tered the flora of Appalachia. The first plants to repop- 
ulate western Pennsylvania were relict survivors of the 
Allegheny flora: Neuropteris ovata, Neuropteris scheuch- 
zert and Pecopteris lamurensis. Of these only Neuwrop- 
teris scheuchzeri regained a lasting place in the higher 
floras. Neuropteris (Mixoneura) ovata was gradually re- 
placed by Neuropteris (Mixoneura) grangeri and Neu- 
ropteris (Mixvoneura) neuropteroides. Pecopteris lamu- 
rensis was quickly eliminated. At the same time there 
was asteady influx of rejuvenating younger types, which 
were the typical Upper Stephanian and Permian plants 
from western Europe. 
In the Upper Conemaugh Walchia, Odontopteris, 
Lescuropteris, and Callipteridium make their first ap- 
pearances. Soon after T'aeniopteris and Baiecra migrated 
into the region of Dunkard sedimentation. The progres- 
sive change culminates in the arrival of Callipteris. 
No marine conditions occurred in western Pennsy]- 
vania above the Ames Limestone, with the exception of 
two local, insignificant recurrences in the Upper Cone- 
maugh. The reported marine limestone in the Dunkard 
of Ohio” is an unfortunate error. 
It is observed then, in the type section of the Upper 
Pennsylvanian, how Wadchia occurs in the normal, un- 
disturbed, stratigraphic sequence. This coniferous genus 
is but one of many genera which appear in chronologic 
succession, precisely as in the standard floral successions 
of the Carboniferous and Permian in western Europe. 
The occurrence of Walchiain the typical ‘ ‘coal flora”’ 
of fern-like foliage is of more than casual interest. The 
rarity and fragmentary nature of the two specimens from 
Pennsylvania indicates that they drifted into the sedi- 
ments in which they became preserved. Walchia prob- 
“Ohio Geol. Surv. (4th. Ser.) Bull. 22. 1920 
[18 ] 
