NORTH AMERICA AND THEIR VERTEBRATE FAUNA. 



IS 



of their sediments. By the time the deposition of the light-colored sediments had 

 ceased the conditions had become such that nearly all the sediments derived from 

 the land surrounding this basin were red. 



"In the Oklahoman region the deposition of red sediments began, perhaps, 

 as low as the Howard or Topeka limestones, and perhaps as high as the Emporia 

 or Americus limestones. The deposits then seem to be uninterrupted until the 

 unconformity below the Dockum beds (Triassic) in the Texas Panhandle is reached. 

 Some of these beds appear to be of subaerial origin, as has been shown by Case," 

 while others are certainly marine. Careful petrologic study will probably demon- 

 strate that much of the arenaceous material is wind-blown sediment, more or less 

 reworked by currents or waves as the regions were sub- 

 merged or flooded. That the sea covered the entire area 

 from Kansas to southern Texas and New Mexico at one time 

 may be questioned. If it did, the sediments contained were 

 of such a nature and abundance, or the waters so concen- 

 trated, as to preclude the free migration of a normal marine 

 fauna throughout the basin. That marine conditions pre- 

 vailed, at least locally, is demonstrated by the Whitehorse 

 and Dozier faunas. 



"In Texas normal deposits were laid down in higher 

 horizons than in Oklahoma, and in Kansas there are reasons 

 for believing that the light-colored sediments were laid 

 down at an even later date than in Texas. These conditions 

 are illustrated by the subjoined table [fig. 3], showing a 

 vertical section of the Carboniferous and Permian rocks of 

 the three States." 



In 191 2 Beede'' gave a second account of the same 

 phenomenon : 



"In tracing the limestones and shales of the basal 

 Permian beds of Kansas southward into Oklahoma, the 

 relationship of the light-colored sediments to the red sand- 

 stones, red shales, and red limestones of Oklahoma is clearly 

 revealed. It is shown that some of the heavier ledges of 

 limestones first become sandy along their outcrops in patches 

 a few rods across. Farther south the sandstone areas in- 

 crease in size until the limestone appears only in local areas 

 in the sandstones, and is finally wanting. Traced farther 

 southward, the sandstones become deep red or brown, with 

 local areas of white. The decimation of the fauna sets in as 

 the limestones diminish, and the remains of life are not found far beyond the limits 

 of the hmestones. The shales become red very much farther north than do the 

 sandstones, and are frequently more deeply colored. Some of the lower limestones 

 become red before they change into sandstones. The sandstone ledges continue 

 for some distance southward as rather even, uniform beds, but farther on they are 

 found to thicken and thin in a somewhat systematic manner. 



"Several ledges of sandstone frequently occur in a single section, and, where 

 one of these ledges is found thickened, the others are apt to be thicker than normal. 

 Likewise, they are all found to be thin over certain areas. The regions of thickening 



TEXAS OKLAHOMA KANSAS 



Fig. 3. — Chart showing re- 

 lation of the Permo-Carbon- 

 ifcrous rocks in Oklahoma, 

 Kansas, and Texas. (From 

 Beede.) 



» Case, Bull. Amer. Mus., vol. 23, 1907, 

 !> Beede, Science, vol. 35, No. 896, 1912, 



p. 659. 

 p. 348. 



