128 



University of California Publications. 



[Geology 



noteworthy is the valley floor. This, instead of being flat, slopes 

 upward gradually to the north, with a range of elevation of 700 

 feet in about two miles. Also, the evenness of the floor is broken 

 by many small granite outcrops, between which there is an ac- 

 cumulation of humus, underlaid by coarse granite sand. The 

 creek here is eroding only the latter material ; in no case seen is 

 the solid rock being worn. These granite outcrops are never 

 flat-topped, but show a form in cross-section typically wedge 

 shaped with the edge upward. Lengthwise they form low ridges 

 of considerable length compared to their width. These low ridges 

 always run north and south. The north fork of Pranktown 

 Creek has been noted as cutting into the alluvium at the south 

 base of one of these ridges. This face where the stream has ex- 

 posed it is vertical. One prominent ridge has a width and height 

 of forty or fifty feet and a length of about two hundred feet. The 

 actual apex is of course rounded, and covered with the usual 

 coarse sand and boulders. The lower side slopes are covered with 

 boulders likewise, but the sand stratum is thin, and solid rock is 

 present. A similar statement holds true concerning the plateau 

 remnants and the steeper slopes below. The former have both 

 boulders of disintegration and deep sand covering ; the latter 

 have many boulders resting on solid rock. The gentler slopes 

 have few boulders and deep sand that is in situ. 



On the ridge crest east of the north portion of Little Valley is 

 a very well preserved plateau remnant. At the north end of the 

 valley this joins the valley floor, but at the south a steep slope 

 separates the two. This latter slope is divisible near the extreme 

 south end of the north valley portion into two distinct parts. 

 From the summit a steep, almost precipitous cliff descends a few 

 hundred feet to a portion of the ridge which slopes in general 

 gently to the valley. This gentle slope is, however, complex, and 

 is composed of a nearly flat, higher lying part, and a much 

 broken lower portion. The whole of this lower slope appears to 

 be the homologue of the low, gently sloping portion of the east 

 crest just south. From the highest point on the ridge north of 

 Franktown Creek Canon the slopes also descend in well defined 

 steps southward. There is here also a typical lower point or rock 

 buttress at the crest of the steep canon wall. 



