THE FRESH- WATER LOCHS OF SCOTLAND. 343 



intervals of 50 feet, and the percentages to the total area of the loch, 

 and indicates the flat-bottomed character of the basin, the comparatively 

 large area of the lake-floor covered by more than 150 feet of water 

 being noteworthy : 



to 50 feet 298 acres 39 per cent. 



50,, 100 228 30 



100,, 150 ,, 121 16 



Over 150 , 109 . 15 



756 100 



Temperature Observations. The following series of temperatures, 

 taken at 4.30 p.m. on the date of the survey in the western basin, 

 shows that the water was nearly uniform in temperature, the extreme 

 range from surface to bottom being only 1 Fahr., the readings down 

 to a depth of 50 feet being identical: 



Surface 50 '0 Fahr. 



lOfeet 50-0 ,, 



25 50-0 



50 50'0 



100 49-5 



150 : 49-0 



Loch Sealbhag (see Plate LXXX.). Loch Sealbhag lies to the east 

 of, and is, as already stated, practically a continuation of Loch Mullar- 

 doch. It trends in a north-east and south-westerly direction, and is 

 two-thirds of a mile in length, with a maximum breadth towards the 

 west end of nearly a quarter of a mile, whence it narrows gradually 

 towards the north-east. Its waters cover an area of about 68 acres, and 

 it drains directly an area of 3J square miles, but since it receives the 

 outflow from Lochs Lungard and Mullardoch, its total drainage area 

 is nearly 54 square miles an area nearly 500 times greater than that 

 of the loch. The maximum depth of 56 feet was observed in the 

 widest part of the loch towards the western end, and comparatively 

 near the southern shore. The volume of water is estimated at 61 

 million cubic feet, and the mean depth at over 20| feet. The loch 

 was surveyed on October 5, 1903, but the elevation above the sea could 

 not be determined. 



The wide western portion of Loch Sealbhag includes a deep basin 

 exceeding 30 feet in depth, which approaches comparatively close 

 to the western end, and is over a quarter of a mile in length. To 

 the north-east of this basin the bottom rises, and falls again on 

 approaching the outfall to a depth of 31 feet, the depth on the rise 

 being 16 feet. The area of the lake-floor covered by less than 20 feet 

 of water is about 39 acres, or 57 per cent, of the total area. The 

 temperature of the surface water on the date of the survey was 

 50-5 Fahr. 



