THE PACIFIC SLOPE consists of the Sierra Nevada and the Cascades, the Coast Ranges, and the intervening valleys of California and Puget Sound. These valleys have been built up by debris carried down from the mountains by rivers in the south, and by glaciers or glacial streams in the north, and they contain much fertile soil. Climatic conditions, though determined to a great extent by the proximity of the Pacific Ocean, are very diversified as a result of the irregular topography of the country. The range between summer and winter temperatures is generally less than elsewhere in the United States, and, along the coast, the mean for the three coldest months of the year varies from about 40° to 43° F. in Wash ington to between 50° and 55° F. in the more southerly parts of California, while the summer mean over the whole coastal area is generally between 55° and 65° F. In the Puget Sound and Cali fornia valleys, the winters are usually a little colder than on corre sponding parts of the coast, while the summers are considerably warmer, the mean varying from 65° to 80° F. The rainfall is heaviest along the coastal ranges and in higher altitudes on the western slopes of the Sierra Nevada and the Cascades, in the former case varying from 15 inches or less in the south of California to over 100 inches in the north of Washington, and in the latter being over 40 inches. In the interior valleys, on the other hand, the precipitation is generally much less ; in the Puget Sound region it is between 30 and 40 inches, while in California it is less than 20 inches in the Sacramento valley, and less than 10 inches in the San Joaquin valley. Over the whole region the greater pait of the rain falls during the autumn, winter, and spring months, and in California the summer months are almost entirely dry. The heavy rainfall on the mountains explains the great Pacific forest, the timber from which amounts to about one-seventh the output of the United States. Washington is at present the leading lumber state in the Union.
Agriculture is a much more important pursuit than formerly. Wheat is grown chiefly in the Willamette, Sacramento, and San Joaquin valleys, and, owing to the greater part of the precipitation occurring during the growing season, large crops can be raised even in districts where the rainfall is light. Within recent years
the area under wheat has greatly declined, as the result of the extension of various irrigation schemes, which have led to much land being devoted to fruit-farming. Barley is also an important product, especially of California, which ranks as the second state in the cultivation of that cereal. Among the fruits for which California is famous are peaches, apricots, pears, plums, and cherries. Flour-milling and fruit-preserving are, therefore, important industries of the Pacific Slope.
The mineral wealth of the region is considerable, though mining no longer comes first among the economic activities of the people. Coal, ranging in character from lignitic to bituminous, is found in various places, but chiefly in Washington, in the vicinity of Puget Sound and on the eastern slope of the Cascades. The total pro duction of the Pacific Region is about 3,300,000 tons, practically the whole of which is mined in Washington. But if California is poor in coal it is rich in petroleum, and about one-third of the United States supply comes from that state, chiefly from its more southerly parts. Gold is found in the Sierra Nevada in California, about one-fifth of the whole output of the United States being obtained in that region. Considerable quantities of copper are also mined there.
The Pacific Slope is not, and owing to its great distance from the more densely populated part of the United States is unlikely to become, a great manufacturing region, and such manufactures as do exist are concerned with preparing the products of the forest, the mine, and the farm for further treatment elsewhere. In the north, around Puget Sound valley, conditions are somewhat more favour able. The more northerly position of Seattle, Tacoma, and Portland, their proximity to the coalfields of Washington and British Columbia, their greater facilities for trade with Alaska and the Far East, and their easier communication with the remainder of the United States, are all tending to give them a more rapid development than is the case with San Francisco.