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Extent of Formations. 63 1. The original extent of Formations. Werner obferves, that the greater number of formations have been uniVerfally depofited; and thefe he denominates Univerfal Formations. A very few, however, are to be confidered as exceptions ; and thefe he terms partial or anomalous forma* tions. Univerfal Formations extend around the whole globe, (not, however, without interruption), and conftitute by far the greater part of the mafs of which its cruft is compofed. Almoft all the primitive, tranfition, and flcetz, formations, are univerfal depofitions; of thefe we may mention Granite, Gneifs, Porphyry, Limeftone, and Bafalt. Partial Formations occur only here and there, and in fingle fpots, and accompanied with appear ances that indicate the partiality of their depofi- ' tion. Thus, at Wehraw, in Lufatia, there is an . excellent example of a partial formation. It con- fifts of Sandftone, Limeftone, Bituminous-ftiale, and Iron-clay ; and thefe reft on loofe fand. The fandftone refembles in many refpedts that found in other fandftone formations; yet it does not belong to any of them, as is evident from its pofition, and the rocks with which it is affociated. Werner conjedlures that it may have been formed by a fmall and partial flood. The examination of thefe partial appearances is of much importance, not only in extending our knowledge
