SECT. 3] 



ESTUARIES, DELTAS, SHELF, SLOPE 



631 



Fig. 9. Mississippi River Holocene sub-deltas. (From Louisiana Coastal Studies Institute, 

 Russell, 1959, p. 370.) Hatchings: Pleistocene terraces. Figures indicate beginning of 

 Mississippi River occupation before present time. 



W 



Jedeida 



Bou 

 Fares Shore Sea 



Continental 

 deposition 



Marine 

 deposition 



Fig. 10. Scheme of Utiquian cyclothems in the Medjerda River delta, Tunisia. (From 

 Pimienta, 1959.) 



in the Rhone delta, which has been carefully investigated in recent years 

 (Duboul-Razavet, 1956; Kruit, 1955; Van Straaten, in Russell, 1959). According 

 to Pimienta, a Pleistocene sub-delta of the Medjerda River is found immediately 

 to the south of Tunis, and the modern delta includes a number of cyclothems in 

 which marine and continental sediments alternate (Fig. 10). This type of 

 stratification is common, and points to alternating advances and retreats of the 

 delta front resulting from changes in balance between supply of sediments, 



