Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/577

 3. Geological Observations on the Waipara River, New Zealand. By T. H. Cockburn Hood, Esq., F.G.S.

In 1859, whilst travelling in the Province of Canterbury, I discovered certain beds underlying the Waipara tertiaries, which I referred at the time to the Liassic series, and obtained from the bed of the River Waipara bones of an Enaliosaurian, which were placed in the British Museum, and which were recognized by Professor Owen as belonging to a new species of Plesiosaur, named by him P. australis.

Returning to the colony after ten years' absence, I found that a survey of that province had been completed by the Government Geologist, Dr. Haast, whilst the northern and southern portions of the Middle Island had been explored by that accurate and painstaking observer Dr. Hector. The Canterbury and Wellington museums afford interesting evidence of their careful labours : in the latter a collection of fossils from Triassic deposits of the Nelson Province is placed ; and an excellent one adorns the former, from the Tertiary beds of the Waipara and other adjacent districts, which crop out here and there from beneath the vast accumulations of Postpliocene gravels.

With the exception of some small fragments of bones (ribs chiefly) of Reptilian origin, nothing appeared to have been found to assist in determining the species of the antipodean monsters. I determined therefore to make as thorough an exploration of the wild ravines of the Waipara as possible, with the assistance of my friend Mr. Innes, who is the proprietor of the Mount-Brown estate, under the base of which the river here runs, and who had taken much interest in collecting specimens.

A portion of this singularly broken country consists of a plain two miles and a half wide by about three miles in length, which appears at one time to have formed a lake (Fig. 1) ; the surface is now varied by a number of circular lagoons of some depth. The river and its affluents, which encircle this area, have cut their beds down through the lower Tertiary limestones and Septaria clays to the depth of many hundred feet ; and the Upper Crag has been removed by denudation. The Cretaceous limestone, which affords an excellent building-material, is distinguished by a great abundance of a peculiar cup-shaped Bryozoon and remains of Echinoderms, and contains many Cetacean bones.

After some days spent in examining the deposits in the broad river-bed and that of the tributary flowing through the fantastically broken gorge shown in the sketch, we returned with a considerable quantity of bones, chiefly of Plesiosaurus (ribs, iliums, ischium, coracoid and digital bones), obtained from the intensely hard crystalline boulders (many weighing several tons), which I came to the conclusion were of an older date than the marly clay in which they are imbedded, having probably fallen from the cliffs on the shore of the Eocene sea, which, for some reason, was apparently destitute of life ; the nucleus of all we succeeded in breaking was either a Saurian's bone, a Gryphoea, or a mass of calcareous spar. Nearly all contain great quantities of fucoids.

vol. xxvi. — part I. 2 f