54 BATHYMETRICAL SURVEY OF 



The river-systems, which arise in the most mountainous and 

 magnificent regions of Scotland, may be divided into four principal 

 branches, viz., the Garry branch (the most northerly), the Tummel 

 branch, the Tay branch, and the Earn branch (the most southerly). . 



(1) The Garry branch rises on the flanks of Beinn Mholach, Beinn 

 Bhoidheach, and Carn Beag an Laoigh, flowing by various streams 

 into Loch Garry, thence by the river Garry into the river Tummel at 

 Faskally, to the north-west of Pitlochry, receiving the waters of the 

 Erochy at Struaii, and those of the Tilt at Blair Atholl. 



(2) The Tummel branch rises in the Black Mount, the westernmost 

 of the sources of the Tay river-systems, flowing by the river Ba into 

 Loch Buidhe, Lochan na Stainge, and Loch Ba, which receives the out- 

 flow from Lochan na h-Achlaise, thence flowing into Loch Laidon, 

 thence into Loch Eigheach an expansion of the river Gaur receiving 

 the waters from Lochan Sron Smeur, and then flowing into Loch 

 Rannoch, which receives the outflow from Loch Ericht, flowing finally 

 into Loch Tummel, thence by the river Tummel into the river Tay at 

 Logierait. 



(3) The Tay branch rises on the flanks of Ben Lui (Beinn Laoigh), 

 and flows by the river Fillan into Loch Dochart and Loch lubhair, 

 thence by the river Dochart into Loch Tay, being joined by the river 

 Lochay at Killin just before entering Loch Tay ; the outflow from Loch 

 Tay is carried into the estuary of the Tay by the river Tay, which is 

 joined shortly after leaving Loch Tay by the river Lyoii, bearing the 

 outflow from Loch Lyon, and further on (at Logierait) the river 

 Tummel, bearing the outflow from the Garry and Tummel branches, 

 still further on (at Dunkeld) by the river Bran, bearing the outflow 

 from Loch Freuchie, still further on (at Cargill) by the river Isla, and 

 still further on, shortly before reaching Perth, by the river Almond. 



(4) The Earn branch takes its rise at the heads of Glen Ogle and 

 Gleann Ceann Droma, the two streams flowing into the west end of 

 Loch Earn, which receives also the waters of the Ample burn, Beich 

 burn, the Vorlich, the Tarkeii, and other smaller streams; the outflow 

 from Loch Earn passes at St. Fillans into the river Earn, which receives 

 the waters of the Ruchill and Lednock near Comrie, those of the Turret 

 bearing the outflow from Loch Turret, near Crieff, and other smaller 

 streams as it flows eastward to join the Tay at the head of the estuary. 



Loch Ericht (see Plates XII. and XIII.). Loch Ericht is a large 

 Highland loch situated partly in Perthshire and partly in Inverness- 

 shire, at a high elevation among the Grampians. It is one of the wildest 

 and most magnificent lochs of Scotland, presenting all along its shores 

 scenes of lonely grandeur and sublimity, the mountains rising from the 

 water's edge to great altitudes, their sides scarred by mountain torrents. 

 The surface, when measured by the Ordnance Survey officers in 1872, 



