Sequence and Character of Rocks, Position of Strata, Fossil Contents.

I have already stated that the last formation, consisting almost exclusively of igneous rocks of submarine origin was in its turn uplifted and brought within the influence of marine and sub-ærial action, so that the strata composing it were not only greatly destroyed, and their outlines considerably changed, but also beds of conglomerate, often of enormous thickness, were deposited along their base, of which we have a notable instance in the Malvern Hills. In other localities, where these eruptive rocks did not exist, the conglomerate was either formed from boulders and pebbles of palæozoic sedimentary rocks in the neighbourhood, or loose sandy beds were page 294deposited. The latter were either derived from the disintegration, of these palæozoic coast ranges, or formed, in many instances, of quartzose sands of light tints, mostly the result of the destruction of the quartziferous porphyries which have travelled so far along the coast, and have in consequence become disintegrated. I have before observed that the conglomerates, consisting of boulders and pebbles of quartziferous porphyry, are of local occurrence, but there is one exception in the outlier behind the Thirteen-Mile Bush range (Big Ben) to which I wish to allude. The base of the whole series in that distant locality consists of a loose conglomerate made up of boulders of quartziferous porphyry quite similar to that occurring on the eastern side of the ranges; and as this outlier is situated amongst the mountains in a depression, the base of which is about 2,800 feet above the level of the sea, and is surrounded by heights of 4,000 to 5,000 feet, it is difficult to understand whence the material for this conglomerate could have-been derived, except from mountains of much greater altitude than at present exist, and from which the material was brought by currents over the summit of the ranges west of the Thirteen-Mile Bush range. A glance at the map will at once convey my meaning, and show how difficult it is to account for this occurrence in such a land-locked locality, separated from the range consisting of porphyries by a whole series of high mountains, unless we assume that the material for these beds was brought from another locality closer by, now hidden from our sight by younger deposits. In some localities, as, for instance, in the middle portion of the Malvern Hills, these conglomerates are of enormous thickness, about 6,000 to 8,000 feet, and are interstratified with ferruginous sands, fire clays, clay iron ore, shales, and small and irregular seams of brown coal, the latter sometimes partly altered and of no practical value. In other localities, including the Waipara, the lowest beds consist of loose sands, more or less ferruginous, about 100 feet thick, towards the upper portion of which small and impure seams of brown coal are interstratified. These beds follow the contours of the ancient shore line, dipping at the same angle. Thus, in the Waipara these sands and the brown coal seams dip 32 deg. to the east, in the Malvern Hills 19 deg. to the east-south-east. Whilst, as before observed, the brown coal formation in the Waipara is only represented by a few small seams of impure shaly coal, in the Malvern Hills it is of large horizontal extent, and many hundred feet thick, containing a number of seams, of which several are workable. At its base, and still separated by porphyry conglomerate, a bed about ten feet thick occurs, consisting almost entirely of fossil shells, of which a large white page 295triangular Ostrea, different from any of the fossil oysters above the coal seams, is the most conspicuous. This oyster is accompanied by casts of Panopæa, Cardita, Tellina, Trigonia, and a few others too fragmentary to be made out.

In all the principal localities the brown coal series is covered by a bed of shell sandstone, containing a great number of fossil shells, of which the following are the principal genera and species:—Dentalium majus, (Sow.), Pleurotoma, Turbo, Neptunea, Gonchothyra parasitica (McCoy), Aporrhais, Scalaria, Turritella, Calyptræa, Neritopsis, Cypraea, Purpura, Natica, Panopæa, Lutraria, Eriphylla, Zenatia, Pholadomya, Lucina Americana, (Sow.), Astarte, Cytheria, Dosinia, Cardium, Isocardia, Myacites, Protocardium, Venericardia, Crassatella, Area, Mytilus, Trigonia, Cucullæa alta, (Sow.), Cucullæa ponderosa (Hutton), Pectunculus, Pecten, Ostrea, Terebratella, Waldheimia, Rhynchonella. The following exuvise were also collected in the same horizon:—Saurian bones (waterworn, in the Malvern Hills); teeth of Lamna, Hybodus, and Otodus; scales of Hybodus; Dicotyledonous leaves; Araucarian cone and branches; leaves and twigs of Dammara.

Above the oysterbeds, (a local name appropriately given to the shellbeds), we meet either with a sandy clay iron ore (limonite) covered by glauconitic, and higher up by argillaceous sands, as in the Gorge of the Waipara, or with deposits of white quartzose sands with bands of ferruginous or calcareous sandstone, as in the Malvern Hills. The latter also gradually alter to sandy beds of a more argillaceous nature, both series being of a thickness of several hundred feet in the localities named. In the Waipara, the upper portion of these sands contains the remarkable concretionary nodules of limestone (Septaria) ranging from one foot to twelve feet in diameter, and enclosing besides saurian remains, specimens of Conchothyra parasitica, Cucullæa, and twigs and leaves of a Dammara. In all other localities these septaria are either missing, or when they do occur, never contain any saurian remains; and instead of them, (as, for instance, on the banks of the Selwyn river), layers, several feet thick, of a somewhat calcareous and micaceous sandstone, divide the sandy beds into a number of banks. In the Broken River basin the large black oyster continues to occur in the sands for a considerable distance, lying either singly or in banks.

