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Show 514 MR. J. J. LISTER ON THE NATURAL [Dec. 4, I believe that; these terraces, though in a general way continuous round the island, except at the headlands, do not correspond at different places terrace for terrace. It was not easy to settle this question, as the slopes were all covered with trees, and travelling over the sides of the island was most difficult. I once, however, had a good opportunity of forming an opinion on the matter, on an occasion I shall long remember. I had started about sunrise from the ship in Flying-Fish Cove to go to tbe western landing. It was a deliciously fresh morning, and as we sped along over the blue water a school of porpoises came plunging alongside of us, while overhead a flock of Frigate-birds, Gannets, and Boobies kept us company, the last often flying so near that the men hit at them with boathooks. As the sun rose over the island the light struck obliquely along the northern side, lighting up the trees on the terraces while the steep slopes were still in shadow. I then saw that the lines of shadow, though in the main horizontal, frequently broke up and joined with one another, showing, as I believe, that the individual terraces are not continuous at the same level on the sides of the island. At tbe headlands the higher part of the island generally terminates in a sheer cliff, from the foot of which a gradual slope extends to the sea. This inland cliff and the slope below it are repeated again and again in the contours of the projecting headlands as they are seen looking along the shore. The low foot of rock extends almost all round the island and ends in a shore-cliff, which varies in height from 15 to nearly 60 feet. It has an abrupt vertical face and is much underworn by the waves and traversed by fissures which penetrate far into the rock and in some places give rise to blowholes from which columns of spray shoot up at intervals from among the green bushes which cover the surface. This shore-cliff is obviously made of coral, but the structure has begun to be obliterated by the deposit of lime in the interstices. This was most clearly seen in one place where some large oval boulders of coral, one of which measured 7 ft. 3 in. in transverse circumference, had been tossed up to the top of the shore-cliff (here about 15 feet from the mean sea-level) and had worn out hollows in the rock. The contrast between tbe clearly defined structure of the boulders and the partly obliterated characters of the coral which formed the cliffs shows that the change is here in progress which has converted the reefs ot the upper terraces into a compact hard rock in which very little sign of their origin is visible. In many places deep water extends up to the cliffs. At the western landing-place and at Flying-Fish Cove was a beach of rolled fragments and shells, then a narrow flat strip of dead coral strewn with lumps carried by the waves, beyond this a narrow line of growing coral-reef sloping down rapidly to deep water, on which as we approached the shore the beds of living coral could be seen, separated by tracts of white sand. |
