STRUCTURE OF THE TURKS ISLANDS 267 



been a northward extension of a few hundred yards since that 

 date. 



The original length of Greater Sand Cay is indicated by the shoal, 

 from which some rocky points protrude a few feet above the sea, 

 that stretches nearly two miles to the north of the island. Originally 

 there was a long narrow island, quite three miles in length, of which 

 the northern half has been swept away; whilst the southern was 

 broken up into fragments that have since been joined together by 

 the reclaiming agency of the waves. This process of reclamation 

 will continue, and a low sandy tract will occupy the place of the 

 shoal extending to the north ; while the island will add to its breadth 

 on its western side. The process of preserving the remains of the 

 original island is, however, not yet completed at the southern 

 extremity, where the aeolian rocks form a steep promontory that is 

 still exposed to the full force of the breakers in the open ocean. 



The opposing forces of destruction and reclamation are in opera- 

 tion all over the Turks Group. Where the tendency to protective- 

 beach formation is slight, as with Long Cay, we see a long strip of 

 aeolian rock being broken into fragments by the waves. We see in 

 Pear Cay and in Eastern Cay two islands that were once one, but 

 are now separated by a rock- studded channel, half a mile in width, 

 that has been the scene of more than one of the shipwrecks in this 

 locality. Pear Cay seems likely to disappear altogether in the 

 course of time. Eastern Cay, however, has since doubled its extent 

 by the formation of a broad sandy tract on its west side ; and while 

 the breakers are ever pounding away against the precipitous cliffs 

 of aeolian sandstone on the eastern side, the waves are ever adding 

 to its area on the west. 



The Composite Structure of the Larger Islands of the 

 Turks Group. — In the larger islands the process is a little more 

 complex. The extension of sandy flats from different " nuclei " of 

 aeolian rock here led to the enclosure of mangrove-fringed lagoons, 

 which are now in various stages of silting up and of being cut off from 

 the sea. Thus the lower levels of these islands are sandy where 

 they have been heaped up by the waves, and loamy where they 

 have been reclaimed by the silting of the lagoon. 



We will begin with Grand Turk, an island about five and a half 

 miles long and averaging rather over a mile in breadth. A ridge of 

 aeolian sandstone runs along the eastern border of the island, attain- 

 ing a height of seventy feet along much of its length, the greatest 

 elevation being seventy-five feet. In addition there are low hills 

 and rising ground of lesser elevation in the north-west, south-west, 

 and centre of the island. But the greater portion of its surface is 

 raised only a few feet above the sea, being no higher than the waves 

 could have elevated it. Two large lagoons, the North and South 

 Creeks, originally penetrated nearly to the centre of the island. 

 Both were lined by a dense growth of mangroves, which are now 

 almost entirely confined to the South Creek; and both occupied 

 depressions that were below the sea-level. 



The ridge and lesser elevations of Grand Turk once formed islands 

 of aeolian sandstone representing a large land-mass of the same 



