Mavcli 3, 1S71.] ^" [Bland. 



JSotes mlating to the PJiysical Geography and Geology of, and the Distribu- 

 tion of Terrestrial Mollusca in certain of the West India Islands. 



By Thomas Bland. 



(Bead before the American Philosophical Society, March 3, 1871.) 



In 1861 I published (Ann. Lye. Kat. Hist., K. Y. VII.) a paper on the 

 Geograpliical distribution of the genera and species of land shells of the 

 West India Islands, and in 18G6 (American Jour, of Conchology, I.) fur- 

 ther papers on the same subject. From a study of such distribution, 

 without reference to the Physical Geography or Geology of the Islands, I 

 arrived at the conclusion that they may be divided into the five following 

 provinces or sections, each having a distinct faunal character, viz. : 



I. Cuba with the Isle of Pines, Bahamas, and Bermudas. 



II. Jamaica. 



III. Haiti. 



lY. Puerto Eico witli Yieque, the Yirgin Islands, Sombrero, Anguilla, 

 St. Martin, St. Bartholomew, and St. Croix. 



Y. The Islands to the south of those last mentioned, to and inclusive 

 of Trinidad. 



I remarked that the Islands to the West of Puerto Rico have the greater 

 generic, as well as specific alliance with the Korth American Continent 

 (Mexico and Central America, of course, included), and those to the 

 East and South, ,with tropical South America. 



Within the last year I have endeavored to learn, if any and what 

 evidence may be gathered from the depth of the' sea around, and in the 

 vicinity of the Islands, of their former greater proximity to each other 

 and the adjacent continents, sufficient to account for or throw light on 

 the observed facts of land shell distribution. The result is extremely 

 interesting, and in the main confirmatory of the views above expressed. 



The British Admiralty Charts have afforded data, chiefly to the 100 

 fathom line of soundings only, wliile recently, through the kindness of Mr. 

 Rawson W. Rawson, Governor in Chief of Barbados and the Windward 

 Islands, I have obtained particulars of the deep sea soundings, taken in 

 the Caribbean sea, especially for Telegraph Cable purposes, by United 

 States and British Naval Officers, which supply information of great 

 value, as I propose in this i^aper to show. I am also indebted for much in- 

 formation to "'The West India Pilot," published by the British Admiralty. 



I reserve, for another opportunity, observations on the faunas of the 

 first three of the above mentioned sections, now confining myself to the 

 fourth and fifth, with incidental reference to that of the second. Since 

 the date of my former papers, my knowledge of the species inhabiting the 

 Islands embraced in the latter sections has been largely increased, for 

 which my acknowledgments are due principally to Mr. Robert Swift, of 

 St. Thomas, Dr. Cleve, of the University of Upsala, Governor Rawson, 

 and Mr. R. J. Lechmere Guppy, of Trinidad. 



