THE FRESH- WATER LOCHS OF SCOTLAND. 81 



larger and deeper basin occupies the wide southern portion of the loch ; 

 the slope off the eastern shore is in places very steep. The surface 

 temperature was 63^0 Fahr. 



Loch an Losgainn Mbr (see Plate XXXI.) is an irregular loch situated 

 about a mile south-east of Loch a' Phearsain, trending nearly east and 

 west, and exceeding half a mile in length. The loch lies in a rock-basin, 

 and covers an area of about 33 acres, the volume being estimated at 

 27 million cubic feet. It was surveyed on May 29, 1903, when the 

 elevation was 508-4 feet above the sea, which differs little from the eleva- 

 tion determined by the Ordnance Survey on October 4, 1864, viz. 508-6 feet. 

 A prominent peninsula projecting from the southern shore cuts the loch 

 into two unequal basins, the smaller to the east of the peninsula having a 

 maximum depth of 29 feet, the larger occupying the wide portion of the 

 loch to the west of the peninsula, and having a maximum depth of 51 feet. 

 Of the entire lake-floor, about 68 per cent, is covered by less than 25 feet 

 of water. 



Temperature Observations. Serial temperatures taken in the deepest 

 part gave the following results : 



Surface.., 60-4 Fahr. 



10 feet 58-0 



20 54-8 



40 49-5 



These observations show a range of about 11 from surface to bottom, 

 the fall of temperature being tolerably uniform. 



Kilchoan Lochs (see Plate XXX.). Two small lochs trending in a 

 north and south direction, and situated in close jyoximity about half a mile 

 from the northern shore of Loch Melfort, are known as theKilchoan Lochs. 

 Both lie in rocky basins, and are separated by a ridge of rock, the difference 

 in level being about 42 feet. 



Upper Kilchoan Loch is the larger and deeper of the two, and is about 

 one-third of a mile in length, covering an area of about 23 acres. The 

 maximum depth of 70 feet was found rather nearer the northern than the 

 southern end. The volume of water is estimated at 29 million cubic feet, 

 and the mean depth at 29^ feet. The basin is simple, and the contour- 

 lines coincide approximately with the outline of the loch, about half the 

 lake-floor being covered by less than 25 feet of water. The loch was 

 surveyed on June 2, 1903, the elevation being approximately 378 feet 

 above the sea. 



Lower Kilchoan Loch is rather longer than the upper one, while the 

 breadth is nearly uniform throughout, and equal to about one-twelfth of a 

 mile, or 150 yards. It is fairly deep, the maximum depth being 45 feet, 

 and the mean depth 20 feet, the volume of water being estimated at 

 16 million cubic feet. The superficial area is about 18 acres, of which 



