196 CORALS AND CORAL ISLANDS. 



are distinguishable in it. Its surface is a low sandy flat, eigh- 

 teen or twenty feet high, without trees, and partly covered with 

 small shrubs. A high sloping beach continuous around. Has 

 a shore platform about 300 feet wide. 



Birnie's.— Lat. 3° 35' S. Long. 171° 30' W. Four- 

 fifths of a mile by one-third, trending northwest. No lagoon. 

 A sandy flat about ten feet high, except near the north-north- 

 east extremity, where it is about twelve feet. To the south- 

 southwest the submerged reef extends out nearly a mile, over 

 which the sea breaks. In passing it, distinguished no vegeta- 

 tion except the low purslane and some trailing plants. 



Swain's.— (Fig. 3, page 168.) Lat, 11° 10' S. Long. 

 170° 52' W. II miles by §; shape nearly rectangular; 

 trends east and west. No lagoon, but the centre a little lower 

 than the sides. Surface covered with shrubbery and large 

 trees, among the latter many cocoanuts ; the centre more 

 sparsely wooded. Height fifteen to eighteen feet, excepting 

 on the middle of the western side, where the surface is covered 

 with loose fragments of coral of small size ; there appears to 

 have been a former entrance to the lagoon at this place. Shore 

 reef, or platform, one hundred yards in average width, and 

 one hundred and fifty yards at the place where we landed. 

 Beach high, ten to twelve feet. At lower part of beach, for a 

 height of tvvo to three feet, the coral reef-rock was exposed, 

 indicating an elevation of the island. For three or four feet 

 above this, layers of the beach sand-rock were often in view, 

 consisting of coral pebbles firmly cemented, and having the 

 usual dip of seven or eight degrees seaward ; in many places 

 it was concealed by the beach sands and pebbles. There was 

 no growing coral on the platform, excepting Nullipores. 

 The outer margin of this platform was very uneven, and 

 much intersected by channels, though less so than at Ender- 



