Go to National Library of New Zealand Te Puna Mātauranga o Aotearoa
Volume 20, 1887
This text is also available in PDF
(189 KB) Opens in new window
– 267 –

Art. XXXIII.—On some Fossils lately obtained from the Cobden Limestone at Greymouth.

[Read before the Philosophical Institute of Canterbury, 1st September, 1887.]

Last January, when I was in Greymouth, the Rev. B. J. West-brooke, F.G.S., Mr. E. Williams, and Mr. R. Helms all kindly allowed me to examine their collections of fossils from the Cobden limestone, which had been found in the quarries now being worked for the harbour works; and I was enabled to identify the following species:—

  • Carcharodon angustidens, Agassiz.

  • Aturia ziczac, Sowerby.

(This is the same as the supposed Ammonite from Ten-mile Creek, Greymouth, mentioned by me in my paper on the Geology of New Zealand, and afterwards doubtfully identified with Nautilus danicus in “Reports of Geological Explorations,” 1881, p. 74, when it was again found at Wharekauri on the Waitaki.)

  • Cassidaria senex, Hutton.

  • Voluta attenuata, Hutton.

  • Scalaria rotunda, Hutton.

[Footnote] † “Quar. Jour. Geol. Soc. Lond.,” vol. xli., p. 206.

– 268 –
  • Pleurotomaria tertiaria, M'Coy.

  • Gryphœa tarda, Hutton (?).

  • Terebratella suessi, Hutton.

  • Terebratella gaulteri, Morris.

  • Terebratella aldingœ, Tate.

  • Holaster spatangiformis, Hutton.

  • Holaster cordatus, Hutton.

  • Pericosmus tuberculatus, Hutton.

  • Schizaster lyoni, Hutton.

  • Flabellum circulare, Tenison-Woods.

These are amply sufficient to show that the Cobden limestone is the equivalent of the Weka Pass stone, and the Ototara limestone, on the eastern side of the Alps.

Last March, in blasting the rock, some vertebræ and ribs were obtained, and presented to the School of Mines at Greymouth. Mr. R. Helms has kindly sent me a drawing of these fossils, upon which I make the following remarks: There are six vertebræ, with five ribs on one side and another detached rib lying on the other side; the vertebræ are, I should suppose, the two last dorsal and the first four lumbar. The vertebræ are said to be divided longitudinally down the middle, and they show centra which are cylindrical, considerably longer than broad, and with flat ends. There is no constriction in the middle. The length of the centra increases backwards, so that the two posterior are about 4 ⅔ inches in length by 3 ⅓ inches in breadth, and the two anterior vertebræ are about 3 ⅓ inches in length by 2 ⅔ inches in breadth. These dimensions are not to be considered as accurate, and are only intended to give some idea of the size and proportions of the centra. The neural arches are not seen, owing to the obliqueness of the section; but what I take to be the transverse processes of one side are exposed. These are nearly as broad as the length of the centra, and with a visible length of nearly twice the diameter of the centra; they must therefore be longer than this. They are set nearly at right angles to the centra, and have straight, parallel sides. The ribs are very robust, being more than an inch in thickness.

The centra of these vertebræ show that they are mammalian, and the large size of the transverse processes are either cetacean or sirenian in character. The proportion of length to breadth of the centra is greater than usual, but agrees well with some of the Ziphioid Whales, to which family I therefore refer them.

The association of a Ziphioid Whale with Carcharodon anqustidens, Aturia ziczac, and Pleurotomaria tertiaria indicates an Upper Eocene or Lower Miocene—i.e., an Oligocene—age for the Cobden limestone. So long ago as 1861 Sir Julius von Haast pointed out that the series of rocks having the Cobden limestone as its upper member rested unconformably on the

– 269 –

Brunner Coal series, at the place where the Davy Mountains reach the sea;* and the short examination I made of the Greymouth District quite bears out his views, although I did not go so far as Mount Davy.

[Footnote] * “Report of a Topographical and Geological Exploration of the Western District of Nelson,” by Julius Haast: Nelson, 1861, p. 109.