320 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Feb. 26, 



rocks occupy the shore, and the calcareous heels retire inland and 

 form a band of some breadth in the beds and banks of the streams to 

 a considerable distance inland, the trap covering having been swept 

 away at these parts, but still existing on the intervening low ridges 

 between the streams. In this tract several faults occur, of which the 

 most striking are : — one on the Leathan-alt, near the hamlet of Half- 

 burn, attended with great disruption and a downthrow towards the 

 sea-shore ; and another at the waterfall of the Loch Me-alt (Miagh- 

 alt), where the calcareous beds are cut off, and the overlying trap 

 occupies the whole of the lofty cliff down to the sea-line. The over- 

 lying trap of the cliffs west of Loch Me-alt now advances inland and 

 connects on to that of the high moors southwards to the base of 

 the great central range of the peninsula, which extends from near 

 Portree to beyond the Quiraing. As the ground lowers again to- 

 wards Loch Staffin, the calcareous beds emerge, and have a con- 

 siderable range round the head of the bay, and westwards by the 

 north base of the Quiraing Mountain. ISTow they are seen in the 

 coast section, and again they are cut off by the intrusive trap which 

 takes their place in the section. This arrangement is continued 

 round the north point of the peninsula, by Aird Point and Bu- 

 Hunish, to Duntulm Castle, where a remarkable change is produced 

 upon them by the trap. By the roadside east of the castle the beds 

 emerge unaltered, and form a narrow band for some distance in the 

 coast-line. They are again seen south-east of this point on the 

 western shore of the peninsula, andon the banks of Mugstok lake drained 

 fifty years ago. Their last appearance on the coast of Trotternish 

 is at TJig Bay. Here, on turning the headland of Ru-Idrigal, con- 

 spicuous from most parts of the western peninsulas of Skye, we come 

 again suddenly on beds which range round the head of the bay, 

 along the narrow band of fertile land between the sea-line and the 

 steep front of the high ridge which shuts in on three sides this 

 secluded inlet, giving it a winter temperature differing little from 

 that of the south coast of Devon. 



The western peninsula presents the same beds in a few places 

 where the level of the sea is reached, or a level very little raised 

 above it, as at the head of Loch-bay in Yaternish, on an island at 

 its entrance, and on the low sea cliff at Yaterstein, west of Dun- 

 vegan. — This low normal position of the beds suggested to Dr. 

 Macculloch the idea that the whole island has a substratum of these 

 rocks, and that the few elevated positions in which we now find them 

 are due to local elevation. He was the first to suggest the former 

 connexion of all his " trap islands, " and to conceive the idea of a 

 Liassic sea embracing all of them, and the north of Ireland also, 

 whose floor consisted of these beds, afterwards broken through and 

 overlain by vast sheets of lava. 



Siiccession of ilie Beds. — In order to obtain a good base for future 

 operations, I went with some care over the district described by 

 Prof. Geikie, and I can bear testimony to the faithfulness, clearness, 

 and accuracy of his paper. The conclusions are so satisfactorily 

 made out that it is only necessary, in consequence of the discovery 



