Speight. — Petrological Notes on Rocks from the Kermadecs. 245 



present most of the characters of an oceanic island. Such appears to be the 

 probable position in the case of the Kermadecs. The great difficulty, how- 

 ever, is in coming to any satisfactory conclusion as to the date of their exist- 

 ence as land above sea-level. It is the fact of the occurrence of plutonic 

 acidic rocks in the group that has suggested the consideration of the 

 geological evidence for the existence of a Pacific tropical or subtropical 

 continent, previously demanded on purely biological grounds. 



Lord Howe Island. 



Lord Howe Island, according to David and Etheridge,* is composed of 

 volcanic and coral-sand rocks. The former include a series of diabasic 

 basalts which David says are certainly pre-Tertiary, and may be Palaeozoic. 



Norfolk Island. 



Norfolk Island is largely volcanic, but, judging from the evidence of 

 its fauna and flora, it has undoubtedly been connected with New Zealand. 



New Caledonia. 



New Caledonia consists of an ancient series of mica-schists and slates 

 with a general north-easterly strike. Limestones are interstratified with 

 the slates. Besides this is a great series of serpentines and serpentine 

 schists with beds of chrome and nickel, and associated with it are beds 

 of melaphyre and tuffs overlaid by altered sedimentaries and shales with 

 fossils identical with those of the New Zealand Trias. The Triassic zone 

 strikes north-west and south-east parallel to the general trend of the island, 

 and is followed by beds of coal of Jurassic age. It is probable that the 

 serpentines are of later date than the coal-beds. The association of beds 

 of serpentine with Triassic sedimentaries near Nelson in New Zealand, 

 containing identical fossils, is suggestive of a common origin, though it may 

 be a mere coincidence. These beds prove that continental conditions have 

 existed in New Caledonia or its immediate neighbourhood for long periods 

 of time. 



New Hebrides. 



Gneisses, crystalline limestones, and serpentines like those in New 

 Caledonia are reported from some of the islands of this group. However, 

 according to Mawson,t the New Hebrides are composed of andesitic con- 

 glomerates with overlying beds of Miocene age consisting of foraminiferous 

 submarine tufis and limestones. These were folded up and formed into a 

 mountain-chain of the alpine type, with a general west-north-west trend. 

 Associated with this were extensive faults, and volcanic eruptions along the 

 line of faulting. Over the folded Miocene series submarine tufaceous beds 

 were laid down, containing at times numerous Foratninifera. These are 

 covered with a thin veneer of coral rock, rising in terraces to a height of 

 over 2,000 ft. The New Hebrides are therefore of recent appearance in their 

 present subaerial form, though biological evidence is in favour of a con- 

 tinuous land connection. In a footnote to his paper Mr. Mawson says, " It 

 is none the less probable that limited outcrops [of beds older than Miocene] 



* " Lord Howe Island " : Memoii's Aust. Museum, No. 2. 

 t Proc. Linn. Soo. N.S.W., vol. xxx, 1905. 



