GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 599 



and Cuba, and that the Gulf of Mexico is a simple while the Carribbean 

 Sea is a compound basin. 



The major tectonic features surrounding and occurring within the 

 basins will now be briefly considered. 



TECTONIC PROVINCES. 



In order to give an adequate conception of the relations of the two 

 basins the general features of both the North and South American 

 continents must be considered as well as the details of the land areas 

 and submarine banks and ridges immediately adjacent to and within 

 the region. The provinces germane to the area will be more par- 

 ticularly considered, while the boundaries of those more remote will 

 be only indicated. Twelve major with several subordinate provinces 

 may be discriminated as follows: 



1. Bahamas. 



2. Atlantic and Gulf Coastal Plain. 



3. Mexican Plateau. 



4. Oaxaca-Guerrero. 



5. Yucatan. 



6. Guatemala — Chiapas. 



7. Cuba and northern Haiti. 



8. Honduras, and its continuation to Jamaica, southern Haiti, 

 Porto Rico, the Virgin Islands, and the outlying island of Saint Croix. 



9. Costa Rica-Panama. 



10. Andes. 



11. Maritime Andes. 



12. Caribbean Islands: 

 12a. Barbadian Ridge. 

 126. Main Caribbean Arc. 

 12c. Avcs Ridge. 



1. Bahamas. — The Bahama Islands and their accompanying shoals 

 occupy a triangular area which lies east of Florida and north of 

 Cuba and Haiti. The islands either occur on one of two large banks, 

 the Little Bahama and the Great Bahama banks, or they rise to the 

 southeast of the latter bank as isolated eminences separated by water 

 as much as 1,000 fathoms in depth. Two bodies of water over 1,0C0 

 fathoms deep, Exuma Sound and The Tongue of the Ocean, indent 

 the Great Bahama Bank. Water 1,000 fathoms in depth is close 

 to the eastern shore of the Bahamas as far north as Elbow Cay on 

 Little Bahama Bank. Eastward from the 1,000-fathom curve the 

 bottom rapidly descends to a depth between 2,000 and 3,000 fathoms. 

 The Bahama Islands are subaerial protuberants above the nearly 

 level, slightly submerged surfaces of extensive plateaus which on one 

 or more sides rise precipitously from oceanic depths. 



