wood, and Eitchie of West 

 Virginia, where the mass beginning at or below the place of the Pitts- 

 burg is at times more than 100 feet thick. 



A widespread deposit is in Ohio at 18 to 46 feet above the Upper 

 Sewickley and varies from 52 to 14 feet in thickness. It appears in 

 many sections from southern Guernsey through Monroe, Morgan, Wash- 

 ington, and Meigs, and it is thicker in Tyler, Eitchie, and Wood coun- 

 ties of West Virginia. For convenience of reference, this may be desig- 

 nated as the Tyler reds. Another deposit, equally well marked, imder- 

 lies the Uniontown coal bed or its place and is reported from southern 

 Marshall, Marion, Wetzel, Doddridge, Tyler, Eitchie, Jackson, south- 

 west Harrison, and northeast Gilmer of West A^'irginia, as well as in 

 Washington, Monroe, Meigs, and Guernsey of Ohio. Its place is con- 

 cealed in most of the published sections from Ohio. It is rather thin 

 in that state, seldom more than 20 feet, but in Eitchie, Gilmer, and else- 

 where in West Virginia it is very thick and at times continuous with 

 the Tyler reds below. Eeds occur at this horizon in counties south from 

 those mentioned, but they are not differentiated in the records. This 

 mass, which may be termed the Eitchie reds, has much greater extent 

 than the Washington reds of the Conemaugh, but much less than 

 the Pittsburg reds. The chief area of reds is in Wood and Eitchie of 

 West Virginia, where there is hardly a foot of the Monongahela section 

 which is not occupied in some well or other by red shale. 



The variation in thickness of the Monongahela — that is, of the in- 

 terval between the Pittsburg and Wajmesburg coal beds — ^is greater than 

 that of the Conemaugh, the interval between the Upper Freeport and 

 Pittsburg beds. The variations in these two formations do not coincide 

 geographically. The greatest thickness of the Conemaugh is in Alle- 

 gheny county of Pennsylvania, at the most northerly exposures of the 

 Pittsburg, and that thickness decreases very slowly southward, losing 

 barely 50 feet by the time the southern line of the state has been reached. 

 Eastwardly the decrease is small, the interval being practically as large 

 in Maryland as in southern Pennsylvania. Along the eastern border 



