IV. Dry Channels in Glen Lednock

Abstract

Introduction. The valleys of the Scottish Highlands are usually divided into two groups (Geikie, 1901, p. 186, Mackinder, pp. 127-8); ( a ) The transverse consequent valleys which trend north-west and south-east and which represent the drainage lines of the old Highland tableland; ( b ) The longitudinal valleys which trend north-east and south-west and which follow more or less the strike of the underlying rocks. In the Southern Highlands, the chief representatives of the former are Glen Garry, with Strath Tay from Ballinluig to Dunkeld, Strathfillan, Glen Ogle and the tributaries of the Earn, Glen Turret and Glen Lednock; of the latter Glen Dochart with Loch Tay, Glen Lyon and Strath Bran. Several of these transverse valleys show considerable evidence of being anterior to the longitudinal depressions, for they cut through watersheds, and are often very large in proportion to the streams which occupy them at present. While Glen Ogle is one of the best known of these through valleys, Glen Lednock, together with Finglen which enters the Tay Valley at Ardeonaig, is probably also along the line of a former transverse valley, since, not only is the watershed between the two glens lower than the mean level of the watershed between the Tay and the Earn, but, as will be shown in the sequel, this watershed cannot have been lowered by the present streams. The valleys must have been initiated by a consequent stream which arose to the north-west of Loch Tay, and which has been partly obliterated by the longitudinal valley This 250-word extract was created in the absence of an abstract