DIFFERENT PROVINCES OF NORTH AMERICA IN LATE PALEOZOIC TIME 65 



(a) APPEARANCE OF RED BEDS IN PENNSYLVANIA AND WEST VIRGINIA. 



The first appearance of red beds in the upper Paleozoic deposits of the 

 Southern Subprovince is not the conventional line between the Pennsylvanian 

 and the Permo-Carboniferous. It has for long been drawn at the top of 

 the Waynesburg, the uppermost bed of the Monongahela series in Pennsyl- 

 vania and West Virginia, but this location has been contested by I. C. White, 

 who claims that the alteration in the character of the sediments at a much 

 lower stratigraphic level indicates a change in climatic and physiographic 

 conditions which warrant the line being dropped to the level of the Saltsburg 

 sandstone member of the Conemaugh in West Virginia, approximately the 

 horizon of the Pittsburgh red shale in western Pennsylvania. 



The original location of the line of division at the top of the Monongahela 

 was determined by the evidence from invertebrate fossils, now somewhat 

 less significant, owing to later discoveries, and from paleobotanical evidence, 

 upon both of which David White still maintains the correctness of the 

 original location. 



[He] "is inclined to draw the Westphalien-Stephanien (Mid- Pennsylvanian) 

 boundary provisionally at or close above the top of the Allegheny, the Mahoning 

 sandstone being interpreted as showing the beginning of a more pronounced 

 erogenic movement which seems gradually to have brought about the final 

 exclusion of the sea." 1 



In his latest discussion of this point, I. C. White 2 says: 



"In this connection it should be noted that the writer has for many years 

 suggested and contended that the sudden introduction of red sediments into the 

 Conemaugh series, after their total absence since the close of Mississippian time, 

 when a long period of erosion supervened, was an event of unusual importance 

 to geologic history. In fact, so distinctive as to warrant the last chapter of the 

 Pennsylvanian being closed at that horizon, and the first chapter of the Permian 

 or Permo-Carboniferous opened with the deposition of the Conemaugh red beds. 



"The Permian fauna already described by Case from the horizon 34-40 feet 

 below the Ames limestone at Pitcairn, Pennsylvania, proves incontestably that 

 Permian vertebrate life had already arrived in the Appalachian field, just as it 

 had in the western coal fields at the closing stage of the Illinois Coal Measures, 

 and hence there can be no valid reason why representatives of Pareiasaurus 

 may not have been among the arrivals that accompanied the new conditions 

 producing the Pittsburgh red shales that succeeded the great white sandstone 

 epoch which began with the Pottsville on top of the Mauch Chunk red beds, and 

 closed with the deposition of the Mahoning, Buffalo, and Saltsburg sandstones 

 making up the lower one-third of the Conemaugh series as now delimited. The 

 marine fauna in the Ames limestone is largely composed of forms common to the 

 Permian beds, as may be seen from the following list of species identified from 

 West Virginia localities by Stevenson, Meek, Beede, Price, and others, as com- 

 piled by Wm. Armstrong Price : 



1 \Yhite, David, in Professional Paper No. 71, U. S. Geological Survey, p. 437, 1912. 



2 White, I. C., Notes on the Paleontology of Braxton and Clay Counties, West Virginia; 



Braxton and Clay County Report, Geological Survey of West Virginia, p. 822, 1917. 

 6 



