154 BATHYMETRICAL SURVEY OF 



preserved ; they contain trout, with pike in Lochs Alvie and Caol na l)oire, 

 salmon in Loch an t-Seilich, and char in Loch Builg. 



Loch Crunachan (see Plate LVI.) lies about 7 miles to the north-west 

 of Dalwhinnie on the Highland railway, and 11 miles to the south-west 

 of Newtonmore, Loch Laggan hotel, at the head of Loch Laggan, being 

 less than 2 miles to the south, The loch trends in a north-east and south- 

 west direction, and is two-thirds of a mile in length, with a maximum 

 breadth of a quarter of a mile, covering an area of about 68 acres, and 

 draining an area of nearly 4 square miles. The maximum depth of 25 feet 

 was observed towards the south-west end of the loch. The volume of 

 water is estimated at 23 million cubic feet, and the mean depth at nearly 

 8 feet. The loch was surveyed on June 5, 1902, but the elevation could 

 not be determined; on December 18, 1872, the officers of the Ordnance 

 Survey found it to.be 878'9 feet above the sea. The loch forms a simple 

 shallow basin, a considerable area at the northern end being under a foot 

 in depth, and about 78 per cent, of the lake-floor is covered by less than 

 10 feet of water. Weeds are abundant, especially at the north-eastern 

 angle, where the burn flows out. 



Temperature Observations. Temperatures taken in the deepest part of 

 the loch gave the following results : 



Surface 56-0 Fahr. 



5 feet 54-0 



10 48-2 



20 ,, 47'5 



These observations show a range of 8-5 from surface to bottom, the 

 greatest fall being one of 5-8 between 5 and 10 feet a fall exceeding 

 1 per foot of depth. 



Loch Caol na Doire (see Plate LVI.). Loch Caol na Doire (or Coul- 

 tree) lies about 3 miles from Dalwhinnie, and about 5 miles to the east 

 of the head of Loch Laggan. In outline it is pear-shaped, trending nearly 

 east and west, and nearly three-quarters of a mile in length, with a 

 maximum breadth across the wide western portion of nearly one-third of 

 a mile. The superficial area is about 77 acres, and the drainage area 

 nearly lj square miles. The maximum depth of 55 feet was observed 

 approximately in the centre of the wide western portion of the loch. 

 The volume of water is estimated at 77 million cubic feet, and the mean 

 depth at 23 feet. The loch was surveyed on May 14, 1904, but the 

 elevation could not be determined ; on December 2, 1872, the Ordnance 

 Survey officers found it to be 1140'7 feet above the sea. The loch is 

 simple in conformation, and relatively deep, one-half of the lake-floor 

 being covered by more than 20 feet of water. The surface temperature 

 was 45-0 Fahr. 



