Named for Calabasas Peak as unit in Topanga Group. Type locality: exposures in Stokes Canyon sec.3 T1S R17W, 3 km west of Calabasas Peak, Santa Monica Mountains, north central Malibu Beach quadrangle, Los Angeles Co, CA. Consists of sandstone with interbedded silty shale and sedimentary breccia 1,200 m thick. Forms medium- to thick-bedded, medium- to coarse-grained, graded bedding which is locally diatomaceous or phosphatic and fossiliferous. Divided into (ascending): Dry Canyon Sandstone, Escondido Canyon Shale, Latigo Canyon Breccia, Newell Sandstone, and Mesa Peak Breccia Members (these recognized only in upper plate of Malibu detachment fault, east-central Point Dume and west-central Malibu Beach quads); and Stokes Canyon Breccia Member (in Stokes Canyon area, where Calabasas is otherwise undivided). Unconformably overlies or intertongues with Conejo Volcanics (Topanga Group) or, locally, overlies Topanga Canyon Formation (Topanga Group); unconformably underlies Modelo Formation. Is middle Miocene age.

Source: GNU records (USGS DDS-6; Menlo GNULEX).