MONONGAHELA FORMATION 39 



iinieh of the western outcrop, and, as in Pennsylvania, some of the more 

 persistent beds are magnesian, being referred to by Andrews as "cement 

 beds." Southwardly it is replaced by sandstone, sometimes 60 feet 

 thick and often very coarse, so that the Upper Sewickley is known as the 

 "Sandstone coal" to distinguish it from the Pittsburg or "Limestone 

 coal." 



The interval of 20 to 40 feet between the Benwood and TJniontown 

 limestones is occupied usually by sandstone or sandy shale. 



The TJniontown limestone (J. J. Stevenson, 1877) is one of the more 

 persistent members of the section. It is wanting east from the AUe- 

 ghenies, but is present throughout the Connellsville basin, is apparently 

 one of the upper limestones near Greensburg, is everywhere in the Lis- 

 bon basin south from the Pennsylvania railroad, extends to the most 

 northerly outcrop of its place in Allegheny county, and seems to be 

 present everyvi^here in Washington and Greene where its place is ex- 

 posed. It is present in northern West Virginia toward the eastern 

 outcrop, but diamond-drill cores do not show it toward the west. It 

 evidently disappears southwardly at no considerable distance from the 

 state line. It is present in the northern panhandle of the state, and in 

 Ohio one finds limestone at this horizon in by far the greater part of 

 the area when the place is exposed. In much of Pennsylvania it has 

 a characteristic yellow color on the weathered surface, wholly unlike' 

 that of any other limestone in the formation. The thickness varies from 

 2 to 12 feet. 



The Uniontown coal bed Maryland and Pennsylvania : TJniontown. 



H. D. Rogers, 1858. West Virginia : Waynesburg, Macksburg, 



Uniontown. Ohio : Hobson, Cumberland, 

 Waynesburg, Clarington. 



This bed is rarely of interest or importance on the northeasterly side 

 of the great basin, where it was first studied and named. Its insignifi- 

 cance in that region caused failure to recognize it in other regions. 

 Doctor White's suggestion, that the West Virginia bed, usually referred 

 to the Waynesburg, might prove to be the Uniontown, proves to be 

 correct. The bed is present as coal, but very thin, in Maryland; its 

 place is marked by shale or coal almost everywhere in the Connells- 

 ville basin, but it is not a workable bed anywhere, for, though thick 

 enough near Uniontown, its coal is very bad. In the Lisbon basin it is 

 present to the most northerly exposure, but for the most part is very 

 thin, except in some places within Fayette and Greene counties, where 

 it is opened occasionally by farmers, but yields miserable coals. Farther 

 west the coal does not extend northward into Allegheny or northwestern 



