The Crocker Flat landslide, located in the vicinity of Recruit Pass and northwest of Fellows, is composed largely of lower Miocene and Oligocene sands and silts and a minor amount of middle Miocene shale which were superimposed upon, and subsequently infolded with, younger Miocene sediments. This landslid mass descended by gravity, in upper Miocene time, from a highland located within or west of the San Andreas Fault zone, prior to the deposition of the Santa Margarita (upper Miocene). During Santa Margarita time coarse clastics derived from crystalline rock masses west of the Temblor Range were deposited unconformably over the Crocker Flat landslide and adjacent areas. The Santa Margarita beds and the Crocker Flat landslid mass were involved in the post-Miocene orogeny w ich elevated the Temblor Range and folded and faulted both of these units. Infolded and downfaulted outliers of Santa Margarita, on top of the Range, have been preserved from later erosion.

On the summit of the Range clastics so coarse that they have been mapped as "Basement complex" by several workers are considered to be Santa Margarita in age because they are intertongued with and grade laterally into sands and boulder beds containing Santa Margarita fossils in adjacent areas. Furthermore a portion of the landslid lower Miocene and Oligocene sediments of the Crocker Flat area are unconformable beneath these coarse clastics. This relationship also tends to preclude the premise of this so-called "basement" being a part of a huge overthrust sheet.

The crystalline rocks previously mapped as "Basement complex" on the west side of the Range are not in place but are detrital in origin and of Santa Margarita age also; these sediments owe their coarseness to a proximity of source and to possible minor landsliding during deposition.

The intercalated lenses of granitoid and schistose boulders and sands in the upper Miocene punky shales on the northeast side of the Temblor Range are equivalent in age to the coarse Santa Margarita conglomerates on the southwest side of the Range. These beds are believed to have had a common western source which must have been near at hand, within or west of the San Andreas Fault zone. The erosional remnants of Santa Margarita conglomerate along the summit and higher parts of the Temblor Range are regarded as being normally depositional in origin and not klippen remnants of an overthrust sheet; these deposits represent an intermediate facies between the interbedded conglomerate and punky diatomaceous Santa Margarita on the northeast and the coarse conglomerates on the southwest side f the Range.

The Recruit Pass fault is a normal fault with its western side downthrown; it is thought to be one of the lines along which uplift occurred to give the present elevation of the Temblor Range.