2.1: Introduction
The traveler passing through California encounters the most remarkable diversity of scenery, as well as of climate and of nature. Nowhere else in the United States is there to be found in an equal area so many interesting landforms, and nowhere else is shown so clearly the influence which these exert upon climate and life. Within the bounds of California are found nearly all the different types of physical features which make up the surface of the earth. We have, then, in our study of California geography, a most remarkable opportunity to learn how human life is so completely influenced upon the conditions surrounding it, and how this life has been modified by these conditions.
The geology of California is highly complex, with numerous mountain ranges, substantial faulting and tectonic activity, rich natural resources, and a history of both ancient and comparatively recent intense geological activity. As the text will cover, California formed as a series of small island arcs, deep-ocean sediments and mafic oceanic crust accreted to the western edge of North America, producing a series of deep basins and high mountain ranges.
One of the most important episodic events was the advent of the San Andreas Fault around 29 million years ago in the Oligocene, when the region subducted a spreading center and its offsets in the East Pacific Rise. This produced major crustal stretching, volcanism, and lateral displacement of up to 350 miles.