Page:Transactions of the Geological Society, 1st series, vol. 3.djvu/270

 Occasionally it may be seen cutting its way through quartz rock, through schist, and, not long before its arrival at the Tarff; through beds of dark bluish limestone. One solitary portion of pure white limestone or marble is also visible in this part of its course. Where it joins the Tarff it also receives another stream of considerable magnitude, flowing from Glen More and collecting the waters from a set of vallies that lie between the foot of Carn-ree and the head of Glen Fernat, as well as from those corys of Ben Gloe which tend in this direction.

It will be unnecessary to particularize the several streams which it receives during its course to the Garry, unless where their sections offer material information respecting the structure of the neighbouring hills.

Having passed the Tarff it begins to run in a more rocky channel, and though often, and for considerable spaces, its true bed is concealed by the alluvial matter which it has accumulated, enough remains exposed to excite the curiosity, and employ no small portion of the time of a geologist. Although in enumerating and describing these several points where the natural bed is visible, I have used all my endeavours to specify the particular places where they occur, yet in this respect the description will still be deficient. Even if an accurate survey of the ground were made, the want of points of reference in a valley which possesses so few permanent marks for distances, would prevent me from referring to them as accurately as would be desired by those who might wish to follow the same track. The difficult nature of the banks, and the many inaccessible points which the river possesses, combined with the dangerous violence of its waters, frequently also deny access, and may consequently have led to omissions. Such omissions will also be found to arise from another cause, to which may equally be