No, 55) at 42 00 feet (estimated 0. 5 knot). However, notes 

 by LT Don Walsh reveal variability in current velocity at 

 this location also. He reported no current on Dive No. 53 

 and stressed the observation by stating that a 15-minute 

 wait was required to allow the sediment to settle following 

 the bathyscaph landing. 



On the deeper dives in the vicinity of Guam, water 

 currents were found to be less than 1 cm per second (Dive 

 Nos. 61, 70, 75, and 76). At approximately 7000 feet, at 

 locations west of Guam (Dives Nos. 76 and 77) water 

 current appeared to be variable in direction and velocity. 

 However, Dive No. 77 revealed the sea floor sediment to 

 be formed into distinct ripples with a crest- to- crest dis- 

 tance of 18 inches and a vertical amplitude of 0. 5 to 1, 5 

 inches. Illumination was not adequate during these two 

 dives to acquire a good measure of water current velocity. 



Below 18, 000 feet, water current velocities were 

 virtually nil. The bathyscaph did not reach the sea floor 

 on Dive No. 69 when it descended to 22, 540 feet, so there 

 was no chance to make a current observation. At 35, 800 

 feet on Dive No. 70, sediment forced into suspension by 

 the landing remained as a dense cloud for the duration of 

 the stay. 



Geology and Biology of the Sea Floor 



Ocean dives to the sea floor in the San Diego area 

 were all made either in the Loma Sea Valley or in the San 

 Diego Trough (fig. 1). In the interest of safety, such dives 

 were limited to the relatively level and obstruction- free 

 basins of these areas. The majority of dives were made 

 to permit U. S. personnel to become acquainted with the 

 operational techniques involved and to survey the environ- 

 mental conditions present in these areas, particularly 

 those that could be expected to influence the safe move- 

 ments of the TRIESTE while submerged. 



In both areas, the sedimentary overburden is predom- 

 inantly olive- green clay- silt. Observations of the Loma 

 Sea Valley, as recorded for Dive 52, are typical for both 

 the Loma Sea Valley and the San Diego Trough, except for 

 the biological constituents occupying each ecological en- 

 vironment. The soft sediment was found to be heavily 



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