PLEISTOCENE RE ELEVATION OF THE LANDS. 



131 



the Greater Antilles had any continental connections. The poyt-Zapata 

 erosion did not exceed from one-fifteenth to one- fiftieth that of the earlier 

 epoch of Pleistocene elevation. 



Minor depressions of 100 or 200 feet, or perhaps more in places, fol- 

 lowed the post-Zapata elevation, as recorded l)y the modern terraces, 

 which have not heen differentiated from those of earlier date except at 

 one or two places. The elevation of the terraces was not uniform, out 

 accomj)anied hy a slight deformation of the heaches. 



The recent movements have heen slight and very uniform, as shown 

 hy the extensive suhmerged plains, now constituting hanks, hy the slight 

 elevation of the modern reefs to a height of 10 or 25 feet, more or less, 

 and the non-deformation of the drowned valleys. In some ])laces the 

 coasts ai>})ear to he sinking, as the eastern side of Florida and the 

 Bahamas, while other localities a])pear to he rising, as the southern 

 side of Cuha. 



P: C 



E 



M 



p 



PI 



M 















Figure T.— Oscillations of the Antillean Continent. 



Horizontal line represents sealevel; dotted line, the oscillations; Pc = pre-Cretaceous ; C= Cre- 

 taceous; J5=Eoeene; 3/= Miocene (variable in different localities) ; P=Pliocene; Pi = Pleisto- 

 cene ; M = modern. 



The changes of level in the ^^'est Indies are graphically rei)resented 

 in figure 7. This hypothetical diagram could not he drawn to accurate 

 scale, either for length of time, represented hy the horizontal measure- 

 ment or for the^changes of level, shown in the vertical scale, hut in a rude 

 way it illustrates the oscillations of the Greater Antilles in the more 

 recent geologic times. 



The Sei'aratiox of tuf Antillran Basins fiiom the Pacific Ocean 

 and their connection with the atlantic. 



It has ))een shown that the drowned valleys are newer than the Miocene. 

 The partial filling uf the Pliocene channels was accomplished at tlu; end 

 of that period, and these accumulations were su])se(iuently removed hy 

 the denudation of the earlier Pleistocene period. The fjords trend west- 

 ward and are traceahle to near the Hoor of the Antillean seas, leaving the 

 inference that those basins were low lands extending to the Pacific side of 

 Central America; hut it is to l)e rememl)ered that this inference is tenta- 

 tive only, and that even if later researches show that the drainage did 



