What are frequently designated collectively as the Coast Mountains begin at the south and adjacent to the shore of the Pacific, in the vicinity of Santa Barbara, Cal., and extend northward along the immediate seaboard far into British Columbia. A continuation or branch of this series of elevations follows the south coast of Alaska, and is prolonged so as to form the Aleutian Islands. The length of the mountain system or succession of ranges referred to is between 3,500 and 4,000 miles. The detailed study of this long, narrow, and in many parts excessively rugged region is as yet in its infancy, and only a brief account of its salient features can be attempted at present. In southern California the structure of the mountains and the deep stream-deposited gravel, etc., in the intervening valleys, as well as the aridity of the climate and character of the vegetation, correspond closely with the similar conditions in the Great Basin. In fact, the Great Basin region, as the term has been used on a previous page, there meets the Pacific, and the islands rising from the adjacent portion of the ocean seem to be the summits of mountains of the Basin Range type. Owing to the dryness of the climate in southern California and adjacent portions of Mexico, the deeply alluvial-filled valleys are treeless, and agriculture is only possible with the aid of irrigation. Where water can be had, however, there are wonderfully productive orchards, vineyards, and gardens, in which the fruits and flowers of both the temperate and torrid zones flourish side by side with marvellous luxuriance. The palm there casts its shadow on fragrant bowers of the most superb roses. The grass-clothed mountain slopes are either bare of trees or but scantily forested, while the upland valleys produce a dense jungle of native trees and shrubs. To the north of the irregular and diversified portion of southern California, where the Great Basin region extends southwestward to the Pacific, rises the southern Coast Range of California. The indefinite beginning of this range is in the neighbourhood of Point Conception, to the north of Santa Barbara, and its northern terminus is at the Golden Gate. The same belt of mountains extends northward, however, and forms the northern Coast Range, which extends to the Klamath Mountains in northern California. The coast ranges of California as a whole are about 500 miles long and from 30 to 40 miles broad, and comprise several seemingly distinct uplifts, some of which have culminating peaks from 4,000 to about 7,000 feet high. In general this elevated region is conspicuously sculptured, and in part at least has the characteristics of an eroded plateau. The suggestion has been offered that the northern portion of the Coast Range is a dissected peneplain.