scaph was oriented with the flotation tank parallel to the incline. This position also per- 

 mitted a view across the slope. A series of channels running downslope were seen to 

 have a crest-to-crest distance of about 4 meters. The height of the crests was about 

 Vz meter above the trough axis. These channels suggested that sloughing down these 

 paths had occurred. 



Evidence that the sediment was at its maximum angle of repose was clearly indicated 

 by the cohesive blocks that had begun to slip from the mantle, but were temporarily 

 halted in their downslope movement by the resistance and structural strength of the 

 sediment. A well-defined leading edge on the blocks extended 2 to 3 inches above 

 the sea floor. 



The bathyscaph landed on the crest of an undulation that scored the face of the in- 

 cline. Sliding down the slope, the bathyscaph remained slightly ahead of a turbidity 

 cloud that was generated. Small chunks of sediment gouged out of the sea floor by the 

 bathyscaph sphere tumbled and slid ahead of the cloud, producing a series of addi- 

 tional trails. Stationary "sediment blocks" were noticed only in the channels. Although 

 small depressions appeared immediately above these blocks, no well-defined grooves 

 or erosion channels were seen. A more complete survey of this slope by a more mobile 

 craft might well reveal such features, particularly since the initiation of such grooves 

 was suggested by the slipping sediment. 



During this dive the TRIESTE'S descent was abruptly interrupted by a sudden impact 

 with a solid object. It is assumed that the mantle of sediment became very thin over a 

 bedrock pinnacle or a ridge and that this was responsible for the pronounced scar found 

 on later examination of the sphere. The craft tilted, at least T/2 meters, into the sedi- 

 ment on the slope. The forward ballast-tank orifice was so firmly filled with sediment 

 that it blocked any possible discharge of ballast. The orifice was washed free of the 

 occlusion during our ascent which was brought to an early completion following this 



harrowing incident. 



The microrelief of the sea floor a few miles south of Capri and the Sorrento Peninsula, 



where most of the diving was accomplished, was always found to be irregular (fig. 8, 

 10, 14). It was pocked by holes, depressions, and diggings of various types, and trails 

 and a pebbly appearance to the mud bottom attested to the variety of biological ac- 

 tivities that prevail (fig. 15, 16). 



The bathyscaph provides an opportunity to view some of the biological and physical 

 forces operating to alter the face of the sea floor and its upper layers of sediments in 

 deep water. Redistribution of sediment is assisted by the activities of animals stirring 

 and digging up the mud, much of which is subsequently transported by the current. A 

 current, about 1 centimeter per second at about 270° true, was found to be present south 

 of Capri at 1000-meter depth. There were no ripple marks. 



Fishes were observed to mark or alter the sea floor by grubbing for food, squirming 

 into the mud to rest or feed, and swimming close enough to the bottom so that they 

 left a trail. Materials lifted into suspension by these actions were noted to be carried 

 many meters while we remained in a fixed position. Other clouds of mud were seen 

 to pass through the area of illumination. The source of these clouds was assumed to be 

 due to fish activifies outside of our view (fig. 7). 



Any interpretation of the source of sediments now located southwest of Capri has to 

 include, after considering these observations, the possibility of contributions from ma- 

 terial coming from the bays of both Salerno and Naples as well as from the volcanic 

 ash disbursed via an aerial route. Any inferences about a chronological history of the 

 earth attributed to uniform sediment deposition in deep water must include the possible 

 effects of the deep-sea animal populations disrupting the continuity of sedimentafion 

 processes. 



17 



