TOPOGBAPHIC FEATUEES OF THE DESEET BASINS. 37 



been sufficiently thorough to warrant a decided opinion. The bottom of the valley 

 is known to carry a playa, but its nature is unknown. The basin area is about 1,000 

 square miles. 



THE GOLD FLAT BASIN. 



Gold Flat lies west of the Kawich Basin and below the northern slope of the Pahute 

 Mesa. Its lowest side is toward the north and is never less than 600 feet above the 

 flat. The topography is such that it can not be considered entirely impossible for 

 this north boundary to be due to recent alluvial accumulation, but it does not seem 

 probable. The -writer is of the opinion that the inclosed character of the basin is pre- 

 Lahontan. The flat carries one playa about 3 square miles in area and several smaller 

 ones. The basin area is 640 square miles. 



THE EMIGRANT BASIN. 



The Emigrant or Timpahute Valley lies south and southeast of the Penoyer Basin. 

 No satisfactory maps of it are available, and it has not been visited by the writer. 

 Nearly everything concerning it is uncertain, but it is believed to be inclosed by per- 

 manent divides and to have a drainage area of about 800 square miles, concentrating 

 in a playa about 10 square miles in area. There is, however, great uncertainty as to the 

 position of the divide between it and the Pintwater Basin (see below), and the actual 

 drainage area may be as large as 1,000 square miles or as small as 400 square miles. It 

 is more likely to be smaller than larger than the figure of 800 square miles given above. 



THE YUCCA BASIN. 



The Yucca Basin lies directly southwest of the Emigrant Valley. Little is known 

 concerning it, but it is separated from the Frenchman Flat Basin to the south by an 

 alluvial divide less than 100 feet high and is believed to have been tributary thereto. 

 It now contains a small playa. The basin area is slightly less than 300 square miles. 



THE FRENCHMAN FLAT BASIN. 



Frenchman Flat lies south of the Yucca Basin in the depression within the crescent 

 of the Spotted Range. There is a pass about 500 feet high opening into the Amargosa 

 Valley, but this divide, though partly alluvial, is believed to be pre-Lahontan. The 

 basin has probably been permanently inclosed. It contains a typical playa. Alone, 

 the area of the basin is about 450 square miles, but including the Yucca Basin (see 

 above), which was probably once a tributary, the area is about 740 square miles. 



THE INDIAN SPRING BASIN. 



The Indian Spring Valley is a north-south trough lying east of the Frenchman Flat 

 Basin and between the Spotted and Pintwater Ranges. It is separated from the Lee 

 Canyon Basin by a divide only 130 feet high. This divide is alluvial and almost cer- 

 tainly recent and there is little doubt that the basin once drained into the Lee Canyon 

 Basin and thence to the Las Vegas Valley and the Colorado River. The area of the 

 present basin is 650 square miles. 



THE PINTWATER BASIN. 



The Pintwater or Desert Valley is a trough similar to that of the Indian Spring 

 Valley and lying east of it. At its south end it is separated from the Lee Canyon 

 Basin by a recent alluvial divide only a few feet high. There is no doubt that the 

 basin was very recently a part of the Colorado drainage. The area of the basin is esti- 

 mated at 730 square miles, but the position of the northern boundary is very uncertain 

 and this area is a very rough approximation. 



