Route construction, the first highway crossing these mountains to connect the Greater Los Angeles and San Joaquin Valley regions. Geology The Tehachapis are largely the result of the movements of the Garlock Fault, located along the southeastern base of the range, a major transform fault which runs from the San Andreas Fault in the west to the Sierra Nevada Fault on the east and some distance beyond. This earthquake fault is unusual in California in that it is a left-lateral fault — meaning that if one stands facing the fault, the land on the opposite side moves to the left — opposite to most of the state's faults which are right-lateral faults. Natural history The Tehachapi Mountains are a major and crucial wildlife corridor and plant habitat bridge linking the other Transverse Ranges and the California Coast Ranges on the west with the Sierra Nevada on the east. Their relative lack of development, especially in the large Tejon Ranch section, have allowed the continuity of these ecological functions to date. Flora The Tehachapis are primarily in the California interior chaparral and woodlands sub-ecoregion, with native grasslands, California oak woodlands and oak savanna the predominant habitats. The higher montane elevations include the California mixed evergreen forest plant community. Some of the chaparral woodland species include: canyon live oak (Quercus chrysolepis), valley oak (Quercus lobata), blue oak (Quercus douglasii), and gray pine (Pinus sabiniana). Montane species include: black oak (Quercus kelloggii), Coulter pine (Pinus coulteri), incense cedar (Calocedrus decurrens), white fir (Abies concolor), and in a few remote locations small stands of quaking aspen (Populus tremuloides). The Tehachapi linanthus (Leptosiphon nudatus) is a phlox plant species endemic to chaparral habitat in the Tehachapi Mountains and the southern Sierra Nevada. The Tehachapi ragwort (Packera ionophylla) is an aster plant species endemic to forest habitat in the Tehachapis and eastern Transverse Ranges. The Tehachapi buckwheat (Eriogonum callistum) is known only from the chaparral of the Tehachapis. Fauna The Tehachapi slender salamander is endemic to the Tehachapi Mountains and a listed vulnerable species. The white-eared pocket mouse is endemic to the Tehachapis and San Bernardino Mountains and a listed endangered species. There are at least 107 bird species, including the Steller's jay and mountain chickadee, found in the Tehachapis, many which consume acorns of the black oak (Quercus kelloggii) as part of their diet. Other flora found here include the buckbrush and mountain mahogany. The