258 REPORT UNITED STATES GEOLOGICAL SURVEY. 
graphic relations, might lead the observer to identify these horizons with 
the Triassic *‘ red- beds, ” the first authentic exposures of which, however, 
are only met with at a ‘point several miles lower down the valley in the 
neighborhood of Warm Spring Creek. 
From the summit of the terrace a broad, shallow depression, occupied 
by a small stream flowing eastward, and probably tributary to the milky 
affluent that joins Wind | River a few miles above Du Noir Creek, iS over- 
looked, beyond which rises a considerably higher outlying bench on the 
flank of the great volcanic mountains whose sedimented horizontal 
ledges tower hundreds of feet above in magnificent architectural mount- 
ain forms. The abrupt southern declivity of this outlying bench, as 
seen from a distance, appears to be composed of more or less indurated 
deposits, including a heavy bed of dull brick-red color, and above a 
rusty weathered ledge which is’ in turn overlaid by light ash-colored 
earth reaching up into the summit. The vertical extent of these depos- 
its, which are nearly horizontal, is estimated at 500 to 800 feet, while 
both from their position and lithologic characters they are doubtless 
identical with the greenish arenaceous beds met with along the upper 
course of Wind River. Their relations to the volcanic mountain bor- 
ders both to the north and southwest, and the inferior creamy-yellow 
sandstones is shown in an accompanying profile section of the valley 
along a line extending northeast from Station LI (1877) on the water- 
shed on the south side of the valley. . 
North of the point where the small parallel tributary leaves the first. 
terrace bench and enters the undulating, grassy region lying just to the 
east, a considerable thickness of banded bluish-drab and red deposits 
appears in low bluffs along the broken eastern edge of the terrace. The 
above exposures occupy a sort of recess in the lower terrace level, to 
the west and north of which the acclivities rise up into the higher bench, 
which here shows obscure, pinkish-drab, red-streaked exposures. The 
probable stratigraphical relations of the banded variegated beds here 
alluded to will be referred to further on. To the northeast, brownish 
earthy deposits appear in a somewhat higher bench, and in the lower 
slopes, descending from the volcanic mountain ridge, quite extensive 
tracts are oceupied by light drab, clayey deposits in the region of the, 
upper course of Du hoir “Creek. 
The above mentioned terrace is continued along the north sade of Wind 
River, east, to within perhaps 3 or 4 miles of the mouth of Du Noir 
Creek, where it assumes the character of a high morainal bench, jutting 
into the valley. It is, however, somewhat lower, interrupted by short 
drainage depressions, and at a "point perhaps 4 ‘or 5 miles above Du 
Noir Creek it is cut by a smaller affluent whose waters are charge 
with milky-colored sediment. The latter phenomenon is doubtless at- 
tributable to the wash of white earthy deposits which were observed 
to occupy a considerable area some miles to the north, or northwest, 
in the region of the sources of this stream. But as we descend the 
valley, the blutis gradually increase in elevation, frequent exposures 
of the component strata appearing in the more or less steep slopes fae- 
ing the valley. Ata point some distance above the confluence of the 
sediment- discolored stream, where the bluffs approach the river, a thin 
seam of lignite outcrops a few feet above the water. level, associated 
with chocolate-red and bluish-drab clays, overlaid by rusty yellow and 
grayish shaly sandstones in bluff-face, 150 feet above the stream. The 
sandstones were observed all along the bluff face before reaching this 
locality, appearing in nearly horizontal ledges separated by soil-covered 
slopes, though in places apparently gently rising to the eastward as the 
