not supplied to the depositional site in any substantial amounts. Higher 

 quartz content occurs in places but these are usually near a sandy sub- 

 strate; thus, the quartz is probably a reworked rather than detrital 

 element. Phosphorite occurs in modest amounts with grains reaching gran- 

 ule or small pebble size. Foraminifera, ostracods, and echinoid spines 

 are usually plentiful in the finer fraction of the better preserved 

 material . 



Typically, type G material is light gray (N7) to gray 016) but locally 

 the upper part of the deposit may be pale brown (10 yr 6/3). Recrystali- 

 zation of the individual carbonate particles has occurred to a greater 

 or lesser degree throughout and this gives the particles a frosty or 

 glazed look under magnification. Type G material appears to be partly con- 

 solidated in most places; however, it was recovered in a well-consolidated 

 state in some cores. Material recovered in a loose, granular state may 

 have been disaggregated during the vibratory coring process. However, 

 there is little evidence of cementation in some samples except that small, 

 pebble-size aggregates of cemented grains are distributed throughout the 

 matrix. Where the material was recovered in a consolidated state the 

 grains are usually cemented at grain contact points only and the inter- 

 stices are open. 



IV. DISCUSSION 



1 . Age and Correlation of Sediment Bodies . 



a. General . An analysis of faunal assemblages (chiefly foraminifera) 

 in core samples indicates that sediments on or close beneath the shelf 

 floor range in age from Late Cretaceous to Holocene. Most of the fossil- 

 iferous core samples were grouped geologically into the following age 

 categories: Late Cretaceous, Paleocene, Eocene, Oligocene, Miocene, 

 Pliocene, and Quaternary. Partial correspondence was established between 

 these age categories and the lithologic types and seismic reflection units 

 described earlier. 



Sufficient data were not obtained on the inner shelf to synthesize 

 the various elements of lithology, age, and seismic reflection patterns 

 into a formal chronostratigraphic framework. However, a comparison of 

 these elements suggests the possible outline of such a framework and 

 indicates that the inner shelf geology generally accords with a projection 

 of the onshore geological framework. 



Figures 23, 24, and 25 show the probable age of pre-Quaternary sedi- 

 ments that occur in cores of the study area. Sediments of more than one 

 age, which occur in a few cores, are indicated by multiple symbols. Age 

 of the sediments was determined in most cases by fauna; however, in a few 

 cases barren sediments were age-classified on the basis of continuity 

 with or lithologic similarity to fossiliferous material. The figures 

 also show the areas underlain by the different seismic reflection units 

 where the tops are predominantly within 3 meters of the shelf floor. 



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