SHALLOW SUBMERGED MARINE TERRACES OF SOUTHERN CALIFORNIA

Profiles across the mainland shelf, island shelves, and bank tops of southern California show five separate flattenings that are interpreted as erosional marine terraces cut during times of low sea level of the Pleistocene Epoch. Similar terraces have been discovered recently in widely separated parts of the world; this supports the interpretation of their relationship to eustatic changes of sea level. A correlation diagram of the terraces of southern California shows that each terrace is deeper around offshore islands and banks than off the mainland; this is attributed to regional warping that from other evidence is believed to have begun in Late Miocene time. The warping indicated by the deepest terrace, at the shelf edge, amounts to about 160 feet per 100 miles.