OKLAHOMA ACADEMY OF SCIENCE 75 



structure, in geologic age, and in physiographic history. The rocks 

 of the Arbuckle plateau range in age, beginning with the oldest, from 

 pre-Cambrian granite and porphyries to the Mississippi limestone, 

 and include some 10,000 feet of sediments of Paleozoic formations 

 distributed among the Cambrian, Ordovician, Silurian, Devonian 

 and Mississippian systems, the thickest of these formations being 

 the Arbuckle limestone, of 5000 to 6000 feet. 



Surrounding the older rocks of the Arbuckle plateau are younger 

 formations of Pennsylvanian age mainly, with some Permian at the 

 western border, which usually lie at a level of 100 to 200 feet lower 

 than the older rocks of the plateau area immediately adjacent. The 

 geologic history of the Arbuckle plateau region involves the pro- 

 cesses of sedim.entation which resulted in the formation of the 

 stratified rocks of the plateau area, the uplift and folding of these 

 formations into mountains, and the erosion of these mountains to 

 a low plateau. There was essentially continuous deposition of sedi- 

 ments in the Arl)uckle plateau area from the Cambrian to the close 

 of the Mississippian as indicated by the general conformation of all 

 the strata of these systems. 



At the c'ose of the Mississippian, however, this long period 

 of essentially conformable deposition ceased, and the rocks of the 

 Arbuckle plateau were uplifted and folded into mountains, and 

 these mountains were subjected to erosion. The material eroded 

 from the mountains was deposited in the low lands and seas sur- 

 rounding the uplifted area and forms the Pennsylvanian and Per- 

 mian sediments that now make up the usually lower lands' that 

 surround the plateau. 



There is essential agreement among geologists who have worked 

 in the Arbuckle region, concerning the geologic history of the area, 

 so far as it concerns the deposition of the pre-Mississippian rocks 

 of the plateau and their uplift into mountains in post-Mississippian 

 time. There is, however, good reason for a difference of opinion 

 concerning the physiographic history of the region after the moun- 

 tains were formed, especially in regard to the age of the develop- 

 ment of the Arbuckle plateau, and it is to this feature of the geology 

 that attention is called. 



Tafif(l), who was the first, in 1904, to present a geologic ac- 

 count of the Arbuckle region, ascribed the development of the 

 Arbuckle plateau to a Cretaceous period of degradation. He further 

 supposed that the Cretaceous sea not only covered the entire pla- 

 teau area but also extended farther to the north and that Cretaceous 



(l)Prof. Paper 31, U. S. Geol. Sur. 



