96 



PHYSIOGRAPHY 



is about 300 feet below sea-level. In 1906, this low land gave much 

 trouble. The Colorado River broke out of its banks where it crossed 

 the land of its own making, and took a new course into the low area 



to the north. Pouring into this 

 basin, it made a great lake, 

 called the Salton Sea (Fig. 

 104). The lake spread over 

 farming lands, villages, and 

 railroads, and vast sums of 

 money were expended in turn- 

 ing the water back into its old 

 course. 



The deltas of the Mississippi 

 (Fig. 99), the Nile (Fig. 101), 

 and the Hoang Ho rivers (Fig. 

 96) are among the large and 

 well-known ones. The delta of 



Fig. 101. The delta of the Nile. the Ganges and Brahmaputra 



is also a great one, having an 



area (above water) of some 50,000 square miles. The Po has 

 built a delta 14 miles beyond the former port of Adria, which gave 



Fig. 102. Diagrammatic profile and section of a delta. 



Fig. 103. Diagrammatic profile and section of an alluvial fan. 



its name to the Adriatic Sea. The Rhone River has advanced its 

 delta about 15 miles in as many centuries. 



