sT JOHN.] WATERSHED—UPPER WIND RIVER VALLEY. 257 
mate source, the stream emerges into a meadow-intervale, at which 
point the valley proper may be said to begin. In this distance the 
stream has made a descent of about 1,800 feet. Towards its source 
the bluff-banks show limited exposures of brownish green arenaceous 
deposits, with indurated streaks of sand and pebbles, dipping at a slight 
angle northwards. At one point these deposits are seen to overlie a con- 
glomerate ledge composed of water-worn quartz pebbles held in a fine are- 
naceous paste, the whole being stained a green tint probably by iron 
infiltrations. This conglomerate is identical with similar occurrences 
along Black Rock Creek on the opposite side cf the watershed, rem 
nants of which were found on the summit of the watershed to within a 
few miles of Union Pass. In all, save its green color, it bears close 
physical resemblance to the great conglomerate elsewhere noticed as 
occurring in the Tertiary area of the Gros Ventre Buffalo Fork Basin. 
Its relation to the great volcanic deposits that make up a thousand feet 
and more of the heights on either side of the pass is not clearly mani- 
fest, nor are its relations to the beforementioned conglomerate of the 
Gros Ventre Basin any better displayed. 
Lower down the stream the greenish arenaceous deposits continue to 
appear, often forming blufis of an hundred feet and more in height, and 
apparently gently inclined in the direction of the stream. Ata locality 
6 or 7 miles from the summit of the pass and about 1.100 feet lower, the 
abrupt terrace-face shows practically horizontal layers of greenish-gray, 
coarse and fine grained earthy sandstone with thin seams of dark car- 
bonaceous clay, the earthy layers yielding imperfectly-preserved leaves 
and stems of plants. Amongst these remains Professor Lesquereux 
doubitfully recognizes a Ficus, whose relations seem to be rather with 
forms prevalent in the Green River Tertiary group than with those 
occurring in the Laramie formation. The greenish arenaceous deposits 
are here associated with lighter-colored strata of similar composition, 
which latter increase in relative importance as we descend the stream. 
A mile or so below the above locality, the steep bluffs bordering the 
north side of the stream show a ledge of coarse conglomerate interbed- 
ded with thin, irregular layers of greenish-gray, soft sandstone, overlaid 
by yellowish sandstones. The conglomerate outcrops 40 feet above the 
water, and in lithological appearance it bears marked resemblance to 
the Tertiary conglomerate on the Gros Ventre and Buffalo Fork. Above 
the confluence of the first considerable north affluent, the bluffs on the 
main stream show 100 to 200 feet thickness of light-yellow soft sand- 
stone, and gritty clays with shaly gray sandstone above, the whole ap- 
rently in nearly horizontal position. 
The north side of the stream for several miles, both above and below the 
confluence of the north tributary, is bordered by a high bench or terrace, 
which is made up of the above-mentioned stratigraphic exhibitions. The 
slope on the opposite side is more gradual, and for the most part densely 
wooded. Ata point perhaps a couple of miles below the confluence, or 
13 miles distant from the summit of Togwotee Pass, the terrace, which 
is here 500 feet above the stream, exhibits several ledges of soft butt- 
gray and greenish-tinted coarse-grained sandstone, in places shaly or 
thin-bedded, with pebble layers, and interbedded with soft arenaceous 
clays. No fossils were observed in these beds, which have aslight east- 
erly or northeast inclination. A little lower down the valley, which 
here opens out into a considerable meadow tract, the gentle lower slope 
of the bluffs reveals obscure exposures of pale-red clays, forming thin 
bands seldom more than a few inches in thickness included in greenish- 
drab clays. A mere glance, without reference to their associated strati- 
17 
