Pleistocene Period.

Raised Beaches.—At the mouth of the River Thames, near Auckland, there is a raised beach some 10 or 12 feet in height containing marine shells^*, and at the North Head of Mánukau Harbour a well-cut beach-terrace is seen at about the same altitude ^†.

Below the town of Tauranga there is a raised beach about 25 feet above the sea. Beach-terraces are plainly seen at Hick's Bay near the East Cape; but I have never landed to examine them. At Taranáki Dr. Hector has described Pleistocene deposits with recent marine shells at 150 feet above the sea ^‡. Beach-terraces occur also near Wellington; and Mr. McKay describes them as much more than 200 feet high near Capo Pelliser, in Cook's Straits ^§. On the west coast of the South Island Dr. Hector mentions comparatively recent beach-terraces extending to more than 220 feet above the sea ^‖, and Mr. Dobson has estimated these terraces at 400 feet ^¶. At Amúri Bluff there are three terraces, and Mr. McKay obtained recent marine shells from the highest, which, he says, is 500 feet above the sea^**. These three terraces are also seen a little further south, at the mouth of the river Conway. At Motannau, in N. Canterbury, a raised beach with marine shells goes to a height of 150 feet above the sea. A deposit of fine silt occurs along the east coast of Canterbury and Otágo from Banks's Peninsula to Moëraki. At its base it is stratified, frequently with layers of gravel, but its upper portions are unstratified. At Timarú it contains a few marine shells ^††. At Oamarú the gravels at its base contain large numbers of recent marine shells ^‡‡, and the upper parts have yielded Moa-bones, and the skull of a large Sea-Elephant (Morunga elephantina). This silt goes to a height of 800 feet in Banks's Peninsula ^§§, and to 500 or 600 feet at Oamarú ^‖‖. Also the entrance to the West-coast Sounds are terraced to an estimated height of 800 feet.

If we plot these heights and distances to scale it appears

^* Rep. Geol. Surv. 1868-69, p. 22.

^† Trans. N. Z. Inst. ii. p. 161.

^‡ Rep. Geol. Surv. 1866-7, p. 3.

^§ Rep. Geol. Surv. 1878-9, p. 84

^‖ Rep. Geol. Surv. 1866-7, p. 29.

^¶ Trans. N. Z. Inst. vii. p. 444.

^** Rep. Geol. Surv. 1874-6, p. 177.

^†† McKay, Rep. Geol. Surv. 1876-7, p. 49.

^‡‡ Geology of Otago, p. 70.

^§§ Haast, Trans. N. Z. Inst. vi. p. 423.

^‖‖ The marine origin of this deposit is, however, disputed. Dr. von Haast considers it to be land löss. See Geol. Canterbury, p. 367, and Trans. N. Z. Inst. xv. p. 411.

page 213 as if the rise were tolerably regular from Auckland to Banks's Peninsula; but we must remember that the observations are still very imperfect; indeed I believe that the sea stood much higher than 800 feet in Canterbury ^*. The remarkable river-terraces found throughout the South Island and the southern and central portions of the North Island furnish collateral proof of elevation. They do not occur in the north part of New Zealand, where also there are no raised beaches.

Peat-mosses.—Several ancient peatmosses have been examined in the South Island, such as those of Waikouaiti and Hamilton in Otágo, and Glenmark in Canterbury. They appear to be very similar in character, and I take the one at Hamilton as an example, as I explored it myself ^†. This was a small dry basin, about 50 feet in diameter and from 5 to 6 feet deep in the deepest part, excavated out of a bed of clay. This small basin was filled with peat and bones inextricably mixed and forming a compact layer from two to four feet thick, and before being disturbed its surface was rather higher than the surrounding country, which was quite flat for a distance of 200 yards. Out of the small hole there were taken about 7 tons weight of Moa-bones, more than half of them quite rotten, the remains of at least 400 birds ^‡. A great quantity of quartz gravel occurred among the bones, some of the stones going up to one or two pounds, and one piece of rock weighed between 10 and 12 pounds. Probably this bog was but the remains of a much larger one. Besides Moa-bones there were found abundant remains of Cnemiornis, and a few bones of Harpagornis and Apteryx, as well as a number of small birds not yet determined: also several bones of Sphenodon punctatum. The bones were not water worn, neither were they broken. I collected from the peat the following land-and fresh-water shells:—Thalassia obnubila, Reeve, and Limnœa leptosoma, Hutton. The former is now common near Dunedin, but requires damp bush to live in. The latter is not now known in the South Island, but is found near Wellington.

Diluvial Epoch.—The Mollusca of the north of New Zealand differ sufficiently from those of the south to make any migration which might take place in either direction easily distinguishable ^§. But neither in the Wanganúi System nor in the raised beaches is there any trace of a northerly migration. Neither are there any signs of a Pleistocene glaciation of New Zealand greater than at present. Consequently there is no evidence to show that the high eccentricity of the earth's orbit that prevailed in Pleistocene times produced a Glacial epoch here. But there are several facts which appear to support the view that this high eccentricity produced a diluvial epoch by causing greater winter snowfall and greater summer floods.

In the first place the occurrence of the bones of Apteryx, as well as those of the water-loving Sphenodon and the land shell Thalassia obnubila, with bones of the Moa at Hamilton, prove that the dry, treeless, interior region of Otágo was at that time covered with forest; and this is corroborated by some of the trunks of the trees themselves still lying on the sides of the mountains. Secondly the extraordinary agglomeration of Moa-bones in the peat-mosses at Glenmark, Hamilton, and other localities, where hardly even two toe-bones were found in their proper places, can only be accounted for by supposing that heavy floods swept these bones up and deposited them in the low ground. And thirdly, the silt of Northern Otágo and Canterbury, usually unfossiliferous but sometimes containing Moa-bones and only stratified at its base, seems to imply heavy and often recurring floods washing away the fine mud left by the retreat of the glaciers during subsidence and its rapid deposition in the sea.