AQUI MOUNTAINS. 457 



massive and heavily bedded, still preserving a westerly dip of 15° to 20°. 

 The few indistinct fossil remains found here are of Carboniferous types, 

 while the thickness of limestone beds which can hardly be less than 5,000 

 feet, makes it evident that they must belong to the great Wahsatch belt. 

 To the north of the pass, the hills are formed of the same limestone beds, 

 but with an easterly dip, forming the other side of a broad anticlinal fold. 

 These easterly-dipping limestones were traced to the summit of the first 

 high peak north of Reynold's Pass. The region between this peak and the 

 head of South Willow Creek, on the eastern slopes of the range, was, how- 

 ever, not explored. On the western flanks, a body of westerly-dipping 

 quartzites comes in, some 4 or 5 miles north of Reynold's Pass, and forms 

 the main mass of the western rids'e from here to a little distance bevond 

 Grantville Peak. Here also the line of contact between the quartzites and 

 limestones south of Bonneville Peak was not observed, and it is not known 

 whether the latter wrap around the former with a western dip, as on the 

 north end of the anticlinal, or are cut off by the fault, as the map would 

 indicate. 



In ascending Bonneville Peak from the west, a body of white quartzites 

 of not less than 6,000 feet in thickness is crossed, whose average dip is about 

 25° to the west, becoming somewhat less steep near the summit. The 

 prevailing rock in these beds is a white, or yellowish-white, semi-granular 

 quartzite. Occasional beds of conglomerate and one or two thin strata of 

 a dark-green argillaceous rock, having an irregularly-laminated structure, 

 with a development of minute spangles of white mica on the laminated 

 surfaces, are found accompanying the quartzite. These imperfect mica- 

 schists, and a bluish-purple quartzite, like that found east of Farmington, 

 containing also the flattened pebbles observed in Ogden Canon, together 

 with the general character of the quartzites, constitute a sufficiently close 

 resemblance to the Cambrian formation of the Wahsatch to justify the 

 assigning them to this horizon, while the fact that no other quartzite body 

 of such thickness is found underlying a limestone belt of over 5,000 feet 

 precludes the possibility of any other supposition. It must be stated, how- 

 ever, that in this range, as in the Oquirrh Mountains, it has not as yet been 



