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BROWN IRONSTONE. £6.5 15. Geognostic Situation. It occurs in primitive, transition, and floctz mountains, font more frequently in the two latter : and when in pri mitive mountains, in those only which are of newer for mation. Its repositories are veins, beds, lying masses (Hegende stoke), and mountain-masses (stuck gebirge). IVhen it occurs in veins and lying masses, the compact a "d ochry subspecies form the principal mass. 1 he hrown hematite occurs often in cavities in these veins or foods, but it docs not fill them up; it only lines their Walls, and is again covered by scaly brown iron-ore ; so that here ochry and compact brown ironstone are the °ldest, and the scaly brown ironstone the newest forma tion. It is usually accompanied with sparry ironstone, c alcareous-spar, brown-spar, and heavy-spar; less fre quently with black ironstone, and rarely with quaitz, end red ironstone. Quartz, which occurs so frequently with red ironstone, seldom appears with brown iron stone : on the contrary, it is accompanied w'ith heavy- 8 Par, calcareous-spar, and in some places with fluor spar, C. Geographic Situation. Europe. It occurs in veins in sandstone, along with heavy.spar, at Cumberhead in Lanarkshire ; in a similar rp pository in Mainland, one of the Zetland Islands ; and 1,1 the Island of Hoy, one of the Orkney group. Small Ve ins of it are met with in the iloetz greenstone of Salis- foury Craigs, near Edinburgh. It also occurs at Schnee- fo er g, Seheibenberg and Rasrhau in the Erzgebiige, and *t Xamsdorf, where it (principally the ochry subspecies) occurs in flcetz rocks, in beds, which are sometimes so thick