ABSTRACTS Sea Floor off Southern California, by K, 0. EMKRY, Universit\' of Southern California, Los Angeles. The sea floor od southern California is unlike that adjoining most other coasts of the world in its great t;opographic irregularity. The area of about 30,000 square miles consists of a checkerboard-like pattern of basins and ranges which are believed to be grabens and horsts that were formed in late and post-Miocene time. A general southward decrease in elevation of the tofis of the

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... es and the bottoms and sills of basins suggests that regional tilting followed or accompanied the local faulting. Basins far from shore are only slightly filled with sediments, those near shore have been nearly conijiletely filled, and the l-os Angeles and Ventura basins have been tilled to overflowing so thai they now are land areas rather than part, of the sea floor. Grain-size, calcium carbonate, and organic content ot the sediments present a smooth graduation from the Los .\ngele3 basin through the nearshore basins to the otifshore basins.