the Sierra Nevada turns southwest and west in the Tehachapi mountains. To the west, the southern Coastal Ranges Province meets the Sierra Nevada Province at the point where the Temblor Range, having turned southeast and east into the San Emigdio Mountains and the Pleito Hills, meets the Tehachapi Mountains. To the east of the junction of the Big Pine and San Andreas faults, the northern boundary of the Transverse Ranges Province is somewhat less distinct. It is formed primarily by "a series of discontinuous faults of large displacement along the flanks" of the San Bernardino mountains and by the Pinto Mountain fault along the northern flank of the Pinto Mountains (Oakeshott 281).
To the south the Transverse Ranges Province is bounded in the west by the Santa Monica Mountains, which form the northern border of the Los Angeles Basin. This southern border also extends nearly 100 miles across the continental borderland into three of the Channel Islands, Santa Cruz, Santa Rosa and San Miguel. Farther to the east the "Santa Monica-Raymond Hill-Sierra Madre-Cucamonga zone of faults" forms the southern border (Mason Hill 24). To the east of the point where this zone of faults meets the longitudinal San Jacinto fault the San Andreas fault "continues southeastward essentially as the southern boundary of the San Bernardino, Little San Bernardino and Orocopia Mountains" (Oakeshott 281).
It is only at its eastern end that the distinctions between the Transverse Ranges Province and its neighbors becomes somewhat uncertain. Generally the Mojave and Colorado Deserts are accepted as the border of the province. But the Orocopia, Chuckwalla and Chocolate Mountains have a geological relationship with the Transverse Ranges and some geologists hold that they should be considered part of the province (Dibblee 7).
In December, 1595 Sebastian Rodriguez Cermeno, on a return trip from the Philippines, described the eastward trend of the coast ...