CXVl PKOCEEDINGS OP THE GEOLOOICAL SOCIETY. 



description of eacli of these maps, with an account of the geolo- 

 gical features which they represent. 



In the eighth volume of the ' Bulletin de la Societe Linneenne 

 de Normandie ' is an account of some of the geological features of 

 New Caledonia, which has been more or less explored since its 

 occupation by the French. M. Eugene Deslongchamps, having 

 collected all the information he could obtain from various sources, 

 concludes with the following remarks : — •" The little we yet know of 

 the geology of our colony proves, by the variety of old meta- 

 morphic rocks (granite, porphyry, diorite, serpentine, &c.), that 

 the soil is of very ancient origin, and that it was long ago raised 

 above the surface of the ocean ; the Silurian, Carboniferous, and 

 Triassic rocks, which are now well known to exist there, also con- 

 firm this statement, and lead to the inference that we now only see, 

 as it were, the backbone of a region formerly much more ex- 

 tended, represented by its most elevated ridges. The Loyalty 

 Islands, arranged in a line parallel to the axis of New Caledonia, 

 probably represent the tops of a Secondary and less elevated 

 mountain-chain. Cretaceous or Tertiary deposits have not yet 

 been noticed. If they do not exist in this region, it would confirm 

 this view, and prove that the land has sunk since the Jurassic 

 period, and that the deposits of the shores of those periods are 

 now under water. In that case New Caledonia would represent 

 the ruins of a more extensive region which preceded the appear- 

 ance of man on our planet." 



M. Deslongchamps also calls attention to the fact that the 

 rocks collected from the neighbouring Isle of Hugon show the 

 great analogy existing between the formations of this island and 

 those of the other great Australian regions, as New Zealand and 

 New Holland, where the same Triassic rocks have also been re- 

 cently noticed. In describing these specimens, he particularly 

 alludes to those from the Isle of Hugon, amongst which is a 

 limestone full of a small bivalve which cannot be distinguished 

 from the Avicida salmaria, Groldf., and particularly var. Ricli-^ 

 mondiana, Zittel. This analogy with the rocks of the Upper Ti'ias 

 of the Alps at Dorrenberg, where the Avieula salmaria occurs by 

 thousands, induces the author to look upon the limestone of the 

 Isle of Hugon as belonging to the upper series of the Trias, but, as 

 M. Zittel remarks, with an antipodial character. Other fossils are 

 also described, and figures are given of some of the most remark- 

 able forms. 



In conclusion, it only remains for me, while thanking you for 

 the attention with which you have listened to me, to request your 

 forbearance for the crude and somewhat disconnected form in 

 which these observations have been made. I am aware that I 

 have omitted many subjects, and have neglected reference to 

 many works which ought to have been noticed, whilst, on the 

 other hand, I may perhaps have introduced much which, to some 

 of you, may appear unnecessary. I will not attempt to justify 

 what I have done, but will only ask you to believe that I have 

 endeavoured to do my best. 



