100 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



It is worthy of notice tliat the position of all the important islands 

 of tlie Great Bahama, Crooked Island, and Caicos Banks — as well as 

 of Little Bahama Bank with the exception of Bahama Island — is on 

 the weather side of the hanks, either on the eastern or northern face. 

 On the western side we hnd only small islets or rocks, the remnants of 

 the western islands which were the first to disappear on the subsidence 

 or the tilting of the western shore. This must have resulted in leaving 

 the northwestern and eastern faces of the banks at a higher level, and 

 must also have given to all the banks of tlie Bahamas a very gradual 

 dip to the westward. Tliis is found to be the case whether we examine 

 the section of the bank from Andros to tlie Santaren Channel, or from 

 Eleuthera to the Tongue of the Ocean, or from Long Island to the Old 

 Bahama Channel, or that of the Little Bahama Bank from Great Abaco 

 to Burrow Cay, or a line parallel to this from Spanish Cay to INIemory 

 Eock. The configuration of these wide shallow banks, flanked by isl- 

 ands on the windward face and by islets or rocks on the western face, 

 plainly shows that the gi'owth of the recent corals, which flourish in 

 from three to fifteen or more fathoms almost around the whole outer 

 face of the banks, has added very little to the amount of land, which con- 

 sists wholly of a?olian rock. It is only here and there that bights in the 

 disintegrating islands Iiave been filled as it were by the material thrown 

 up from adjoining coral reefs, and thus coral sand flats have been formed 

 abutting upon older scolian hills. These flats, however, form but an 

 insignificant part of the laud which remains, and play no important 

 part in the configuration of the islands of the Bahamas. 



While crossiuiT the Caicos Bank we encountered large masses of 

 gulf- weed. 



The Turk's Islands. 



Plates I. and VIII. ; Plate IX. Figs. .'>, 6. 



The easternmost of the Baliama Islands are the Turk's Islands, which 

 rise from a narrow bank running about thirty-five miles in a north and 

 south direction. From the middle of the bank a wide tongue extends 

 for seven miles eastward, on which the soundings are from eight to ten 

 fathoms. Grand Turk Island is five and a half miles long and about 

 one mile broad. The eastern f;ice is formed by a narrow ridge of a3oli;ui 

 hills about seventy feet high, witli their steep face on the east. The 

 western slope of the ridge is flanked i)y recent shore coral rocks, which 

 have formed the flats between the landing and the hills, and have iso- 



