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has closer resemblance thereto, both in characters and products, than 

 to any other region of the state. It comprises the Imperial Valley and 

 other valleys adjacent to the Colorado River. It differs from the 

 Great Valley in having a higher temperature both in summer and 

 winter and in its rainfall, which is practically negligible, as all 

 cropping is conditioned upon irrigation. 



The Great Valley differs from the coast regions west of it in having 

 a lower winter temperature, because its dominating environment is 

 the snow-clad Sierra on its east side, while the dominating environ- 

 ment of the coast is the ocean. This contrast is more marked through 

 the central and southward stretches of the Great Valley. Another 

 contrast is found in summer temperatures which may average more 

 than twenty degrees higher on the east than on the west side of the 

 Coast Range, because the ocean then has a cooling effect upon the 

 regions open to its influence. 



In rainfall the Great Valley has such marked differences that 

 generalization is impossible. Roughly speaking the Sacramento Valley 

 may be said to have from 20 to 40 inches of rainfall in different years, 

 while the San Joaquin has from 4 to 16. This variation in rainfall is, 

 however, overcome by irrigation which is practiced in the Great Valley 

 over a greater acreage of land than in any other region of the state. 

 The products include all grown anywhere in the state. 



The Mountain and Plateau Region. It has been found by observa- 

 tion during many years that what are known as valley conditions 

 prevail to an elevation of about fifteen hundred feet over the rolling 

 region known as the "foothills" which are the steps up to the high 

 ranges. Above this elevation winter temperatures fall lower, rainfall 

 increases, snow flurries begin, and thence upward mountain valleys and 

 plateaux are found at different levels up to about six thousand feet, 

 which is about the top of California's agricultural lands, and above 

 four thousand feet such lands are used principally for summer pas- 

 turage. This mountain region has a winter like that of the eastern 

 states with a great precipitation of rain and snow to cause great 

 rivers to flow down the west side of the Sierra and give the state its 

 invaluable and ample water supply for power and irrigation. In the 

 valleys among the great snow mountains there are farming districts 

 of considerable present production and great future promise. The 

 most marked character of these high lands is the limitations placed 

 upon cropping by the short growing season and the frequency of 

 frosts during the spring and, at the higher elevations, even during the 

 summer months. Therefore this division differs most markedly from 

 other California regions and has closer resemblance to some of the 



