THE FRESH-WATER LOCHS OF SCOTLAND. 263 



Loch Crann (see Plate LVIL). Loch Crann is a small shallow loch 

 situated a short distance to the west of Loch a* Chroisg, and lying at a 

 slightly higher level. Its striking characteristic is the large area of 

 hilly country draining into it an area nearly 600 times greater 

 than that of the loch. It is roughly quadrangular in outline, with a 

 maximum diameter of less than a quarter of a mile, and it covers an 

 area of about 13J acres, 80 per cent, of which is under less than 10 feet 

 of water. The deeper soundings were taken in the southern half of the 

 loch, the maximum depth observed being 17 feet. The volume of water 

 is estimated at 4 million cubic feet, and the mean depth at nearly 

 7 feet. Loch Crann was surveyed on August 19, 1902, when the level 

 was determined as being 513'7 feet above the sea. The temperature of 

 the surface water at 5 p.m. on that date was 59*6 Fahr., and at a 

 depth of 14 feet 56-2. 



Loch a' Chroisg (see Plate LVIL). Loch a' Chroisg (or Loch 

 Rosque) is^ne of the larger and more important lochs within the basin, 

 lying amid beautiful scenery, the hills on both sides rising to heights 

 exceeding 1500 feet, and culminating in Meall a' Chaoruinn (2313 feet) 

 on the northern shore (see Fig. 45). It is a good trout loch, and char 

 also occur, but the fishing is strictly preserved. The loch trends almost 

 due east and west, though very slightly sinuous in outline ; the shore-line 

 is on the whole very regular, except that two conspicuous alluvial cones 

 have been laid down on the northern shore at the mouths of the Allt 

 Duchairidh and neighbouring stream. The loch is 3J miles in length, 

 with a maximum breadth of nearly half a mile, the mean breadth being 

 over a quarter of a mile. Its waters cover an area of about 640 acres 

 (1 square mile), and it drains directly an area of over 1\ square miles, 

 but, as it receives the outflow from Loch Crann, its total drainage area 

 is over 19 square miles. The maximum depth of 168 feet was observed 

 approximately near the centre of the loch, opposite the mouth of the 

 Allt Duchairidh entering the loch on its northern shore, and about 2 

 miles from the east end. The volume of water contained in the loch is 

 estimated at 2057 million cubic feet, and the mean depth at nearly 74 



average ; for August, 1901, the mean was 58-7, or 2 above the average, while for August, 

 1902, the mean was 54-2, or 2 below the average. Sunshine records are available for 

 Strathpeffer within the Conon basin during 1 these seasons, and they bear the same relations: 

 thus during July, 1901, 162-1 hours of sunshine were recorded at Strathpeffer (or 34-5 above 

 the normal for that month, and 30 per cent, of the possible amount), while during July, 

 1902, the duration of sunshine was 95-6 hours (or 32-0 below the normal, and 18 per cent, of 

 the possible amount) ; during August the difference was not so marked in the two years, 

 the duration in August, 1901, being 140-0 hours (or 18-5 above the normal, and 30 per cent, 

 of the possible amount), while in August, 1902, the duration was 131-8 hours (or 10-3 above 

 the normal, and 28 per cent, of the possible amount). The sunshine records for Inver- 

 ness agree closely with those given above for Strathpeffer for the two seasons under 

 consideration. 



