III. — GEOLOGY. 



Art. XXXIX. — On the Age of the Orakei Bay Beds near Auckland. 



By Captain F. W. Hutton, F.G.S. 

 [Read before the Philosophical Institute of Canterbury, 11th November, 1884.] 

 In bis lecture on the geology of the Province of Auckland, delivered to the 

 members of the Auckland Mechanics' Institute, on 24th June, 1859, Dr. von 

 Hochstetter, after describing the brown coals of the Province, and the tertiary 

 strata on the west coast from Waikato to Kawhia, said that " the horizontal 

 beds of sandstone and marls which form the cliffs of the Waitemata and 

 extend in a northerly direction towards Kawau, belong to a newer tertiary 

 formation."* This he considered to be of miocene age, but fossils were 

 obtained only at Orakei Bay, and in an ash-bed at Wangaparoa. Subse- 

 quently, on his return to Europe, Dr. von Hochstetter followed Dr. Zittel 

 in placing the " Waitemata series " with the west coast or " Aotea series," 

 but he considered both as older miocene. t Dr. Stache, however, considered 

 the Aotea series to be oligocene, j and Dr. Zittel considered it to be eocene. § 

 The first attempt to ascertain the relative age of these two series by 

 stratigraphical evidence was made in a paper read to the Auckland Institute 

 on 8th August, 1870. || In this paper I showed that the Waitemata series 

 can be traced eastward beyond the Tamaki and Howick to Turanga Creek, 

 where it consists of a set of yellow clays and white or pale yellow sand- 

 stones, stained in places by iron oxide. It rests here unconformably on a 

 dark green or bluish sandstone, generally showing a concretionary structure, 

 which can, in its turn, be traced nearly to the Papakura Biver, and on the 

 other side of the valley it reappears, on the north side of the Hunua hills, 

 where it is associated with the Papakura limestone, and, with other beds, 

 forms the "Papakura series," which rests unconformably on the coal series 

 of Drury. Consequently the Waitemata series is separated from the coal 

 series of Drury by two unconformities. The Papakura series was con- 

 sidered to be the equivalent, or very nearly the equivalent, of the Aotea 

 series, and to be of oligocene age, while the Waitemata series was considered 

 as miocene. 



* Geology of New Zealand, Auckland, 1864, p. 26. 



t Reise der Novara, Geology, I., p. 34. J Reise der Novara, Palaeontology, p. 298. 



§ On the Palaeontology of New Zealand, Quar. Jour. Geol. Soc, xix. (1863), Misc., p. 20, 



|| Trans. N.Z, Inst., iii., p. 244, 