The remains of fossil Reptilia from these septaria, collected by Mr. Hood, myself, and others, have been described by Professor Owen in page 296the "Transactions of the British Association for the Advancement of Science," 1861, p. 122, et seq., and in the "Geological Magazine," February, 1870, Vol. VII, p. 49, and by Dr. Hector, in the "Transactions of the New Zealand Institute," Vol. VI, p. 333 et seq., the latter summing up the main results as follows (page 334):—

"The general result is that portions of 43 individual reptiles, mostly of gigantic size and all of aquatic habits, and belonging to at least 13 distinct species, have been discovered. These species represent two distinct groups, the first with flat or slighlty biconcave vertebrae, being true Enaliosaurians, belonging to the genera Plesiosaurus, Mauisaurus^* (gen. nov. allied to Elasmosaurus of Cope), and Polycotylus (Cope); and the other having procoelian vertebrae, as in most recent Lacertilia and Crocodiles, but provided with swimming paddles, and therefore representing probably the order Pythonomorpha of Professor Cope.^‡ This order is represented in the collection by two distinct genera, Liodon (Owen), and Taniwhasaurus,^‡(gen nov. allied to Clidastes of Cope.) In addition there are several fragmentary remains, which, for the present, I only venture to place provisionally under one or other of these groups, and two vertebrae, which appear to belong to an exceptional form of the genus Crocodilus."

The following species have been obtained in the Waipara, of which remains are in the Canterbury Museum:—

Plesiosaurus	Australis	Owen
Plesiosaurus	Crassicosfatus	Owen
Plesiosaurus	Hoodii	Owen
Plesiosaurus	Holmesii	Hector
Plesiosaurus	Traversii	Hector
Plesiosaurus	Mackayii	Hector
Polycotylus tenuis		Hector
Mauisaurus	Haastii	Hector
Mauisaurus	latibrachialis	Hector
Liodon haumuriensis		Hector
Taniwhasaurus Oweni		Hector

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There are also some other fragmentary portions of bones in the Canterbury Museum which appear to belong to species as yet undescribed; but as the explorations of the beds by the Geological Survey of New Zealand is being actively prosecuted, I have no doubt that considerable light will be thrown upon the occurrence of these remarkable saurians, of which many have their nearest allies in the mesozoic beds of the North American Continent.

The next bed in ascending order is of great thickness, and consists principally of greensands, the grains of glauconite being often so numerous that the rocks appear almost black. Sometimes marly or argillaceous beds are interstratified with these greensands. There is generally found in this horizon a great sameness of character in all the sections examined. A few saurian bones hare been discovered in these greensands, but they are very scarce, generally very fragmentary, and seem to indicate that the true enalosaurians now neared their extinction. In the Malvern Hills these green sands gradually get lighter in colour, and are capped by quartzose sands in light tints, the whole forming cliffs 300 to 400 feet high. In the more northern portion of the Province the former alter by degrees to argillaceous aud calcareous deposits, forming sometimes small beds of chalk marls, or even chalk-like limestones, which are succeeded by a glauconitic, calcareous sandstone. This last is the highest bed in the whole series, and by it the interesting Waipara formation is closed in that district and its neighbourhood, where it forms generally high cliffs and bold escarpments. In the Malvern Hills, on the other hand, the calcareous beds are entirely missing, the uppermost arenaceous deposits belonging to this formation being covered by several coulées of basic rocks, with sometimes beds of palagonite tufa between them. In some localities a break seems to occur between the upper and lower calcareous series, as, for instance, in the Weka Pass ranges, where the lower, more calcareous strata are sometimes separated from the glauconitic massive upper beds by a small band of greensand containing concretions of a more calcareous nature. However, in many other localities this small bed does not occur, and the boundary between the two series is either gradual or sharply defined. Moreover, the upper beds are found to be always conformable upon the lower where the latter exists, being, in fact, a continuation of the same series, and owing to the sinking of the land, of greater horizontal extent than the more calcareous beds underlying them. Such a concretionary structure in the middle of the Calcareous series is, however, not uncommon, and occurs, also in the page 298next or Oamaru formation, of which a notable instance is found in the Otaio, where the lower calcareous beds are divided from the upper more glauconitic ones by a layer, possessing a similar concretionary structure, the same fossils being found above and below the division. Whatever may be the origin of this layer, in any case it is a proof that important changes did take place, by which the mode of deposition and lithological character of the rocks were considerably influenced, without, however, causing a break of any consequence in the continuity of the beds. The lowest chalk marls have yielded hitherto no fossils except a number of foraminifera, of which I have recognised several species as being identical with those described by Karr and Stache in the palseontogical portion of the great Novara work. The upper beds, offering the well-known building stones in the Waipara, Weka Pass, and Castlehill basin, contain a number of shells and other exuviæ, but the former mostly in the form of casts, generally difficult to recognise.

The following is a list of the genera and species, represented in the Canterbury Museum:— Mammalia — Cetacean bones. Aves— Small fragments of bones. Pisces—Teeth and vertebrae of Carcharodon, Lamia, Oxyrhina. Mollusca—Nautilus, cast; Pleurotoma, cast; Voluta elongata (Hutton), cast; Scalaria rotunda (Hutton), cast; Struthiolaria, cast; Solarium, cast; Imperator, cast; Cerithium, cast; Cardium, cast; Area, cast; Lucina, cast; Cytheria, cast; Mactra, cast; Lima, cast; Pecten Hochstetteri (Zittel); Pecten Williamsoni (Zittel); Ostrea; Waldheimia. Crustacea—Carapace of crab (Porcellana); Balanus, two species. Echinodermata—Schizaster rotundatus (Zittel); spines and portions of plates of Cidarites. Actinozoa—Turbinolia, several species; numerous fragments of Bryozoa.