BARBOUE: notes ox the HERPETOLOGY of JAMAICA. 279 



his chapters in " The Three Cruises of the Blake " entitled " American 

 and West Indian Fauna and Flora," and " Permanence of Continents and 

 Oceanic Basins." The following {loc. cit., 14, p. Ill) is pertinent : 



" At the western end of the Caribbean Sea the hundred-fathom line 

 forms a gigantic bank" off the Mosquito coast, extending over one third 

 the distance from the mainland to the island of Jamaica. The Rosalind, 

 Pedro, and a few other smaller banks, limited by the same line, denote 

 the position of more or less important islands which may have once ex- 

 isted between the Mosquito coast and Jamaica. On examining the five- 

 hundred-fathom line, we thus find that Jamaica is only the northern spit 

 of a gigantic promontory, which perhaps once stretched toward Hayti 

 from the mainland, reaching from Costa Rica to the northern part of 

 the Mosquito coast. There is left but a comparatively narrow passage 

 between this promontory and the five-hundred-fathom line Avhich 

 encircles Hayti, Porto Rico, and the Virgin Islands in one gigantic 

 island. 



" The passage between Cuba and Jamaica has a depth of over three 

 thousand fathoms, and that between Hayti and Cuba is not less than 

 eight hundred and seventy-three fathoms in depth." 



Referring to the same subject, Mr. Agassiz writes (p. 112-113) : 



"At the time of this connection, if it existed, the Caribbean Sea was 

 connected with the Atlantic only by a narrow passage of a few miles in 

 width between St. Lucia and Martinique, by one somewhat wider and 

 slightly deeper between Martinique and Dominica, by another between 

 Sombrero and the Virgin Islands, and by a comparatively narrow passage 

 between Jamaica and Hayti. The hundred-fathom line connects the Ba- 

 hamas with the north-eastern end of Cuba ; the five-hundred-fathom line 

 unites them not only with Cuba, but also with Florida. The Caribbean 

 Sea, therefore, must have been a gulf of the Pacific, or have been con- 

 nected with it by wide passages, of which we find the traces in the ter- 

 tiary and cretaceous deposits of the Isthmus of Darien, of Panama, and 

 of Nicaragua. Central America and northern South America at that 

 time must have been a series of large islands, with passages leading be- 

 tween them from the Pacific into the Caribbean." 



And on page 1 1 .3 : — 



" While undoubtedly soundings indicate clearly the nature of the sub- 

 marine topography, it by no means follows that this ancient land connec- 

 tion did exist as has been sketched above. At the time when the larger 

 West India Islands were formed and elevated above the level of the sea, 

 they may have been raised as one gigantic submarine plateau of irregular 



