The Sierra Nevada is an approximately north-south trending mountain range which lies in eastern California. It is about 450 miles long and has a width of about 75 miles (figure 1). It is flanked on the west by the San Joaquin and Sacramento valleys, the average elevation of which is only a few hundred feet. On the east it is bordered by the valleys of the Great Basin, most of which are more than 3,000 feet above sealevel. The average elevation of the crest of the Sierra Nevada is perhaps 9,000 feet, but it includes several peaks that rise to heights exceeding 14,000 feet. Bear Mountain and the Tehachapi Range, often spoken of as southern parts of the Sierra Nevada, are regarded as separate structural entities and are therefore not included in this discussion.
This paper presents a brief description of a series of escarpments which extend along . . .