OF THE UPPER MISSOURI. 
19 
The Carboniferous limestones at this locality present a peculiar appearance not unlike 
the fused and semifused strata overlying the burned lignite beds on the Yellowstone. 
The fused masses are very compact and heavy, varying in composition, red, yellow, and 
mottled, oftentimes containing small fragments of partially changed rock, thus forming a 
kind of conglomerate. These appearances are more fully illustrated about eight miles 
west of Rawhide peak, where there is a vertical wall of limestone which exhibits every 
variety of character which we have mentioned. After leaving this ridge we descend into 
a valley stretching off to the northwest, and into every ravine the Tertiary beds seem to 
have penetrated or to have been deposited high upon the sides of the ridges. 
Fig. 6. 
In the above wood-cut, a represent the azoic rocks upheaved in the form of conical 
peaks; b , the Tertiary beds deposited in the valleys and jutting against the older rocks on 
all sides. 
At the head of Niobrara river we have indications of upheavals, but to a limited extent, 
near our camp, in the following section, the unchanged sedimentary strata lie unconfor- 
mably on the vertical edges of the metamorphic rocks. 
After crossing the Niobrara 
the Tertiary beds occupy the 
country with the exception of 
a few isolated exposures of Car¬ 
boniferous limestone. Passing 
the dividing ridge between the 
Niobrara and Shyenne rivers 
into the valley of Old Woman’s 
branch, we find that the Ter¬ 
tiary rocks by erosion assume a 
n~i~ 
1 i HT 
)\ 11 
T; « 
/ i i 
/ F 
i 
,i , i c 
a. Quartzose sandstone. 
b. lied argillaceous slate. 
22 feet. 
5 feet. 
cl\ 
c. Yellowish sandstone with reddish 
tinge. 37 feet. 
cl. Metamorphic and granitic rocks. 
80 to 100 feet. 
