DESCRIPTIVE CHAPTERS. 

 GENERAL WATERSHEDS. 



The great Basin of the river Tay and its tributary streams alone 

 covers a vast area, greater in capacity than that of any other river 

 system in Scotland. It contains no less than some 2600 square 

 miles. The whole of this great basin may be described, along v^ith 

 that of Strathmore and its easterly flowing waters, as being almost 

 completely hemmed in by the continuous chain of the Grampians 

 and their extensions, as already spoken of, separating Tay from 

 Dee, and from the Moray Basin along its northern boundaries ; 

 even the passes through the crests of this huge watershed are of 

 great altitudes, as for instance at the head of Glenshee at or near 

 the Devil's Elbow (2060 feet), and at lesser altitudes; at Glen 

 Tilt (1413 feet), and at Drumouchter (1500 feet), before the 

 descent into the valley of the Spey, vid the course of the river 

 Truim, begins; whilst other much lower passes occur near Tyndrum, 

 and between the head- waters of Fokth and Tay, by the Allan 

 Water. 



Westwards, after the huge mass of Ben Alder is passed, which 

 towers high above the west end of Loch Ericht, the vast Moor of 

 Rannoch stretches for many dreary miles to the bases of the western 

 mountains — the Bhuachaille Etive and the group of mountains 

 which cluster around the head of Glencoe and the Black Mount 

 Deer-forest. These practically form the western boundary between 

 Tay and Argyll. The new West Highland line of railway passes 

 through the fringes of the Moor of Rannoch, entering over the 

 watershed near the county march of Perthshire, and near the heads 

 of the Water of Tulla. But westwards from the line of railway 

 there is a great broken stretch of flow-land intersected by the ramifica- 



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