64 ENVIRONMENT OF VERTEBRATE LIFE, ETC. 



II. THE SOUTHERN SUBPROVINCE. 



As stated above, it is impossible to correlate at all exactly the deposits 

 of the Northeastern Subprovince with those of the Southern Subprovince; 

 indeed, it is very possible that these two subprovinces may bear very much 

 the same relation to each other that exists between the Basin and Plains 

 Provinces. The close similarity in the material and the sequence of deposits 

 which exists between the Permo-Carboniferous beds in Prince Edward 

 Island, Nova Scotia-New Brunswick, and Massachusetts-Rhode Island, the 

 disposition of the beds in local basins between anticlinal elevations, the 

 location to the east of masses of ancient igneous rock which form the northern 

 extension of a part, at least, of Appalachia, all seem to indicate the original 

 separation of these areas of deposition from the Southern Subprovince, 

 either completely or in large part. The lie of the whole series of basins, 

 ending with the Narragansett Basin, is such as to suggest a continuation 

 southward upon the submerged and buried eastern portion of the ancient 

 Appalachia continent. Such a possibility is entirely in consonance with 

 the idea of gradual compression of the edges of the continents by suboceanic 

 shove, as advocated by Ulrich. 1 On the other hand, there is a total lack of 

 paleontological evidence either for or against such a separation. 



The recognition of the two areas as distinct provinces must wait for 

 accumulated evidence, if it is ever to be done. There is much evidence, 

 however, that both subprovinces were affected by a climatic change during 

 the same interval of time or during approximately equivalent intervals. 



The nature of the record of this change lends support to the suggestion 

 that the basins of the Northeastern Subprovince are but a portion of a 

 series which extended farther south, east of the present Piedmont Plateau 

 and nearer to the area whose elevation initiated the climatic disturbance, 

 for in these basins the red beds have as their basal members conglomerates 

 and tillites, while the more abundant red shales and sandstones lie higher 

 in the series and extend farther to the west. In West Virginia and Pennsyl- 

 vania it is only the red shale and sandstone which appear in any quantity- 

 just such a phase of deposition as one would expect if the elevated area 

 were more distant (to the east) from the aggrading basins. 



It is just this evidence of climatic change, though present in slightly 

 different phases, which serves to bridge the gap in the correlation of the two 

 subprovinces and also serves to mark the beginning of Permo-Carboniferous 

 time, as it was not only a major change in itself, but points to a period of 

 diastrophism, other evidence of which is largely hidden by younger deposits 

 on the eastern side of Appalachia or did not develop until the close of the 

 Permo-Carboniferous period. 



1 Ulrich, E. O., Revision of the Paleozoic Systems, Bull. Geol. Soc. Amer., vol. 22, pp. 439- 

 442, 1911. 



