CHAPTER III. 

 THE PLAINS PROVINCE. 



The Plains Province of deposition in Permo-Carboniferous time was 

 in all probability a continuous whole, as described in Publication 207 of the 

 Carnegie Institution, with a gradually shrinking body of clear water sur- 

 rounded by large areas of red-bed deposition traceable from the Black 

 Hills of South Dakota to New Mexico along the eastern front of the Rocky 

 Mountains. The red beds deposited, in all probability, on the eastern side 

 of the shrinking body of water have either been removed by erosion north 

 of southern Kansas or are covered by younger deposits. The following 

 summary description is given by States or by convenient units ; it is obvious 

 that the beds frequently extend across the artificial political boundaries. 



A. THE LATE PALEOZOIC IN KANSAS. 



The series of upper Paleozoic rocks in eastern Kansas is the most com- 

 plete and illuminating of any section in the western portion of North America 

 and is taken as the standard with which are compared the various exposures 

 in the Plains Province. The long-drawn-out controversy as to the age of the 

 upper Paleozoic rocks of Kansas has now little more than historic value, but 

 it has, for good or ill, definitely attached to the upper part of the series the 

 name Permian. This has been, with little doubt, the cause of much of the 

 difference of opinion and the source of many of the controversial papers 

 that have been published. Had this difficulty, more than half a historical 

 matter, not persisted, the effort to find a sharp dividing-line between Penn- 

 sylvanian and Permian would not have been so vigorous or so long sustained, 

 and a recognition of the essential similarity of the beds under the name 

 Pennsylvanian and Permo-Carboniferous would have been much earlier 

 recognized. As it is, the line between the "Permian" and Pennsylvanian 

 has been forced downward by successive stages until now the Kansas lower 

 "Permian" includes all the rocks from the base of the Elmdale formation 

 to the top of the Wellington shales. These include series iv and v of the 

 Kansas Geological Survey, with stages i, j, the Chase, Marion, and Welling- 

 ton, as given by Beede in the volume ix of the Kansas University Geological 

 Survey. 



Whatever may be the final outcome of the controversy concerning the 

 terminology of these beds, they are very certainly the equivalent of beds 

 called Permo-Carboniferous elsewhere in the United States, and the author 

 will consistently regard them as of such age in this work. 



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