200 GEOGNOSTICAL SKETCH OF THE 
contain foliated and radiated actynolite, fibrous tremoiite, 
and disseminated iron-pyrites. The tremoiite and actyno- 
lite occur also associated with a beautiful white variety of 
felspar, in the neighbouring strata of granite. None of the 
gems, except rock-crystal and garnet, have been as yet dis- 
covered in these mountains : but it is probable that zircon, 
and perhaps tinstone, might be found, by a careful and 
minute examination. 
Having thus noticed the general characters of the range 
lying between Dochfour and Fort Augustus, we shall not 
trace the strata farther towards the west ; but, in pursuance 
of the plan laid down at the commencement of this sketch, 
continue our description, by giving an account of the chairs 
running along the south side of Loch Ness. This chain 
commences at Fort Augustus, and terminates near the vil- 
lage of Dores ; it forms therefore the third chain we pro? 
posed to describe. 
Third Raivge. 
For the first eight miles, after leaving Fort Augustus, 
the mountains in this direction are principally composed of 
granite and syenite. 
These rocks possess no great peculiarities of structure or 
position. They are not independent formations, but seem 
rather to be connected with the great ranges of primitive 
mountains that stretch across the island in a north-easterly 
direction from Lochaber and the borders of Argyleshire. 
I need not therefore notice them any farther, as any obser- 
vations of mine (and they are as yet but few and imperfect) 
could only corroborate more accurate and better known 
descriptions. These mountains of granite and syenite are 
si|cceeded, near the celebrated Fall of Foyers, by a chain 
composed of quartz-rock. This beautiful rock has always 
