THE FRESH- WATER LOCHS OF SCOTLAND. 43 



Corr-scriach, and is nearly 2 miles in length j the maximum depth in this 

 basin, 97 feet, was observed near the southern end of the basin off Eilean 

 nan Corr-scriach. A third small 50-feet basin occupies the extreme north- 

 western end of the loch, and has a maximum depth of 78 feet observed 

 near the north-eastern shore. Within the main 50-feet basin the bottom 

 sinks in three places below the 100-feet line : (1) a subcircular basin, 

 two-thirds of a mile in length, situated in the wide portion of the loch at 

 the south-east end, the 100-feet contour-line approaching to within 300 

 yards of the shore; (2) an isolated sounding of 101 feet about three- 

 quarters of a mile farther down the loch ; and (3) about half a mile still 

 farther down an irregular basin a mile and a half in length. As already 

 indicated, the maximum depth of the loch (144 feet) was observed in both 

 of the 100-feet basins numbered 1 and 3, in the former about 530 yards 

 from the south-east end of the loch, and in the latter about 220 yards from 

 the western shore of the loch at Eudha Dubh. An inspection of the map 

 will show how irregular the lake-floor is in the shallower parts of the 

 loch, and even in the deeper water several conspicuous undulations of the 

 bottom may be observed. The areas between the consecutive contour-lines 

 drawn in at equal intervals, aid the percentages to the total area of the 

 loch, are as follows : 



Feet. Acres. Per cent. 



Oto 25 482 ... 21-4 



25 50 581 ... 25-8 



50 75 463 ... 20-5 



75 100 440 ... 19-6 



Over 100 285 ... 12-7 



2251 100-0 



It will be noticed that the area between 25 and 50 feet is larger than 

 that between the shore and the 25-feet contour, indicating an average slope 

 steeper near shore than in depths beyond 25 feet. 



The surface temperatures taken on August 4 and 5, 1902, showed a 

 range from 54-2 Fahr. to 55"'l. In winter the loch is covered all over 

 with thick ice. 



Dubh Loch (see Plate XVII.). The Dubh Loch is situated in a corrie 

 forming the natural head of the Fionn Loch, surrounded by high and 

 steep hills. There is a bend in the outline of the loch, following the 

 shape of the corrie, the narrower upper portion trending north-west and 

 south-east, while the wider lower portion trends almost east and west. 

 The loch is about l miles in length, with a maximum breadth of two-fifths 

 of a mile, the mean breadth being a quarter of a mile. Its waters cover 

 an area of over 200 acres, or nearly one- third of a square mile, and the 

 area draining into it is about 6 square miles. The maximum depth of 88 

 feet was observed near the centre of the loch, where the outline commences 

 to widen out towards the west. The volume of water contained in the loch 



