CHAPTER XXXIX 
THE BASALT-PLATEAUX OF SKYE AND OF THE FAROE ISLES 
iv. TIIE SKYE PLATEAU 
This largest and geologically most important of all the Scottish plateaux 
comprises the island of Skye, at least as far south as Loch Eisliort, and 
the southern half of Kaasay, but is shown by its sills to stretch as far as the 
Shiant Isles on the north, and the Point of Sleat on the south (see Map VI.). 
It may be reckoned to embrace an area of not less than 800 square miles. 
The evidence that its limits, like those of the other plateaux, are now greatly 
less than they originally were, is abundant and impressive. The truncated 
edges of its basalts, rising here and there for a thousand feet as a great sea- 
wall above the breakers at their base, and presenting everywhere their succes- 
sion of level or gently inclined bars, are among the most impressive monuments 
of denudation in this country. But still more striking to the geologist is the 
proof, furnished beyond the margins of the plateau, that the Jurassic and 
other older rocks there visible were originally buried deep under the basalt- 
sheets, which have thus been entirely stripped off that part of the country. 
Throughout most of the district, wherever the base of the basalts can 
be seen, it is found to rest upon some member of the Jurassic series, but 
with a complete unconformability. The underlying sedimentary strata had 
been dislocated and extensively denuded before the volcanic period began. 
On the southern margin, however, the red (Torridon) sandstones emerge 
from under the basalts of Loch Scavaig, and extending into the island of 
Soay are prolonged under the sea into Bum. This ridge probably 
represents the range of the ancient high ground of the latter island already 
referred to. 
Nowhere are the distinctive topographical features and geological 
structure of the basalt-plateaux better displayed than in the northern half 
of the island of Skye. The green terraced slopes, with their parallel bands 
of brown rock formed by the outcrop of the nearly Hat basalt-beds, rise from 
the bottoms of the valleys into flat-topped ridges and truncated cones (Pig. 
283). The hills everywhere present a curiously tabular form that bears 
witness to the horizontal sheets of rock of which they are composed. 1 And 
1 These features are more fully described in my Scenery of Scotland, 2nd edit (1887), pp. 74, 
145, 216. 
