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but the exceptions I believe are so nume-rous, as to do away the generality of therule. In the veins which I have had anopportunity of examining in Derbyshire and Cumberland, barytes and calcareousspar change places continually. It is noteasy to discover a lode in Cornwall , wheretin and copper lie in the orderly mannerwhich Werner described. At Glencloy *in Arran , a vein, of which the centre iswhin, has one of its sides composed ofbrecchia, the other of siliceous sand-stone.At Tormore in the same island, the oneside of a dyke is basalt, the other porphyry.

“ By all the information I could ever“ procure,” says Hutchinson, “ I cannot“ perceive there is any instance of a dis-“ position of ore in Hungary , Saxony ,“ Mexico , Achin, or elsewhere, of which“ we have not some example in England,« so that he who is thoroughly informed of

Jameson’s Scottish Islands, p. 27.