4 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 134 
nent linear or circumscribed exposures. Northeast of locality $123 
in the center of the map several zones of sandstone float alternately 
with fusulinid limestones. 
Large amounts of insoluble materials, such as chert and sand 
grains, occur locally in the Permian limestone. At locality S68 in the 
northeastern portion of the area, dark, irregular chert layers up to 10 
inches in thickness are interbedded with the limestone. In other oc- 
currences the siliceous material replaces the limestone as irregular 
patches and permeates it in varying degree. In some instances, as 
along the southwest side of Spotted Ridge, the limestones are dolo- 
mitic and in extreme cases are apparently recrystallized, giving the 
rock a light gray or pale cream color. 
Thickness.—At the type section on Coyote Butte the Permian beds 
measure approximately goo feet. Estimates of thickness on Spotted 
Ridge and north of Tuckers Butte are approximately the same. How- 
ever, exact thicknesses cannot be given because bedding is poor and 
folds within the massive limestone are difficult to unravel. Where 
the formation is to a great extent arenaceous, exposures are poorly 
developed. Unconformable relation of the Permian to overlying beds 
further conceals their thickness in some localities. 
Stratigraphic relations—The Coyote Butte is unconformable on 
the Pennsylvanian Spotted Ridge formation. This relation is ‘sug- 
gested by pinching out of the Pennsylvanian strata in sec. 5, T. 19 S., 
R. 25 E., where the contact between Coyote Butte limestone and the 
Lower Carboniferous Coffee Creek formation is apparently deposi- 
tional. At locality S105 north of Tuckers Butte an exposure of the 
lower contact of the Permian shows a slight angular discordance and 
a definite truncation of the conglomeratic and sandy beds of the 
underlying formation. On the basis of lithology and position the 
latter beds are presumed to be the Spotted Ridge formation. Further- 
more, on the west side of Spotted Ridge and at several other locali- 
ties the basal Coyote Butte strata are very pebbly limestones and 
calcareous conglomerates, probably indicating reworking of subjacent 
Pennsylvanian clastics. 
LOCALITIES FROM WHICH BRACHIOPODS WERE COLLECTED 
Some of the localities listed below are uncertain and sketchy be- 
cause of the early lack of maps in this region. Inasmuch as good 
fossils are difficult to find in this complicated area, it seemed best to 
use all the specimens regardless of the sketchy quality of some of the 
locality descriptions. Completeness of faunal description seems a 
