156 
PROCEEDINGS OF THE ACADEMY OF 
cedony, A few mammalian remains were found, mostly of Oreodon and Rhino- 
'-eros. 
On the right or east side of the Shyenne, as we pass over to White River, the 
Cretaceous bed No. 5 presents some peculiarities which may be worthy of no- 
tice, inasmuch as the upper portion seems to form a transition or bed of passage 
into the Tertiary. We have, first, No. 4, black laminated clay gradually pass- 
ing up into dark brown clay, then becoming deep ferruginous ; again a dull 
purplish hue, with seams half an inch to an inch in thickness of ferruginous 
matter passing up into a deep yellow arenaceous clay ; lastly, a brown clay un- 
derlying the Titanotheriura bed. I have been thus minute in describing these 
beds, from the fact that the transition from the Cretaceou? to the Tertiary period 
seems as gradual and as natural as that of any of the subdivisions of the Creta- 
oeous system into each other ; and were it not for the organic remains which 
characterize each, we would scarcely be aware that we were passing from one 
great geological period to another. 
At another locality the Titanotherium bed at the base consists of clay with 
a purplish tinge, filled with angular grains of quartz and water-worn pebbles, 
two feet ; then a loose incoherent gravel, with pebbles, four inches ; then six 
to eight feet of light gray clay, filled with pebbles and angular grains of quartz, 
sometimes forming a sort of quartzose sandstone, passing up into a dark ash- 
■'olored clay, with a greenish tinge. 
A section of the different beds, is shown on White River, would be as 
follows : 
f Flesh colored marl, ...... 10 feet. 
'J I Bluish laminated clay with a yellowish tinge, ... 2 feet, 
■cs j Flesh colored indurated marl, . . . . .15 feet. 
[Light gray, indurated, argillaceous grit, with nodules of clay, . 4 to 6 feet. 
^ Flesh colored indurated grit, . . ... 20 feet. 
^ Bluish argillaceous grit, . . . . .10 inches 
■ Flesh colored marl. ...... 4 feet' 
Argillaceous grit, . . . . . 6 to 12 inches' 
B Flesh colored marl, ...... 30 feet" 
A fine light gray calcareous grit, passing down into an 
ash-colored clay, with micaceous and silicious sandstonej 
at base tinged with a purplish hue, . . . 80 to 100 feet. 
Cretaceous Beds J^os. 5 and 4. 
In the valley of White River the Cretaceous beds Nos. 5 and 4 are exposed 
by the erosion of the overlying Tertiary beds, as may be seen by reference to 
the accompanying map. No. 5 reveals numerous fossils in similar tough argil- 
laceous concretions, as those observed on the west side of the Shyenne. All 
the calcareous matter has been dissolved away from the shells, leaving only 
casts. The upper portion presents a variety of lithological characters, and is 
destitute of fossils. 
Leaving the valley of V/hite River, we proceeded nearly a south-east course, 
ascending gradually to the dividing ridge between White and Niobrara Rivers, 
where we find the largest development of bed Z>, which exhibits its usual litho- 
logical characters, but contains very few fossils. Passing the head of wounded- 
knee creek, we begin to see indications of the Pliocene formation, with a few 
mammalian remains, and on reaching the Niobrara, the upper Miocene bed^ 
are covered with a thick deposit of Pliocene strata. This more recent forma- 
tion presents at this locality the same lithological characters as those given in 
the vertical section, and extends nearly to the mouth of Turtle Hill creek, where 
Cretaceous beds Nos. 4 and 3 gradually rise to the surface and cover the coun- 
try. Outliers of Pliocene are visible, however, on both sides of the Missouri 
River in many localities, the principal of which are Medicine and Bijoux Hills, 
the latter of which has yielded several very interesting species of Mammalia 
[June^ 
