Page:Transactions of the Geological Society, 1st series, vol. 3.djvu/303

 connected with the schist which forms the bed of the river throughout this space, they were concealed from me. The channel becomes so deep and the sides so clothed with wood, that it is scarcely possible to examine the banks; and the bed of the river itself may safely be called inaccessible during nearly the whole of its remaining course to Blair. Within about two miles of Blair, however, at a point which is marked by a cascade and a small bridge, a large mass of yellow marble is seen crossing the river. It is, like that before described, of an uniform ochre colour, and like it, applicable to architectural uses. Lower down, near the junction of the Fender, where there is again access for a short space, the great body of blue limestone is found. This may be traced across the grounds of Blair, and in the bed of the Banavie, where it exhibits those minute reticulations of siliceous matter which I have already described. From hence it is again to be traced to the opposite side of the Garry, where it forms a great part of the green hill of Tulloch. On this hill, at Invervach, many of the beds are white, and resemble those already described at Gow's bridge, being interlaminated in a similar manner with steatitical clay, and accompanied by mica. But I have passed my proposed boundary.

Having anticipated no more of the description of the two ridges which bound Glen Tilt, than, was necessary to understand the nature of the rocks which are seen in the bed of the river, I must now return to them, taking up the right hand ridge, or north side of the glen, at the place where I have now stopped.

That portion of the ridge which lies from Blair to Gow's bridge is so encumbered with wood in some places, and offers so little interest in others, that I am content to pass it by in a superficial manner, particularly as its more minute examination would throw