much of his published post-war work was on the geomorphology of scotland, including a series of papers on river capture. he identified the importance of glacial breaching of main watersheds (divides), and recognised that this process had been more intense in the west, with glacial dissection of the mountains declining eastwards (although his synthesis of this was published posthumously by keith clayton, see publications). concerned with denudation chronology (the reconstruction of long-term landform history), he became involved with study of the origin of tors in scotland, on dartmoor, the pennines and south africa. his view was that the british tors were a product of deep chemical weathering under a tropical climate in the tertiary, exposed by erosion in the pleistocene. this contrasted sharply with the views of others that tors are essentially arctic features produced by periglacial processes. this was part of his wider view of the importance of pre-glacial events and forms. however his attribution of the prevailing eastward flow of the major rivers of scotland to emergence and tilted uplift of a fresh chalk seabed in the early tertiary was dismissed in the phd studies of french geomorphologist alain godard (later professor at paris).