22 A NATURALIST'S WANDERINGS 



my yisit I had no very calm days ; but in the still waters of 

 tlie lagoon there ^yas enough to occupy the busiest pair of eyes 

 for weeks. 



The wonderful display of colour seen in the placid water of a 

 lagoon has been often described ; but it can give to one, who 

 has not himself visited a coral reef, but a very slight idea of 

 the fairy bowers to be seen from over the side of a boat 

 gliding gently across the surface of such a marine lake. 



I carefully examined that part of the lagoon over which the 

 poisoned water had spread, on a day when the water was so 

 calm that I could see the minutest objects on tlie bottom. Its 

 whole eastern half was one vast field of blackened and lifeless 

 coral stems, and of the vacant and lustreless shells of giant 

 clams and other MoUusca, paralysed and killed in all stages 

 of expansion. Everywhere both shells and coral were deeply 

 corroded, the coral especially being in many places worn down 

 to the solid base. Since the catastrophe, there had been, till 

 almost the date of my visit, no sign of life in that portion of 

 the lagoon ; I saw very few fishes, and only here and there 

 a new branch of Madrepora and Porifes. I found only one 

 tridacna alive (its three years' growth being 12 inches in 

 length, and 13 in breadth). 



That an earthquake certainly occurred on this reef, as 

 recorded by Mr. Darwin, two years before the visit of the 

 Beagle, is an interesting fact. That an earthquake took place 

 in 1876, cannot, I think, judging from the tidal wave, be 

 doubted, although no tremor was detected by any one on the 

 island — scarcely to be wondered at during the war of the 

 elements. The wave, as well as the darkened water which 

 issued, doubtless from a submarine rent, was almost certainly 

 the result of volcanic disturbance in the close vicinity of the 

 atoll. Mr. Darwin has described a dead field of coral observed 

 by him, in the upper and south-east part, and has accounted 

 for it by assuming, from information given him by Mr. Leisk, 

 that S.E. island had been at one time divided into several 

 islets by channels, whose closing up had prevented the water 

 from rising so high in the lagoon as formerly; and that, 

 therefore, the corals, which had attained their utmost possible 

 limit of upward growth, must have been killed by occasional 

 exposure to the sun. 



