That feature of the island of Eigg which renders it so remarkable and conspicuous an object on the west coast is the long ridge of the Scuir. Rising gently from the valley which crosses the island from Laig Bay to the Harbour, the basaltic plateau ascends south-westwards in a succession of terraces, until along its upper part it forms a long crest, from 900 to 1000 feet above the sea, to which it descends on the other or south-west side, first by a sharp slope, and then by a range of precipices. Along the watershed of this crest runs, in a graceful double curve, the abrupt ridge of the Scuir, terminating on the north-west at the edge of the great sea-cliff (975 feet), and ending off on the south-east in that strange well-known mountain-wall (1272 feet high) which rises in a sheer cliff nearly 300 feet above the basalt-plateau on the one side and more than 400 feet on the other (Fig. 278). The total length of the Scuir ridge is two miles and a quarter, its greatest breadth 1520, its least breadth 350 feet. Its surface is very irregular, rising into minor hills and sinking into rock-basins, of which nine are small tarns, besides still smaller pools, while six others, also filled with water, lie partly on the ridge and partly on the basaltic plateau. No one, indeed, who looks on the Scuir from below, and notes how evenly it rests upon the basalt-plateau, would be prepared for so rugged a landscape as that which meets his eye everywhere along the top of the ridge. Two minor arms project from the east side of the ridge; one of these forms the rounded hill called Beinn Tighe (968 feet), the other the hill of A chor Bheinn. [Illustration: Fig. 278.--View of the Scuir of Eigg from the east.] Singular as the Scuir of Eigg is, regarded merely as one of the landmarks of the Hebrides, its geological history is not less peculiar. The natural impression which arises in the mind when this mountain comes into view for the first time is, that the huge wall is part of a great dyke or intrusive mass which has been thrust through the older rocks.[252] It was not until after some time that the influence of this first impression passed off my own mind, and the true structure of the mass became apparent. [Footnote 252: Hay Cunningham remarks:--"In regard to the relations of the pitchstone-porphyry of the Scuir and the trap-rocks with which it is connected, it can, after a most careful examination around the whole mass, be confidently asserted that it exists as a great vein which has been erupted through the other Plutonic rocks--thus agreeing in age with all the other pitchstones of the island." Macculloch leaves us to infer that he regarded the rock of the Scuir to be regularly interstratified with the highest beds of the dolerite series (_Western Isles_, i. p. 522). Hugh Miller speaks of the Scuir of Eigg as "resting on the remains of a prostrate forest."--_Cruise of the Betsy_, p. 32.]