6 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



of the same material as the seolian rock of the rest of the Bahamas, 

 but from want of drainage it has become thoroughly saturated with salt 

 water. In that condition it crumbles readily, and is then triturated 

 into a fine impalpable powder, almost like deep-sea ooze, which covers 

 the bottom of the immense bank to the west of Andros. After leav- 

 ing Andros we crossed the bank to Orange Cay, following the east- 

 ern edge of the Gulf Stream to the Riding Rocks, Gun Cay, and the 

 Beminis. We then passed to Great Isaac, where we saw some huge 

 masses of aaolian rock which had been thrown up along the slope of 

 the cay about eighty feet from high-water mark to a height of twenty 

 feet. One of these masses was fifteen feet six inches long by eleven 

 feet by six feet. We then kept on to Great Stirrup Cay, and, coasting 

 along the Berry Cays, crossed over to Morgan's Bluff on the east side of 

 Andros, running down as far as Mastic Point, and then returned to 

 Nassau. 



We made several attempts to examine the eastern side of Andros, but 

 only succeeded in reaching North Bight, being invariably driven back 

 to Nassau by northers. We made a special expedition to the Little 

 Bahama Bank, running eastward from Nassau south of Rose Island to 

 Fleeming Channel, where we passed into Northeast Providence Channel 

 and anchored near Current Island Cut. We crossed to Great Abaco at 

 the Hole in the Wall, following the southwest shore of that island to 

 Gorda Cay. We entered the bank at Mores Island Channel, steamed to 

 the Woollendean Cays and to Rock Harbor, examining the " Marls " to the 

 westward of Great Abaco. Returning, we passed into Northwest Provi- 

 dence Channel, steamed north to Burrow Cay, and skirted the southern 

 shore of Bahama Island as far as Settlement Point. At Memory Rock 

 we entered the bank, steering east past Great Sale Cay for Pensacola 

 Cay, and from there keeping in the channel between the outlying cays 

 and Great Abaco as far as Green Turtle Cay. Here we passed out from 

 the Bank through Whale Cay Channel, and skirted the eastern side of 

 the Little Bahama Bank back to Hole in the Wall, and crossed to Egg 

 Island. We examined both it and Egg Reef on our way to Nassau. 



The islands of the Bahamas from the Little Bahama Bank on the nortk 

 to Cay Sal on the west, and as far as Turk's Island on the east, are all of 

 peolian origin. They were formed at a time when the banks up to the 

 10 fathom line must have been one huge irregularly shaped mass of low 

 land, the coral sand beaches of which supplied the material that must 

 have built up the successive ranges of low hills which we still find in 

 New Providence, and which are so characteristic of all the ridges of the 



