330 Voyages of Discovery and Survey. 



and scatter them over the sides, and we have the foundation for a co- 

 ral reef. From the edge of a continuous or nearly continuous notch, 

 due allowance being made for the effects of prevailing winds and 

 breakers round a volcanic island, keeping its main mass above the 

 sea, there would be shallow water to the cliff or new shore, havino- a 

 breadth depending upon the time the breakers have been employed 

 in cutting it back, and upon the power of the rocks to resist this 

 abrading force. In the case of the shoal there might be a coral 

 reef having a round or oval form, or some modification of this form, 

 according to circumstances, the habits of the reef-making corals 

 causing them to work outwards, so that a sort of lagoon might bo 

 inside, especially if the old crater should permit a hollow to remain. 

 In the case of the notched islands, the abrasion of the coast, and 

 the readiness with which detritus from it would be raised in me- 

 chanical suspension by heavy gales, would cause the reef-making 

 corals to keep the outer edge, where the proximity of the deep sea 

 would give them clear water. Here once established they would 

 form a barrier, and working outwards would form a slope with their 

 debris, and gradually rising would protect the island coasts from the 

 heavy action of the breakers, which would then fall upon the coral 

 reefs. These would correspond with the old shape of the island, and 

 therefore would probably differ little from its shores, round which 

 they would form an outer rampart with shallow water inside, better 

 fitted for the presence of other corals and of molluscs and marine ani- 

 mals loving quiet and clearer water, than could have been found over 

 the same shallow ground while heavy seas rolled over it. As regards 

 both the shoals and the notched sides of conical accumulations, the 

 outside of the barrier or atoll reefs would plunge into deep water. 

 In making these remarks we by no means doubt the correctness of 

 Mr Darwin's reasoning respecting the effects of depression in the 

 formation of coral lagoon islands and barrier reefs ; on the contrary, 

 we coincide with his views, the application of which can scarcely but 

 be correct in so many instances. The foregoing appeared to us, 

 however, to be conditions which might often obtain, and that there- 

 fore they were deservmg of considei'ation, to be taken, with other con- 

 ditions, for what they might be worth ; it being so desirable that in 

 questions of this kind the subject should be regarded from all points, 

 and that the various probable causes should be considered in our 

 pursuit of that truth which it ought to be our constant endeavour to 

 attain. 



In the account of the voyage of the Samarang, under the com- 

 mand of Sir E. iJelcher, there are several scattered notices respect- 

 ing the rocks observed at different places, such as the I'aised coralline 

 limestone of the west side of Abayat, near Batan, between Formosa 

 and the Philippines, the basaltic character of Hoa-pin-san, the igne- 

 ous rocks of Quelpart and the Korean Islands, and others. Nume- 

 rous remarks upon the habits of various marine animals, which by 



