A Fossil Nothofagus (Nothofagoxylon?) from the Central Otago Coal-Measures.
[Read before the Wellington Philosophical Society, Geological Section, 8th October, 1930; received by Editor, 18th October, 1930; issued separately, 30th September, 1931.]
The broken carbonised stem referred to in this paper was taken directly from a face in the open workings at Coal Creek Flat, some four miles north of Roxburgh, Central Otago.
After a short treatment with hydrofluoric acid and prolonged boiling in water portions of the wood cut fairly well, and showed sufficient detail to allow it to be identified as that of a New Zealand beech.
The accompanying photomicrographs of transverse, radial, and tangential sections show so clearly the structure of the wood that detailed description is unnecessary.
The coal from which the wood was taken has evidently been. derived chiefly from wood, which, in some sections at any rate, is all drift material. Short stumps and roots lie at all angles in the coal, and generally some fine prostrate trunks are visible. To the unaided eye nearly all the wood appears to be of one sort, but microscopical examination proves that both angiosperms and conifers are represented.
The exact geological age of the measures at Coal Creek Flat is still uncertain. Professor R. Speight, in whose company the writer has been lucky enough to make more than one visit to the district, has not yet found any fossils other than the wood, so that this very important line of evidence as to age is missing. We have therefore to trust to comparisons with similar areas in other parts of Central Otago, assuming that they were laid down at the same time. The St. Bathans beds have been recently placed by Henderson* in the lower Pleiocene, and, as the beds at Coal Creek Flat are comparable with the St. Bathans beds, it seems likely that they also may be regarded as of Pleiocene age.
The occurrence of fossil beech-wood showing a structure almost identical with that of our present Nothofagus fusca proves clearly that the beeches have flourished in New Zealand for a considerable time.
[Footnote] * Henderson, J.; Trans. N.Z. Inst., vol. 60, 1929, p. 294a.