8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 134 
crop of fresh-water limestone interbedded with coarse-grained vol- 
canic sandstone. The beds of limestone contain some fine-grained 
volcanic material, and at most places are highly siliceous with large 
irregular masses of gray to green chalcedony and chert that has re- 
placed the limestone. Small well-defined nodules of black chalcedony 
are common. The limestone is abundantly fossiliferous in localized 
areas; gastropods are commonest, pelecypods and vertebrate remains 
Isolated deposits of mixed 
volcanic and clastic material 
ae \ 
ray and tan Pre-Tertiary rocks of Owl Creek 
volcanic sediments and Big Horn Mountain ranges 
Upper 
Green ond brown 
member 
Hendry Ranch member 
(coon 
(White clastic 
facies) 
= 
ws 
S 
S 
(See note) 
Brightly colored 
facies 
Wind River formation Tepee Trail formation 
Note: Relation of Tepee Trail forma- 
tion to underlying Eocene strata con 
be observed only in vicinity of Wind 
River Canyon 7 miles west of map 
in figure 2. 
Fic. 3.—Diagrammatic cross section showing relations of facies of Tepee 
Trail formation. 
being less abundant. Prop roots of palms, replaced by bluish-black 
chalcedony, are abundant and conspicuous in the limestone. On Bad- 
water Creek, the siliceous limestone apparently passes laterally to the 
northwest into bright emerald-green volcanic sandstone. 
The volcanic rocks in the Absaroka centers are mostly andesitic, 
although basaltic breccias and tuffs are present (Love, 1939, p. 76). 
The detrital volcanic rocks in the northeastern part of the Wind 
River Basin are similar in composition to the Absaroka rocks. Labra- 
dorite, as determined by measurement of extinction angles, is the 
commonest plagioclase, although one thin section contained bytownite. 
Biotite and euhedral hornblende are abundant; hypersthene and 
pigeonite are common. Shards of somewhat altered glass are abun- 
