GEOGRAPHICAL CnxVNGES DURING PENNSYLVAlSriAN 161 



ing, it becomes necessary for comparison to consider separately the 

 lower and the upper portion of the Washington. The lower, extending 

 from the Waynesburg to the Washington coal bed, is shown broadly. 

 The length of the column along a west-northwest line from the eastern 

 outcrop is 120 feet in Maryland, 135 feet in Fayette, and 180 in Greene 

 of Pennsylvania, 117 in eastern Belmont of Ohio, and 100 feet at the 

 western outcrop. Along a south -southwest line one finds 50 feet at the 

 most northerly exposure in Pennsylvania, which increases gradually to 

 130 feet at the Greene County line and becomes 170 feet in Wetzel county 

 of West Virginia, where well records are very numerous; and this 170 

 feet seems to be the interval in much of central West Virginia; but it 

 decreases farther south. The upper portion, seen in much smaller area, 

 shows similar variation. The full section is not found exposed any- 

 where east from the Monongahela in Pennsylvania, but in Fayette county 

 an approximate measurement gives about 200 feet from the Washington 

 coal to the Upper Washington limestone; westwardly in Greene the in- 

 terval increases to 240, and then to 300 feet, while at Moundsville, on 

 the Ohio river, it has decreased to 244 feet. Along a south-southwest 

 line it is 110 feet at the most northerly exposure, increases steadily to 

 190 feet at the northern line of Greene, and across that county it in- 

 creases to 308 feet in West Virginia. The formation thus increases 

 from 160 feet in northern Washington of Pennsylvania to above 480 

 feet in the northern counties of West Virginia, thus showing a con- 

 tinuance of the Jlonongahela conditions, with the greatest subsidence in 

 north central West Virginia. 



The sandstones tell the story of steadily contracting area. The Waynes- 

 burg sandstone is persistent in Maryland, in most of Pennsylvania, as 

 well as southward in West Virginia for a long distance. It is massive 

 and at times pebbly, though, like all sandstones of the higher formations, 

 it is sometimes replaced abruptly by shale. In Ohio, along the north- 

 western border, it is not a coarse sandstone, but farther south it becomes 

 coarser and more prominent, being Professor Andrews's upper sandstone 

 and conglomerate. Thence southeastwardly along the southern border, 

 in Jackson and Putnam of West Virginia, the rock marking this horizon 

 is a coarse sandstone, with quartz pebbles sometimes an inch in diameter. 

 In the interior portion of West Virginia records of oil borings show sand- 

 stone persistent in this interval except in a small area. The Waynes- 

 burg is the first sandstone of wide extent in the interior region. No 

 notable sandstone above the Waynesburg appears in Pennsylvania, except 

 that underlying the Upper Washington limestone, which is confined to 

 the borders of the remaining area and disappears southwardly. Below 



