Page:Transactions of the Geological Society, 1st series, vol. 3.djvu/65

 junctions. These are the only detached masses, the remainder of the stratified trap forming one continuous mass, occupying the limits already referred to. It would be an endless toil to follow the varieties of this rock in the narrative as I did in the examination, as fatiguing to the reader as the writer, and equally useless either in a topographical or geological view. After describing such of its connections with the secondary strata as can be discovered, I shall content myself with enumerating a few of the most leading varieties, particularly such as add any illustration to the history of the rock, and with describing the localities of the most remarkable strata.

The contact of the stratified trap with the secondary rocks is seen very frequently on the eastern coast, as well as on the western shore of Loch Snizort, but it never occurs between Dunvegan head and Soa. In speaking of the secondary strata, I have already mentioned the most remarkable points where these contacts are visible, and need not therefore repeat them: they are most accessible in the neighbourhood of Duntulm, and from Portree northwards the alternations can be readily traced. I observed nothing so particular at the junctions in any place as to require a detailed description, except the contact of the basalt at Duntulm Castle, with the siliceous schistus, which I shall describe hereafter.

Among the numerous species of the trap family here existing, basalt is the most conspicuous, and it occurs almost every where, alternating in an irregular manner with all the other species or varieties. It is most frequently amorphous, displaying at the same time so great a variety both in its natural mode of breaking, in its external appearance on weathering, and in its texture and colour, as to form a great number of subordinate varieties much more remarkable in their natural situations than when broken into hand specimens. At Talisker it is found perfectly black, and of an exquisitely