98 



Cores 



Coincidentally with the collection of snapper and 

 Hayward grab samples, a nvunber of cores ranging in length 

 from 14 to 68 inches were obtained in several localities, 

 A total of 15 cores were collected along the proposed out- 

 falls and at the head of Santa Monica Canyon. A description 

 of the cores is given in the Appendix of this report. 



Most of the cores along the traverse from Hyperion to 

 the edge of the shelf are uniform, but marked changes in 

 lithology occurred in some (Fig. 31), Close to shore the 

 sediments are generally composed of sands and silty sands. 

 In a few cases some shells mark the only vertical changes 

 in lithology. Farther offshore the sediments are predomin- 

 antly sandy silts, but gravel and other coarse sediments 

 sometimes occur. The two cores at the edge of the shelf 

 and on the basin slope contain sand and silty sands which 

 are overlain by gravelly silty sand, sand with shell frag- 

 ments, or by gravel. These cores on the outer shelf and on 

 the basin slope are therefore unique since they have abrupt 

 changes in lithology. 



Two cores taken along the axis of the Santa Monica Canyon 

 (3342 and 3345) have gravel and sandy gravel, but the other 

 three are rather uniform in texture. Gravel, sandy gravel, 

 and shell debris are common in all of the cores taken from 

 the head of Ssinta Monica Canyon. 



Additional cores and jettings were taken elsewhere in the 

 bay and close to shore, near Hyperion, An examination of 

 the logs show that the lithology varies greatly in a vertical 



