Mugu Submarine Canyon resembles the subaerially eroded canyons inland except that the two branches at its head are somewhat unusual in having an isolated ridge protruding from the floor of each branch and parallel to the canyon axis. Cores indicate that there are hard rock outcrops at several points on the floor along the deeper portions of the canyon. The maximum gradient of the canyon occurs at its two heads and may represent the maximum angle of repose of recent fill. There are indications that the heads and sides of the submarine canyon are relatively unstable as compared to the more gently sloping shelf areas on either side of the canyon. The sediments on the shelf areas adjacent to the canyon show a somewhat systematic variation in type; however, the distribution of sediments from the floor and sides of the canyon is complex and not a function of depth. Analysis of the samples shows that the upper canyon sediments are poorly sorted and have an asymmetrical size distribution which differs from the well sorted and more symmetrical shelf sediments.