886 



THE WONDERS OF GEOLOGY. Lect. VIII. 



earliest strata, belong to orders having a highly developed 

 organization. Nor does the vegetation of those remote pe- 

 riods lend any support to such a hypothesis ; fungi, lichens, 

 hepaticse, and mosses, do not form the flora of the palaeozoic 

 epochs, but coniferae, and the most perfectly organized of 

 the cryptogamic class. 



44. Geological effects of dynamical and chemical 

 action. — The physical changes that have taken place on 

 the earth's surface, are in perfect harmony with the modi- 

 fications observable in animated nature ; for the laws of 

 mechanical and chemical action are inseparably connected 

 with those which govern vital phenomena ; and we have 

 incontrovertible evidence, that throughout the vast periods 

 over which our observations have extended, the same 

 causes have operated, the same effects followed. Thus, 

 heat and cold, drought and moisture, and other meteoric 

 influences, have denuded the loftiest peaks — rivulets and 

 torrents have eroded the sides of the mountain-chains — 

 streams and rivers have worn away the plains, and trans- 

 ported the spoils of the land into the bed of the ocean — the 

 waves of the sea have wasted its shores, and destroyed the 

 cliffs and rocks which opposed their progress — silt has been 

 changed into clay — calcareous mud into limestone — sand 

 into sandstone — pebbles into conglomerates and breccia — 

 and animal and vegetable remains have been imbedded, 

 and added to the mineral accumulations of the past ages of 

 our planet. 



Beneath the surface, the action of electro-chemical forces 

 has been alike unintermitting — vegetable matter has been 

 converted into bitumen, coal, amber, and the diamond — 

 earth into crystals — limestone into marble — clay into slate, 

 and sedimentary into crystalline masses traversed by metal- 

 liferous veins ; the volcano has poured forth its rivers of 

 molten rock — the earthquake rent the solid crust of the 

 globe — beds of seas have been elevated into mountains — 



