NO. 4 GEOLOGY, WIND RIVER BASIN—TOURTELOT 23 
they do now. Anderson (1933) has described volcanic mudflows that 
traveled much farther than the present distance between Squaw 
Buttes and the Absaroka Range, and on slopes that were similar to 
those that must have existed in the Big Horn Basin. The interpre- 
tation that formerly much more extensive volcanic mudflow masses 
were present in both the Wind River and Big Horn Basins is believed 
to be reasonable and helps explain the presence of volcanic cobbles in 
the northeastern part of the Wind River Basin. 
The volcanic cobbles have a somewhat peculiar distribution along 
the south side of the Big Horn Mountains. The northernmost sec- 
A’ A 
| Ttg 
j (Structure In pre-Tertiary rocks not shown) 
Sogebrush Draw 
Tig 
(Structure in pre~Tertiory rocks not shown) X5 exaggeration 
| Fic. 7.—Cross sections along Sagebrush Draw (B’-B) and along ridge parallel to 
|} and 1 mile west of Sagebrush Draw (A’-A) showing position of Tepee Trail forma- 
tion on north flank of Big Horn Mountains and in valley on south flank of mountains. 
tion of figure 4 illustrates this distribution. The rocks shown in the 
section are exposed at the mouth of Sagebrush Draw where that 
stream leaves a canyon as much as 500 feet deep in the pre-Tertiary 
rocks and has its course on the Tepee Trail formation. A cross sec- 
tion through this canyon and a parallel section through the ridge a 
mile west of the canyon is shown in figure 7. At the north end of 
the section, strata of the Tepee Trail formation from the main mass 
| 
of Lysite Mountain almost enter the upper part of the canyon. A 
remnant of Tepee Trail strata is preserved within the canyon, and 
Tepee Trail strata extend into the lower part of the canyon from 
its mouth. The strata in the northernmost section of figure 4 are very 
nearly within the mouth of the canyon, being less than half a mile 
distant from pre-Tertiary rocks both to the east and to the west. Vol- 
—— ee eee 
canic conglomerate is moderately abundant in a unit about 50 feet 
below the top of the Tepee Trail strata exposed there but, curiously, 
is present in somewhat larger amounts than similar-sized material 
ee 
