GRAND CANYON SECTION 
411 
the Archeozoic sequence, and an undeterminable thickness of the 
^crystalline Azoic complex. 
^ The Coconino sandstone appears to be only a local development, 
and requires no further consideration in the present connection. 
But the Supaian series of shales, a thousand feet in thickness, 
although yielding no coals in the Canyon region carries important 
deposits in the eastern part of the State and in New Mexico, and 
seems to be the western attenuation of the Arkansan, and perhaps 
the Des Moines, series which in the Wachitas are 20,000 feet in 
thickness. 
Famed Red Wall limestone remains today the same lurid cliff 
that it presented to first European eyes in that fateful summer 
of 1540, when Garcia Cardenas and his handful of conquestadores 
ventured upon its brink, having treked over from Cibola (Zuni) 
in what is now New Mexico, along the path laid out by Tobar 
to the Moqui villages, and thence on to the Canyon. It is yet 
undifferentiated faunally; and even so eminent a paleontologist as 
Professor Schuchert on a recent visit deprecated the extreme 
paucity of its fossils and the universal unsatisfactory understand¬ 
ing of the formation. Yet only a short distance away Red 
Wall resolves itself into distinct faunal zones and lithologic units 
as clearly defined as is its more familiar equivalent section on the 
Mississippi River. In sight of El Tovar Keokuk fossils are as 
characteristic and as plentiful as they are at Keokuk itself. Burl¬ 
ington crinoids are more abundant than at the famous fossil 
locality in Iowa. And Chouteau fossils surpass in numbers, size 
and perfection anything ever obtained from the original localities 
in central Missouri. 
The thin Temple Butte limestone barely denotes the presence 
of Devonic sediments, which farther east are a thousand feet thick. 
The unconformity plane at its base in the Canyon walls, to which 
scant attention is usually given, is amply explained in its great 
magnitude by the presence to the eastward of 2000 feet of Devonic, 
Siluric and Ordovicic strata. To the southeastward, under the 
Mogollon escarpment the Cambric strata exceed a mile in thick¬ 
ness. 
Proterozoic sediments, which are exposed only in a slender 
thread along the River’s edge, find elsewhere in Arizona broad 
