THE FRESH-WATER LOCHS OF SCOTLAND. 
285 
Still further east, this characteristic zone has been followed from Ben 
Wyvis across Strath Glass and Strath Husdale to the hills near Fearn. 
The constant reappearance, throughout the metamorphic area of ‘the 
Conon basin, of the two main subdivisions of the Moine series suggests 
the repetition of these zones by folding. Indeed, such is the view 
adopted by the Geological Survey, and hence the actual thickness of 
this series may be much more limited than the persistent dip of the 
strata in one direction would lead us to suppose. The researches of the 
Survey indicate a probable order of succession in these schists which 
obtains in the tract between Ben Wyvis and Ben Dearg, and between 
Garve and the Carron that flows into the Dornoch firth. 
In the flaky muscovite biotite schists, and in the quartzose granulites, 
bands of garnet amphibolite and hornblende schists occur, which have 
a wide distribution and are characteristic of certain horizons. 
Reference must now be made to the foliated granite, intrusive in 
the Moine series, which is one of the most interesting features in the 
geology of the Conon basin. Its boundaries are of prime importance, 
because the distribution of the boulders supplies valuable evidence 
regarding the direction of the ice-flow during the glacial period. There 
are two important masses of these older intrusive rocks. The larger 
one extends from Cam nan Aigheinn, near the head of Strath Rannoch, 
north-east by Cam Chuinneag to Cnoc an Liath-bhaid beyond Strath 
Rusdale, and measures about 12 miles in length and about 5 miles in 
breadth. The smaller one stretches from the hills above Loch Luichart 
north-east by Inchbae to Cam More east of Strath Rannoch, being 
about 5 miles long and less than 3 miles broad. Again, on the north 
shore of Loch Luichart there are four outcrops of foliated granite, 
evidently belonging to the same set of intrusions. The Inchbae type 
of augen-gneiss or granite is well known, with large porphyritic crystals 
of orthoclase felspar oriented in a definite direction, enclosed in a 
granulitic ground-mass of quartz, felspar, and micas, together with 
crystals of garnet and sphene. This coarse porphyritic variety is 
largely developed in the Cam Chuinneag mass, where it is associated 
with foliated riebeckite granite or augen gneiss. Frequently the rock 
is fine grained, and merges into a finely crystalline schist. 
Evidence has been obtained that these older granite masses with 
their basic modifications were intruded into the series of Moine 
sediments before they were converted into crystalline schists. A well- 
marked aureole of contact metamorphism accompanied this intrusion, 
which in places has been obscured by subsequent deformation. But 
at intervals round the margin the sediments are hornfelsed, and still 
show their original bedding-planes, while garnets and crystals of 
andalusite have been developed. It is further apparent that the granite 
masses and the Moine sediments have been subjected to a common series 
of dynamic stresses, for the planes of schistosity in the granite are 
