IN TOUCH WITH NATURE

Hokitika Guardian, 19 November 1924, Page 4

IN TOUCH WITH NATURE

RKM ARK. Mil. E ANCIENT TERRACES^ By J. Drummond, E.L.S., F.Z.S., in " l.yltellou Times”l. Remarkable terraces, legular and persistent, w hich nestle near mountain slopes in the West pint district, have attracted the attention of geologists. They are one of the most noticeable leatures in the neighbourhood of Westport, ami have been mentioned by several eoriespomleiits who are not geologists, and who have visited that part ol the West Coast. 'The terraces, which are about 100 feet above sea-level, seem to he known as the “o()0-fool, terraces.” Mr J. A. Ilart i'll ill, a member of the New Zealand Geological Survey, who has contributed the latest account of them, states that they are absolutely uniform ill their sill lace, and in the regularity of their margin. They consist of a substratum ol blue sandstone, known as “ hluehottoin ” on the West Coast, capped by deposits of gravel. Mr IhiiTruni,expresses an opinion that north of the Little Tolara River, wave-action sculp-* Hired the surface of the blue-hot tom on which the gravels of the terraces rest. South of that river, the advance of the sea was resisted by limestone. (’lose to Die Charleston Rond, about a mile and a half north-east of the Tolara River Bridge, there is a remnant of the former extension of the terraces towards the coast. This escaped (omplcte destruction hv the ad-

valuing sea. The erraoes lose llieir distinctive liaracter south of l.itlle To tarn Hivet After some hummocky country, there begins a great belt of level terraces, consisting of Idin; bottom capped with gravel, reaching a height of (10(1 feet, and occupying a depression between (he mountains and a coastward limestone ridge. Amongst the mountains, the blue-bottom beds roach a height of more than 1000 feet. Kvon tit that height, there are traces of terraces, made by streams that now flow in deeply cut gorges, 100 (>•• .100 feet below. The surface of all the terraces seem to have been shaped mainly by the sea, hut the Buller and other streams have taken a hand in the work, and stream gravels are scattered here and there. Bold is present in the gravels, in small quantities. The Xgakawati, in that district, has cut a hill in two. making a deep gorge in gneissie rocks, and the Makihinui Gorge rivals the Buller in grandeur. The latest geographical events in that district are the formation of a delta at the month of the Buller Biver, and a process by which the shore-line advances towards the sea on account of waves throwing up sand or gravel as they break. This is the opposite process to the cutting hack of a-coast by the waves by erosin. The shore-line is advancing in the same way along the Ninety-mile Beach. Can- ( terhnry. the waves there using coarse gravel transported by rivers that flow across the Canterburv Plains.