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114 Cincinnati Soctety of Natural History. 
chiefly arenaceous, were deposited in greater thickness than either of 
the other groups, and extended from the base of the Park range tu 
the flanks of the Wasatch mountains. The beds of the Green river 
series contrast with those of the other two groups by the relative prev-. 
alence of calcareous material, and the fineness of their sediments. They 
consist of a lower series of calcareous sandstones and impure limestones, 
containing some lignite seams, overlaid by a great thickness of re- 
markably fissile calcareous shales, abounding in remains of fish and 
insects, which reach an aggregate thickness of about 2,000 feet, and 
are characterized throughout by their prevailing white cvlor. The 
Bridger Group consists of a thickness of about 2,500 feet of arenaceous 
beds, with a small development of calcareous material, of a prevailing 
dull, greenish-gray color, characterized by the great quantity of verte- 
brate remains which have been buried in them. Its greatest develop- 
ment is in the southern portion of the Bridger basin. In the Washakie 
basin, on the western borders of the Little Muddy creek, and at Wash- 
akie mountain and Cathedral bluffs, the Wasatch series are exposed, 
weathering in castellated forms, and recognizable from great distances 
by their bright pinkish and reddish coloring. Washakie mountain 
and the line of bluffs which extend to Cathedral bluffs, are formed of 
beds of the Green river series in the upper portion, and with the red 
Wasatch beds at the base, the line of division can be distinctly traced, 
descending somewhat in horizon toward Barrel springs, and ascending 
again beyond toward Cathedral bluffs. A section taken at Sunny 
Point, near Little Snake river, gave a thickness from the river to the 
summit of the cliff of about 2,000 feet. The upper 950 feet belonging 
to the Green river series, and the remaining 1,050 feet to the Wasatch 
Group. The Green River Group is exposed in the valley of Brown’s 
Park, which is a bay-like depression, from 6 to 8 miles in width, occu- 
pying the geological axis of the eastern end of the Uinta mountains, 
from 1,000 to 1,200 feet in thickness. Throughout the valleys of the 
Little Snake and Yampa rivers, these groups have been worn into 
rounded ridges, where, generally, only disintegrated material is found. 
In the basin of Vermillion creek, the beds of the Wasatch Group have 
their greatest development. It was on one of the broad benches, be- 
tween the branches of this creek, to the east of Ruby Gulch, that the 
originators of the famous diamond fraud, of the summer of 1872, lo- 
cated their pretended discovery. An exposure of coarse, iron-stained 
sandstone, on the surface of the mesa, at the foot of Diamond Peak, 
was strewn by them with rough diamorfds and rubies, which were in- 
