WEST SLOPE OF DIAMOND RANGE. 1C,.; 



ing along the canyon. The distance between them measures only about 

 one-half mile and is mainly occupied on the surface by rhyolitic pumices 

 and tuffs. 



No special mention need be made of the physical characters of the 

 Weber conglomerate, as it has been described in sufficient detail in the chap- 

 ter devoted to the Carboniferous rocks, nearly all the observations there 

 given being taken from this region. 



west slope of Diamond Range. From Newark Canyon northward and west- 

 ward of the Alpha fault, the country, both in topographical features and 

 geological structure, presents much the same general aspect over the entire 

 area. It is the most monotonous and least disturbed region within the 

 limits of the survey. The opposite sides of Newark Canyon offer marked 

 geological contrasts; on the one side folded and distorted beds of coarse 

 conglomerates, on the other a uniformly inclined slope of limestones. Along 

 the lower end of the canyon the contact of the two rocks is broken by 

 overflows of pumices, tuffs, and basalts, but higher up and north of the 

 drainage channel the relations between the two horizons are strikingly shown 

 on the north slope of Weber Peak about 150 feet below the summit. Here 

 the conglomerates lie inclined about 18 to the west, with the limestones 

 resting against them at an angle of only 6, but without any essential 

 difference in their strike, both rocks following the trend of the Alpha and 

 Fusiliua ridge. This change is all the more strongly marked by the con- 

 trast in topographical features and unconformity of strata between the two 

 bodies of limestone on the opposite sides of the Alpha fault. This region 

 is sharply denned by the Alpha fault on the east. From the fault to the 

 Quaternary deposits of Diamond Valley there is a nearly uniform slope 

 three miles in width, with a fall of over 1,200 feet. It is crossed by fre- 

 quent drainage channels at fairly regular intervals, all of them having a 

 course a little north of west. Nowhere have they cut down into the under- 

 lying limestones more than a few hundred feet, the bottoms of the valley-, 

 as a rule, being shallow ravines with narrow strips of meadow land along 

 the stream bottoms. All the intervening slopes present much the same 

 superficial features, for the most part smoothly worn down, with here and 



