16 University Geologicai Survey of Kansas. 
y g y 
until along the south line of the state the Permian and Red 
Beds combined have a thickness nearly ten times as great as the 
Permian has at the north Kansas line. Within Kansas terri- 
tory, therefore, the Permian ocean was driven southwestward 
rather than westward, as is abundantly proved by the extraor- 
dinary thickening southward of these formations. 
At the close of the Permian period, however, it seems that 
throughout the whole of the ‘‘ Mediterranean Sea’’ the reverse 
conditions obtained, so that ultimately the great inland sea was 
driven northward into the Arctic ocean. This phase of the sub- 
ject was discussed at considerable length in Volume II of this 
Survey, and was illustrated by Plate XX VI, which shows that 
within Kansas there is a great thickening of the Cretaceous 
beds to the north corresponding to the thickening of the Permian 
beds to the south; and the further fact, well established, that in 
the southern part of Karisas, and much more markedly so south 
through the Indian Territory and into Texas, the lower Creta- 
ceous beds only are found, while in northern Kansas and Colo- 
rado and further to the north the upper Cretaceous occurs in 
great abundance. 
This leveling up, so to speak, of the horizons by the thicken- 
ing of the Cretaceous formations over the territory where the 
Permian was the thinnest is an interesting point in connection 
with the geology of the formations laid down in the great 
‘‘Mediterranean Sea’’ area and confirms the view already 
stated, as emphasized by Grimsley, that throughout the period 
of gypsum formation there was a great lack of stability in 
oceanic boundaries which made it possible for the frequent em- 
bayment of bodies of ocean water, so that by their surface 
evaporation gypsum deposits could be produced, and that the 
same irregularity in stability of conditions produced such de- 
posits at yarious times and in various places throughout the 
ereat western interior area. Sometimes two or more beds of 
gypsum are found one above the other, implying a repetition of 
such conditions in the same locality with an interval of sedi- 
mentation between, but generally the series of conditions have 
migrated southwestward as time advanced. 
