FRENCH MELANESIA. 



339 



In New Caledonia the prevailing formations are syenites, serpentines, dio rites, 

 metamorphic schists, and trachites. The very pumice cast up as flotsam by the 

 waves attests the existence of former eruptive centres. The great geological resem- 

 blance of these rocks to the East Australian ranges at one time held out expectations 

 of rich auriferous discoveries ; but the financial results of the local mining opera- 

 tions have not hitherto been encouraging. The metals which really occur in 

 abundance, and which may yet contribute to the industrial prosperity of New 

 Caledonia, are iron, nickel, cobalt, antimony, and chromium. Copper mines have 

 also been worked, and coalfields, though of little economic value, have been dis- 

 covered at the foot of the serpentine rocks on the seaboard. 



Fig. 144. — New Caledonia. 

 Scale 1 : 5,000,000. 



hasboF OreenwicK 



to 1,000 

 Fathoms 



Depths 



1,000 Fathoms 

 and upwards. 



. 120 Miles. 



New Caledonia is at least doubled in size by the reefs skirting its shores and 

 extending it in the direction of the north-west and south-east. The hydrographie 

 surveys of Chambeyron and other explorers leave no doubt of the existence of 

 these fringing and barrier reefs on the east side, though their presence had been 

 denied by Darwin and Dana. Towards the southern extremity, however, the 

 encircling coralline rocks disappear below the surface, at first a few yards, then 

 from 16 to 20 fathoms, forming, north of the central passage, near the Isle of 

 Pines, a continuous bank, above which rise at intervals chaplets of coral, some 



