ABSTRACT Rapid changes in the lower Salt River, a tributary to the Knysna estuary, southern Cape, is documented through the use of an air photo time series. The evidence plotted for the flood plain and estuary, over the period 1936–1998, demonstrates rapid changes in the channel course, the loss of an extensive Phragmites australis bed and siltation of the estuary. Land use changes in two western catchments particularly impacted on the hydrology. The validity of local oral evidence is confirmed. The floods in 1996 exacerbated siltation by impacting on a development in the upper Simola catchment. Sedimentation in the estuary was greater than previously recorded. The presence of coversand on interfluves and valley heads renders the entire catchment, an area of landscape sensitivity, susceptible to rapid change.

ABSTRACT The contribution of geomorphic evidence to the reconstruction of the Cenozoic chronology of southern Africa is traced for the period 1967–1996. Selected examples are provided based almost entirely on the author's own contribution. The significance of karst evidence is stressed. Further evidence should be sought in ecotone sites which respond sensitively to climatic changes, however the preservation of evidence is often fortuitous so correlation from one region to another is difficult.

Sequences of sediments exposed by gullies incising into deposits held within cirques in the highlands of Lesotho have already enabled a Quaternary chronology to be established for high altitudes in eastern southern Africa.(1-3) The chronology was Fred with twelve radiocarbon dates from Lesotho: eight from Sani Top and four from Tlaeeng. Two additional dates are now available from Tlaeeng Section B2, thus permitting further refinement of the Holocene record. This paper reports the two new dates and discusses their significance with respect to the later Holocene chronology.

ABSTRACT Although various marine still-stands have been identified around the Knysna Lagoon, still-stands below present mean tide level have not previously been recognised. Winter storms exposed a palaeosol with preserved in situ tree stumps on the western shore of the Lagoon. A date indicating formation during the Little Ice Age was obtained.

In southern Africa, stratified, closed canopy forests are regarded as relict from former wetter phases. In the eastern Cape such forests are found on the slopes of the Great Escarpment and at one coastal site south of the town of Alexandria. This Alexandria forest is anomalous with regard to its coastal situation, substrate, climatic environment and geographical location. In an attempt to identify the environmental factors controlling forest survival, an interdisciplinary study was undertaken employing biogeographical techniques and computer factor analysis. The results point to water availability as the principle control of forest distribution in the Alexandria area.

A variety of fluvial deposits of various ages occur in the middle Kuiseb valley in the arid Namib. The characteristics, lithology, spatial and altitudinal relationships and possible chronology of these fluvial deposits are considered. A framework of events is suggested and these events are shown to have wider than local significance. It is postulated that only one major and general arid phase has occurred attendant on the establishment of the Benguela Current in the late Tertiary period. Present conditions are less arid. This conclusion is at variance with earlier chronologies: it postulates that major fluvial activity is probably mid Tertiary period at latest.

The temporal variations in rainfall at seventeen sites in South West Africa are investigated using the maximum entropy spectral technique. Oscillations with wavelengths in agreement with previous work conducted for South Africa emerge from the analysis. It is shown that the longer wavelengthed oscillations are spatially dependent being nine to fourteen years near the coast, increasing to seventeen years on the escarpment, and longer still in the hinterland. Those at the shorter end of the spectrum are ubiquitous, since they are in evidence at all the sights considered. This also follows the pattern obtained from investigations of South Africa’s rainfall and each analysis assists in substantiating that of the other.

Deposits located in hollows, reminiscent of nivation cirques and restricted to altitudes over 2 900 m, are described form an area south of Sani Pass. The deposits consist of layers of gravel with and without boulders, alternating with organic clays. It is postulated that these deposits provide evidence of former climatic fluctuations.

Work in Europe has shown that the horizontal development of caves at different depths may be associated with erosion surfaces. Since the South African landscape is composed of erosion surface remnants dating back to, the Jurassic period, it was felt that the hypothesis, that cave levels are associated with specific erosion .surfaces could usefully be tested in the Transvaal. aves from two areas of the Transvaal dolomites were analysed and found to fall into three groups. The validity of these groupings was statistically tested and it was shown that the groups were highly significant at the 99% level and that the cave levels were most unlikely 10 have occurred by chance. Correlation of these groups of caves with the African, Post African I and a 3650 foot surface, which tentatively has been designated Proto-Quaternary, has been made. It appears that cave system.s in the Transvaal are related to erosion surfaces and ;that therefore the hypothesis can be accepted.