sea-level. Porirua and Wellington Harbours prove the depression of the southern end of the Island. According to Cotton, the depression on the eastern side of Wellington Harbour is about 200 ft. (104, p. 140). Palliser Bay, like Wellington Harbour, occupies part of a tectonic depression, and once extended some miles up the Wairarapa Valley, as is proved by the raised shell beaches that occur round the shores of the lake (11, p. 86). That the land has been higher in this locality is suggested by the wide low-lying plains and the sprawling spurs that project into them. The streams flowing to the eastern coast of Wellington are all small. The Akitio and Wainui (34, p. 103), and probably others also, near the sea, flow slightly entrenched in raised estuarine deposits. Hill has shown that the extensive Heretaunga Plain is an old extension of Hawke Bay filled with detritus brought down by the Tukituki, Ngaruroro, and Tutaekuri Rivers (74, p. 288; 76, p. 431). The silts, sands, and gravels of the plain reach 369 ft. below sea-level at Havelock (84, p. 444). The lower valleys of the Wairoa, Waipaoa, Uawa, and Waiapu Rivers are all obviously infilled estuaries (52, p. 22). The loose deposits in the Waipaoa Valley at Makauri, on the flats four miles from the sea, extend to 200 ft. below sea-level (86, p. 434). In the Bay of Plenty the harbours of Ohiwa, Tauranga, and those on the eastern side of Hauraki Peninsula amply prove depression. At Tauranga, valleys cut in a 200–300 ft. bench have later been depressed and partly filled. The submerged forest at Opotiki (50 ft.), and the swamps at Coromandel (150 ft.) (29, p. 12), and near Thames (30 ft.) (116, p. 244), probably belong to a late period of oscillation. Hauraki Gulf, like Palliser Bay, is the drowned portion of a structural depression. The numerous peat-beds passed through by bores on the lowlands south of the inlet prove a depression of this portion of New Zealand of at least 400 ft. (117, p. 6). At Horotiu, in a tectonic trough adjacent to the Hauraki depression, peaty beds occur at a depth of 550 ft. below sea-level (96, p. 614). The coast round Golden and Tasman Bays has obviously been depressed. On the shores of the former Parapara, Onekaka, and Onehau inlets are partly filled drowned valleys carved in a raised terrace of the 200–300 ft. standstill. Croixelles Harbour and the sounds are definite proof of the depression of the Marlborough Peninsula. The pattern of the valleys now forming the inlets indicates that they were excavated along a system of parallel faults. Thus the valley-floors of relatively small streams became maturely graded in relatively short periods, so that, when depression occurred, the sea penetrated unusually long distances. The Pelorus River has filled in several miles of its old narrow estuary, and has produced decided shoaling for eight miles below the present head of the sound. But the drainage area of Queen Charlotte Sound is so small that only a trifling amount of infilling can have occurred. Cotton (93, p. 216) has discussed the amount of depression of this area, and considers it to have been from 250 ft. to 500 ft. The neighbouring lower valley of the Wairau River is an infilled estuary. This low-lying area is primarily of tectonic origin, but the choking with debris of minor valleys excavated in Pleistocene gravels south of Blenheim suggests recent depression unconnected with the earlier structural movements. From Wairau River to Motunau there is convincing evidence of uplift, but the only definite recorded evidence that the land was once lower than now is furnished by the submerged forests at Grassmere (68, p. 97) and near the mouth of Conway River (4, p. 40). The embayments, however, in the rock-platform surrounding Kaikoura Peninsula and the lower valley of Kahutara Stream suggest depression. Farther south the drowned valleys
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