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The deposits of the useful minerals & rocks; their origin, form, and content . T:ite, and otherwise consists ofconglomerate and tufE-hke rocks which, in addition to Hercynian material,. ^ Elbinge- Lower Middle Zeclisteiu Gypsum Bunter DiluTium Melaphyre Porphyrite Ore- rode and Upper Deposits wacke Kotliegendes Fig. 381.—The manganese lodes at llfeld in the Harz. Scale 1 : 100,000. Survey by the Pr. Geol. Landesanst. also include fragments of porphyrite and melaphyre. For the upperRothegendes only a narrow horizon is set apart, which, as in the otherGerman districts, contains no eruptives. In
The deposits of the useful minerals & rocks; their origin, form, and content . T:ite, and otherwise consists ofconglomerate and tufE-hke rocks which, in addition to Hercynian material,. ^ Elbinge- Lower Middle Zeclisteiu Gypsum Bunter DiluTium Melaphyre Porphyrite Ore- rode and Upper Deposits wacke Kotliegendes Fig. 381.—The manganese lodes at llfeld in the Harz. Scale 1 : 100,000. Survey by the Pr. Geol. Landesanst. also include fragments of porphyrite and melaphyre. For the upperRothegendes only a narrow horizon is set apart, which, as in the otherGerman districts, contains no eruptives. In connection with the manganese lodes the porphyrites particularlyare concerned, these being separated from a melaphyre below by sediments,while, in part at least, they are covered by slates, etc. Both these erup-tives, as Naumann pointed out, are bedded occm-rences. The porphyritesare distinguished by large segregations of felspar, by decomposed hornblende,and more seldom by specularite and garnet, in a compact, brown, reddish- THE MANGANESE LODES 859 grey, or green coloured ground-mass, consisting presumably of the sameconstituents. This eruptive forms in the Ilfeld district a
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectminesandmineralresou