BT. JOHN.] SOUTHERN PORTION HOBACK CANON RIDGE. 183 
here referred to are clearly of Triassic age, while the overlying drab and 
variegated deposits are undoubtedly referable to the Jura. The depres- 
sion alluded to is believed to be merely a sag in the strata between two 
points of maximum elevation, as it appears to be in line with, and not 
transverse to, the general north-south direction of the mountain folds. 
The same is further indicated from points of view foreshortening the 
mountain wall and bringing into profile the great headlands defining its 
amphitheaters, where the strata uniformly incline westward. 
But at Station VI the mountain ridge presents a very marked syn- 
clinal fold, on a high point on the eastern flank of which the station 
was located, at an altitude of 10,800 feet. In an east-west direction the 
ridge is, perhaps, a mile across, either flank exhibiting the upturned 
strata in the position of monoclinals due to erosion. On the west side 
the strata rise much more steeply than on the opposite, and from certain 
points of view they appear to be almost vertical. The axial portion or 
erest of the west-side fold, however, has been removed by erosion at this 
point, but to the south it presents the appearance of a rather low, broad 
arch flagged with the variegated chocolate-drab Jurassic deposits, the 
same that fill the synclinal and constitute the greater height of the 
flanking ridges. The Jurais here made up of drab limestone layers 
and chocolate-drab shales including reddish arenaceous deposits, the 
whole, exclusive of the dirty buff deposits below, attaining a thickness 
of probably, at least, 1,500 feet. 
A few miles north of Station VI, in the neighborhood of Station V, 
the ridge assumes its double character, the latter station being located 
on the western ridge, 10,050 feet above sea-level. The above-mentioned 
broad-spanned anticlinal fold southwest of Station VI is not recognized 
at this locality, unless it prove to be identical with the sharp fold of the 
western ridge occupied by Station V. The western ridge rises abruptly 
from the valley of the lower fork of the Hoback, its crest nearly corre- 
sponding to the axis of a sharp anticlinal fold in the Carboniferous lime- 
stones, which is preserved as far north as the lower entrance to the 
Hobach Cafion. The upper portion of the western slope is faced by the 
westerly-dipping Carboniferous limestones, succeeded by the buff and 
flesh-colored hard sandstones lower in the slope, which is covered with 
angular siliceous débris. The latter horizon holds the brecciated layers, 
composed of angular fragments of the quartzitic sandstone and drab 
limestone, recalling conglomeritic horizons in the Carboniferous in the 
region of Ross Fork basin south of Fort Hall, Idaho. These deposits 
reach well down the slope, where they are in turn overlaid by typical 
red sandstones of the Trias, which form the first bench rising on the 
east of the little valley. From the crest of the ridge the inner syneli- 
nal is overlooked, occupying a belt about one and a half miles across 
extending over to Station II ridge, and which is eroded into irregular 
sharp ridges more or less parallel to the border mountain ridges. This 
synclinal trough is filled with the Triassic “red beds” overlaid by a few 
hundred feet thickness of the drab-colored Jurassic limestones and 
shales; the latter being mainly confined to the eastern portion of the 
depression, risiag into the crest of the east or Station IL ridge. The 
latter mountain, however, is principally composed of the inferior “red 
bed” series, which also reaches well up on the eastern flank of the west 
or Station V ridge, upon which it is steeply inclined. 
The continuity of the western ridge is interrupted by deep gorges cut 
by tributaries flowing west into the lower south fork of the Hoback, con- 
trasting with the east ridge in this respect, which forms the water-divide 
as far south as station VI. These caiions afford natural sections in 
