The ice which occupied Puget Sound was the extreme southern portion of a great but irregular Piedmont glacier which fringed the rough and ragged coast of the continent all the way to southern Alaska. A remnant of this former ice body still exists near Mount St. Elias, and constitutes the very instructive Malaspina glacier.
In a preceding chapter the rugged topography of the western margin of the continent has been briefly described, and a general explanation given of the contrasts which it presents to the coastal plains and plateaus on the Atlantic border.
The long, narrow peninsula known as Lower California, as yet unstudied in the light of modern geography, is known to be mountainous throughout. Although nearly surrounded by the waters of the ocean, the climate of the peninsula is hot and arid and its surface desert-like. The Gulf of California, which separates such a large portion of the Pacific border of Mexico from the main body of the republic, has the characteristics of a drowned intermontane or orogenic valley. But whether the great depression was ever dry land or not is unknown. The waters of the gulf are shallow, however, and a moderate upward movement of the earth's crust in that region would transform it into a great valley similar in its general features to the central basin of the State of California.
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.