81«5 FLORAL ZONES OF THE POTTSVILLE FORMATION. 



SEWELL FORMATION. 



The next higher general flora of marked characters and distinction 

 in either the bituminous or the anthracite regions is that which I have 

 indicated as characteristic of the proximate horizons of coals Xos. 3 

 and 2 in the Southern Anthracite held. The zone of this flora is 

 characterized b}' the development of both the Rhacopteroid and the 

 broad-lobed types of Eremopteris ; by small, round, and inflated- 

 pinnuled species of ]\lariopteris ; by triangular Alethopterids : by small, 

 palmate-lobed, and Pecopteroid Sphenopterids : by narrow Alethop- 

 teroid forms of Xeuropteris, such as JT. SchUliani ; by MegalopUrh 

 species and the ]Megalopteroid types ; by the broad-leaved Whittlesti/a', 

 and by the introduction of the dentate Pecopterids, as well as a great 

 diversity- of gymnospermous fruits. The more explicitly distinctive 

 species of the zone of Lvkens coals Nos. 3 and 2 — Eremopteris Cheat- 

 Juiiiil and E. decip)'ie)u^ Mainopteris py(jmi^a of the M. inflata group 

 and J/, tennesseeana^ Sphenopteris jnlosa and S. palmatiloha^ Alethop- 

 teris Evcmsil^ the Callipteridioid t3'pes, Neiiropteris acutimontana and 

 J\\ tennesseeana^ SpliemplnjUuni cunelfolium {saxifragcefolium form), 

 the Whittleseyas, and many of the fruits — are present in identical 

 forms and associations in the shales over the Sewanee and Sewell 

 coals. In fact, the elements of the flora from Lvkens coal No. 3 are 

 so preponderantly identical with those in the roof of the Sewanee 

 coal in Tennessee and the Sewell coal in southern West Virginia that 

 these coals can only be regarded as practically contemporaneous.^ 

 The paleontologic evidence for the identitication of the horizon of 

 the Sewell-Sewanee coals presents the most complete and convincing 

 as well as the most interesting case that has yet come within my 

 observation. 



Marlopti^'is piigiiHi'H and the identical forms of Alethopteris Lacoei 

 and Axt&ropliylllUs arkansanus^ which are especiallv t3'pical of the 

 roof of Lvkens coal No. 2 in the Southern Anthracite field, have 

 general!}' a somewhat higher occurrence and range in the bituminous 

 fields. 



The zone of the plants of Lvkens coals Nos. 2 and 3, which, in recog- 

 nition of the long-known flora of the Sewanee coal, at Sewanee and 

 Tracy City, in Tennessee, I have in a previous paper"" called the Sewanee 

 flora, may be termed the Sewanee zone. The distinctly Sewanee flora 

 is present above the Sewanee coal in the lower part of the Walden for- 

 mation in the Sewanee,^ Kingston, Pikeville, and Chattanooga quad- 

 rangles of the Tennessee-Alabama region, and over the Sewell coal in 

 the Raleigh, Kanawha Falls, and Hinton quadrangles in West Virginia. 



1 The contemporaneity of the Sewell coal and the Sewanee coal, as well as the similarity of their 

 stratigraphic relations in the Tennessee and Virginia sections, was pointed out in the description of 

 the Pottsville section along New River, West Virginia : Bull. Geol. Soc. America, Vol. VI, p. 316. 



- Loc. cit. 



^Geologic Atlas of the Unite>l Stales, folio s. 



