CORRELATIONS 683 



"The limit recognized for the Permo-Carboniferous fauna is, then, from the 

 Pittsburgh red shales to the top of the Clear Fork. The stratigraphic extent 

 of the space delimited it is impossible to state, since there is no direct correla- 

 tion of the eastern and western beds possible, but may be roughly stated as 

 from the middle of the Conemaugh to the top of the Permo-Carboniferous. 

 The limits of the fauna in America, however, are not those of Europe ; the 

 fauna there are continued into the Triassic." 



In order to get a clear understanding of the whole subject, which can 

 not be fully reviewed here, the two articles should be read in full. 



After discussing the red beds and their fossil remains as local evidence 

 of the gradual elevation of the Appalachians, he states : 



"These local proofs of elevation are but contributory evidence of the whole 

 eastern part of North America, probably as a continuation of the same move- 

 ment which formed the Hercynian somewhat earlier in central Europe. The 

 elevation of North America, which began on the eastern side, was gradually 

 extended to the west, as is shown by the progressive disappearance of the 

 Mississippian sea and the Pennsylvanian coal swamps in that direction. 



"The elevation was attended *by gradual change in climate ; instead of gray 

 and black shales and white sandstones the prevailing deposits were colored 

 red by the oxidation of iron under the influence of a less equable climate, as 

 seasons of relative drought and humidity succeeded each other. 



"As the climatic change migrated toward the west only slowly, red sediments 

 were formed at progressively higher and higher levels. In western Kentucky, 

 Indiana, and Illinois the conditions necessary for the formation of red beds 

 did not arrive until after the highest sediments now preserved had been 

 formed, or only thin deposits were formed which have since been removed by 

 erosion. That the surface of these regions was dry land by the time 'Permo- 

 Carboniferous conditions' had reached them is suggested by the mode of occur- 

 rence of the vertebrates in Illinois and the Merom sandstone in Indiana." . . 



"Beyond the elevated region of Missouri, the upper Pennsylvanian and 

 Permo-Carboniferous are limestones and gray to black shales, but farther south 

 the Permo-Carboniferous beds of Oklahoma, Texas, and New Mexico are red. 

 These beds lie above the Missourian of Missouri and Iowa which extend well 

 up toward the top of the Pennsylvanian, as developed in Pennsylvania and 

 West Virginia, certainly much higher than the first appearance of red beds in 

 the Conemaugh of those States." 



"As the uplift affected regions farther and farther to the west, the climate 

 altered progressively in the same direction, and the resultant changes in physi- 

 ography, hydrography, and vegetation compelled an alteration of the environ- 

 ment which permitted the migration of the Permo-Carboniferous amphibian- 

 reptilian fauna with but little morphological change." . . . 21 



There are three phases of this postulate, the first two of which have 

 been treated, to be discussed: First is the development of invertebrate, 

 vertebrate, and plant life during the Pennsylvanian and early Permian ; 



21 Carnegie Institution of Washington, Publication 207, 1915. 



