Page:Transactions of the Geological Society, 1st series, vol. 3.djvu/23

 difference between the two groups. We have seen that the Cuchullin and Blaven form one irregular mass, continuous in the ridges and much confounded both with each other and the general mass of the island. But the Red hills form rather a distinct assemblage of mountains, being separated either singly or in small associations by deep vallies, and placed as it were upon the general level. This group is bounded on the west by the vale of Strath, which extends from Broadford to the head of Loch Slapin, and skirting the sound of Scalpa terminates at Loch Sligachan. I may add that except the slight mixture of substances which appears to take place in Glamich hill, and in one or two more of those which come into contact with the Cuchullin and with Blaven, these two groups do not interfere, but are composed respectively of different and well characterized rocks.

The great mountain of Blaven is skirted by lower hills, descending gradually into the table land of Strathaird, which we shall hereafter see to be the largest portion of the secondary stratified rocks existing in Sky.

An uneven land, rising into irregular low hills, occupies the whole tract to the southward of the valley of Strath, with the exception of a nook which may be defined by an imaginary curved line drawn from Loch Oransa to the castle of Inverfuchag. This part of the island forms another distinct mountain group rising into two principal summits, and attaining an elevation apparently of fifteen or eighteen hundred feet.

The general elevations of the remainder of the island may be discussed in a few words.

Having passed Loch Sligachan, an irregular ridge of high land appears branching in two directions. The main ridge occupies the eastern side of the island to Portree, where it is interrupted by the