Paleogeography 



75 



Figure 66. Paleogeography for Eocene. Oligocene (Refugian and Zemorrian), Early Miocene (Saucesian), Middle 

 Miocene (Relizian and Luisian), Late Miocene (Mohnian and Delmontian), and Pliocene. Cross-hatching indicates 

 probable land areas for each time unit. Circles show sample positions for underwater area and for islands. Modified 

 from Corey (1954). 



The upthrust blocks formed high island 

 areas, erosion of which supplied sediment to 

 surrounding seas, and banks, atop which 

 only phosphorite, glauconite, and organic 

 sands were deposited. During Pliocene time 

 the blocks restricted the sea to long narrow 

 bays that occupied the downthrown areas. 



It is believed that during the Pleistocene 

 Epoch the topography of the offshore area 

 was essentially as at present, but that some 

 of the blocks moved individually and that 

 sea level fluctuated a few hundred feet. 

 These movements connected some islands 

 with the mainland, permitting migration of 



