156 BATHYMETRICAL SURVEY OF 



LOCHS OF THE ROE BASIN. 



THE two principal lochs only in this basin, Lochs Crocach and an Tuirc, 

 were surveyed; the smaller ones could not be sounded from lack of 

 boats. 



Loch Orocach (see Plate XXXVII.). Loch Crocach lies about three 

 miles to the north of Loch Inver, and about a mile to the north-west of 

 Loch an Tuirc, into which its waters are discharged. It is most 

 irregular in outline and in conformation, and is studded with islands 

 large and small; indeed the insulosity (i.e., the ratio between the area 

 of the islands and the total area of the loch) is one of its distinguishing 

 characteristics, being probably higher than in any other loch visited by 

 the Lake Survey, the lochs most nearly approaching it in this respect 

 being Lochs Maree and Lomond. The islands are mostly congregated 

 in the large western bay; they are low, heather-covered, and not 

 wooded as in the majority of the lochs in the district. The ground 

 around the loch is low; from 350 to 700 feet above the sea. Loch 

 Crocach trends north-east and south-west, and is nearly 1| miles in 

 length and over one-third of a mile (or about 700 yards) in maximum 

 breadth, the mean breadth being about one-sixth of a mile (or rather 

 less than half the maximum breadth). Its waters cover an area of 

 about 160 acres (or one-quarter of a square mile), exclusive of the 

 numerous islands, and it drains an area seven times greater, or If square 

 miles. Nearly 80 soundings were taken, the maximum depth observed 

 being 71 feet. The volume of water is estimated at 147,987,000 cubic 

 feet, and the mean depth at nearly 17 feet. Loch Crocach is deeper 

 than the other small lochs in this district. A large 2 5 -feet area occupies 

 the greater portion of the length of the loch to the north-west of the 

 islands ; a second smaller area occurs in the south-western expansion of 

 the loch, and a third very small area lies near the south-western end 

 of the loch, based on a sounding of 30 feet. The bottom falls in two 

 places below the 50-feet level, the larger basin being centrally placed, 

 between the entrance of the Uidh nan Lion and the largest of the 

 islands, with a maximum depth of 64 feet, the smaller but deeper basin 

 lying in the south-western expansion of the loch, the maximum depth 

 of 71 feet having been observed quite close to the small island off the 



