HEAD OF PKOVO EIVEE. 315 



the ridges to the south of Provo Valley, are so covered with forest growth 

 and surface debris, that, in a somewhat hasty examination, it was impos- 

 sible to detenriine definitely the present limits of the Tertiary beds. On 

 general lithological grounds, and on account of their heightened dip, the 

 beds immediately adjoining the Wahsatch on the east have been assigned to 

 the lower Cretaceous formations, while outcrops of nodular limestone, 

 which have a dip of 45° to the eastward, overlying the red sandstone in 

 Hobble's Canon, though barren of fossils, have been considered as repre- 

 senting the Jurassic formation. 



The thickness of the southern Tertiaries, like those to the north of the 

 Uinta, seems to increase as it approaches the Wahsatch, and, like those also, 

 to become more conglomeratic and be composed of coarser material gen- 

 erally; and it maybe that these beds, like those to the north, represent only 

 the lower members of the Tertiary formation, which farther east is covered 

 by the more recent beds, from which were obtained the fossils which have 

 led us to assign to this group a later age than that of the Bridger beds. 

 Moreover, as already remarked in Chapter II, the high position of these 

 beds, with no apparent barrier between them and the Tertiaries along the 

 flanks of the Wahsatch to the north, which have been considered as belong- 

 ing to the Vermillion Creek series, renders it probable that the seas, in which 

 they were deposited, were originally connected, and that they are therefore 

 of the same age. 



The Provo River rises in a similar basin to that of the Duchesne at the 

 southwest of Bald Mountain, and flows for a short distance across the strike ; 

 its upper valley, known to the settlers as Soapstone Canon, then bends to 

 the eastward, running approximately with the strike of the rocks, and mark- 

 ing roughly the line of division between the Weber Quartzites and the 

 Upper Coal-Measure limestones. Croppings of the latter are found in the 

 wooded hills to the south of this canon, from which the fossils already men- 

 tioned have been obtained. They are much obscured, however, by surface 

 accumulations and Tertiary and glacial ddbris, and near Kamas Prairie are 

 lost under the beds of trachyte which form the hills between this valley and 

 Provo Valley. 



The plateau-like summit of the Uinta becomes narrower toward the 



