J14 REPORT UNITED STATES GEOLOGICAL SURVEY. 
Inie deposits of similar lithological appearance is not clearly discernible 
at this locality. Dr. White refers the most prevalent Ostrea to O. sole- 
miscus Meek, of the Upper Cretaceous sandstones near Coalville, Utah. As- 
sociated with the above form there were also recognized Barbatia coal- 
villensis White, and a small Ostrea which resembles O. insecura White, 
of the Bitter Creek Laramie series, although it may be the young of the 
first-named species. The strata are so generally concealed by loose ma- 
terials in the surface as not to afford the means for determining either 
their vertical thickness nor the extent of their outcrops. ‘The occur- 
rences are confined to the high benches well beyond the foot of the Pa- 
leozoic-plated mountain, in the upheavalof which they evidently par- 
took, although at no point do they probably remain on the high ridges 
of the range. The above stratigraphical occurrences probably occupy 
the synclinal trough intervening between the north and south folds of 
the range, the latter exposures pertaining to the remnant of the north 
flank of the south fold which here exhibits extraordinary abruptness of 
declivity. 
Two or three miles below the cascade the brook enters a pretty inter- 
vale and terrace bordered valley eroded out of the soft basin deposits. 
The hill-sides are covered with large tracts of vigorous young pines from 
a foot and upwards in height, amidst which rise the stark trunks of their 
burned predecessors. Not unfrequently the same phenomenon was ob- 
served at other places in this region, which seems to prove that the 
conditions for forest growth are as favorable to-day ag at any time in the 
past. Af, a locality north of Hoback Caion, a tract of burned spruce 
forests occupying a northwesterly slope was renewed by adense growth 
of young pines. 
Just below the valley expansion, well defined lateral moraines are de- 
veloped, rising 75 feet, more or less, above the stream, and clinging to 
the steep slopes. There are two or three of these ridges one above the 
other. Lower down the moraines decline and spread laterally over 
the more gentle declivities, in the hollows of which wet meadows fre- 
quently occur. The lowermost one finally converges, throwing a low 
embankment in the shape of a terminal moraine clear across the valley, 
through which the stream has eroded a narrow channel to the depth of 
25 feet. How far below this the moraines extend was not ascertained. 
The one described was the most perfect example of terminal moraine ob- 
served during the visit to these mountains, although it probably does 
not mark the ultimate distance the ancient glacier traveled beyonds its 
mountain limits. The position of these morainal deposits conclusively 
shows that the glacier which transported their materials flowed downa 
pre-existing valley of nearly the same spaciousness as the present trough, 
and which possibly had almost equal preglacial extent within the mount- 
ain area as that which it there presents to-day. There was noted no 
unmistakable glaciation on the sedimentary mountain flanks in the de- 
bouchure, although the limestone-incline over which the cascade glides 
was bared and smoothed by the effects of the ice-fall. But within the 
caiion, doubtless, all the concomitant phenomena of glacial action would 
reward a more careful exploration than it was possible to undertake 
during the present visit. 
To the east the mountain wall curves round into a shallow recess, 
which is drained by another tributary of the Hoback. Occasional expos- 
ures of gray Laramie (?) sandstone were met with in the high sloping 
_ basin benches that here reach close up to the foot of the abrupt mountain 
declivity. The east side of the recess is defined by the ridge reaching 
north from the angle of Gros Ventre Peak, which here, as in the south 
