2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 134 
illustrate a few of them. The brachiopods described herein are of 
great interest because of their obvious affinities to Russian species and 
because of the occurrence of genera never, or only seldom, seen in 
more familiar areas of Permian rock in this country. When first 
reported these brachiopods were thought to be of Lower Permian 
age (Merriam and Berthiaume, 1943, p. 158) but this more detailed 
study requires a revision of this view. They now appear to be of 
Medial Permian age with probable affinities to the fauna of the lower 
part of the Word formation of west Texas. 
DESCRIPTION OF COYOTE BUTTE FORMATION 
The following description of the Coyote Butte formation is revised 
from Merriam and Berthiaume (1943). The youngest Paleozoic 
beds of the area comprise a sequence in which massive limestones 
form the most conspicuous exposures. These produce prominent 
ridges, buttes, and small circular hills or knobs subsidiary to the main 
ridge slopes. Steeply dipping strata forming the crest of Coyote 
Butte near the southern limit of the map (text fig. 1) constitute the 
type section of the formation. The Coyote Butte beds here lie in the 
north limb of a tight syncline overturned toward the south. Another 
bold outcrop of the formation appears in the belt extending north- 
northeast from the vicinity of Tuckers Butte for about 4 miles. A 
third area of Permian beds includes exposures in the northeast portion 
of the map, one tongue of which extends southwest beyond Twelve- 
mile Creek where it is covered by Tertiary lava. 
At the type section the lower portion of the Coyote Butte forma- 
tion is generally a light olive-gray limestone, often crinoidal and 
locally containing fusulinids in great abundance. Higher in the section, 
at the summit of Coyote Butte, the limestone becomes purer, finer 
grained, deep olive gray in color and possesses more distinct bedding. 
In this upper portion fusulinids are less frequently met while brachio- 
pods are common. 
The character of the Coyote Butte limestone throughout the area is 
similar to that found at the type locality. Coarse crinoidal debris is 
abundant at several localities not far above the lower contact of the 
formation. Conglomeratic phases of the basal limestone also occur 
locally. At locality S73 in the eastern part of the area rounded chert 
pebbles and subangular chert grains are distributed throughout a 
crinoidal and fusulinid-bearing limestone. Another conglomeratic 
phase at the base of the limestone occurs on the west side of Spotted 
Ridge. Here pebbles of green, white, red, and black chert become 
