Speight. — Collection of Rocks from Norfolk Island. 327 



collection made by Mr. Laing is as complete as the circumstances of his 

 visit allowed, and gives a thoroughly accurate idea of the general geological 

 structure and origin of the islands. As it includes numerous specimens 

 from localities not referred to by Carne or David, I think it right to pub- 

 lish a short description of the collection, especially as interest always 

 attaches to apparently trivial facts bearing on the geological history of 

 islands remote from large land-masses, since they are the only means at 

 our disposal for acquiring a knowledge of vast tracts of the earth's surface 

 now covered by the ocean, and since a careful consideration of their form- 

 ation may throw light on the troublesome questions of land connections 

 and the origin of faunas and floras. This is especially true in the case of 

 Norfolk Island, because from a consideration of the biological evidence it 

 can be concluded with certainty that this isolated spot of land once had 

 a fairly close connection with New Zealand on the one hand and with 

 Australia and New Caledonia on the other. This has been admitted by 

 all zoologists who have studied the question, among whom may be men- 

 tioned Wallace, Forbes, Hutton, Hedley, and Oliver. The last-named, 

 from a consideration of the distribution of the birds inhabiting the Lord 

 Howe Group, the Norfolk Islands, and the Kermadec Islands, came to the 

 conclusion that Norfolk Island had never formed part of an actual land 

 connection, but existed as an island off the coast of a land stretching from 

 New Zealand to New Caledonia, and including Lord Howe Island as an 

 integral part of its western shore-line.* 



The fact that plutonic rocks occur in the Kermadec Group has been 

 recorded by Thomasf and the present author,J thus proving that a laud- 

 mass of continental character did once exist over a part of the earth in 

 that region which is now covered by sea. These islands occupy a 

 position between New Zealand and Oceania analogous to that of Norfolk 

 Island between New Zealand and New Caledonia, so that the rocks of 

 Norfolk Island were examined with a special object of determining, if 

 possible, whether or not they would yield similar material of deep-seated • 

 origin, especially as the biological evidence of a contin-ental connection 

 is so much stronger in its case than in that of the Kermadecs. I have, 

 however, been somewhat disappointed in the result, there being only the 

 very slightest indication, afforded by an inclusion in the tuffs of Philip 

 Island, that below the volcanics which now compose almost the entire island 

 there exists a rock of different character, if not of different origin. This 

 evidence will be given in more detail later. Apart from this occurrence, 

 the rocks as a whole are very monotonous, being basalts of varying 

 degrees of coarseness and basaltic tuffs, almost entirely the product of 

 surface volcanic action, a doubtful dyke being recorded from Norfolk 

 Island, although Carne reports that they are common on Philip Island, 



The reports by Carne and David, referred to previously, contain descrip- 

 tions of only two specimens from Norfolk Island — viz., the coral-sandstoue 

 from Emily Bay and a basaltic lava from Anson Bay. Mr Laing's collection 

 includes numerous samples of the former, and from them it appears to be 

 a yellowish-brown rock composed largely of clear colourless calcite, and con- 

 taining numerous fragments of corals and tests of Forminifera of various 

 genera, and a small amount of volcanic matter. In treating of the volcanic 



* Trans. N.Z. Inst., vol. 44, p. 217; 1912. 

 t Trans. N.Z. Inst., vol. 20, p. 31.5; 1888. 

 t Trans. N.Z. Inst., vol. 42, p. 244; 1910. 



