156 bulletin: museum of compakative zoology. 



The Banks of the Caribbean Sea. 



Between Jamaica and Honduras and off the Mosquito Bank rise a 

 number of banks, the most easterly of which is the Pedro Bank (Hydro- 

 graphic Chart No. 373, Admiralty Charts Nos. 450, 486), which rises 

 abruptly from depths of three hundred and fifty to five hundred fathoms. 

 It is irregular in shape, nearly a hundred miles long east and west, quite 

 narrow at the eastern end, not more than nine miles, while at the western 

 end it is fifty-five miles broad. The surface of the bank is level, ranging 

 from nine to fifteen fathoms except near the eastern and the southeast- 

 ern edge of the bank, where there are many shoals and cays said to 

 consist of white limestone. The bottom on the bank is generally white 

 sand and fragments of corals, but there are patches of coral heads and 

 of coralline algse. Portland Rock is thirty-two feet high ; Plover Rock 

 is two to three feet high. Off the Pedro Cays, about twelve feet high, reefs 

 extend parallel with the 100 fathom line between the cays. Banner Reef 

 is just awash. 



Next comes to the westward the Rosalind Bank (Hydrographic Charts 

 Nos. 373, 394). It is pear-shaped, nearly sixty-three miles long, and 

 ranging in width from fifteen to thirty-five miles. The only shallow 

 ground upon it is near the southeast end, where there is a wide coral belt 

 nearly three miles wide, and trending in a northeasterly direction for 

 fourteen miles, with depths upon it varying from four to ten fathoms. 

 On the eastern face there is also a second ledge about thirteen miles 

 north of the first, eight by four miles, on which we find eight fathoms. 

 The general depths on the bank vary little from ten to twenty fathoms ; 

 the bottom is coarse coral, coralline sand, and broken shells. 



Between Rosalind and Mosquito Bank lies a narrow bank, thirty-seven 

 miles long, not more than ten miles wide, with from thirteen to thirty- 

 five fathoms close to the 100 fathom line. This bank is separated from 

 the Mosquito Bank by a narrow channel with a depth of about one hun- 

 dred and seventy-five fathoms, and by a somewhat deeper channel from 

 the Rosalind Bank. 



To the south of Pedro Bank rises the small, isolated Bajo Nuevo Bank 

 (Hydrographic Chart No. 379, Admiralty Chart No. 391) on which 

 there are two remarkable hook and bow shaped coral feefs rising from 

 the 5 fathom line on the eastern and southern face of the bank. On the 

 bank the soundings vary from six to fifteen fathoms close to the 100 

 fathom line. 



To the south of Rosalind are the smaller banks, the most northerly of 



