MIOCENE. PLIOCENE TERTIAPcY. 
OF THE UPPER MISSOURI. 105 
VERTICAL SECTION, continued. 
Subdivisions. Localities. 
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1st. Dark gray or brown sand, loose, incoherent, 
with remains of mastodon, elephant, &c. 2d. Sand 
and gravel, incoherent. 3d. 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, Lirnnea, Paludina, Helix, 
&c., perhaps all identical with living species; also 
much wood of coniferous character. 
Covers a very large area oy Loup fork, 
from the mouth of North branch to 
source of Loup fork; also in the Platte 
valley. 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. 
300 to 400 feet. 
Usually a coarse-grained sandstone, sometimes 
Most fully developed along the upper 
heavy-bedded and compact; sometimes loose and 
portion of Niobrara river and in the re- 
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incoherent; varies much in different localities. 
gion around Fort Laramie. Seen also on 
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Forms immense masses of conglomerate; also con- 
White river and on Grindstone hills. 
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tains layers of tabular limestone with indistinct 
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organic remains; very few mammalian remains 
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detected, and those in a fragmentary condition. 
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Passes gradually into the bed below. 
A dull reddish brown indurated grit, with many 
Niobrara and Platte rivers; w r ell deve- 
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layers of silico-calcareous concretions, sometimes 
loped in the region of Fort Laramie ; also 
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forming a heavy-bedded fine-grained sandstone; 
in the valley of White river. Conspicu- 
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contains comparatively few organic remains. 
ous, and composing the main part of the 
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dividing ridge between White and Nio- 
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brara rivers. Also in Green river valley. 
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Very fine yellow calcareous sand, not differing 
White river, Bear creek, Ash Grove 
very materially from bed I), with numerous layers 
spring, head of Shyenne river. Most 
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of concretions and rarely organic remains, passing 
conspicuous near White river. Near the 
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down into a variegated bed, consisting of alternate 
eastern base of the Black hills. 
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layers of dark brown clay and light gray calcareous 
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grit, forming bands, of which I counted twenty- 
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seven at one locality, varying from one inch to two 
feet in thickness. 
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A deep flesh-colored argillo-calcareous indurated 
Old Woman’s creek, a fork of Shyenne 
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grit; the outside, when weathered, has the ap- 
river; also on the head of the South fork 
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pearanee of a plastic clay. Passes down into a 
of the Shyenne; most conspicuous on 
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gray clay, with layers of sandstone; underlaid by a 
Sage and Bear creeks, and at Ash Grove 
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flesh-colored argillo-calcareous stratum, containing 
spring. Well developed in numerous lo- 
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a profusion of mammalian and chelonian remains. 
calitics in the valley of White river. 
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Turtle and Oreodon Bed. 
VOL. XIT.- 14 
