168 bulletin: museum of comparative zoology. 



PART V. 



Relations of the Jamaican Formations to those of Adjacent 



Regions. 



Having given every known evidence of paleontology, geologic struc- 

 ture, and geomorphology bearing upon Jamaican history, and having 

 presented the conclusions in the preceding Part, this work would not 

 be complete without an attempt to point out the extension of the de- 

 scribed phenomena throughout the adjacent Great Antilles and other 

 regions of Tropical America, where similar or related geological forma- 

 tions and topographic features of the land and sea should be found. 

 While the facts to be set forth in the present Part make no pretensions 

 to finality or completion, they will be a further contribution to the sub- 

 ject which will assist whoever may hereafter take up and continue these 

 investigations. 



I must leave the discussion of the biologic and oceanographic phases 

 of the question to others, and in this place I shall endeavor to discuss 

 only the testimony of the stratigraphy and structural geology, present- 

 ing a brief conspectus of the extent throughout the adjacent regions 

 of formations similar to or identical with those found upon the island 

 of Jamaica, together with remarks on the source of the material. In 

 Part VI. I shall review the history of the deformation, including the 

 evidences of elevation, subsidence, and degradation, which often occurred 

 synchronously in different parts of the region, and finally make an 

 inquiry as to their influences upon the present land and submarine 

 configuration of the West Indian region. 



The regions with which comparison will be made will be : (1) The 

 Great Antilles proper, including the Virgin Islands and the Bahaman 

 Plateau ; (2) The Caribbee Islands ; (3) Barbados ; (4) The Venezuelan 

 coast of South America, including Trinidad ; (5) The Central American 

 region, including the Isthmus of Panama and Yucatan peninsula, and 

 the Guatemala-Chiapas or Tehuantepec Province; (G) The Coastal Plain 

 of ^lexico and the United States. 



In these presentations I shall be able to show that the Jamaican 

 sequence, so far as it reaches backward in time, is remarkably like 

 that of all the Great Antilles, and may be distinctly termed the 

 Antillcan type. Tliis typo presents great lithologic variation from 

 that of the peripheral coast lands of the American Mediterranean, yet 



