CH. n ON BOABD H.M.S. ' FLYING FISH ' 23 



On this occasion the race ended somewhat in favour of 

 the canoe, but had the wind been a Httle more abeam the 

 result would have been very different. , 



The following day I accompanied one of the surveying 

 officers to a promontory on the north coast to the west of 

 Likupang. This promontory is fiat and bordered by a belt 

 of mangrove swamp. I cannot give an accurate estimate 

 of the breadth of this swamp, for it stretched away inland 

 far beyond our sight, and none of the maps nor charts give 

 any plan of the true coast line. 



The occurrence of a broad shore plain bordered by a 

 broad belt of mangrove swamp is by no means a rare one 

 in these climates. It is, in fact, such a common feature 

 that it deserves a few words of explanation. 



In the first place it cannot for a moment be supposed 

 that these broad level plains on the sea-coast represent the 

 true bearing of the hOl rocks. It is inconceivable that 

 broad plains of the primitive volcanic rocks should be found 

 at precisely the same (sea) level in so many places. We 

 are bound, therefore, to believe that they were built up of 

 some secondary formation at a much later period. "What, 

 then, is the probable nature of this formation ? 



In nearly every case where we find a dense mangrove 

 swamp on the sea-coast we find a vigorous coral ree 

 beyond it. Taking for granted at present — for I shall re- 

 turn to argue this point in a later chapter — that coral reefs 

 under certain favourable circumstances have a tendency 

 slowly to grow out seawards, we must believe that the soil 

 between the reef and the rising slopes of the hUls is com- 

 posed of coral sand and debris resting on a substratum of 

 coral rock. This area is covered with water at aU times 

 except at low water of the spring tides, but on the shore side 

 banks of sand are formed by the continual ebb and flow of 

 the tides. The mangrove trees flourish best in such a soil 



