118 On the Flora and Fauna of Santa Cruz. 



connects, as a gigantic island, the banks uniting Anguilla to 

 St. Bartholomew, Saba Bank, the one connecting St. Eustatius 

 to Nevis, Barbuda to Antigua, and from thence extends south 

 so as to include Gnadeloupe, Marie-Galante, and Dominica. 

 This 500-fathom line thus forms one gigantic island of the north- 

 ern islands, extending from Saba Bank to Santa Cruz, and 

 leaving but a narrow channel between it and the eastern end of 

 the 500-fathom line running round Santa Cruz. As Santa Cruz 

 is separated from St. Thomas by a channel of forty miles, with 

 a maximum depth of over 2,400 fathoms, this plainly shows its 

 connection with the northern islands of the Caribbean group, 

 rather than with St. Thomas, as is also well shown by the geo- 

 graphical relations of its mollusca." 



Professor Agassiz gives (1. c.) an extract of a letter addressed 

 to him by Commander Bartlett, from which I quote the follow- 

 ing : — " 1 finished up the line connecting Saba Bank with St. 

 Croix. I found the connection perfect, but the ridge has 700 

 fathoms water on it near St. Croix. There is 1,000 fathoms 

 three miles north, and 1,800 fathoms five miles sonth of the 

 ridge." 



Professor Agassiz refers to the connection of Santa Cruz 

 *^with the northern islands of the Caribbean group, rather than 

 with St. Thomas." As he bases his argument on the deep chan- 

 nel which separates Santa Cruz from St. Thomas, I judge that 

 he excludes the Virgin Islands, of which St. Thomas is one, 

 from the Caribbean group. In that case, in his view. Sombrero, 

 Anguilla, St. M^irtin and St. Bartholomew (the three latter on 

 the Anguilla Bank) and Saba (the Saba Bank connected by a 

 ridge with Santa Cruz), are the '"northern islands," to which the 

 Professor alludes. 



In my paper '^ On the Physical Geography of, and the Distri- 

 bution of Terrestrial Mollusca in the Bahama Islands" (Ann. 

 N. Y. Lye, X, 1873, 320), after quoting some of the views of 

 Professor Dana, expressed in his work, '^ Corals and Coral 

 Islands," 1872, I wrote as follows : — 



'' The facts regarding the diminution in size of the islands of 

 the West Indies to the eastward, are of peculiar interest, not only 

 as affording conclusive evidence of the greater subsidence in that 

 direction, but in connection with geographical distribution." 



