Permian Question in America. — Keyes. 219 
ford solutions to the chief problems which now demand atten- 
tion before all others. Everything points to districts outside 
of this state for the critical information so long sought. 
The recent excellent paper on the "Revised Classification 
of the Upper Paleozoic Formations of Kansas,"* by professor 
Charles S. Prosser, sums up certain phases of our knowledge 
on some of the vexed questions presented. Not the least val- 
uable feature of professor Prosser's notes on Kansas geology 
is the clearness with which he usually states the positions and 
observations of others and adjusts them to his own plan. Be- 
fore passing to the main theme, however, I wish to call at- 
tention briefly to several of the points especially dwelt upon 
in the recent paper just referred to; and to restate several of 
my conclusions formerly reached, which I think professor 
Prosser has not reiterated quite in the sense I originally in- 
tended — a fact due partly no' doubt to my own neglect to make 
certain statements sufficiently clear. 
Whether or not the term Oklahoman shall eventually be 
regarded as the proper serial title for one of the provincial 
terranes of the Carboniferous in the continental interior makes 
little difference ; but I cannot agree with professor Prosser 
that it is synonymous with Cragin's name Big Blue series of 
Kansas. When the title Oklahoman was first proposed for the 
uppermost series of the Carboniferous its upper limits were not 
very definitely fixed — further than it was stated that in a gen- 
eral way the terrane corresponded to what had previously been 
called Permian. At that time the Red Beds were regarded as 
post-Carboniferous in age. Until more conclusive and exten- 
sive evidence is forthcoming there seems at the present time 
no good reason for considering the geologic age of all of these 
formations Paleozoic. 
Notwithstanding the very positive statements of professor 
Prosser that the Oklahoman is coextensive with Cragin's Big 
Blue Series it is very clearly not exactly so. As it now appears, 
even according to professor Prosser's published data, the Okla- 
homan in central Kansas includes at the base at least one im- 
portant formation more than the Big Blue series; and at the 
top at least one formation less. The Oklahoman series in 
Kansas is delimited above by the top of the Marion limestones. 
•Journal Geology, vol. x, pp. 703-737, 1902. 
