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may be carried to the sea. If there have been several years 

 of only small rains, the stream may have built up to a thick 

 deposit of sediment in its channel. Then when a flash flood 

 occurred the sediment in the channel may move out into the 

 bay as a plug of sediment (Revelle and Shepard, 1939). Under 

 such circumstances a great heterogeneous mass of unsorted 

 fragments will be deposited in the bay. Waves and currents 

 may then redistribute the sediment over a larger area. 



The presence of considsrable quantities of coarse sedi- 

 ments, especially gravel, over a large part of the bay probably 

 indicates that sedimentation in the past was faster than now 

 and the source of sediments was much greater. The volvime of 

 sediment brought to the bay during periodic storms must have 

 been great. Cores taken far out on the shelf generally do not 

 show many distinct beds of gravel, but gravel is widely distri- 

 buted over most of the bay as was shown in Hayward grab samples. 

 This distribution may be the result of extensive reworking by 

 marine processes after initial deposition. 



Distinct and correlative beds of clay are conspicuous at 

 the site of the Santa Monica breakwater and farther to the 

 south. Clay can only be deposited in quiet waters which are 

 not disturbed appreciably by waves or currents which would 

 wash away the clay, nor can there be a large supply of coarse 

 detritus. The thick deposits of clay are therefore difficult 

 to explain unless it is assximed that one or more offshore bars 

 allowed fine grained sediments and vegetation to accumulate in 

 the quiet water behind the bars. These hypothetical offshore 

 bars migrating landward might have been the major source of 



