18 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



Salvador by a shallow narrow bank, which in its turn is connected with 

 the northern extremity of Cat Island. The latter island forms the east- 

 ern side of Exuma Sound and the most easterly jDoint of the Great 

 Bahama Bank. AVe may now proceed with the description of the islands, 

 beginning at New Providence and taking the eastern shank of the Great 

 Bahama Bank first. 



New Providence. 



Plate X. Figs. 3, 3 ; Plates XV. to XX. 



Although the island of New Providence is not one of the largest of the 

 Bahamas, yet the character of its surface varies greatly, and it is of suf- 

 ficient size to give an excellent epitome of the features which probably 

 characterized the land which once must have covered the greater part of 

 the Great Bahama and Little Bahama Banks. 



New Providence occupies the northwest corner of that part of the 

 bank lying between the Tongue of the Ocean and Exuma Sound, its 

 westei'n extremity probably extending nearly as far out toward the 

 edge of the bank, as is indicated by the outlying islands to the west, 

 ■which were perhaps once a part of it. The sea has encroached but little 

 upon its northern shore, except near the entrance to Nassau Harl)or, wliere 

 a few small islands to the west of the entrance show its former northern 

 extension, and indicate that the same causes, together with the subsidence 

 of the bank, have separated it from Hog Island. 



The 100 fathom line is quite close to the north shore of the island, 

 as well as to the western extremity, a depth of one hundred and fifty 

 fathoms being reached within five hundred feet from the southwestern 

 extremity of the island. 



Hog Island, Athol, and Pose Island to the east, as well as the small 

 outlying islands to the west of the entrance of Nassau, constitute the 

 outer line of n?olian hills wliich were separated from the ridge upon 

 wliich Nassau is built by a valley, now the harbor of Nassau. It is 

 evident, from an examination of the Nassau ridge, that it is of fcolian 

 formation, consisting of sand dunes closely packed together and heaped 

 up one upon another. The outer hill, called Hog Island, tlie land which 

 makes the breakwater of Nassau Harbor, is nuieh lower, and runs par- 

 allel with this in a general way. The valley which separated the two 

 outer ranges now forms Nassau Harbor, and its continuation to the 

 eastward is the channel which leads to Cochrane Anchoi-ago and to the 

 parts of the Great Bank lying between Nassau and FJeuthora. The 



