MUSEUM OF COMPARATIVE ZOOLOGY. 285 



answer. We have recorded evidence that similar terrace phenomena 

 occnr in Nicaragua, Yucatan, Jamaica, and San Domingo, and the coasts 

 of South America have participated in these regional uplifts of Pleisto- 

 cene and recent time, to which the slight elevation of the Gulf coast of 

 the United States is insignificant. 



In these studies I have found no evidence that Cuba, since its earliest 

 historj' (the Mesozoic) has had land connection with the United States. 

 Unless there was some profound subsidence in Post-Tertiary time, such 

 as I have been unable to detect, no possible deduction can make such a 

 connection. In fact, I know of no positive evidence that it has been 

 connected with our continent at all, and have only hypothetical evidence 

 that the Pre-Tertiary land may have once extended toward the Yucatan 

 peninsula, and that it was only then, if ever, that the Antillean and 

 Cordilleran islands were united. Neither can we avoid conceiving that 

 the subsequent elevations have brought the isthmian region up with it, 

 making the present land connection between tlie continents. 



The axial direction of the general Antillean Post-Tertiary elevation is 

 approximately east and west, and hence it is presumable that the sub- 

 marine ridges wei-e more likely to have been extended in that direction, 

 and that to the north and south of this axis, which must theoretically 

 be the remnant of a great east and west swell or fold, there must have 

 existed corresponding sloping sides and synclinal troughs. It is but 

 natural, then, that evidence of the continuation of the Cuban dias- 

 trophism must be looked for in east and west lines rather than in lines 

 north and south. 



We can also reasonably conclude that the orogenic development of 

 Cuba, begun in some unknown period of antiquity, was practically com- 

 pleted at the commencement of the Pleistocene, — that is, the develop- 

 ment accompanied by displacement, folding, and vulcanism, — and that 

 the stage of elevation then began, bringing iip the old Pre-Pleistocene 

 architecture and carving the mass into its terraces and present outlines. 

 The group of regional elevations which I have described, although 

 marking a wide interval of time, all occurred in a comparatively recent 

 geologic period. To fix this time exactly would be impossible wuth the 

 scant data at hand, but we can make some approximations. 



The oldest of the elevations, now represented by the Yunqne level, 

 certainly followed the period of folding wliich the Tertiary limestones 

 underwent after their deposition. This folding, we may safely say, was 

 Post-Tertiary, and took place in late Pliocene or early Pleistocene time, 

 approximately, and marks the beginning of the re-emergence of modern 



