STRUCTURAL FEATURES IN THE FOOT-HILL REGION. 259 
the dips settle back approximately to their normal amounts 
as given at Bear creek. 
The general fold 'parallel with the base of the Colorado 
Range .—The surface exposures of the prominent and sharply 
defined fold of general occurrence along the base of the Colo¬ 
rado Range and resulting from its uplift are, for the greater 
part of the area under consideration, to be found within a 
short distance of the line of union of the Denver and Arapa¬ 
hoe formations. North of Van Bibber creek, however,— 
where the Denver formation ceases to exist, followed within 
two or three miles by the disappearance of the Arapahoe,— 
the bend is almost entirely transferred to the Laramie, the 
Arapahoe for that part of the distance over which it is present 
entering into it only in the slighest degree. 
Faidts .—There are along the line of the older formations in 
this region four easily recognized fault localities: one near 
the termination of the Niobrara just north of Bear creek; a 
second in the isolated Dakota hill two miles south of Clear 
creek ; the third near the southern end of the Dakota hog¬ 
back first north of Golden, and a fourth a half mile to the 
south of the latter, near the line of union of the lower and 
upper divisions of the Trias. The faults of each region have 
the present appearance of approximately east and west cross¬ 
fractures, along which the ends of the upturned strata are 
thrown to one side or the other. In the southern half of the 
field the northern ends of the interfault blocks are carried to 
the westward, while in the northern half it is the southern 
ends that are carried to the westward. The fractures in the 
isolated Dakota hill south of Clear creek are irregular and 
apparently local in their character. As a rule, the extent of 
throw of the faults mentioned is slight and confined to the 
formations in which it has been stated they occur, a single 
fracture only—one of those in the southern portion of the 
area—extending beyond one or two hundred feet, this includ¬ 
ing both Niobrara and Dakota, but of a much less pronounced 
character in the older formation than in the younger. 
