sr. JOHN.] WIND RIVER RANGE-—MORAINES AND SEDIMENTARIES. 231 
the placer gold occurring hereabout as exceedingly finely comminuted 
and in consequence difficult to save by the ordinary processes employed 
in working the auriferous gravels. 
Fifteen to eighteen miles of the western mountain front north of the 
debouchure of Frémont’s Creek is denuded to the crystalline rocks, and 
the streams that flow down from the mountains, with the exception of 
Frémont’s Creek, which issues on the south line, are small and rise in 
the beforementioned Alpine bench. They all show wonderful exhibi- 
tions of glacial action in the rock-polished surfaces of t..e cailon-walls 
and the enormous quantities of débris built up into moraines outlying 
their debouchures. The latter materials are spread well out over the 
low slopes, effectually concealing from view the Tertiary deposits along 
the margin of the Green River Valley. Within this Archean west 
front lies one of the grandest cations, that by which Frémont’s Creek 
emerges, whose sources cluster about the mountain peak bearing the 
same name. This stream issues from the aforesaid Alpine bench, through 
a profound gorge hemmed in between precipitous glacial-polished walls 
of granite, its exit flanked by ridges of morainal origin a thousand feet 
and more in height. The minute description of these immense accumu- 
lations of morainie materials would require many pages; and while in 
the main features repetition is encountered along the whole mountain 
front, each debouching stream has something peculiar to offer in the dis- 
position of the erratic materials brought down by the great ice rivers 
and heaped up on or spread out over the plain. All the phenomena 
connected with the attained work of the glaciers is both striking and 
beautiful, and perh:ps no field in the west offers so favorable opportu- 
nity for the study of these phenomena as does that of the Wind River 
Mountains. 
Sedimentary border belts.—Twenty-one miles north of the south bound- 
ary of the district, Green River issues from the mountains at a point 
eighteen miles northwest of Frémonts’ Peak. Rising in the neighbor- 
hood of the latter peak, its mountain course is eroded hundreds of feet 
into the crystalline rocks which flank the gorge with precipitous glacial- 
polished walls scarcely inferior in height and grandeur to those that have 
rendered famous the scenery of the Yosemite. The cation was ascended 
a distance of six miles above its mouth, where the way was obstructed 
by the flooded condition of the few-yards-wide intervales, the adjacent 
rocks aliording no practicable trail. Four or five miles above the mouth 
a huge block of granite with nearly vertical sides and truncated sum- 
mit, rises on the south side of the stream to a height of perhaps two thou- 
sand feet. Below this mountain the valley expands, and is occupied by 
a pair of beautiful lakes. The upper and smaller lake is perhaps a 
mile in length and half a mile wide, its waters of a milky green from sedi- 
ment brought down by the main stream, and margined by low willowy 
bogs and flats. The lower lake, a mile or so to the northeast, is about 
twice the length of the upper, its half mile breadth of deep green water 
nearly filling the narrow valley. The contrast in the color of the water 
in the upper and lower lakes was very marked, as though all the sedi- 
ment had been caught and retained in the upper basin and the water 
pertectly filtered on its passage thence to the larger lake. 
A very interesting geological feature of this locality, and one which 
is So far as known unique on this side of the range, is the occurrence 
of a considerable remnant of Palaeozoic formations adhering to and 
lifted high up onthe mountain flank on either side of the debouchure of the 
Green. These great tables of seidmentary strata, in places flexed and 
shattered, present a peculiar feature in the topographical aspect of this 
