STRUCTURAL FEATURES IN THE FOOT-HILL REGION. 257 
In the northern part of the region, opposite the first hog¬ 
back north of Golden, the exposures of the Montana group 
are rare, but a half mile north of Van Bibber creek and 
from this point to Ralston, the discrepancy in strike observe 
able to the south has for a time almost wholly disappeared; 
beyond Ralston creek, however, a divergence of 20° is still 
noticed in the general trend of the Laramie and Dakota 
sandstones, which extends to a line due east from the entrance 
to the canon of Coal creek. This area is regarded as corre¬ 
sponding to that in the vicinity of Bear creek in the south, 
over which a thickness of Montana beds equivalent to that 
on the southern border of the field is regained, by which the 
geological symmetry of the region is rendered complete. 
Over the middle portion of the region the Montana beds 
follow closely the behavior of the Laramie, but show fre¬ 
quent variations in thickness arfd corresponding changes in 
their strike relations with the beds below. Regarding the 
individual members of the Montana group, if the general 
thickness of the Fox Hills is taken at between 800 and 1,000 
feet, the Fort Pierre has not been deposited for a long dis¬ 
tance in the middle portion of the region, having gradually 
thinned from the confines of the area towards the center of 
Golden by successive losses of its lower beds. The Fox Hills 
alone is of general occurrence, although its thickness, also, 
over the central portion, varies greatly and often. 
The Laramie .—The prominent feature of this formation is 
its remarkable bend from a course approximately parallel to 
the foot-hills and to the formations below to a broad sweep¬ 
ing curve, by which it is gradually carried to the westward 
until at Golden, its point of greatest deviation, it lies between 
two and three miles to the west of its former course. The 
general trend is slightly wavy, but with reference to the 
early Cretaceous and older formations, is of notable steadi¬ 
ness, passing all their individual deviations without the least 
disturbance of its own. Its dip is vertical or slightly over¬ 
thrown for the entire length of the area under considera- 
