Acknowledgements
The authors thank Scottish Natural Heritage for commissioning interpretative work on the Cairngorms. A. M. Hall wishes also to acknowledge the support of The Carnegie Trust of the Universities of Scotland for fieldwork in the Cairngorms. M. R. Gillespie and C. W. Thomas publish with permission of the Executive Director, British Geological Survey, NERC. The paper benefitted from the careful reviews of John Gordon and Brice Rea.