78 ENVIRONMENT OF VERTEBRATE LIFE, ETC. 



As stated above, Stauffer believes that this discovery proves the equiva- 

 lence of the Dunkard with the Permo-Carboniferous beds of Texas and 

 Oklahoma. 



The Monongahela series is but slightly more extensive in Ohio than the 

 Dunkard, having lost material from the western edge by erosion. 



"The character of the rocks interstratified with the coal beds' changes greatly 

 in passing from the Monongahela River southward to the Great Kanawha. 

 At the northern end of the basin * * * limestone forms about one-half of the 

 rock material, and the same is true on the western side * * *. Red shale is 

 unknown in the series at the north, but in passing southward from Harrison 

 and Lewis Counties [West Virginia] the limestones practically disappear, and 

 with them all the coals but the Pittsburgh. With their disappearance red shales 

 come in and apparently replace the limestones, so that on the Great Kanawha 

 nearly one-fourth of the rock material in this series is red shale, while the thickness 

 is reduced to 270 [from 413] feet." 



The Conemaugh extends beyond the edge of the Monongahela in Ohio 

 and reaches into eastern Kentucky. 



"This series,' as thus limited above and below by important coal beds, consists 

 of two very different members- — an upper one composed largely of shales, therefore 

 soft, easily eroded, and always making rounded hills and rolling topography, the 

 other, or lower, composed largely of massive sandstones which resist erosion. * * * 



"The upper portion always contains a large percentage of red and marly 

 shales, which make a broad band of red soil from Pennsylvania through central 

 West Virginia, to and beyond the Kentucky line on the one hand, and thence 

 circling around through eastern Kentucky and southern Ohio, back to Pennsyl- 

 vania again on the other. * * * 



"The coal beds of this series are, with one or two exceptions, noted for their 

 variableness and uncertainty. They may be in fair development on one farm 

 and absent entirely on the adjoining one. They are also usually rich in ash and 

 poor in carbon, and although they are patchy in their distribution, yet the main 

 beds appear to maintain the same horizon in the stratigraphy, and can thus be 

 identified with reasonable certainty over wide areas. The sandstones found with- 

 in the limits of this group are of more economic importance than the coal beds, 

 since the former nearly always furnish most excellent building stones. * * * 



"The limestones of this series, like the coals, are generally thin and impure, 

 so they are of more importance in determining the stratigraphy than for economic 

 purposes." 



The deposits of the Western Interior Coal Field are here considered 

 as a part of the Eastern Province, but it is probable that the major 

 portion is below the middle Pennsylvanian and so throws little direct light 

 upon the conditions during late Paleozoic time. Upon the usual basis of 

 correlation by fossils there is no suggestion that any layers below Coal 6 

 are higher than the base of the Conemaugh. The uppermost division of the 

 series, Coal 6 (Grape Creek, Herrin) and above, may be of Conemaugh age. 



1 White, I. C, Stratigraphy of the Bituminous Field Coal of Pennsylvania, Ohio, and West 



Virginia, Bull. 65, U. S. Geological Survey, p. 43, 1891. 

 ' White, I. C, loc. cit., p. 71. 



