ST. JOHN.] WIND RIVER RANGE—SAGE CREEK CANON. 249 
teresting fact, and deserves to be thoroughly investigated with the view 
to determining their economic value. 
The Palzeozoic series exposed in the walls of the Bull Lake Fork cafion is 
of no less interest in a geological point of view. But for want of time only 
the upper member of the Carboniferous was studied with any pretension 
to minuteness. Of the latter member, including the uppermost and dis- 
tinctively Permian horizon, the foregoing section exhibits the detail 
stratigraphy with close approximation to the truth. The full thickness 
of the strata lying between the great sandstone of the middle division 
of the Carboniferous, No. 7, and the base of the Triassic “red beds,” No. 
16, reaches a maximum of about 400 feet, of which the Permian or Permo- 
Carboniferous horizon comprises the upper 120 to 150 feet. The fossils 
of the lower strata of this upper series belong, in the main, to character- 
istic upper Carboniferous types. Their absence in the uppermost strata, 
in which such forms as Pleurophorus and Bakevillia exclusively occur, 
presents a striking faunal contrast to what obtains in the lower beds, 
and one that unmistakably indicates in this remote quarter a state of 
things analogous if not identical with what prevailed at the close of the 
Carboniferous period in the Mississippi basin along the western border 
of these occurrences in the States of Kansas and Nebraska. 
Just within the lower entrance to the cation of Bull Lake Fork a sin- 
gular low ridge spans the valley, through which the stream has forced 
a wide passage. It is made up of the middle Carboniferous sandstones 
whose tilted edges are presented in an abrupt bluff barrier facing up the 
valley, the opposite side, which is flagged with the overlying limestone, 
declining more gently with the dip of the strata. The abrupt bluff-face 
of the ridge gives a section of the sandstone along a line closely corre- 
sponding to the strike of the strata, in which are revealed some interest 
ing minor undulations, as though the beds had been crumpled by a force 
acting laterally, but which is probably attributable to slight inequality 
in the intensity of the vertical movements that forced the strata up into 
their present inclined position on the flank of the mountain. Mr. Perry 
observed similar phenomena, though on a much larger scale, in the up- 
lifted Paleozoic formations in Jake’s Creek Cation, where the strata are 
described as having the appearance of a low fold transverse to the 
mountainupheaval. Inregardto the Bull Lake Fork locality, it is difficult 
to account for the existence of the sandstone barrier, which has main- 
tained itself in spite of fluvial and glacial erosion to which it has been 
exposed for ages. 
The mountain flank between Bull Lake Fork and North Fork Little Wind 
River, 10 miles to the south, is gashed by the drainage of Sage Creek, 
whose sources, to judge from the character of the erratic materials swept 
down by the stream, scarcely penetrate to the Archean area. This 
little stream debouches from a narrow caiion in the middle Carboniferous 
sandstone and overlying limestones, the upper course of the stream being 
defined by the earlier members of the series which, in the summit of the 
ridge, attain altitudes between 9,000 and 10,000 feet above the sea. The 
Carboniferous sandstone and dark-wreathed fragmentary limestones 
everywhere appear in the grassy slopes along the foot of the mountain, 
the edges of the various upraised geological members breaking down in 
abrupt declivities facing the great inclined planes in which the outer 
slope rises over successively lower formations until it culminates in the 
crest overlooking the Archean area. The summit of the mountain ridge 
is formed by the Silurian limestones; to the north the lower member of the 
Carboniferous or so-called Niagara magnesian limestone may constitute 
the coping ledge. The latter horizon is often weathered in picturesque 
