The sediments in the numerous submarine canyons off the California coast may be characterized as sand, mostly find sand, with an abundance of silt and some clay. They are in general very well sorted. Rock fragments and boulders have been dredged from many canyons. Bed rock crops out on the sides of Monterey, Carmel, and Scripps canyons.The median grain sizes in the canyons are slightly lower than on the adjacent parts of the shelf. There are variations in median grain sizes in the canyons but there is not always a decrease in median grain size with increasing depth. Short cores from Fire Hill canyon showed no stratification of the sediments. Heavy minerals make up only a very small part of the sediments. Authigenic minerals and organic material are common in the deeper portions of the canyons. The calcium carbonate content increases with depth due to the increase in abundance of organisms.