Geology of the Peninsular Range Province, Southern California and Baja California

The Peninsular Range province is a well-defined geologic and physiographic unit that occupies the southwestern corner of California and extends southeastward to include the Baja California peninsula (fig. 1). It is characterized by elongate ranges and valleys whose general northwesterly trend is terminated abruptly on the north by the east-west grain of the Transverse Ranges. The part of the province that lies above sea level is approximately 900 miles long, 140 miles in maximum width, and 55 miles in average width. An additional large part is mainly submerged beneath the Pacific Ocean, and is represented by Santa Catalina, Santa Barbara, San Nicolas, and San Clemente Islands.