220 The American Geologist. October, 1903. 
Tn my various papers, with one exception due to a typograph- 
ical error arising from inability to see the proof sheets of the 
article, this fact is clearly indicated. This is particularly em- 
phasized in the memoir frequently quoted by professor Pros- 
ser, on the detailed comparison of the Upper Carboniferous of 
Kansas with the Russian Permian. 
In reality, the Oklahoman is very different in its delimita- 
tions from the Big Blue series, notwithstanding the fact that in 
central Kansas the two may appear perhaps at first glance to be 
approximately the same. Were only Kansas to be considered 
there would probably be little hesitation in reaching a satis- 
factory conclusion. In this case so far as I am personally con- 
cerned there would be no necessity of quibbling over what 
might be regarded as mere titles, and professor Cragin's name 
might be easily accepted if it properly expressed the strati- 
graphy. 
It so happens that the horizon of the summit of the Mar- 
ion limestones is stratigraphically a very important one. Its 
significance is not so apparent in Kansas as farther southward. 
The most remarkable developments of the vaguely understood 
"Red Beds" are found in Oklahoma, northwestern Texas and 
to the westward in New Mexico. It is here that the real differ- 
entiation of the Upper Carboniferous is to be considered in its 
various phases. The history of the Oklahoman series is a very 
different one from that indicated within the stratigraphic lim- 
its of the so-called Big Blue. The two terms are not synonym- 
ous by any means. They stand for two very different ideas. 
A full statement of these distinctions will probably be shortly 
given out. 
Tentatively the Cimarron terrane is regarded as the upper- 
most series of the Carboniferous of the continental interior. 
However, it is by no means certain as yet that either the name 
can be retained or the series kept intact. Should the title be 
preserved it is quite likely that the limits of the formation to 
which it is applied will have to be considerably modified. As in 
:be case of the Oklahoman the criteria of ultimate classification 
are to be drawn not from Kansas but from the country to the 
southwest. 
There should not be any juggling of words in such questions 
as those under consideration. Yet professor Prosser says : "A 
