79 



,05 to 0.10 mm size range. This range of median diameters 

 includes all the fine sediment of the shelf in the area which 

 has been interpreted as the zone receiving most sediment at 

 the present time. This probably accounts for the apparent 

 well-Kiefined minimum grouping of sorting coefficients for 

 these sediments, for most coarser sediments in the bay con- 

 tain some relic material relating them to a previous stage 

 of deposition, and also contain authigenic minerals and shell 

 fragments. In addition, most finer sediments occur on slopes 

 where slumping and sliding of sediment take place and contain 

 numerous Forarainifera in their coarse fraction. These com- 

 ponents and occurrences would tend to indicate that the 

 sorting of these sediments is unrelated to the mechanics of 

 sedimentation which have caused deposition of the well-sorted 

 sediment on the shelf. It should be remembered that most 

 statistical theoretical studies deal with sediments from a 

 single source which have been transported and deposited by 

 a single uniform process. 

 Sorting of Sediments in Santa Monica Bay 



The sorting of sediments in Santa Monica Bay is shown in 

 Figure 24 „ On the shelf, most of the sediment is well sorted 

 with small patches of moderately-sorted sediment close to 

 shore in the vicinity of Venice, Hyperion and the Palos Verdes 

 Hills o Moderately-and poorly-sorted sediment occurs on the 

 central shelf projection and adjoining areas and at the 

 head of Santa Monica Canyon. Two relationships are evident, 

 (1) the moderately-or poorly-sorted sediments tend to 



