st. JOHN.| NONCONFORMITY OF WIND RIVER TERTIARY AND JURA. 261 
Below Horse Creek the variegated Tertiary skirts the stream, forming 
_ beautifully eroded blutis 300 feet or more in height, the lower portion 
showing some discordance in deposition, but not in constituents and gen- 
eral appearance. The coloring matter appears not to have been distrib- 
uted with perfect regularity, the belts of red becoming locally intensified 
by the merging of several narrow bands in one, and associated with fre- 
quent indurated arenaceous bands, which give rise to a great variety of 
monumental forms in the weather-sculptured bluff-face. These deposits 
continue thence along the north side of Wind River to near the eastern 
boundary of the district. In the vicinity of the confluence of North 
Fork they are again crowded back some distance from the stream and 
rest unconformably on the Jura, which at this place crosses to the north 
side of the river, forming a rather high sboulder outlying the Tertiary 
uplands east of North Fork. 
Above Campbell’s Fork, on the north side of the river, there occurs a 
heavy series of dirty-yellow and drab clays or arenaceous deposits, the 
stratigraphical relations of which, for lack of time, could not be satis- 
factorily determined, although they apparently underlie the banded Ter- 
tiary. The latter again reaches the stream opposite the confluence of 
Campbell’s Fork, where it forms bluffs 200 to 300 feet high. It is made 
up of alternating pale-red and bluish-drab layers, often of considerable 
thickness, the disintegration of which produces a drab soil covering the 
talus slopes for more than half the height of the blutis. A couple of 
_ mniles or so below Campbeli’s Fork the variegated deposits appear in the 
terrace on the south side of the river, the red and drab bands alternating 
with yellow sandstones. The terrace bordering the opposite side of the 
valley exhibits frequent though rather obscure exposures of the same 
deposits, showing a preponderance of sandstone layers as we advance, 
and which are gently inclined in the direction of the descent of the val- 
ley, though locally varying in the direction and amount of inclination. 
A few miles below the confluence of Crow Creek an isolated hill rises 
nearly a thousand feet above the level of the valley, forming a promi- 
nent landmark, which is known as Crow-Heart Butte. This eminence, 
which was detached by erosion from a high terrace level lying a few 
miles to the north, is based upon obscurely exposed variegated deposits, 
overlaid by a heavy deposit of rusty-yellow sandstones and drab clays 
forming the middle portion of the butte, upon which rests a somewhat 
less thickness of similar clays with reddish layers, the summit capped 
with a heavy ledge of rusty-yellow sandstone. The summit sandstone 
belongs to a heavy ledge that recurs in the above-mentioned high ter- 
race, while the middle sandstone horizon is the same that constitutes 
the main terrace bordering the valley. The inferior basis deposits re- 
semble the variegated horizon noticed higher up the valley, as men- 
tioned above. Wherever this region was overlooked from the mountain 
border on the southwest the above-mentioned deposits always had the 
appearance of gently rising to the northwest in ascending the valley. 
Yet these appearances should be taken with due allowance when it comes 
to determining the geologic relations of the horizons here alluded to. 
Below Crow-Heart Butte, as far as the stream was followed, the bor- 
der blufis on either side revealed frequent exposures of greenish-yellow 
soft sandstones and arenaceous shales with layers of blue clay. The 
concentrated clayey portions of the rock are often weathered away, form- 
ing shallow caverns in the mural exposures. In the vicinity of Dry 
Creek, a few miles below Bull Lake Fork, rusty buff-weathered sand- 
stones appear in the bluffs on the north side of the valley, where they 
are gently upraised to the southwest and overlaid by a considerable 
