AGASSIZ : BAHAMAS. 39 



district ; but the number of species is not so varied as upon the other 

 kinds of bottom. 



By far the most striking of the sand bore districts is the one which 

 forms the great sweep of the southern cul-de-sac of the Tongue of the Ocean 

 (Pkxte XII. Fig. 1). South of tlie cays to the southward of Washer- 

 woman's Cut (Plate XL Fig. 3) is a tract of about ten by hfteen miles which 

 is a mass of sand bores, many of them dry. To the eastward for a dis- 

 tance of tiiirty-five miles they run in a southwesterly direction, at a sharp 

 angle with the course of the 100 fathom line. In this part of the bank 

 they are broad ridges, more or less undulating, some of them half a mile 

 in width and sometimes twelve miles in length, often nearly dry in places, 

 and with from one to three fothoms on the ridges, separated by broad 

 channels with from four to six fathoms of water. Some of the wider of 

 these cliannels are regularly used as approaches to the interior of the 

 bank, and are known as Queen's, Blossom, Thunder, and Lark Channels, 

 through which vessels bound for Cuba cross the bank, coming out either 

 through the Man-of-War Channel, south of Flamingo Cay, or running 

 west of the Ragged Islands and crossing the Columbus Bank. The east- 

 ern extremity of these sand bores is formed by a tract of narrow sand 

 ridges, with deep -water between them, extending some fifteen miles 

 along the edge of the bank on the eastern face of the Tongue of the 

 Ocean. 



To the eastward of Hawk's Bill Rock there is a line of sand bores to 

 the south of the line of small cays reaching to the centre of the west 

 shore of Great Exuma. To the west of the north end of Great Exuma 

 occur a series of dry sand bores, with from one to two fathoms of water 

 between them. They trend in a westerly direction, and run north, whei'e 

 they join the southern bores of the Galliot Bank. An extensive series 

 of sand bores, many of them dry, runs east from Green Cay across the 

 bank to within about ten miles of Conch Cut. During one whole day's 

 sailing from Harvey Cay south nearly to our anchorage off Flamingo 

 Cay we did not come across any patches of Gorgonians or of coral 

 heads. 



The Brigantine Cays, the Barracouta Rocks, and Hawk's Bill Rocks, 

 low cays and patches of teolian rock, are the fragments of the western 

 extension of the northern extremity of Great Exuma. 



"When we reached our anchorage off Flamingo Cay, we found the bot- 

 tom a mass of broken shells, of fragments of corals and Gorgonians, and 

 covered by Nullipores. As we approached Flamingo Cay we came in 

 sight of some of the small islands forming a part of the chain of cays 



