C—2b

20

with a height of 5,260 ft. North of the Hapuku River and south of the Kahutara, spurs of the Looker-on Range reach the shore, but the greater part of the area between these points is a fertile tlelta-fan,* built mainly by the Kowhai and Hapuku rivers. This plain has a considerable upward slope to the base of the mountains, the grade, of course, increasing as the high land is approached. Its outer margin is interrupted by the moderately low smooth hills that form Kaikoura Peninsula. These, on the seaward sides of the peninsula, terminate in cliffs descending 'to 'high-water mark or to low raised beaches. Several stacks and numerous outlying rocks, with tops at or above high-tide level, mark comparatively recent encroachment of the sea upon the peninsula, a process contemporary with the outbuilding of the Kaikoura Plain by the rivers. Considerable elevation of the land in not very remote periods is shown by the presence of numerous wave-cut platforms on the peninsula. These may be traced to the highest points (150 ft. or more), and are especially well marked at levels ol approximately 100 ft. and 160 ft., Where also fine beach-shingle is present. The 100 ft. stage is well represented north of the Hapuku River by a fluvio-marine terrace. The most modern period of standstill is distinguished by raised beaches a few feet above high-water mark on the north and south sides of Kaikoura Peninsula, which continue along the seaward margin of the Kaikoura Plain, and by sea-worn caves 10 ft. or 12 ft. above high-tide level on its eastern side. The long straggling township of Kaikoura is built mainly on strips of raised beach flanking the northern coast of the peninsula. Especially noteworthy is the magnificent raised storm-beach, with crest 6 or 7 chains wide, that extends for nearly two miles northward from the mouth of Lyell Creek. Low sandhills, backed by a small terrace, then take its place. Extensive rock benches or shelves, with a very slight downward slope from high-water mark, are developed on the eastern and southern sides of the peninsula, and constitute additional evidence of the encroachment of the sea upon its solid flanks of comparatively hard rock. Similar shelves are seen on many other portions of the New Zealand coast, but have not received much attention in the geo'Ogical literature.t The principal streams of the Kaikoura district are the Hapuku (with its tributary the Puhipuhi), the Kowhai, and the Kahutara. These streams, especially the Hapuku and the Kowhai, fed with abundant, debris from the crumbling rocks of the Seaward Kaikoura Mountains, have built great delta-fans, which by their coalescence form the Kaikoura Plain. Noteworth)- are the large blocks, some 6 ft. in diameter, brought by the Hapuku River to its fan. thus causing the material to resemble morainic or fluvio-glacial gravel, a feature noted by McKay in 1890 (16, p. 183). Though the three streams named above carry large bodies of water in time of flood, yet during dry seasons such as that prevailing at the end of 1915 their visible flow is reduced to a few cubic feet per second. There need.be no doubt, however, that the water escaping by percolation through the gravels of the various fans greatly exceeds that sieen .in the stream-channels.,: - The valley of the I'uhipuhi River, as seen from the neighbourhood of Kaikoura, is remarkably straight, and almost'typically U-shaped in cross-section. Thus glaciation is inevitably suggested, but the features noted are clearly related to structural causes, with some modification due to stream-erosion. The neighbouring valley of Irongate Creek presents similar characters. No physiographic account of the Kaikoura district could be written without some description of the faults that dislocate all the rocks except those of Quaternary age, and it is doubtful if even these latter have entirely escaped. A tremendous fault or fault-zone, the Kaikoura fault of McKay (16, p. 98;. 17, pp. 12-14), marks the eastern base of Mount Fyffe, and evidently extends far to the south-west into the Cherwell Valley. North-eastward it passes Up the Puhipuhi Valley and, crossing a saddle, enters the lower Clarence Valley. Thence, according to McKay, it reaches the mouth of the Flags Riven,- and, crossing Cook Strait, extends up the Wairarapa Valley along the eastern base of the Rimutaka Range. McKay remarks that " between the lower Clarence and the eastern base of Mount Fyffe, west of Kaikoura Peninsula, the fault-line is single." But this is doubtful, for a parallel dislocation probably extends through the upper part of Irongate Creek valley, and there is certainly strong parallel faulting along the coast-line, as shown by the smashing and. crushing of the pre-Quaternary rocks wherever these are exposed. Thus the essentially faulted nature of the coast-line is clearly demonstrated. This feature, which forms part of the ; subject-matter of an elaborate paper by Cotton,{ was somewhat crudely described by J. Buchanan (1, .p.. 36) almost half a century ago. The much-disturbed rocks of Kaikoura Peninsula show several considerable faults with a north-east trend, approximately parallel to the strike of the fractured beds, besides a great number of minor dislocations. Several small faults may be seen traversing the rock bench near the eastern headland of the peninsula, whilst, at, a spot near the Maori settlement on the south side (South Beach) no less than fourteen faults may be seen dislocating the limestone and Grey Marl in a distance of less than 7 chains. These are small normal faults striking into the northwest, quadrant, and in: most cases dipping steeply to the south-west. Thus they are nearly at right angles to the strike of the dislocated rocks and to the major faults of the district. A sketch showing a number of these faults is given by McKay in one of his reports (13, p. 76). General, Geology. Although a fairly comprehensive idea of the geology of the Kaikoura district can be obtained i>\ studying McKay's reports (6, 11, 13 16), yet a recapitulation of the main points may be useful to the reader. The'oldest rocks of this part of New Zealand are the strongly-folded much-

* See page 14 for explanation of this term. fSee. however, J. M. Bell and E. de ,C. Clarke in "The Geology of the Whangaroa Subdivision." N.Z.G.S. Bull. Xo. 8. 1909. p. 30, for a careful discussion of rock-benches on the shore* of the Whangaroa Subdivision. See also a short paper by J. A. Birtrum. which will appear in the 191.6 volume of the Trans. N.Z. Inst. •| Cotton, C. A.: "Fault Coasts in New Zealand," the Gftographioti Btj/iem vo' i, No 1, JYmvy, 19:6, pp. 20-47.