OF THE UPPER MISSOURI. 
VERTICAL SECTION, continued. 
105 
SuBDIVISIONS. 
Locawirigs. 
Estimated 
thickness. 
PLIOCENE TERTIARY. 
Bed F. 
Ist. Dark gray or brown sand, loose, incoherent, | 
with remains of mastodon, elephant, &e. 2d. Sand 
and gravel, incoherent. 8d. Yellowish white grit, 
with many calcareous, arenaceous concretions. 4th. 
Gray sand with a greenish tinge; contains the 
greater part of the organic remains. 5th. Deep 
yellowish red arenaceous marl. 6th. Yellowish 
gray grit, sometimes quite calcareous, with nume- 
rous layers of concretionary limestone from two to 
six inches in thickness, containing freshwater and 
land shells, Succinea, Limnea, Paludina, Helix, 
&c., perhaps all identical with living species ; also 
much wood of coniferous character. 
| valley. 
Covers a very large area on Loup fork, | 
from the mouth of North branch to | 
source of Loup fork; also in the Platte 
Most fully developed on the 
Niobrara river, extending from the mouth 
of Turtle river three hundred miles up 
the Niobrara. - Also on Bijoux hills and 
Medicine hills. Thinly represented in 
the valley of White river. In isolated 
patches over a large portion of Dakota 
territory, west of the Coteau de Prairie. 
800 to 400 feet. 
MIOCENE. 
Bed H. 
Bed D. 
Bed C. 
Bed B. 
Turtle and Oreodon 
Usually a coarse-grained sandstone, sometimes 
heavy-bedded and compact; sometimes loose and 
incoherent; varies much in different localities. 
Forms immense masses of conglomerate; also con- 
tains layers of tabular limestone with indistinct 
organic remains; very few mammalian remains 
detected, and those in a fragmentary condition. 
Passes gradually into the bed below. 
Most fully developed along the upper 
portion of Niobrara river and in the re- 
gion around Fort Laramie. Seen also on 
White river and on Grindstone hills. 
A dull reddish brown indurated grit, with many 
layers of silico-caleareous concretions, sometimes 
forming a heavy-bedded fine-grained sandstone ; 
contains comparatively few organic remains. 
Very fine yellow calcareous sand, not differing 
very materially from bed D, with numerous layers 
of concretions and rarely organic remains, passing 
down into a variegated bed, consisting of alternate 
layers of dark brown clay and light gray calcarcous 
grit, forming bands, of which I counted twenty- 
seven at one locality, varying from one inch to two 
feet in thickness. 
Niobrara and Platte rivers; well deve- 
loped in the region of Fort Laramie ; also 
in the valley of White river. Conspicu- 
ous, and composing the main part of the 
dividing ridge between White and Nio- 
brara rivers. Also in Green river valley. 
50 to 80 feet. | 350 to 400 feet. : 180 to 200 feet. 
White river, Bear creek, Ash Grove 
spring, head of Shyenne river. Most 
conspicuous near White river. Near the 
eastern base of the Black hills. 
A deep flesh-colored argillo-caleareous indurated 
grit; the outside, when weathered, has the ap- 
pearance of a plastic clay. Passes down into a 
gray clay, with layers of sandstone; underlaid bya 
flesh-colored argillo-calcareous stratum, containing 
a profusion of mammalian and chelonian remains. 
Turtle and Oreodon Bed. 
Old Woman’s creek, a fork of Shyenne 
river; also on the head of the South fork 
|of the Shyenne; most conspicuous on 
Sage and Bear creeks, and at Ash Grove 
spring. Well developed in numerous lo- | 
calities in the valley of White river. 
80 to 100 feet. 
4 
S) 
a 
14 
