FRAMEWORK OF ARIZONA 
245 
movements and other planation activities doubtless were repeat¬ 
edly in operation before. Despite the circumstance that this ero¬ 
sion might have gone on simultaneously with copious deposition 
elsewhere, the fact remains that the extent and location of this 
hypothetical sedimentation are not yet determined. 
The Moenkopian red beds series consists mainly of alternating 
shales and sandstones. Because of their striking coloration the 
formations are sometimes regarded as Triassic in age and some¬ 
times Permian. Ward’s title is taken from the Moenkopi Wash, 
in the lower valley of the Little Colorado River. The sequence 
\ 
is well described by him and the subdivisions which he differen¬ 
tiated appear to constitute good terranes. The names here applied 
are selected from localities in the neighborhood where the respec¬ 
tive formations are fully exposed. Ward’s descriptions are also 
summarized by Gregory, but no special designations are given. 
This series of red beds may be comparable to either the Ber- 
nallian shales, or the Cimarronian shales of New Mexico, the 
Guadalupian limestones not extending into Arizona. It is most 
likely, however, that exact and final parallelism will show that the 
Moenkopian section is very nearly the precise stratigraphic equiv¬ 
alent of the Bernallian series; in which case two great Carbonic 
series are not represented in the west. 
For reasons recently stated ^ at some length the Russian title 
of Permian for any Arizona terranes is inappropriate, uncertain 
and best dropped. 
If, in Arizona, there be missing two great serial successions of 
the Carbonic rocks, the Guadalupian and the Cimarronian, there 
are also absent two more adjoining series of the general column, 
together representing two-thirds of Triassic time. The strati¬ 
graphic hiatus which exists in the middle of the red beds on the 
Colorado Dome is, therefore, a major break covering an erosional 
interval of long duration and involving mayhap complete pene- 
planation of not only the general region but of the country far 
around. Treatment of the red beds as all of the same age is 
evidently the direct occasion for all the confusion and uncertainty 
which have so long existed concerning them. 
For the subdivision of these red beds Ward makes very satis¬ 
factory units and units that well express the course of the geologi- 
1 This journal, Vol. XXXVIII, p. 147, 1922. 
