st. JoHN. TUFACEOUS SPRING DEPOSITS WARM SPRING CREEK. 269 
of the mountains. Its outcrop forms a mural coping in the bluffs hem- 
ming the drainage depressions and in the summits of the isolated mesas 
with which this region is diversified. The highest benches in this re- 
gion may reach an elevation 1,000 to 1,200 feet above Wind River; the 
aneroid indicating nearly the same actual altitude for the deposits at 
this locality and in the vicinity of Warm Spring Creek, 16 miles above. 
South of Campbell’s Fork, 6 miles, a deposit evidently of the same 
origin appears in the low plutts bordering a little stream that here crosses 
the foreland slope, and resting nearly horizontally upon upraised Car- 
poniferous and Triassic horizons. It isa coarse or partially consolidated 
eray limestone, in rather even thin layers, with small siliceous pebbles. 
No fossils were detected, and the rock resembles some of the limestone 
layers of the Pliocene “lake-beds” of lower Bear River V alley, Utah. 
It was not detected on Bull Lake Fork, but just to the south of the 
latter stream, in the outlying bench slopes belonging to the Sage Creek 
drainage, apparently quite an extensive conglomeritic deposit was met 
with, which is probably synchronous with the above-mentioned occur- 
rences. The conglomerate is chiefly composed of water-worn limestone 
fragments and sandstone, more or less firmly cemented with calcareous 
matter. The bed reaches a thickness of at least 50 feet, and rests upon 
various members of the Mesozoic series occurring in the belt along the 
toot of the mountains. The same formation recurs in the bluffs north 
side of North Fork Little Wind River, where it rests upon the Triassic 
“red beds,” at an elevation of 800 feet above the stream. Metamorphic 
pebbles and small bowlders enter largely into the components of the 
deposit at this locality, interbedded with thin local sheets of soft buit 
sandstone, the whole loosely cemented and obscurely stratified. Con- 
elusive evidence of the preglacial origin of the deposit is not wanting 
at the present locality; the ridge above being loaded with the morainal 
materials brought down by the Little Wind River glacier. There can 
be no question as to the identity of the latter occurences with those 
briefly described in foregoing pages; the only contrast they present is 
the absence of the tufaceous limestone which at other localities forms 
an important member of the formation. 
