ORIGIN OF THE S ALTON BASIN. 103 



built a bar across the narrow gulf and cut off the upper portion, now 

 the Sal ton Basin, from the sea. a 

 Barrows says: 6 



All this took place in very recent times. The Coahuila Indians, who to-day inhabit 

 the upper end of the valley, have a distinct apd credible tradition of the drying up 

 of this lake and of the occasional sudden return of its waters, and the Dieguenos, who 

 lived at a time when the supply of water along the central portion of the valley was 

 probably much greater than at present, raised on the naturally irrigated soil abun- 

 dant crops of maize, melons, and beans. But slowly the valley was abandoned to 

 aridity. Almost unvisited by rainfall, except about the edge of the mountains, the 

 loss of the river left it cruelly dry. Low, and inclosed between heat-reflecting ranges 

 that shut off the breezes of the ocean, it gained a temperature which is one of the 

 highest on the globe. The windstorms that rage up the valley from the southeast 

 have drifted great dunes of sand over certain portions, and much of the country 

 never reached by the deposits of the lake is as black, stony, and repulsive as erup- 

 tive rock formations in the desert can be. Apparently about the middle of the first 

 half of the century the overflow from the Colorado was largely checked and not 

 resumed to any extent until the year 1849. The Indians, who had lived in plenty 

 along the central valley, were driven by the drought forever from their homes. 



During the high flood of the Colorado River in June and July the 

 water breaks through its banks near Algodones, in Mexico, a few 

 miles below Yuma, and flows westward through an old channel for 

 some thirty miles; then, turning north into the United States, it flows 

 through the Salton River to Salton Lake, filling up Mesquite Lake 

 on the way. Most of the stream, however, goes on to Lake Jululu, 

 or Volcano Lake, from which the New River flows northward to Sal- 

 ton Lake, and the Hardy River southward to the Gulf of California 

 (see fig. 10). The Salton and New rivers flow only during the high- 

 est floods, but the Hardy River flows all the year, being fed by the 

 Rio Padrones. 



The Maquata Basin, a region similar to the Salton Basin, and, like 

 it, lying below sea level, lies to the west of the Cocopah Mountains in 

 Mexico. It is usually a waterless desert, but, at times of very high 

 flood in the Hardy River, water flows around the mountain range, 

 creating the Laguna Maquata c (see fig. 10) in the center of the basin. 

 This is probably the only region in Mexico which, when irrigated, 

 will be suitable for the culture of the best sorts of dates. 



Some students of this region believe that an upheaval of the region covered by 

 the delta aided in cutting off Salton Basin from the Gulf of California. The occur- 

 rence of mud volcanoes and of extinct craters, such as the Sierra Prieta, lends 

 strength to the view that the piling up of such enormous masses of sediment has 

 induced geologic changes. The old beach lines of the Salton Basin are, however, 

 still approximately at sea level, which would go to show that there has been but 

 slight change in the level of the region as a whole since it was cut off from the sea. 

 (See Barrows, David P., The Colorado Desert, in National Geographic Magazine, Vol. 

 XI, No. 9, September, 1900, p. 340.) 



&L. c., p. 341. 



c Barrows, 1. c., p. 344. 



