(chiefly C. incana), tends to encroach slowly on to unstable shingle. A number of smaller plants, most of which are also of a sprawling habit, take advantage of the shelter provided. One true scree species, Parahebe spathulata with its remarkably extensive root system, is unique in its ability to establish itself on unstable ground, and has even been observed growing among frost stripes. Another scree species, Epilobium pychnostachon has only recently been observed, and appears to be a rapid colonizer of suitable habitats. Below 5,000ft the prostrate snow totara, Podocarpus nivalis, plays a considerable part in holding unstable slopes, forming mats up to 30ft across, in which wind-drifted soil accumulates—a seed bed for a considerable variety of other plants. Dick's spur.. The eastern scarp of the range drops 2,500–3,500ft in steep spurs to the main Kaweka fault along its foot. It certainly carried more vegetation, including forest, in pre-European times, but how continuous this was is problematical. Dick's Spur was the main mustering route down this face until about 1905, and though it now displays barren rock, occasional logs of Podocarpus hallii occur on it up to 4,500ft. In the eastern-facing basins on either side, however, there are at this altitude considerable areas of mountain beech regeneration unusual in that they are uniformly 40–45 years old. It would appear that burning or heavy browsing prevented regeneration until after the date of mustering off, when for a short period, before the arrival of deer and the build-up of stragglers into wild merino flocks, regeneration of beech was possible. These basins are noteworthy also in that some hundreds of acres of steep and partly eroded slopes are now dominated by sprawling colonies of Celmisia incana which appear to have replaced Danthonia flavescens tussock and probably to some extent beech forest. Cook's Horn Basin. The processes of erosion and regeneration have been investigated most closely in a tributary basin near the head of the Tutaekuri River, which possesses most of the characteristics of Area 3; vestiges of original forest, forest regeneration following fire, some of the original tussock cover, induced manuka scrub, wind-blown pumice scars, screes, and rock falls. The Cook's Horn Basin is roughly circular, measures about a mile across, and ranges from 4,600 to 2,000ft in altitude. In 1937 the vegetation was surveyed and a quadrat was pegged out in regenerating pole beech. At that date the main features were the absence of regeneration under the forest canopy, the evidence of heavy pig and deer populations, and the unexpected discovery that none of the three main scree systems was delivering spoil to the waterways, but that they were separated from them by belts of stabilized rock fragments already in process of being recolonized by vegetation. Since that date the recolonization of screes has proceeded at a slow rate from the bottom, and a fourth scree appears to be reaching stability; the animal population has decreased sharply following the erection of a tramping hut in 1936; the spread of beech into manuka scrub has become conspicuous and regeneration within the forest has become dense. The latter has been closely associated with the opening of the canopy, and particularly with the destructive effect of snowfall and icing on pole timber. This destruction was first observed in the winter of 1936 in a narrow belt of pole timber, snapped or bent, and beech regeneration was first noticed along this belt. A similar narrow belt was formed about 1943, since when no certain evidence of snow break has been recorded here, though an even more spectacular snow break occurred in the neighbouring Kiwi Saddle area in the winter of 1956. Generally the picture is one of a rapid recolonization by beech and at higher altitudes a slower recolonization of bare slopes and screes by scrub and other alpine plants, but three or four active gutters in the pumice slopes suggest early stages in the development of fresh scree systems. One extensive face of shattered rock from the highest part of the circumference is still much affected by frost action and contributes large quantities of spoil to the main watercourse.