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n8 PRIMITIVE ROCKS. 7. This is a very widely diftributed rock. It oc cupies almoft the whole of the Saxon metalliferous mountains: it abounds in Bohemia and Silefia; it is not uncommon in the Black Foreft, the Upper Palatinate, in Carinthia, in the Southern Alps, the Pyrenees, the Vofges, and Scandinavia. It occurs alfo in Greece; and in the vicinity of Athens, the old mine-works of the ancients are fituated in itj in Ruffia, and many parts of South America. In this county, it has been obferved in the iflands of Coll, Tiree, and Rona; alfo in the Shetland iflands, and many parts of the mainland of Scotland. 3. Mica-flate.lj Glimmer-Schiefer.—Werner. Micaceous Shiftus, Kir wan.—Schifte micace, Brocbant. I. This rock is compofed of mica and quartz, and, like gneifs, has a flaty ftrucfture. The mica is almoft always grey ; frequently greenilh grey, and the quartz is generally greyilh-white. An other fofiil occurs in great abundance in this rock, and fo very frequently, that it may almoft be con- fidered as one of its eflential conftituent parts: it is Precious Garnet. This gives it a porphyritic ( ftrudlure. Befides garnet, the following foflils oc cur in it. a. Hornblende. This occurs but feldom ; and not Xo frequently as it does in gneifs. b. Schorl
