Geology from a Motor Car 357 



that reaches to Death Valley. This outlet was through a low 

 notch cut in the rock hills north of Silver Lake playa. The 

 outlet channel was cut into the bed-rock about eight feet below 

 the top of the beach ridge. 



Highway to Amargosa Valley through 

 Riggs Valley and over Mountains 



Riggs Valley is a part of the large trough that extends south- 

 ward from the southeast end of Death Valley, and includes 

 Silver Lake and Soda Lake Valleys. The eastern border of 

 Riggs Valley north of Silver Lake playa is formed by the 

 Silurian and Turquoise Mountains. The western border of 

 the Valley for a large part of its length is formed by the 

 Avawatz Mountains, which rise to a height of more than 6,000 

 feet, or nearly 5,500 feet above the lowest part of the Valley. 

 The lowest part of Riggs Valley is occupied by a playa, Riggs 

 Dry Lake, formerly known as Silurian Dry Lake. From a low 

 point of 576 feet east of the Avawatz Mountains the highway 

 crosses a low range of mountains, past another Devil's Play- 

 ground, and descends into the Amargosa Valley, then climbs 

 along the east side of the Ibex Range to Ibex Pass (El. 2,250 

 feet) , then descends again 27 miles to Shoshone, again in the 

 Amargosa Valley, passing Tecopa and Zabriskie, near an old 

 borax works. The valley floor is much dissected for a distance 

 of 10 miles. At Shoshone the valley in narrowed by the en- 

 croachment of mountains on either side. North of Shoshone 

 the valley is two to five miles wide and is a comparatively 

 smooth desert floor. Eagle Mountain stands in the middle of 

 the valley five miles south of Death Valley Junction, and causes 

 a playa by ponding the waters of the Amargosa (when there 

 are any!) . 



Incomparable Death Valley and Good 



Roads Are Ahead 



Death Valley Junction and Amargosa Hotel are near the 

 California-Nevada State line at .,. an . elevation of 2,000 feet. 



