286 THE WONDERS OF GEOLOGY. Lect. III. 



and simple forms of vegetable structure peculiar to that 

 element. 



The state of the inorganic world is not less manifest : 

 the abrasion of the land by streams and rivers, — the de- 

 struction of the sea-shores by the waves, and the formation 

 of beach and shingle, — the desolation inflicted by volcanic 

 eruptions, — all these operations were then, as now, in 

 activity. The bed of an ancient sea, containing myriads of 

 the remains of fishes, Crustacea, and shells, now forms the 

 site of the capital of Great Britain ; and accumulations 

 of tropical fruits and plants, with remains of crocodiles, 

 serpents, turtles, and birds, drifted by ancient currents 

 from other climes, constitute islands in the estuary of the 

 Thames ; while the sediments of inland seas, lakes, and 

 gulfs, teeming with the skeletons of beings which are 

 blotted out from the face of the earth, compose the country 

 around the metropolis of France. 



Notwithstanding that the changes in the relative level of 

 the land and sea during this epoch were numerous and 

 extensive, one region still preserves traces of its original 

 physical geography ; and though the earthquake has rent 

 its mountains to their very centre — though hundreds of 

 volcanoes have again and again spread desolation over the 

 land — and inundations and mountain torrents have exca- 

 vated valleys, and chequered the plains with ravines and 

 water-courses — yet the grand primeval features of that 

 country remain ; and we can trace the boundaries of its 

 ancient lakes, and the successive changes which its surface 

 has undergone, from the first outbreak of its volcanoes, to 

 the commencement of the present state of repose. The 

 lowermost lacustrine deposits in Auvergne, which are 

 spread over the foundation rocks of gneiss and granite 

 unmixed with igneous productions, mark the period ante- 

 cedent to the volcanic era ; while the intrusions of lava and 

 scoriae in the superincumbent strata, denote the first erup- 



