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According to Jameson*, the granitemountains in Arran rest on clay-slate.

A rock, differing from granite only in theimperfect cohesion of its ingredients, isfound, in many parts of Cornwall and De-vonshire, incumbent upon killas. Altern-ations of the two substances are seen atHuel Fortune near Marazion , and at themore celebrated mines of Cooks-kitchenand Dolcoath. At Gwarnock, in the parishof St. Allan, a steatitic granite accompaniesthe lode, which is worked in killas. TheMorwelham tunnel, driven through a killascountry, traverses three distinct beds ofgrauany elvan. At Cliggar point, on theeast of St. Agnes, a rock of the same naturelies upon killas.

At a small cove, called La Poulet, in theneighbourhood of Cherbourg, I have ob-served killas passing into granite, and dip-ping beneath it. Of the intermixture ofthese substances numerous examples maybe found in Cornwall ; in Wicklow; in the

* Von Buch’s Norway , Black’s translation, p. 139, note.

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