190 REPORT UNITED STATES GEOLOGICAL SURVEY. 
There appears to be no break in the conformity of the earlier and later 
deposits of this series of strata, and this fact, notwithstanding the mod- 
ern appearance of the upper sandstones, suggests their identity with the 
Laramie formation. The impingement of the late sandstone deposits 
against the Carboniferous limestones in the foot of the sharp rise culmi- 
nating in the crest of the John Day ridge is shown in the section dia- 
gram, and needs no further explanation. The junction of the Laramie 
and Carboniferous beds marks the position of the fracture in which resulted 
the fault, the downthrow of which probably amounts to not less than 
6,000 feet at its locality. The crest of the John Day ridge was followed 
from this point, south, as far as the heights overlooking the gorge of the 
East Fork John Day’s River, the Carboniferous limestones forming a 
marked monoclinal the whole distance. To the north, although this part 
of the ridge was not visited, except at its extreme northern end, where it 
terminates on Snake River, the appearances indicate precisely the same 
state of things. 
Between the line of the last section and the Hoback the earlier Mesozoic 
formations again pass to the east side of the valley basin, where the 
later or Bear River beds are tolerably well exposed in clayey slopes and 
tilted ledges to the north and in the vicinity of Station IV. But in this 
quarter the earlier members are less well exposed in the outlying slopes 
on the west foot of the Hoback Canon ridge. At Station [V, which occu- 
pies an eminence of afew hundred feet elevation, and between twoand three 
miles south of the confluence of the Lower South Fork and the Hoback, 
obseure ledges of grayish buff and reddish laminated sandstone inter- 
bedded with bluish shales appear, and in the summit underlying a 
similar sandstone ledge occurs a considerable thickness of dark-blue in- 
durated clays. Below the latter, arenaceous indurated layers afforded 
a few fossils, amongst which Dr. White has recognized Limnwa vetusta, 
Meek, Compeloma megaspira, Meek? Corbicula( Veloritina) Durketvi, Meek? 
and a fragment of reptilian bone. ‘These depos?ts incline westwardly at 
an angle of 30°. Onthe opposite, west, side of the stream similar de- 
posits appear in steep bluff slopes, presenting more or less distinetly 
banded dark leaden and gray exposures along the line of strike, which 
may be traced several miles up and down the stream, and rising up in 
the east flank of the John Day ridge, where they pass into the before- 
mentioned yellow-weathered sandstones and clays. Above the station 
the valley narrows, the Bear River ledges appearing in hog-back ridges, 
made up of blueish, brown-weathered sandstones, and more or less arena- 
ceous clays, including layers of light drab limestone, associated with va- 
riegated chocolate-red, shaly caleareous sandstone, all dipping south of 
west at angles of 30° to 45°. Higher up the valley widens into a beautiful 
terraced intervale, the adjacent slopes wooded with pine and fir trees, 
although vast tracts have been devastated by forest fires. Below the 
cafion the Hoback flows through a fine terraced basin-valley, closing up 
a little lower down, but retaining its valley character to the confluence 
of the Snake, four or five miles below. 
To the east, south, and west the view as seen from Station IV is 
limited by the bordering mountain ridges, but to the north, looking out 
into the lower part of Jackson’s Basin, the southern half of the Téton 
Range rises boldly into view. In the latter direction are observed some 
interesting phenomena in relation to the position of the geological de- 
posits occurring in the northern portion of the present basin area. 
Along the course of the little stream 3 to 5 miles north of the Hoback, 
_ and in the bordering hil!s, there appears a rather heavy deposit of dull- 
