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THE WONDERS OF GEOLOGY. Lect. IV, 



the inhumation of animals and vegetables — the slow depo- 

 sition of sediments by lakes and rivers — the imbedding of 

 innumerable generations of insects, and the formation of 

 limestone from their almost invisible skeletons — the con- 

 struction of solid stone out of fragments of bones and 

 rocks, shivered by earthquakes — the engulfing in estuaries 

 and inland seas, of land animals, birds, and reptiles — the 

 conversion of organic and inorganic substances into rock, 

 from the infiltration of flint and lime by thermal waters — the 

 transmutation of submerged forests into coal and lignite — 

 the destructive and conservative effects of volcanic erup- 

 tions — the consolidation of sand, gravel, and clay, into 

 indurated masses by heat — and the production of metal- 

 liferous veins of gold and silver — all these phenomena 

 have passed in review before us, although our inquiries 

 have extended through periods which, however vast and 

 remote in relation to the records of our race, are but brief 

 and modern in the physical history of our planet. 



The geological events previously described, though 

 forming a connected series, may be divided into periods, 

 each of which is marked by certain zoological characters ; 

 namely, 1st. The Modern, or Human Epoch; 2d. The 

 Elephantine, characterized by the preponderance of large 

 pachydermata ; 3d. The Pa Ice other tan, in which animals 

 allied to the tapirs prevailed, and Europe presented a 

 system of gulfs and lakes. 



2. Formations of the secondary epoch. — We pro- 

 ceed to the consideration of an antecedent epoch,— that 

 which comprehends the Secondary Formations. Hitherto 

 our attention lias been principally directed to deposits con- 

 fined within comparatively limited areas, as the basins of 

 lakes, gulfs, estuaries, and inland seas ; and the superficial 

 accumulations of drifted materials, produced by the action of 

 torrents, rivers, icebergs, glaciers, inundations, &e. We have 

 now arrived on the shores of that ocean, of whose spoils the 



