STIUJCTURE OF THE ISLAND. 



sembrvanthemum ?) and low trailing bushes. On 

 this green carpet were multitudes of young terns 

 that fluttered before us like flocks of ducklings, 

 with the old birds darting and screaming over our 

 heads. In the single tree (which was in fact a small 

 clump of the common nandanus of these seas, with 

 its roots exposed above ground), was a large rude 

 mass of old sticks, the nest of some bird of prey, 

 probably the osprcy. To the northward and east- 

 ward of the island stretched the shoal lagoon, its 

 bottom of clean white sand and dark patches of dead 

 and living coral, bounded by the usual rim of snow- 

 white breakers. Just round the island, part of the 

 body of the reef was now exposed at low water. 

 This was a flat surface of about a quarter of a mile 

 in width, dotted here and there with pools and holes 

 of water. It consisted of a compact, tough, but 

 rather soft and spongy rock, many loose slabs of 

 which, two or three inches thick, were tying about. 

 It was rather fine grained, and only here and there 

 exhibited any organic structure or remains. There 

 were no signs of living coral, except a few stunted 

 specimens in some of the deeper holes of the reef, 

 where also were some dead masses still standing in 

 the position of growth. The whole was verv differ- 

 ent from my preconceived notions of a coral reef, 

 and I erroneously imagined it must be an exception 

 to their general character. It looked simply like a 

 half drowned mass of dirty brown sandstone, on 

 which a few stunted corals had taken root ; and it 



