Bland.] "" [March 3, 1871. 



Sawkins, in the Report on Jamaica, to which I have already referred, 

 shows that the highest elevations on that Island are situated to the east, 

 and the inclined slope rises from the west. With respect to this, he 

 draws "deductions from two important elements: 



"1. The great equatorial currents have existed in times past as at present. 



" 2. That the trade winds also prevailed with the same uniformity." 



Referring to vestiges of volcanic action and certain stratified deposits 

 towards the eastern end of the Island, containing pebbles and debris of 

 previously existing rocks, Sawkins remarks: "This (volcanic) action 

 might have operated intermittently, so as to permit the growth of coral 

 reefs, marine animals, &c., of which the remains are contained in the 

 limestone formations. Again, supposing the deposits to have originated 

 from local igneous or volcanic action, or from debris derived from islands 

 to the east, submersion having intervened, the lighter materials and tiner 

 sediment would be transported by the currents to the westward, these in- 

 fluences combining with subsequent changes of level, account for the 

 prolongation of the land to the westward." 



In connection with the facts stated I can only incidentally refer to the 

 barrier presented by Trinidad, Tobago, the Grenada bank, and St. Vincent 

 to the distribution, to the westward, of marine forms living at greater 

 depths than 400 fathoms ; and to the same barrier and others offered by the 

 Islards and banks to the North of St. Vincent, to the flow of the equatorial 

 current into the Caribbean sea. Also to the existence of a cold current at 

 great depths between Barbados and Tobago, shown by the temperatures 

 ascertainf:d by Capt. Parsons, viz. : 



Surface, ]Max. 79^ Fah., at 1,030 fathoms, Min. 38° 

 " 820 " " 1,0G0 " " 380.5 



