A-17 



consists of a silty sediment with occasional sandy patches. 

 The axis is flanked by extensive outcrops on both sides with 

 frequent talus blocks at the base of these outcrops. The 

 wall of Heezen Canyon, a very narrow and deeply incised 

 canyon, consists of silty sediment with minor consolidated 

 clay outcrops between 800 and 1300 meters. The axis of this 

 canyon is extremely narrow and has a silty floor heavily 

 littered with large talus blocks. The axis is flanked by 

 massive outcrops with numerous sediment dusted ledges. The 

 wall of Corsair Canyon is characterized by silty sediment 

 with minor outcrops at 900, 1150 and 1300 meters. 



Faunal Density 



The density of epibenthic fauna shows a marked varia- 

 tion with depth. Faunal density is uniformly high in the 

 shallower region, with a peak between 350 and 500 meters 

 (Figure Bl) . The density then drops and remains relatively 

 uniform from 600 to 1600 meters. There is a secondary peak 

 between 1600 and 2300 meters, after which it shows a marked 

 decline to 3150 meters. The shelf and shelf-break regions 

 are areas of high nutrient flux and the fauna is composed 

 of a variety of trophic types. The peak in faunal density 

 between 350 and 500 meters is mostly the result of high 

 concentrations of the scavenging quill worm Hyalinoeaia 

 artifex. This species has a very patchy distribution and 

 occurs in high concentrations when it is present. Thus, 



