280 DESCEIPTIVE GEOLOGY. 



found on the norlliern spurs, tlie beds forming the lower extremities, dippit^g 

 quite steeply to the south. The lower part of the second stream cast of 

 Coal Mountain cuts a narrow canon through the outlying southerly-dipping 

 beds, which here have the same angle of dip of Sl'^, in which is a spring, 

 whose waters are highly charged with salts of iron. On the cliffs above 

 this canon, on the east side, are seen a considerable thickness of sand and 

 gravel beds lying almost horizontal, the observed dip being about 3° to 

 the northward, which extend high up on to the spur, and from their position 

 are supposed to represent an upper portion of the Brown's Park Tertiaries. 

 These same Tertiary beds are seen by the structure of the hills to form 

 the summit of the White River divide to the westward; though from their 

 being easily degraded, on account of the incoherency of their material, no 

 good exposures were found. In the deeper portions of the ravines, on the 

 northern side of this divide, were found croppings of sand-rock, correspond- 

 ing in dip and strike with those at the mouth of the canon, and which have 

 therefore been referred to the same group. 



Junction Peak is the culminating point of a high, narrow ridge, trend- 

 ing a little east of north, near the confluence of the Little Snake and Yampa 

 Eivers, cut through by the latter, near its southern end, in a deep, narrow 

 caiion about 2 miles in length. Its structure is similar to that of Yampa 

 Peak, representing a secondary roll in the pre-Tertiary beds, which dip 

 away from it in every direction. The incUnation of these beds is steeper 

 toward the north and west, and more gentle to the east and south, the strata 

 at the summit being nearly horizontal, while on the east and west flanks 

 they seem to have been broken, and fall off very abruptly, showing evidence 

 of a similar folding and dislocation to that which has taken place throughout 

 the Uinta Range. The general idea of this structure is given in the section 

 C D at the bottom of the map. 



In Lily's Canon, an excellent section is shown of the Upper Coal- 

 Measure limestones and a portion of the underlying red sandstones, forming 

 an arch of the general shape of an inverted U. At its eastern mouth, the 

 white Tertiary beds rest directly upon the limestones of the Upper Coal- 

 Measures, while at the western mouth of the canon the red and buff sand- 

 stones of the Triassic formation are exposed in places, dipping westward at 



