242 
FRAMEWORK OF ARIZONA 
from beds of the same geologic age elsewhere. One familiar with 
the organic remains of the Carbonic rocks of the Mississippi Val¬ 
ley finds himself as much at home in these rocks in Arizona as he 
does in Missouri or Iowa. Every fossil that he picks up he exactly 
matches with one from the distant Ozarks. Not a single new face 
presents itself. The paleontological reports of Iowa Missouri and 
Illinois might just as well have been written in Arizona. Chief 
reason why collectors in this region are not set aright by their Mis¬ 
sissippi volumes is that they search for their subjects nowhere else 
than on the Canyon’s brink, which, for some unaccountable cause, 
is the most unfavorable spot for such work in the whole Southwest. 
When, as a distinctively descriptive title, the term Red Wall Lime¬ 
stone first appeared in geological literature, a designation suggest¬ 
ed by Gilbert in 1875, the age of the formation is, already 20 years 
before, correctly determined by Marcou and by Newberry to be 
Early Carbonic. In long years afterwards a side-canyon is espe¬ 
cially dignified with the title of the Red Wall Canyon, and the 
formation is regarded as having its type-locality here; but this 
surely is stretching the canons of nomenclature to breaking point. 
Of late it becomes customary to speak of the Red Wall rocks 
and their correlations in the West as the Mississippian unit, sig¬ 
nifying thereby that they occupy all of the Early Carbonic inter¬ 
val. But the Red Wall section is not the so-called Mississippian 
section, completely spanning Early Carbonic time. As indicated 
by the faunas the western rocks cover only the middle portion of 
the Early Carbonic succession of the Mississippi Basin. They em¬ 
brace only the exact section to which Winchell originally gave and 
restricted the title of “Mississippi Limestone Series.” 
Above this median and typical Mississippian section of Early 
Carbonic strata in the Mississippi Valley is another sequence 
known as the Tennessean Series, a title which covers those sedi¬ 
ments carrying faunas which originated not in the West but in the 
Southeast. This is a subdivision that is especially stressed both 
by Schuchert and by Ulrich. 
Below the median section is the basal Waverleyan Series, whose 
company of faunas may have closely followed the Hungerfordian 
fauna, which, originally, starting from its homeland in central Asia, 
tarried awhile in Arizona and then in Iowa on its way to New 
York, and on around the world. The median faunas also appear 
