『Abstract
　The mountains in the eastern region of southern Africa are of significant regional importance, providing for a diverse range of land use including conservation, tourism and subsistence agriculture. The higher regions are comprised of flood basalts and are immediately underlain by predominantly aeolian-origin sandstones. Our understanding of the weathering of these basalts and sandstones is reviewed here, with particular focus on the insights gained from the Lesotho Highlands Water Project and on going study into the deterioration of rock art. While the chemical weathering attributes of the basalts have been substantially investigated, it is evident that the environmental surface conditions of rock moisture and temperature, as affecting weathering processes, remain largely unknown. Within the sandstones, studies pertaining to rock art deterioration present insights into the potential surface weathering processes and highlight the need for detailed field monitoring. Outside of these site-specific studies, however, little is understood of how weathering impacts on landscape development; notably absent, are detail on weathering rates, and potential effects of biological weathering. Some palaeoenvironmental inferences have also been made from weathering products, both within the basalts and the sandstones, but aspects of these remain controversial and further detailed research can still be undertaken.

Keywords: Weathering; Lesotho; Drakensberg; Rock art; Lesotho Highlands Water Projects』

1. Introduction
2. Weathering of the basalts
　2.1. Composition and alteration of the basalts
　2.2. Case study: the Lesotho Highlands Water Project (LHWP)
3. Weathering of the sandstones
　3.1. Chemistry, weathering and durability of the sandstones
　3.2. Case study: sandstone weathering and rock art deterioration
4. Weathering and palaeoenvironmental inferences
5. Conclusions
Acknowledgements
References