The rocks within the Verdugo Mountains block are almost entirely igneous and metamorphic rocks similar to the crystalline basement rocks exposed to the north in that portion of the San Gabriel Mountains south of the San Gabriel Fault.
The Verdugo Mountains are part of the western Transverse Ranges, which have risen in the last 7 million years as the result of contractional deformation resulting from transpressional motion and rotation of crustal blocks in the "Big Bend" region of the San Andreas Fault [REF].