THE FRESH- WATER LOCHS OF SCOTLAND. 311 



rather shallow, since 70 per cent, of the lake-floor is covered by less 

 than 25 feet of water: 



to 25 feet 388 acres 70 per cent. 



25,, 50 149 27 



Over 50 , 18 , 3 



555 100 



The temperature of the surface water at 10 a.m. on the date of the 

 survey was 53 0- Fahr. The deposits brought up were all very dark 

 (black) muds. 



Loch Naver (see Plate LXX1I.). Loch Naver lies about 5 miles to 

 the south-east of Loch na Meide, with Ben Klibreck to the south rising 

 gently up from the shore of the loch. Altnaharra Inn, at the west end 

 of the loch, is a well-known rendezvous for anglers. On the northern 

 shore Reidhachaisteil and Gruamamor,- and on the southern shore 

 Ruighnasealbhaig, are the remains of considerable villages destroyed 

 at the beginning of last century when the crofters were turned out. 

 There are the ruins of Pictish towers near Gruamamor and on the 

 island close to the opposite (southern) shore, and the remains of several 

 artificial crannogs rise towards the surface of the water, in one case 

 reaching above the surface. Loch Naver is broadly sinuous in outline, 

 the general trend being east-north-east and west-south-west, while the 

 upper portion for about a mile runs east and west, and it exceeds 6 

 miles in length. It is a comparatively narrow loch, the maximum 

 width towards the west end not exceeding two-thirds of a mile, whence 

 the width gradually diminishes towards the east end, the mean breadth 

 of the entire loch being about one-third of a mile, or 6 per cent, of the 

 length. Its waters cover an area of about 1446 acres, or 2J- square 

 miles, and it drains directly an area of nearly 81 square miles; but 

 since it receives the outflow from Loch na Meide, its total drainage 

 area is nearly 89 square miles. The maximum depth of 108 feet was 

 observed in the wider part of the loch about a mile from the west end. 

 The volume of water contained in the loch is estimated at 2461 millions 

 of cubic feet, and the mean depth at 39 feet. The loch was surveyed 

 on September 24 and 25, 1902, when the elevation of the lake-surface 

 was determined, by levelling from bench-marks, as being 247 '6 feet 

 above the sea ; when visited by the officers of the Ordnance Survey on 

 June 24, 1870, the elevation was found to be 246'9 feet above sea-level. 

 The highest drift-mark observed was 4J feet above the surface of the 

 water at the time of the survey, and it was said that the water might 

 fall to the extent of 4 feet, giving a range in level of about 8J feet. 



The floor of Loch Naver is rather irregular, as may be seen in the 

 longitudinal section taken along the axis of maximum depth, which 



