398 University of California Publications in Geology [Vol. 13 



the evidence which it in itself presents we must also consider the fact 

 that this scarp parallels that from Cushenbury Springs to Rabbit 

 Springs and that through Old Woman Springs. It therefore fits in 

 with a general system of northwest-southeast faults. 



Another fault which may belong to this system is found along the 

 southwest side of Fry Mxmntain. This mountain is capped with basalt 

 which slopes 15° to the north and is continuous with a flat area more 

 than two miles in length. At its highest point the basalt is about a 

 thousand feet above other areas to the south and in the vicinity of 

 Negro Butte to the southwest. But this uplift did not take place as 

 one progressive movement. On the upper part of this hill, extending 

 southeastward from the peak and just below the crest of the ridges, 

 there are remnants of an old valley with stream beds of low gradient. 

 This part of the drainage system of the hill is in marked contrast with 

 the southwest margin, where the stream beds drop off precipitously 

 through steep narrow canons. It is therefore certain that during the 

 uplift of Pry Mountain there was a period of rest, and this was near 

 the beginning of the movement. That the major uplift is of compar- 

 atively recent date is shown by the geomorphic discordance. 



The big hill two miles northwest of Means Wells is probably a 

 recently upthrust block. This conclusion is based partly on its physio- 

 graphic resemblance to Fry Mountain. Although no remnant of an 

 old surface was seen near the top, the precipitous nature of the drain- 

 age on all sides is very similar. Furthermore, its alluvial fans are 

 poorly developed while those in the hills to the northeast are very 

 large even though the hills themselves are small. So, this hill can 

 hardly be an erosional remnant of an extensive block, but must repre- 

 sent a recent local uplift. 



Several other small faults are shown by offsetting of areas of 

 basalt. Negro Butte is a granite hill with a basalt covering sloping 

 about 30° southwest. Two miles farther east three small areas of 

 basalt resting on granite also dip to the southwest in such a manner 

 as to suggest faulting (fig. 8). The hill four miles northwest of Old 

 Woman Springs is capped with basalt which lies horizontally and just 

 south of this hill and 300 feet lower there are two other small areas. 

 This relationship is probably due to faulting. The age of this faulting 

 is hard to determine, but it is probably earlier than that described 

 above. This is suggested by the development of an old surface just 

 below the top of Fry Mountain. This indicates that the uplift was 

 in two stages and the first was of about the same amount as the off- 

 setting of the basalt to the southwest. There is also a nearly north- 



