The late Paleozoic(?) Hozameen Group consists of four divisions composed of various proportions of ribbon chert, basic lavas (now greenstones), limestone, and argillite, totalling at least 20 000 ft in thickness. In late Paleozoic or Triassic time, these rocks were metamorphosed to form the Custer Gneiss, a high-grade migmatitic complex of layered gneiss and schist. A second episode of high-grade regional metamorphism in Late Cretaceous time is associated with the emplacement of the Spuzzum Intrusions. This was followed by the Yale Intrusions (mainly foliated granodiorite), deposition of Eocene conglomerate and sandstone, and intrusion of Chilliwack batholithic rocks (mainly tonalite), which are partly of Miocene age. Several periods of deformation, some associated with the orogenies mentioned above, produced fold axes trending northwest, northeast, and northerly. The area contains three main fault zones. One separates the Custer Gneiss from its overlying cover of Hozameen rocks. A second, the Hozameen fault, separates the Hozameen beds from Mesozoic formations to the east and contains the 'serpentine belt'. The third, the Fraser River fault zone, is represented by the Hope and Yale faults.