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170 CHAP. XXVIII. Hornblende Schist. Actinolite Schist. The term Hornblende schist implies a familiar strati fied rock, of which it is a sufficient definition to say, that it consists of hornblende, alone, or intermixed with felspar, common, or compact; while generally, if not invariably, schistose. Thus it may resemble the green stone of Trap, in specimens; while the chlorite series just described contains some compact beds of it, often remarkable for a prismatic structure, and thus capable of deceiving even a good observer. But in every other case, nothing but extreme ignorance or prejudice can confound hornblende schist with an unstratified rock: while the terms primitive greenstone and greenstone slate, here suppressed, have produced utter confusion, in this case, in the hands of those who have so widely perverted all geological philosophy: confounding, not merely the schistose concretionary traps with this rock, but all the traps of apparently antient associations, with a stratified substance. H ornblende schist is so rarely found, in this country at least, independent, and occupying a distinct place, that little can be said respecting its great external fea tures. The only example which has occurred to me, is the mountain Ben Lair in Rossshire, which consists almost entirely of this substance, surrounded by gneiss. It rises to the height of 3000 feet or upwards; dis playing a very rugged and picturesque surface, with extensive faces of bare rock. In all other situations, hornblende schist either forms a portion of the great mass of gneiss, or alternates with the other primary schists; so that the general aspect of the country is determined by a variety of concurring circumstances. Like the other primary strata, it occurs in distinct