NO. 2 



OLGA HARTMAN : SUBMARINE CANYONS 



Studies. The results may not have differed much, however, because 

 the hard-packed sediments in many shelf depths (100 meters or less) 

 are not easily taken with either orange-peel, or Campbell, or any other 

 kind of grab. 



The thirteen largest offshore submarine canyons of southern Cali- 

 fornia ( Fig. 1 ) are scattered along the shelves, where they cross 



121* 120° lir 118° 



Fig. 1. Index map showing the locations of the thirteen submarine 

 canyons biologically sampled. 



slopes, extend to basins, and occur also out beyond the offshore islands. 

 Compared to the oval-shaped basins, which comprise about a third of 

 the offshore area and attain depths of 627 to 2107 meters, the canyons 

 comprise much less area, are V-shaped furrows or valleys, in some 

 places extending from the shallow shelf near shore to the deep basins, 

 where they form broad fans. These thirteen canyons differ in location, 

 source and in physical features. Nine border the mainland and include 

 those named from Hueneme south to Coronado canyon (see list below) ; 



