GRIMSLEY. | Origin of Gypsun. ag 
The western part remained a sea until the close of the Cretaceous 
period. 
The evidence of alternating shales, limestones, and gypsum 
layers shows that the conditions were undergoing changes 
through much of Permian time. The land was undoubtedly 
oscillating up and down. There were probably marked climatic 
and other physical variations. The Permian was a period of 
unrest. Part of the time the waters were clear, with conditions 
favorable for marine life, and the limestones were formed. 
At other times the waters were muddy through quantities of 
sediment carried in, and shales were deposited. These shales 
were sometimes sandy and light colored in the central and 
northern parts of the area, but more argillaceous and red to- 
ward the south. The conditions at the south were unfavorable 
for life, as no animal fossils are found throughout the Red Beds 
series. 
The swamp conditions of the Carboniferous had almost disap- 
peared, for no coal seams are found. In the earlier part. of the 
period, the marine life did not differ much from the later portion 
of the Carboniferous, and the fossils are quite similar. There 
is no evidence of any great disturbance through the period, so 
the changes must have taken place very slowly. The land 
movements probably formed bays, which were sometimes tem- 
porarily and sometimes permanently cut off from the main 
ocean. 
Origin of the Kansas Gypsum. 
There is no evidence of volcanic activity in the Kansas Per- 
mian, Cretaceous or Tertiary rocks, and volcanic rocks of any 
extent are absent; so Dawson’s theory of sulphurous vapors 
acting on limestones, or the action of acids from decomposed 
volcanic tufa, cannot be applied to these deposits. Magnesian 
rocks are not found near the gypsum strata, and there is no 
evidence at hand to even suggest Hunt’s chemical theory. The 
deposits are too extensive and of too great thickness to be ex- 
plained by the action of iron pyrites on carbonate of lime. 
The only theory which seems to accord with all the facts is 
