152 LEWIS G. WESTGATE AND E. B. BRANSON 
clearly known. On the upper tributaries of the Sweetwater, 
between the Granite Hills and the main range, No. 3 is post- 
maturely dissected by a system of valleys which are widely opened 
on the gravels and are narrower on the granites. This valley 
system may belong to No. 2. The Sweetwater cuts the crystallines 
south of the Granite Hills in a narrow valley which has doubtless 
been cut at a later date. Further east, at South Pass City and at 
Atlantic City, Willow and Rock Creeks are flowing in narrow 
valleys, cut below broad shallow valleys which are in turn cut 
below No. 3. South toward Oregon Buttes, and from the Beaver 
Divide toward the Sweetwater, the surface drops away to lower 
levels in such manner as to suggest very strongly that after No. 3 
had been formed a later plain was developed to a very advanced 
stage throughout this part of the Sweetwater basin. 
The best development of No. 2, however, is north of the Beaver 
Divide. Along the Beaver itself large remnants of this plain occur 
at 6,500 feet, 300 feet below No. 3 as developed on the divide. 
The only area which stands above No. 2, north of the Beaver and 
east of the mountains, is the higher part of Sheep Mountain. The 
plain is well shown along the north side of Beaver Divide as a 
broad bench sloping to the top of the cafion of the Beaver above 
Hailey. It forms the flat divide between Beaver and Twin Creeks 
and continuing from there north makes the high country about 
Bruce, and either just touches or rises slightly above the hills of 
folded Red Beds and Cretaceous which run northwest to beyond 
Lander. 
At the south end of the range gravel occurs on No. 2 as scattered 
bowlders washed from near-by regions rather than as heavy deposits 
swept out from the central range. For example, in climbing from 
the Beaver where it bends to the north, to the Beaver Divide, 
one finds the hill-tops which come up to No. 2 carrying scattered 
bowlders of angular and subangular shape, frequently five or six 
inches and occasionally a foot in diameter, and derived from 
Paleozoic and crystalline rocks. But on the summit of the divide 
there is found a t1oo-foot layer of Tertiary conglomerate with 
bowlders quite like those occurring on the plain below. These 
bowlders on No. 2 are a thin veneer of local origin, derived from 
