144 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



as no specimen was collected at either of the soundings beyond that, it 

 must have been rocky bottom. On steaming back to our starting point 

 for dredging, as we reached seventeen fathoms we found a few coral heads, 

 with huge patches of tine white sand between them. 



On the line of soundings we ran at right angles to the bank off 

 Exuma Harbor (Plate VI. Fig. 3) we brought up as far as seventeen 

 fathoms the coarse sand of the banks ; at eighty fathoms we found rather 

 finer coral sand and a few broken shells ; at one hundred and forty-two 

 fathoms the bottom was composed of fine nummulitic and coral sand ; 

 the bottom was rocky at one hundred and fifty-seven and two hundred 

 and forty-two fathoms, and at two hundred and sixty-six fathoms we 

 struck fine coral ooze. 



Neither of these slopes differs materially from the northerly slope of 

 Hogsty Reef. Off the reef the 900 fathom line (Plate II. Fig. 1) is 

 about four miles from the 100 fathom line. Off Fortune Island it is 

 at about the same distance, and off Exuma Harbor the 800 fathom 

 line is four miles from the 300 fathom line. (Plate IV. Fig. 6.) The 

 sudden drop of these banks to the 100 fathom line occurs from the 15 

 to the 20 fathom line, the distance to the 100 fathom line varying from 

 one sixth to three fifths of a mile from these soundings, or even less at 

 other points on the banks, as off Green Cay, where it is not more than 

 five hundred feet. Off the coast of Florida the 100 fathom line is from 

 four to nine miles distant from the 10 fathom line, the line of the reef. 

 (Plate IV. Figs. 1-3, Plate V. Fig. 16.) 



Off the Mosquito Bank, south of Rosalind Bank, the GOO fathom line 

 is nearly thirty miles from the 100 fathom line, and between the Rosa- 

 lind and Pedro Banks the slopes east and west from each bank are fully 

 as flat as that. (Plate IV. Fig. 7.) Off the northeastern edge of the 

 Yucatan Bank the slope is even less, the 600 fathom line being more 

 than thirty-five miles from the 100 fathom line. (Plate VI. Fig. 5, 

 Plate VIII.) 



The west face of the banks of the Windward Islands is often much 

 the steeper. Off Saba the 600 fathom line is about twelve miles distant. 

 (Plate VII. Fig. 3). The slope of the bank at the east end of Santa Cruz 

 is about the same. (Plate VIII.) Off the west side of Barbados the 

 800 fathom line is over twelve miles distant. (Plate VII. Fig. 7.) At 

 some points of the Grenadines Bank (Plate VII. Fig. 7, Plate VIII.) the 

 1,000 fathom line is within fifteen miles of the 100 fathom line. The 

 eastern end of the Virgin Island Bank is steep on the sea faces ; the 1,000 

 fathom line is in many places less than ten miles distant. (Plate VII. 

 Fig. 1.) 



