THE FRESH- WATER LOCHS OF SCOTLAND. 167 



loch, especially in the one to the south of Creag a' Choire Mhoir, the 

 current was so strong that the greatest difficulty was experienced in 

 rowing the boat against it, though assisted by a strong north-west wind. 

 The loch is nearly 2J miles in length, with a maximum breadth of oyer 

 one-third of a mile (or about 600 yards), the mean breadth being about 

 one-seventh of a mile (or about 250 yards). Its waters cover an area 

 of about 209 acres (or nearly one-third of a square mile), and it drains 

 directly an area of about 6J square miles, but since it receives the 

 outflow from Loch Veyatie and the other lochs in the basin, its total 

 drainage area is nearly 53 square miles an area 160 times greater 

 than that of the loch. Over 100 soundings were taken, the maximum 

 depth observed being 90 feet. The volume of water is estimated at 

 185,510,000 cubic feet, and the mean depth at 20J feet. Fionn Loch 

 is very irregular in outline, broads and narrows alternating with each 

 other, and the contours of the bottom are correspondingly diversified. 

 There is a long narrow tortuous area exceeding 25 feet in depth, 

 extending from near the north-west end of the loch to north of the 

 reedy bay where the stream from Na Tri Lochan enters, and about 

 H miles in length; a short distance to the south-east is a second small 

 25-feet area, with a maximum depth of 37 feet. The deepest water 

 occurs in the wide part of the loch about half a mile to the south-east 

 of the exit of the Kirkaig river, where there is a small area exceeding 

 75 feet in depth, the maximum depth of 90 feet having been observed 

 about 120 yards from the south-western shore. The areas between 

 the consecutive contour-lines, and the percentages to the total area of 

 the loch, are as follows : 



to 25 feet 153 acres 73 '0 per cent. 



25 50 49 23-5 

 50,, 75 2 ,, 1-0 



Over 75 . 5 . 2*5 



209 ., 100-0 



This table shows how circumscribed the deep-water area is, 97 per cent, 

 of the lake-floor being covered by less than 50 feet of water. The Fionii 

 Loch was surveyed on September 16, 1902. The elevation of the lake- 

 surface was determined, by levelling from bench-mark, as being 356-9 

 feet above the sea ; when levelled by the officers of the Ordnance Survey 

 on October 21, 1870, the elevation was found to be 357*1 feet above 

 sea-level. The temperature of the surface water on September 16, 1902, 

 was 53-0. 



