252 ENVIRONMENT OF VERTEBRATE LIFE, ETC. 



"The folding of the Ouachita beds has been referred by Dana and others to 

 the Appalachian revolution. However, unless published correlations are seriously 

 in error, we must conclude that the Ouachita folds had been formed and truncated 

 before the deposition of the latest Pennsylvanian sediments, whereas the Appa- 

 lachian folds were not begun until after the early Permian strata had been laid 

 down. It is now generally agreed that the climax of that disturbance came near 

 the close of the Permian period. If these correlations are correct, we must then 

 recognize two separate orogenic epochs. There is apparently ground for cor- 

 relating the Arkansan crumpling with that which produced the Armorican and 

 Variscian systems of western Europe, which Haug assigns^ to the opening of the 

 Stephanian (upper Pennsylvanian) epoch." 



Disturbances coincident with Blackwelder's Arkansas orogenic move- 

 ment are not recorded in any folding or disturbance of the rocks on the 

 east side of North America later than the end of Mississippian in the southern 

 Appalachians, but that there was an approximately coincident uplift of 

 the land east of the Appalachian trough is recorded in sedimentary changes 

 from Prince Edward Island to West Virginia. The descriptions of the 

 Glasgow conglomerate, Roxbury tillite, and the red beds of West Virginia 

 and Pennsylvania are given in the stratigraphic section. 



The evidence for an uplift to the south and east of the Canadian and 

 Massachusetts localities is included in the description of the rocks of those 

 areas, and I. C. White's argument for the meaning of the sudden appearance 

 of the red beds has been given (pages 65 et seq.). 



^ Haug, Emile, Traite de Geologic, vol. 11, pt. i, p. 829, 1910. 



