Other formats

    Adobe Portable Document Format file (facsimile images)   TEI XML file   ePub eBook file  

Connect

    mail icontwitter iconBlogspot iconrss icon

The Pamphlet Collection of Sir Robert Stout: Volume 65

Wanganúi System

Wanganúi System.

Marine beds belonging to this system have been proved by palæontological evidence only in the southern half of North Island, from Patea and Wanganúi on Cook's Straits (Pútiki Serios), to the Ngaruroro River (Kéreru Series), and Esk River (Pétano Series) in Hawkes Bay. There can be no doubt, however, that the system also occurs at Poverty Bay (Ormond Series), at Taranáki, round Mánukau Harbour, on the west side of Whangarei Harbour, and in various other places in the province of Auckland. In the South Island the marine beds of the north appear to be represented by thick unfossiliferous gravels, which are very difficult to distinguish from the upper gravels of the Pareóra System. These beds rest unconformably on the Pareóra System in the western part of Wellington Province *, and also in Hawkes Bay, wherever the junction has been seen, the only doubtful place being at Pohui, east of Napier, where, according to Mr. Cox , the unconformity mentioned by Mr. Percy Smith below his "Pohui papá §" does not exist. The marine beds attain an elevation of more than 2000 feet near Napier.

I have elsewhere given reasons for concluding that the former great extension of our glaciers was caused by greater elevation of the land during the interval between the Pareóra System and the marine beds of the Wanganúi System. As these marine beds are fossiliferous in the North Island only, where there are no traces of former glaciation, it is not possible to get direct proof of this; but in Otágo the old Taieri moraine, between Lake Waihola and the sea, which forms low rounded hills between 400 and 500 feet in height, is, on the seaward side, covered nearly to the top by marine gravels, which may belong to this system or may be younger.

The fossils of this system are very different from those of the last. We miss the species of Struthiolaria and Pecten; and there is no Conus or Limopsis. On the other hand Murex, Trophon, Pisania, and Cassis appear for the first time. It is also remarkable that there should be three genera, Oliva, Sigaretus, and Risella, not now represented in our seas. From 70 to 90 per cent, of the Mollusca, and all the Brachiopoda are recent. Dr. von Haast has found Moa bones in morainic deposits belonging to this system. A list of some of the Foraminifera from the Pétane Series by Mr. G. R. Vine, junior, will be found in the 'Transactions of the New Zealand Institute,' vol. xiii. p. 393. In addition to the large percentage of recent species, this system may be recognized by:— page 212
  • Trophon expansus, Hutton.
  • Pisania Drewii, Hutton.
  • Pleurotoma wanganuiensis, Hutton.
  • —tuberculata, Kirk.
  • Galerus inflatus, Hutton.
  • Trochus conicus, Hutton.
  • Zizyphinus Hodgei, Hutton.
  • Dentalium nanum, Hutton.
  • Cytherea assimilis, Hutton.
  • Ostrea corrugata, Hutton.
  • Trochocya thus quinarius, Ten.- Woods.
  • Flabellum rugulosum, Ten.-Woods.

There are also many others, the descriptions of which are not yet published.

* McKay, Rep. Geol. Surv. 1877-78, p. 19; and I.c. 1878-79, p. 84.

McKav, I.c. 1878-79.

Rep. Geol. Surv. 1874-76, p. 97.

§ Trans. N. Z. Inst. ix. p. 568.

Trans. N. Z. Inst. v. p. 384, and Geology of Otago, p. 83.

Geology of Canterbury and Westland, p. 380, and Quart. Journ, Geol. Soc. xxi. p. 135.