326 Tra?isactions. 



Further evidence of deuundation and weathering can be obtained from 

 the cliffs between Anson Bay and the Cascades, on the northern half of 

 the island. Thus at Duncombe Bay there is a series of stratified volcanic 

 tufEs, conformably bedded from 75 ft. to 100 ft. in thickness, lying under 

 basaltic rocks, which show columnar structure. Immediately under this 

 basalt lies red followed by yellow tuffs, and then by a tuff with pisiform 

 nodules. At the eastern end of the bay these strata dip at an average 

 angle of 45°, but elsewhere they are approximately level. Here these 

 stratified tuffs come down to high-water mark ; but at Anson Bay, where 

 the same or a similar series is found, they are at a height of 50 ft. or more 

 above sea-level, and are underlain as well as overlain by basaltic rocks. 



I did not see any dykes on the island, except a narrow band some 6 in. 

 wide, exposed only for a few feet near the landing-rock at the Cascades. 

 Dykes are said to occur plentifully at Philip Island, which is apparently 

 of somewhat different structure from Norfolk Island, and very possibly 

 has never formed a portion of the same land-mass. Unfortunately, I was 

 only able to give this off-lying islet a very cursory examination. I made 

 one excursion to it in a whale-boat, but our visit was cut short by the 

 rising surf. Philip Island, like Norfolk Island, is ringed with cliffs, low 

 on the side facing Norfolk Island, high on the outer side, as already noted. 

 A landing can only be effected in fine weather. The surface of the island 

 is covered with brilliantly coloured blue, red, yellow, and brown volcanic 

 earths, which are conspicuous from a distance. Here and there are ex- 

 posures of harder undecomposed rocks. I had hoped to examine the cliffs 

 on the northern side of the island for dykes or sedimentary rocks, but the 

 abrupt ending of our visit prevented me from doing so. 



The island at one time bore a fairly abundant vegetation, but this is 

 fast disappearing. The destruction of plant-life by the pigs and rabbits 

 introduced by convicts and settlers has led to a loosening of the soil. This 

 is being fast washed away, and the island is rapidly becoming desert. I 

 hope, however, to deal with this matter further in a paper on the botany 

 of Norfolk Island. 



Art. XL. — On a Collection of Rocks from Norfolk Island. 

 By R. Speight, M.Sc, F.G.S. 



[Read before the Philosophical Institute of Canterbury, 6th November, 1912.'] 



(See sketch-map in previous paper by R. M. Laing.) 



The specimens of rocks referred to in this paper were collected by Mr. 

 R. M. Laing during a visit to the group in the summer of 1911-12, and 

 were subsequently handed to me for identification. They include repre- 

 sentatives from all parts of the island, and also a few specimens collected 

 during a hurried visit to Philip Island, a small and rapidly disappearing 

 islet situated about three miles south of Norfolk Island, The only reference 

 that I can fijid to the nature of the rocks in the group is that contained in 

 Appendix II of the Annual Report of the Department of Mines, New South 

 Wales, for the year 1885 (Sydney, 1886), where there is a short descriptive 

 account of the geological features of the islands by J. E. Carne, and a 

 petrological description of a few rock-specimens by T. W. E. David. The 



