WEST SLOI'K OF DIAMOND lixV^fGE. 1(58 



ing along the canyon. Tlie distance between tliem measures only about 

 one-half mile and is mainly occupied on the sui'face by iliyolitic pumices 

 and tuffs. 



No sj)ecial mention need be made of the physical characters of the 

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

 ter devoted to the CJarboniferous rocks, nearh- all the o])ser\iitions there 

 given lieing taken from this region. 



West Slope of Diamond Range.— From Newark Canx'ou Hortliwurd and west- 

 ward of the Alpha fiiult, the country, both in to])ographical features and 

 geological structure, pi-esents juuch the same general aspect over the entire 

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

 limits of the survey. The oj)posite sides of Newark Canyon offer marked 

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

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

 the lower end of the canyon the contact of the two rocks is bi-okcn by 

 o\erfiows of pumices, tutfs, and basalts, but higher up and iioi-th ot the 

 drainage channel the relations between the two horizons are strikingK' 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 

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

 trast in toi^ographical features and unconformity of strata between the two 

 bodies of limestone on the o})posite sides of the Alpha fault. This region 

 is sharply defined 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 regidar intervals, all of them having a 

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

 lying limestones more than a few hundred feet, the liottomsof the valleys, 

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

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

 supei-ficial features, for the most ])art smoothly worn down, with Jiere and 



