178 D.WHITE — RELATIVE AGES OF KANAWHA-ALLEGHENY SERIES 



ditions but slightly different during early Kanawha time. The condi- 

 tions of subsidence and detrital supply # and distribution in this region 

 appear to have been such that the greater part of the Kanawha series 

 was laid down within the interval represented in part at least by the 

 conglomerates and sandstones of the uppermost Pottsville in the Poto- 

 mac and northeastern basins.* 



The subsidence in the Virginian basin appears to have waned rapidly 

 northeastward from the Kanawha river, since beyond Webster and Up- 

 shur counties, about 75 miles distant, the Pottsville assumes a some- 

 what regular though variable thickness, while the thickness of the Al- 

 legheny series at Moatsville, Barbour county, hardly 100 miles from the 

 Kanawha river, is, as I am informed by Doctor White, but about 350 feet. 

 The transition from the northern to the southern phases of the forma- 

 tions would seem to be most marked in Braxton and Webster counties. 

 There are indications that from the highly arenaceous and very variable 

 sections in the latter region the lithologic boundaries diagonal somewhat 

 rapidly in passing southward under the conditions attending the south- 

 ern Virginian isostatic movement. 



If, as I believe, the respective Allegheny floras in the Potomac basin, 

 the Allegheny valle}^, and the Kanawha sections are contemporaneous, 

 the major portion of the sedimentation in the Kanawha valley, or over 

 2,200 feet, eastern outcrop measurement, antedates the deposition of 

 the Brookville coal in northwestern Pennsylvania. Similarly, from 

 such paleobotanic evidence as is now in hand, it appears that the upper 

 boundary of the representatives of the Allegheny series lies some dis- 

 tance, probably over 200 feet, above the Black Flint; so that from the 

 paleobotanic standpoint the Cannelton and Mahoning coals in the 

 Charleston section f cannot safely be regarded as younger than the Free- 

 port group of the Allegheny valley. If this be true, the Allegheny series 

 will show no extraordinary expansion on the Kanawha river, while 

 the Conemaugh series J will retain its full normal thickness as in north- 

 ern West Virginia or in Pennsylvania. 



* The paleontologic evidence bearing on this subject will be presented when the Pottsville and 

 Kanawha floras are fully elaborated. 

 fOp. cit., p. 85. 

 J XIV, Lower Barren Measures ; Elk River series. 



