MUSEUM OF COMPARATIVE ZOOLOGY. 277 



a plateau, and subjected it to the erosion whicli has since dissected it 

 into its present rugged outlines. The Yumuri cliffs were carved from 

 it where it formed a sharp coastal scarp, and the Havana and Matanzas 

 lienches represent synchronous levels with the latter in the west end of 

 the island, where the Cuchilla level was of less extent. That this mod- 

 ern group of elevations was intermittent, as shown by its alternate cliflFs 

 and terraces, is evident, the modern soboruco representing the latest 

 uplift. 



The elevated benches and terraces which border the coast of Cuba, 

 with the single exception of the soboruco, or modern coast reef, are not 

 ancient coral reefs either topographically or lithologically, as has been 

 asserted, but, on the other hand, are beach and erosion plains, produced 

 by rapid elevation of the island in Post-Tertiary time, and carved from 

 various formations, principally the older limestones, regardless of struc- 

 tural arrangement and composition. Even though the old limestones 

 may be remotely of coral origin, which I do not think, and which idea 

 I have discussed on a previous page, these old terraces can in no wise be 

 interpreted topographically as elevated reefs, for none of the original 

 reef topography is preserved. On the other hand, 1 can give numerous 

 instances where the same benches are carved out of the varying compo- 

 nent material, which was much folded or disturbed prior to their erosion, 

 as is shown in most of the figui'es. 



The series of terraces around Cape Maysi and Yumuri are carved out 

 of a massive matrix of old limestone of undulatory structure, as shown 

 in the figures. The terraces or base levels at Matanzas are cut out of a 

 series of beds widely divergent in lithologic composition, all dipping at 

 angles of from ten to twenty-five degrees. The Moro and Principe Pla- 

 teaus at Havana form a planation surface upon a floor of folded limestone, 

 in which distinct anticlinal structure can be traced. The terrace i;pon 

 which the Military Hospital at Baracoa is situated is carved across tb.e 

 almost vertically inclined edges of the older Miocene limestones. The 

 summit of the Yunque, instead of being a coral reef, is a greatly degraded 

 peneplain. The soboruco alone of all the levels is topographically an 

 elevated reef, and this, as before stated, dees not rise anywhere over 

 fifty feet. 



Lack of Evidence of Subsidence. 



I must confess my inability to distinguish any positive evidences of 

 subsidence since the beginning of Tertiary time or accompanying these 

 elevations, although it would be rational to think that tlie movements 



