Page:Transactions of the Geological Society, 1st series, vol. 3.djvu/27

 supplies the river running into Portree harbour appears to have had some effect in filling up its southern branch which the ebb of the loch has no tendency to remove. From below Portree to the northern point of the island, the coast consists of high cliffs of trap, which exhibit the species of decomposition characteristic of these rocks, in the vast slopes which decline from them to the shore wherever the action of the tide has not been sufficient to prevent that accumulation. Continuing round the point of Ruhunish, similar cliffs of trap resting on the secondary strata extend to the bottom of Loch Snizort, at the end of which as well as of Loch Uig the same appearances of encroachment are visible. The parish of Kilmuir offers the only considerable tract of alluvial land in Sky, from which its superior and long established fertility is probably to be accounted for. I cannot speak positively of the shores which form the point of Vaternish, having only seen them from a distance, but as they resemble both in aspect and composition the division of Trotternish just noticed, it is probable they possess no great peculiarity in this respect. Neither does Dunvegan offer any thing worthy of remark.

The shores of Loch Bracadale exhibit when low, considerable portions of clayey alluvial soil, characterised like those of Kilmuir by extraordinary fertility. A similar alluvium may be observed at the head of Loch Harpart, and the little valley of Talisker appears to have been entirely gained from the sea at some distant period, by a combination of the waste of the land with the counteracting efforts of the western swell, which has thus formed a natural embankment for its further protection.

A remarkable difference is to be seen along the whole western shore of the island from Dunvegan head to Loch Brittle, between