20 



University of California. 



[Vol. 3. 



debris elsewhere in the valley. No stream has flowed through 

 the pass since the Eed Bluff epoch. 



North of the range, on the south border of Antelope Vallej', 

 there is a broad old detrital slope which has been eroded into a 

 series of low hills. Beyond this the detrital slopes are not dis- 

 sected for many miles to the north and east. 



Antelope Valley, extending from Gorman's Station on the 

 west to the Mohave River on the east, a distance of eighty-five 

 miles, and from Palmdale to Rosamond Station about twenty 

 miles due north, is a gently rolling plain without ordinary stream 

 courses, the Mohave River excepted. The soil is a uniform light 

 brown, coarse, rather angular granite sand with some silt 

 particles. The altitude of the central portion is about 2,300 

 feet, and it rises gradually thence to the mountain areas on both 

 sides but principally that on the south. A low portion of this 

 basin at Lancaster has artesian wells. Slightly depressed areas 

 are lake-beds, usually dry. I believe the basiu to be underlaid 

 by Tertiary formations, but the surface deposit everywhere is 

 late Quartenary, although hardly Recent in age. 



The largest of a chain of three lake-beds extending eastward 

 from near Rosamond is "Rogers dry lake," said to be twelve 

 miles long by six miles in average width. The railway crosses it 

 for seven miles. The lake-bed is flat and in many places as hard 

 almost as an asphalt pavement. It is of clay containing much 

 fine gravel, probably scattered over the lake-bed by the wind. 

 A low beach ridge of cross-bedded sand and fine gravel, trend- 

 ing north- south, cuts off a broad arm of the dry lake. This 

 latter is bordered on the north, east, and south by a broad belt 

 of dune ridges of coai'se, partly angular sand. On other shores 

 of the lake-bed 'the beach phenomena are very weak. It seems 

 to have a foot of water in rare years, and I am told that, once 

 in every three or four years, an unusually prolonged rainy spell 

 causes several inches of water to cover the remarkably even 

 floor. All the phenomena found in connection with this lake-- 

 bed indicate ■& very recent age, and probably even its inception 

 long post-dated the close of the Red Bluff epoch. 



From the dune belt east of Rogers lake-bed the Santa Fe 

 railway courses eastward through a broad basin-like valley. 



