PENNSYLVANIAN. 447 



The Sewell formation constitutes the middle Pottsville and paleobotanically corresponds 

 approximately to the "Upper Lykens division" of the type section of the anthracite region 

 (see p. 440), which contains the floras characteristic of Lykens coals Nos. 2 and 3. It is made 

 by Campbell, Stevenson, and I. C. White to include at the top the Nuttall conglomerate member 

 (equivalent to the Fayette sandstone), which is correlated with the Sharon conglomerate member 

 by the two geologists last named. The present writer, regarding the Nuttall as the initial 

 sea-expansion member of the upper Pottsville subcycle of deposition, would prefer to separate 

 it from the Sewell; and, while provisionally correlating it with the Sharon conglomerate mem- 

 |jgj.^898d xvould restore the latter to its old place in the base of the Beaver River formation, thus 

 conforming to the early establishment of that division by Chance "^ and D'lnvilliers.^'^ Chance 

 shows that the irdtial omission of the Sharon conglomerate member in the definition given by 

 Lesley in the preface to I. C. White's Report Q (p. 65) was due to the misapprehension that the 

 sandstone was Mississippian. 



The Kanawha formation is upper Pottsville and on the paleobotanic evidence corresponds 

 roughly to the "Upper Intermediate division" of the type section of the anthracite region. 

 (See p. 441.) Together with the underlying Nuttall sandstone member and the sandstone which 

 is just above the overlying black flint and which corresponds to the Homewood sandstone 

 member, it is correlated by the writer with the Beaver River formation as already described 

 for the northern strip (p. 441). 



The Charleston sandstone covers the entire Allegheny, here about 120 feet in thickness, °''"' 

 together with a portion of the Conemaugh and the heavy sandstone (''Roaring Creek" or 

 Homewood) at the top of the upper Pottsville. Most of the Allegheny coals are thin or lacking 

 in the Charleston and Huntington quadrangles. 



The Braxton formation represents the balance of the Conemaugh with so much (a small 

 thickness) of the Monongahela as caps a few summits in the northwestern portion of the area. 



The remarkable reduction in the thickness of the Pottsville toward the northwest is due 

 both to thinning of the divisions and to the disappearance of the older terranes as the section 

 passes beyond the older and smaller early basin. At the same time the absence of paleontologic 

 material from the drill holes makes it more difficult to determine the preciste limits of the several 

 divisions. The lower Pottsville, which appears to attain a thickness of over 1,200 feet in the 

 vicinity of Norton, Va., in the Estillville quadrangle, is said to measure 1,080 feet on Barrenshe 

 Creek, McDowell County, W. Va., in the Tazewell quadrangle; 815 feet at Wolf Gap,''""'' Wyoming 

 County, W. Va. ; and 736 feet at Grand View, in the Raleigh quadrangle. Apparently it was 

 not deposited in the Charleston quadrangle. It is less difficult, however, to distinguish the upper 

 Pottsville in many of the sections in which the two lower divisions are not clearly differentiated. 

 Thus, at Powelton, Fayette County, W. Va., the Kanawha is reported by I. C. White ""k at 

 1,295 feet and the middle and lower Pottsville at 812 feet; at Hernshaw, a few miles south of 

 Charleston, the upper is 890 feet and the middle and lower 787 feet; at Charleston the upper is 

 600 feet and the middle and lower 660 feet; 5 miles farther west the upper measures 490 feet 

 and the two lower divisions 480 feet; at Winfield, in the same quadrangle, the upper is 365 feet 

 and the middle and lower combined 275 feet; whereas in the well at Letart, to the northwest, on 

 Ohio River, the entire Pottsville measures but 360 feet, of which the lower 60 feet is perhaps 

 referable to the middle Pottsville. The direction of most rapid thickening is somewhat east of 

 south. At Naugatuck, on Tug River, in Mingo County, W. Va., the upper Kanawha is said by 

 I. C. White """ to measure 2,116 feet, a thickness that is possibly equaled in the Estillville 

 quadrangle. 



The determination of the northernmost outcrop of beds of middle Pottsville age along the 

 western border of the coal field is subject to differences of opinion. Stevenson ^"^^ interprets 

 the Jackson shaft coal, in Jackson Coimty, Ohio, as just beneath the Sharon conglomerate 

 member, and, placing the Sciotoville fire clays and coal at the same horizon, is inclined to regard 

 the highest of the middle Pottsville terranes as a thin veneer extending as far north, at least, as 

 Ohio River, with local developments of an underlying conglomerate (A'icinity of Jackson, Ohio) 



