46 BATHYMETRICAL SURVEY OF 



depth. The volume of water is estimated at 19 million cubic feet, and the 

 mean depth at over 14 feet. The area covered by less than 25 feet of 

 water is about 27 acres, or 90 per cent, of the total area. The loch is not 

 liable to any great change in level. 



Loch Fada (see Plate XVII.). Loch Fada lies about 2 miles to the 

 north-north-west of the Fionn Loch, and a similar distance to the south- 

 west of the head of Gruinard bay. It must not be confounded with 

 Lochan Fada, situated to the south-east of the Fionn Loch and draining into 

 the head of Loch Maree, which, though designated by the diminutive term 

 " lochan," is a much larger sheet of water. This Lochan Fada has already 

 been described when dealing with the lochs of the Ewe basin.* 



Loch Fada trends in a north-east and south-west direction, and is 

 irregular in outline, with a length of lj miles, and a maximum breadth in 

 the central portion of the loch of half a mile. Its waters cover an area 

 of about 145 acres, or nearly one-quarter of a square mile, and it drains an 

 area ten times grearter, or over 2J square miles. The maximum depth of 

 56 feet was observed near the centre of the wide central portion of the 

 loch. The volume of water is estimated at 109 million cubic feet, and the 

 mean depth at over 17 feet. Loch Fada was surveyed on July 31, 1902, 

 but the elevation of the lake-surface could not be determined by levelling ; 

 when visited by the Ordnance Survey officers on August 10, 1870, the 

 elevation was found to be 498'1 feet above the sea. Loch Fada is most 

 irregular in conformation, with a few large islands, and with stones and 

 boulders rising to the surface in many parts. The deepest water is found 

 in the wide central portion, where there is a small 50-feet basin, based 

 upon soundings of 51 and 56 feet, enclosed within an irregular 25-feet 

 basin nearly half a mile in length by over a quarter of a mile in width. 

 The main 10-feet basin is nearly a mile in length, approaching to within 

 250 yards from the north-east end. Outside the main 10-feet basin 

 the bottom sinks in three places below that depth : (1) an isolated sound- 

 ing of 13 feet in a large bay on the south-eastern shore towards the north- 

 east end; (2) a sounding of 26 feet recorded about a quarter of a mile 

 from the south-west end ; and (3) an isolated sounding of 20 feet about 

 200 yards from the south-west end. Of the entire lake-floor about 45 per 

 cent, is covered by less than 10 feet of water, and 25 per cent, by more 

 than 25 feet of water. A series of temperatures taken at 5.30 p.m. on the 

 date of the survey, in the deepest part of the loch, gave 56*5 Fahr. at the 

 surface, 55'5 at 25 feet, and 55'3 at 50 feet. 



Loch na Beiste (see Plate XVII.). Loch na Beiste is a small sheet 

 of water situated on the peninsula of Rudha Mor, Uttle more than half a 

 mile from the western shore of Gruinard bay. The loch is reputed to be 

 the abode of a great beast, and Mr. Banks, a former owner, attempted 



* See Geographical Journal, vol. 24, pp. 554-557, November, 1904. 



