72 EEPOET UNITED STATES GEOLOGICAL SURVEY. 



diate vicinity of the foot-hills, or mountains, is a steep one ; but soon the 

 strata assume a nearly horizontal position again. As we go westward, 

 along the crest of Book Cliffs, we observe nothing but a slight inclina- 

 tion a little west of north, averaging, probably, 2° or 3^. This is con- 

 stant throughout, from the western slope of the Hogback to the west- 

 ern terminus of our district. No variation can be observed from this 

 general rule until we approach the White River from the south. Here 

 we lind the last remnants of those flexures that have beeu mentioned 

 as occurring in Dr. White's district. About 5 miles below the agency 

 the first instance of this kind is observed. A well-expressed anticlinal 

 fold is cut by the river, and occurs as such for a short distance farther 

 south ; is soon lost, however, by a flattening out and subsidence of the 

 disturbed strata. Farther north this is well developed, and forms a 

 l)romineut feature of the district. Still lower down, on the river, at 

 liaven's Park, another remnant of a most interesting uplift reaches 

 southward across the river. In that park, a level, approximately oval 

 valley, the lower Cretaceous beds are exposed in consequence of having 

 been raised to their present position. On all sides of the valley the 

 bluffs, composed of younger strata, dip off in every direction. Those 

 having an inclination toward the southeast, south, and southwest, fall 

 within the limits of my district, and form a series of rather prominent 

 hogbacks, grouped in an almost regular curve south of the White. 

 From that locality, down the river, no further disturbance was noticed. 

 The general dip, a little west of north, sets in again, and remains con- 

 stant as far as our explorations extended. 



It will be seen, from these remarks upon the general stratigraphy, 

 that the region examined by our party during the season is one which 

 was subjected to but few of the disturbing influences that wrought such 

 thorough changes farther east in the Elk Mountains and west in the 

 Uintas. Whatever action may have produced the plications observed, 

 however extended that may have been, the region south of White River 

 is the one where first again we notice normal conditions of the structure. 

 South of it this continues for some distance until the great folds found 

 by Dr. Peale are encountered. Bo far as the stratigraphy is concerned, 

 therefore, we have but few and not very extensive exceptions to note, 

 to the evidence of normal, almost undisturbed deposition. 



JUEA-TEIAS. 



Red Beds. — From Marvine's district of 1874 the palaeozoic formations 

 extend westward, just reaching the eastern border of our work. The 

 groui)S forming the area directly east of our section belong mainly to 

 the Carboniferous series. As a rule the dip of the strata is toward the 

 west, but local plications and small faults have produced some disturb- 

 ances that are of small extent, however. Resting conformably upon the 

 Carboniferous, which does not enter into consideration in this report, are 

 the Mesozoic beds. The series commences with the characteristic group 

 of the "Red Beds," to which has been assigned a Triassic age. In no man- 

 ner were they observed to differ particularly from those observed on the 

 eastern slope of the Front Range. Most likely their vertical develop- 

 ment is somewhat larger here than there, but in all lithological and 

 stratigraphical features they agree closely. Owing to the development 

 of superincumbent Jurassic and Cretaceous strata the Red Beds appear 

 within out district generally in the caiions, and only in some instances 

 do they reach more elevated portions. According to Marvine's survey, 

 the Red Beds cross the White River about 2 miles above the agency. 



