. II. RELICS, into Min. Kingd. 21 



formation of plants; the surface of the ocean 

 then so much above its present level, as to cover the 

 summits of all secondary mountains. ( v. . III. Soil. ) 



process, and not by that of a mere mechanical subsidence, the 

 materials of priraative rocks, as just stated, are supjx>sed to have 

 been compacted. Vide G. Essays, p. 21, also View of Nept. 

 and Ilutt. Syst. Geol. p. 106, where the massive structure of the 

 unstratified primary rocks, and the frequent vertical position of the 

 beds in such as are stratified, are accounted tor on Werner's principles. 

 De Luc, in explaining the formation of mountainous tracts, and 

 the dislocation of the strata which compose them, states, that all rocks 

 were fonned by simple deposition, and that, consequently, the ori- 

 ginal position of the strata was horizontal. That these horizontal 

 strata, constituting the bottom of the ancient sea, from which they 

 had been gradually deposited, formed a kind of shell or crust, over 

 a mass of moistened matter, with which the original, dry, central 

 part of the globe was surrounded, (see former Obs. to prop. 1.) 

 That during the consolidation of these strata, the water, from the 

 mass under them, was gradually absorbed by the dry substances in 

 the centrical nucleus; and hence, in process of time, instead of a 

 uniform, soft support to the incumbent beds, one of a solid but 

 ramified structure was formed, the mineral materials, of which it 

 consisted, coalescing and becoming compact on being de- 

 prived of moisture. That, in proportion as the branches of this 

 support were more contracted by subsequent consolidation, the in- 

 tervening cavities were necessarily extended ; and that, at length, 

 the superficial crust gave way, in different parts of the earth's sur- 

 face ; and while one edge of a fragment sunk down, the other re- 

 mained elevated on the solid ramifications, which had previously 

 supported the whole external shell of concentrical strata. Thus 

 our author endeavours to explain the retreat of the ocean, into the, 

 at present, depressed parts of the globe, the first appearance of the 

 great mountains which branch through our continents, and the va- 



