76 



median diameter in this range and increase the arithmetic mean 

 while the median and low values would remain almost the same. 

 Below the shelf break the effect of slumping is clearly 

 shown. The values show a decrease to a depth of 500 feet and 

 in this range there is still a wide range of maximum median 

 diameters. In the interval from 500 to 1,000 feet there is 

 a slight increase in the median value and the mean shows a 

 sharp rise. This shows clearly the effect either of coarse 

 material vrfiich has slumped into Redondo Canyon in a zone of 

 generally fine-grained sediment and the median diameter of 

 the samples of this slumped material forms the high maximum 

 value in this range, or the possible effect of organic contri- 

 bution. At depths greater than 1,000 feet the median diameters 

 show a sharp decrease and the mean and median are nearly the 

 same. Also, the maximum and minimum values are evenly distri- 

 buted about the median. This indicates the existence of 

 normal sedimentation in this region without visible effects of 

 slumping. Undoubtedly slumping occurs, but is out of the range 

 of delivery of coarse sediment from the regions of the shelf 

 near the break. The slumping is probably of sediments of 

 similar size ranges and its effect is not evidenced by any 

 apparent anomalous pattern of distribution of sediment. 



Sorting 



Definition and Significance 



The sorting coefficient (Trask, 1932) is computed from the 

 cumulative curve of grain-size distribution. By definition. 



