PERMO-CARBONIFEROUS CONDITIONS AND TIME 505 
Beyond the elevated region of Missouri the upper Pennsylvanian 
and Permo-Carboniferous rocks of Kansas 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 series in those states. 
The appearance of red beds is generally accepted as evidence 
of a decided climatic change and it is also generally accepted that 
this change in the late Paleozoic was largely the result of an eleva- 
tion of the continent which began in the eastern side and progressed 
toward the west, though other causes, as a change in the amount of 
CO, in the air, very probably had some part in the final result. 
As stated above, red beds appear at successively higher levels 
toward the west. Detailed evidence for this will be given in a 
forthcoming monograph in the publications of the Carnegie Institu- 
tion of Washington. 
As the uplift affected regions farther and farther to the west, the 
climate altered progressively in the same direction and the resultant 
changes in physiography, hydrography, and vegetation compelled 
an alteration of the environment which permitted the migration of 
the Permo-Carboniferous reptilian-amphibian fauna with but 
little morphological change. 
This environment remained fixed in the east as it spread west- 
ward, resulting in a wedge-shaped series of beds which can be 
correlated as formed under ‘‘Permo-Carboniferous conditions”’ 
from the observed effects produced by climatic factors. The 
wedge shape of this series causes it to extend deeply into the 
Pennsylvanian series (to middle Conemaugh) in the east and to 
involve only the true Permo-Carboniferous in the west. The 
development and migration of the vertebrate life were governed, 
not by the passage of geological time, but by the development and 
spread of the peculiar environment. 
The occurrence of Permo-Carboniferous reptiles and amphibians 
much lower in the stratigraphic series on the east than on the west 
is no longer a puzzle. The animals appeared with the environment 
and migrated with it. They occur strictly within the time and 
