Between West Gormack and the Muir of Drumlochy the Cateran trail crosses a series of ridges and shallow valleys running south-eastwards from Middleton Muir, an area known as Garry Drums. While you might expect to find a series of streams in the valleys, some of them are dry. These particular dry valleys are understood by geologists to be glacial meltwater channels, formed at a time towards the end of the last Ice Age when water running off the hills to the north was forced to run as streams along the edge of a large mass of stagnant ice which filled Strathmore at the time, only to run dry as the ice disappeared.