23 



bluish gray glauconitic and f ormainif eral siltstones. Deposits 

 of Lower Pleistocene age are marine marls, silts, and sand, 

 while sediments of Upper Pleistocene age are mainly nonmarine 

 deposits. 



The shores around Palos Verdes Hills are rocky with steep 

 sea cliffs. The beach sediments are mostly cobbles and only 

 occasionally are there any small sandy pocket beaches. 



SUBMARINE TOPOGRAPHY OF SANTA MONICA BAY 



The bathymetry of Santa Monica Bay has been determined 

 largely from U. S. Coast and Geodetic Survey "smooth sheets'* 

 numbers 4559, 4784, 5235, 5364, 5390, 5396, 5397, 5507, 5653, 

 5851, and 6259. Certain unavoidable errors were introduced 

 when contouring due to survey methods employed by the U. S. 

 Coast and Geodetic Survey. For example, most of the sounding 

 lines, especially those close to shore, were run along lines 

 parallel to shore. As a result, the exact position of the 

 constructed contours are not as accurately positioned as they 

 would have been if the sounding lines had been run normal to 

 the coast. Also, soundings were rounded off to the nearest 

 fathom, and the conversion to feet introduced more uncertainties 

 as to the exact position of the contours. None of the inaccur- 

 acies mentioned are critical and they become less important 

 with increasing depth. Additional soundings by the VELERO IV 

 were used only in the vicinity of the terminal ends of the 

 proposed outfalls and in the rocky area to the south of Santa 

 Monica Canyon, The data gathered by the VELERO IV indicated 

 no significant changes of the nearshore topography so that 



