32 BULLETIN 54^ U. S. DEPARTMENT OF AGKICULTUEE. 



THE SODA SPRINGS TROUGH. 



South of the Gabbs Valley and west of the Pilot Mountain Range is a short trough, 

 now separated by alluvial divides into four small basins — the Acme, Luning, Mina, 

 and Rhodes. Each basin contains a small playa, that of Rhodes being very saline, 

 though the others are not especially so. The present a,reas are: Acme 130 square 

 miles, Luning 175 square miles, Mina 65 square miles, and Rhodes 210 square miles, 

 making a total of 580 square miles. 



It is very difficult to guess the topography of tliis trough during the Lahontan period. 

 Both divides and playas have been raised hj post- Lahontan alluvial deposition and it 

 may be either that the whole trough once drained into Rhodes or that it all, including 

 Rhodes, drained northward into Walker Lake. The writer inclines to the opinion 

 that the trough drained partly one way and partly the other, the Acme Basin being 

 tril)utary to "Walker Lake and the Luning and Mina Basins to Rhodes. If so, tliis may 

 account for the greater salinity of the Rhodes playa, though the writer has been unable 

 to discover any conclusive evidence of the existence of a Quaternary lake in this basin. 

 On the assumption stated the Lahontan period drainage area of the Rhodes Basin 

 would be 450 square miles. There is also a bare possibility that the Garfield Flat, 

 next to be descril^ed, once drained into the Mina Basin and thence to the Rhodes. 

 Including this and the Acme Basin, the Rhodes drainage area would be 670 square 

 miles, which is a maximum value. 



THE GARFIELD BASIN. 



Just west of the Mina Basin and north of the main ridge of the Excelsior Mountains 

 lies a small inclosed valley, the deepest depression of which is the Garfield Flat playa. 

 The divide between tliis basin and the Mina Basin is in one place scarcely 150 feet 

 above the playa and it is barely possible that there may once have been an outlet 

 over or through tliis divide. The drainage area of the basin is but 90 square miles and 

 this is l^elieved far too small to have attained discharge over a divide of the present 

 height, but the divide may formerly have been lower and subsequently raised by the 

 deposition of alluvium. The question could probably be settled by careful study 

 of the basin, but is unimportant, since the area is too small to give the basin any 

 interest. 



THE TEELS BASIN. 



The Teels Basin lies directly south of the Garfield Basin. The lowest pass opens 

 into the Rhodes Basin, but is over 800 feet above the floor and apparently never could 

 have been a channel of overflow. Neither has the basin ever had any tributaries. 

 The only chance of former inflow would be from the Hun toon Basin (described below) 

 and the di\ading pass is so high as to render this extremely improbable. The area of 

 the basin is 320 square miles. In its deepest depression is the well-known Teels Salt 

 Marsh, a playa of high salinity and which has unusual interest for the present inquiry 

 because of the reported occurrence of hanksite and other saline minerals associated with 

 the potash deposits at Searles Lake, California. 



THE HUNTOON BASIN. 



The Huntoon Basin is another basin quite similar to the Garfield and the Teels and 

 lying west of the latter. The lowest pass leads into Teels, but since it is over 300 feet 

 a}jove the bottom, it is not considered probable that it was ever a line of discharge. 

 The deepest depression contains a playa of the usual type, and not especially saline. 

 The area of the basin is 115 square miles. 



