These places are doubly dowered. They have the wealths of the two zones, without the drawbacks of either. In South California this results from two causes: first, the presence of a temperate current in the ocean, near the coast; second, the configuration of the mountain ranges which intercept and reflect the sun's rays, and shut South California off from the rest of the continent. It is, as it were, climatically insulated,--a sort of island on land. It has just enough of sea to make its atmosphere temperate. Its continental position and affinities give it a dryness no island could have; and its climatically insulated position gives it an evenness of temperature much beyond the continental average.
It has thus a cool summer and a temperate winter,--conditions which secure the broadest and highest agricultural and horticultural possibilities. It is the only country in the world where dairies and orange orchards will thrive together.
It has its own zones of climate; not at all following lines parallel to the equator, but following the trend of its mountains. The California mountains are a big and interesting family of geological children, with great gaps in point of age, the Sierra Nevada being oldest of all. Time was when the Sierra Nevada fronted directly on the Pacific, and its rivers dashed down straight into the sea. But that is ages ago. Since then have been born out of the waters the numerous coast ranges, all following more or less closely the shore line. These are supplemented at Point Conception by east and west ranges, which complete the insulating walls of South, or semi-tropic, California. The coast ranges are the youngest of the children born; but the ocean is still pregnant of others. Range after range, far out to sea, they lie, with their attendant valleys, biding their time, popping their heads out here and there in the shape of islands.
This colossal furrow system of mountains must have its correlative system of valleys; hence the great valley divisions of the country. There may be said to be four groups or kinds of these: the low and broad valleys, so broad that they are plains; the high mountain valleys; the rounded plateaus of the Great Basin, as it is called, of which the Bernardino Mountains are the southern rim; and the river valleys or cañons,--these last running at angles to the mountain and shore lines.