Geology

Geology and Geomorphology The River Tay occupies an ancient pre-glacial valley which is deeply incised into the Dalradian Quartz-mica schists which underlie this part of the Grampian Highlands. Quartz-mica schist is a metamorphic rock derived from earlier marine sediments - sandstones and mudstones - the varied character of which is reflected in the outcrops to be seen in stream-beds and on surrounding hill-sides, as well as in the natural stone used to construct many of the village buildings and walls.

The recent glacial epoch resulted in a significant over-deepening of the Tay Valley by ice. The end of this period saw the upper part of the valley occupied by a large valley glacier which later disappeared, leaving behind the water-filled basin of Loch Tay. The present level of the loch is determined by unconsolidated deposits of unknown depth which block the valley downstream of Kenmore. These take the form of a broad alluvial plain, concealing morainic mounds and fluvio-glacial deposits which break through the surface of the plain in places to form hummocks and other features on the valley floor.

The river has cut through these deposits, creating a number of steep-edged alluvial terraces along its course. To the north of Taymouth Castle, across the River Tay, the ground rises steeply to the rocky ridge of Drummond Hill, to the south rather more gently onto the Braes of Taymouth. All around are ice-scoured hills with a patchy cover of late-glacial or post-glacial deposits. There is reference by Pennant (1769) to the clearance of boulders - presumably glacial 'erratics' - from the valley floor in the 18th century. The natural terraces and mounds, together with the higher ground on either side of the valley, has provided opportunities for the development of a complex network of intersecting views within the designed landscape, both along and across the axis of the valley. The terrain has allowed long views to be developed towards the east and west along the valley - particularly towards the prominent peaks of Ben Lawers and Ben More in the south-west.