MONONGAHELA FOEMATION 41 



double, sometimes still further divided. Its peculiarities possess much 

 interest, considered in reference to the origin and accumulation of coal 

 beds. The carbonaceous shale at this horizon usually contains frag- 

 mentary remains of fish, with small lamellibranchs and other forms of 

 undetermined relations. In Monroe of Ohio and Doddridge of West 

 Virginia it is associated with plant-bearing shales. Near Uniontown, 

 Pennsylvania, it underlies an impure limestone containing lamelli- 

 branch shells. 



The interval between the Uniontown and Waynesburg coal beds is 

 the most variable in the formation. In Marion county of West Vir- 

 ginia the Waynesburg coal bed is somewhat more than 100 feet above 

 the Uniontown limestone, but this interval decreases northward until, in 

 Allegheny and northern Washington of Pennsylvania, the coal and 

 limestone are practically in contact. 



The Uniontown sandstone (I. C. White, 1891) is a rather persistent 

 deposit occupying much of the interval, though, like other sandstones, 

 it is apt to be replaced rather abruptly by shales. One finds it very fre- 

 quently in southern Pennsylvania, at times tenacious enough to form 

 cliffs, but only moderately coarse in grain and very seldom containing 

 pebbles. It shows the same features in much of the exposed area in 

 West Virginia as well as across the northern portion of the state, as 

 appears from oil-well records; but farther south, in Lewis, Gilmer, Dod- 

 dridge, Tyler, and Pleasants counties, a broad band crossing the state 

 from east to west, the sandstone is massive, coarse, and even conglom- 

 erate, exposed in many places and recorded elsewhere in oil wells. It is 

 one of the "Carroll" sands in Eitchie county. In Washington, Morgan, 

 and Athens of Ohio the band continues and the rock is the 300-foot 

 conglomerate of Professor Andrews. Northward and apparently south- 

 ward from this strip the conglomerate is wanting, the sandstone, where 

 present, is fine grained, and in broad areas the interval is filled by shales. 

 This conglomerate, much resembling that above the Waynesburg coal 

 bed, proved a stumbling block in correlation. It geographical distribu- 

 tion is puzzling. 



The Waynesburg limestone (J. J. Stevenson, 1877) is in the upper 

 part of the interval between the coal beds and is of wide extent. It is 

 from 10 to 40 feet below the Waynesburg coal bed. It is present in 

 Maryland and it may be part of the thick limestone in Broad Top; it 

 seems to be present throughout Payette and Westmoreland counties 

 wherever its horizon is reached, but is wanting in Allegheny and north- 

 ern Washington, where the Waynesburg coal bed approaches closely to 

 the Uniontown limestone; yet it was seen farther south in Washington^ 



