AGASSIZ: BAHAMAS. 151 



fathoms of water ; the bottom is clean white calcareous sand, with a 

 depth of from twelve to fifteen or twenty fathoms, gradually increas- 

 ing to thirty fathoms, where the slope becomes very abrupt. 



St. Bartholomew is nearly one thousand feet high, and rises from a 

 flat bank of considerable extent, composed chiefly of broken shells, white 

 sand, and corallines. 



St. Martin, and also the smaller islets near St. Bartholomew (Hydro- 

 graphic Charts No. 1002, Admiralty Chart Nos. 130, 2038), are fringed 

 with reefs on the eastern and greater part of the northern faces. On 

 the shores of St. Bartholomew itself there are but few coral patches. 

 St. Martin is nearly thirteen hundred feet high. Tintammare is bor- 

 dered on all sides except the west by coral reefs extending one quarter 

 of a mile from shore. 



A small inverted-comma-shaped bank is formed by the 100 fathom 

 line uniting Montserrat (Hydrographic Chart No. 1011, Admiralty Chart 

 No. 254) and Redonda, both of which are volcanic rocks. The isolated 

 peaks of Montserrat rise to three thousand feet above the sea. It is 

 fringed here and there with corals on the east end. Redonda reaches a 

 height of six hundred feet. 



The volcanic island of Saba (Admiralty Charts Nos. 130, 487, Hydro- 

 graphic Chart No. 1002) stands by itself, and to the westward of it 

 rises within the 100 fathom line the Saba Bank, on the southern and 

 eastern face of which a belt of coral reef is found. 



An elongated bank is formed by the 100 fathom line uniting Nevis, 

 St. Kitts, and Eustatius. 



Nevis (Admiralty Chart No. 487, Hydrographic Chart No. 1011) is 

 also volcanic, and over thirty-five hundred feet above the sea. With St. 

 Kitts and St. Eustatius (Hydrographic Chart No. 1011, Admiralty 

 Charts Nos. 487, 2600), it stands upon a bank entirely detached from 

 the adjoining islands, separated by channels of more than two hundred 

 fathoms in depth. From the south end of the bank a remarkable coral 

 ledge about a mile in breadth extends along its southwest edge for a dis- 

 tance of five miles, and has from eight to ten fathoms on it, with deeper 

 water within. Except on the west side, the shore is fringed with a coral 

 reef extending three quarters of a mile out to a depth of ten fathoms. 



St. Kitts (Admiralty Chart No. 487) rises to a still greater height, 

 viz. over forty-three hundred feet ; a great part of the eastern face of 

 the island is flanked by a fringing reef. 



Antigua (Hydrographic Chart No. 1004, Admiralty Charts Nos. 917, 

 2600), which rises to a height of thirteen hundred feet, is near the 



