30 THE DOCTRINE OF DESCENT. 



Even after the appearance of Lyell's " Principles of 

 Geology," the hypothesis of catastrophes received its 

 special completion by Elie de Beaumont's theory of the 

 structure and genesis of mountain chains. From the 

 first, however, Lyell interposed, and derived the following 

 conclusion from a comparison of the slow but continued 

 and perceptible upheavals and subsidences occurring 

 in historic times, with the various modifications which 

 organisms had meanwhile undergone. " In a word, the 

 movement of the inorganic world is obvious and pal- 

 pable, and might be likened to the minute-hand of a 

 clock, the progress of which can be seen and heard ; 

 whereas the fluctuations of the living creation are 

 nearly invisible, and resemble the motion of the hour- 

 hand of a time-piece. It is only by watching it atten- 

 tively for some time, and comparing its relative position 

 after an interval, that we can prove the reality of its 

 motion." 



Careful observation and logical deduction had thus 

 arrived at conclusions diametrically opposite to the 

 assertions of Cuvier, who inferred the geological catas- 

 trophes mainly from the striking difference of successive 

 organisms. While botanists and zoologists prosecuted 

 their studies on Cuvier's system, Geology was being 

 metamorphosed under the hands of Lyell and his adhe- 

 rents. He proceeded from the most tangible basis. 

 That it rained during the era of the coal formation, as 

 it now rains, may be seen by the impress of rain-drops 

 on the levels of that formation. The actions of rivers, 

 the sediments of deltas, previously neglected, were now 

 studied, and likewise the colossal mud deposits, such as 

 are exhibited by the Nile and the Amazon, and also the 



