38 ANNIVERSARY ADDRESS. 



Over all the beds and on the heights of the Noumea Peninsula 

 and the neighbouring islets, and on all the hills about Paiia near 

 the sea, is found a very recent limestone with some badly 

 preserved remains of living shell-fish. 



White, and sometimes a little grey, and so earthy that it is 

 easily penetrated, it contains from 9 to 12 per cent, of clay, which 

 is a good proportion for hydraulic purposes. It is easier to work, 

 and is freer from water and salt than coral. This limestone is 

 very similar to that which composes the Loyalty Isles (Mare and 

 Ouvea), and it is met with in the Isle of Pines, &c. At Lifii. the 

 limestone contains casts of shells, which Mons. Fischer has recog- 

 nised as those of Terebra, Turbo, Trochus, Psamaiobia, Cypricardia, 

 Nautilus, Sfc. 



In the Houagap valley also we meet with a very recent mica- 

 ceous fine-grained argillaceous sandstone. 



We come now to the most important formation of New Cale- 

 donia. The eruptive Magnesian rocks form, in fact, the greatest 

 part of the prominent profile of the country — or we might rather 

 say that the formations already mentioned are only isolated 

 patches in the midst of the Magnesian eruptions. 



If we imagine a broken line shooting from Mont d'Or to 

 Ouitchambo and Ouailou peaks, the mean direction of which is 

 north-north-west, all the part of New Caledonia placed to the 

 south-east of that line is nearly exclusively formed of magnesian 

 eruptions, essentially represented by serpentines, with or with- 

 out diallage — JEuplwtides, Amphibolites, and Diorites. But this 

 is not the whole extent of these rocks ; they show themselves 

 also on the west coast, particularly at Ouarai, Kone, Gatop, 

 Paquiepe, Cape Duverd, Koumac, Neoue, Tanlep, Neba, Nande, 

 and Belep. The great surface occupied by these eruptions com- 

 pared with the sedimentary formations, would induce us to say 

 that the Island is nothing but an elevation of magnesian rocks 

 in the midst of which there remains here and there a small over- 

 thrown islet belonging to the old sedimentary formations. These 

 magnesian rocks have contributed the most important forms 

 which the island now possesses ; but their composition is such as 



