24 



Geologically considered, the Uintah Mountains are the re- 

 sult of an upheaval which followed closely the Carboniferous 

 Epoch. In this upheaval a great belt of country from 25 to 

 30 miles wide was raised to its extreme elevation, without 

 materially disturbing the inclination of the strata ; it being 

 possible that the present dip, which increases from 3 at the 

 summit to 6 at the south, is the same that existed before the 

 mountains were lifted. Upon both edges of this belt the 

 strata are broken axially, dipping on the north side 38 to 

 the north, 12 12' west, from the true meridian, and on the 

 south about 43 to the south, 12 12' east, in the longitude of 

 Gilbert's Peak. The main anticlinal axis is on the north edge 

 and in the same longitude bears north 77 48' east from the 

 true meridian. 



The uplifted beds, as displayed by the lateral erosion, are 

 almost entirely composed of a brownish red rarely gray- 

 sandstone of the subcarboniferous epoch, scarcely fossilifer- 

 ous, which is metamorphosed into quartzite along the anti- 

 clinal cracks. They are of very great thickness, from 2500 

 to 3000 feet being visible near the summit. 



Along the main anticlinal axis, and especially across the 

 uplifted belt previously alluded to, are numerous lateral 

 cracks that have been the starting-points of an amount of ero- 

 sion that seems wonderful. They have been worn into enor- 

 mous amphitheatrical basins from 2000 to 3000 feet deep, 

 from two to three miles wide at the head, which gradually 

 widen till they reach a point some four or five miles down 

 the valley, and then again they come together in a canon 

 or precipitous valley, which continues for some eight or ten 

 miles below. Those on the north are generally worn quite 

 across the axis into the high belt beyond. 



The large basins, previously described, range along either 

 side of the summit line, and thus have a direction consid- 

 erably oblique to that of the prevailing winds, and, in con- 

 sequence, the amount of snow which drifts into them dur- 

 ing the winter must be enormous. At such an altitude this 

 snow melts comparatively slowly, and furnishes an almost 

 continuous supply of water to the very numerous mountain 

 streams, much of it having been first caught in the multitude 

 of small lakes which are sprinkled along in the basins. On 



