Projekt: Bestände der Universitätsbibliothek Freiberg
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Parlamentsperiode
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Wahlperiode
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Titel
Chap. IV. General Account Of The Different Formations, In Regard To Their Succession And Stratification, And This Illustrated By A Short Description Of The Hartz And The Saxon Erzgebirge
Succession of Formations. 69 A comparifon of thefe different claffes teaches us, 1. Phat the older rocks are principally compofed of Siliceous, Argillaceous, and Magnejian earths. 2. That the Primitive parts of the crufl of the earth are entirely Chemical productions; whereas in the Newer and Newer, we find a beginning and jncreajing quantity of Mechanical depofitions. 3. That Limefione occurs but fparingly in the Pri-> mitive, more abundantly in the TV unfit ion, and in the Flatx clafs in immenfe quantity. 4. That in the earlier periods we meet with no Bitutninous or Saline matters, hut that thefe occur in great quantity in the newer formations. 41. The preceding obfervations point out how the claffes of rocks are related to each other, in regard to fucceffion. We fliall next date how they are related to each other in regard to Jlratification. In the Firft Clafs, we obferve feveral rocks al ways difpofed in conformable and unbroken drati- fication, and in which the newer and newer drata have always a lower and lower level. Gneifs, Mica-date, and Clay-date, are of this kind. The granite dretches under them uninterruptedly, and fometimes rifes up through them, or juts up in the form of lingle caps or great maffes; fo that the gneifs and other rocks are difpofed on its fur- face, fometimes in a concave, fometimes in a con- y?x direction; fometimes faddle-fhaped, and fre quently