288 BATHYMETRICAL SURVEY OF 



by the Conon valley towards the Black Isle. The striae, trending about 

 east-south-east, found on the tops of Meall na Speirag and Beinn Liath 

 Beag at elevations of about 2000 feet, on the watershed between the 

 Blackwater and the streams flowing into Loch Luichart, clearly show 

 the development of the ice during this period. 



Important evidence regarding the transport of materials during the 

 time of the confluent glaciers is furnished by the distribution of boulders 

 of foliated granite and Old Red Sandstone on the slopes of Ben Wyvis. 

 These have been carried from the west or west-north-west, and have 

 been traced up to a height of 2400 feet on Cam Gorm and Little Wyvis, 

 while their upper limit on Ben Wyvis itself is 2300 feet. It is further 

 apparent that the ice moved through the pass between Little Wyvis and 

 An Cabar, and streamed down the valley of Loch Glass north of Ben 

 Wyvis. Still further north in Kildermorie forest and Strath Rusdale, 

 the direction of the ice-flow was south of east, as proved by the striae, 

 and the transport of boulders of foliated granite or augen gneiss. From 

 the period of confluent glaciers to the time of their disappearance in 

 the upland glens, the various stages of retrocession are represented by 

 the moraines. 



Loch Fannich. The soundings clearly show that this lake gradually 

 deepens towards the eastern portion, the deepest sounding, 282 feet, 

 being situated about a mile above the outlet. The hill-slopes on both 

 sides of the loch for considerable distances are covered with morainic 

 drift, save near the outlet, where there is a prominent barrier of rock. 

 At the latter point the southern spur of An Coileachan approaches the 

 northern margin of the lake, and is prolonged on the south side in An 

 Cabhar and Carn na Beiste. Along the eastern side of this ridge, the 

 quartzose granulites and muscovite biotite schists are isoclinally folded 

 on vertical axes striking north and south that is, at right angles to 

 the course of the lower part of the loch. At the outlet, and for a mile 

 below that point, the Grudie river flows on alluvial deposits, these 

 materials having been largely contributed by side streams, and especially 

 by Allt a' Choin Idir, draining from the north. Beyond the alluvium, 

 at the 800-feet level, the Moine schists are exposed in the bed of the 

 river and on the hill-slopes, and there is here no indication of a pre- 

 glacial river channel filled with drift. The surface of Loch Fannich is 

 822 feet above Ordnance datum, so that the depth of the rock basin 

 below the rocky barrier, visible about a mile beyond the outlet, is 

 260 feet. 



Loch Luichart. This lake is a true rock basin lying among the 

 crystalline schists, with a barrier formed of these materials at its outlet. 

 Where the stream issues from the loch, it runs through a narrow gorge 

 of rock and over successive waterfalls. In this sheet of water there are 

 three basins, of which the most westerly is the most important, its 

 greatest depth being 164 feet. The surface of the lake is 250 feet above 



