THE FRESH- WATER LOCHS OF SCOTLAND. 211 



The geology of this district is described by Drs. Peach and Home, 

 their important contribution being illustrated by a special geological 

 map. 



Loch Maree (see Plates XLVI. and XLVII.). The loch derives its 

 name from Saint Maelrubha, who in 671 A.D. left Bangor, and after 

 founding one church at Applecross, founded another on Isle Maree. 

 It is the largest sheet of fresh water in Scotland north of Loch Ness, 

 and trends in a north-west and south-east direction. 



On the north-east side of the loch, and parallel to it, runs a grand 

 series of mountains Beinn Airidh Charr, Meall Mheannidh, Beinn 

 Lair, Slioch, Sgurr an Tuill Bhain, and Beinn a Mhuinidh ; the slope 

 for the first 1000 feet all along this north-eastern shore is very steep, in 

 many places exceeding 45. To the south-west rise Beinn Eighe, Beinn 

 a Chearcaill, and Beinn an Eoin ; the sharp ridge of the former, com- 

 posed of white quartzite, forms an especially fine object from the loch to 

 the north of the Gruididh. But the two most striking features of Loch 

 Maree are Slioch and Isle Maree; the huge sugar-loaf form of Slioch 

 is conspicuous from almost every part of the loch, and, though one of 

 the smaller islands, Isle Maree, owing to the large number of trees 

 growing upon it, stands out against the dark background of the heather- 

 covered islands and the cliffs of the north-eastern shore. 



The great feature 'of Loch Maree is the large number and great 

 area of its islands. Prof. Penck, in his work on the Lake of Constance, 

 lays great stress on the ' ' insulosity, " i.e., "the proportion of the area 

 of the islands to that of the water surface ; " this in Loch Maree is 0'09, 

 or three times as great as that of the Lake of Cheim (0'03), and nine 

 times as great as that of the Lake of Constance (0-01). Its insulosity is 

 also greater than that of any other large lake in Great Britain, that of 

 Loch Lomond being 0'08, though it is surpassed in this respect by one 

 of the small lochs in the Assynt district (Loch Crocach, whose insulosity 

 is 0-091). 



Many of the islands were joined together when the Lake Survey 

 visited the loch, owing to the low level of the water. A few small 

 rocks and reefs occur out in the channel to the north of the main 

 group of islands and removed some considerable distance from the rest. 

 Large numbers of the Lesser Black-Backed Gull (Larus fuscus) breed 

 on the larger islands, and two pairs and young of the Greater Black- 

 Backed Gull (Larus marinus) were observed on two of the smaller islets. 

 Isle Maree, Eilean Ghruididh, Eilean Subhainn, and Eilean Ruairid 

 Bheag have been used at one time as fortresses or habitations. 



The level of Loch Maree was found by the Ordnance Surveyors to 

 be 32-1 feet above sea-level on September 15, 1870; on July 16, 1902, 

 the surface of the water was 29-5 feet above sea-level. The loch was 

 surveyed on July 16 to 24, 1902, and the water remained at very nearly 



