THE STORY OF NINETEENTH-CENTURY SCIENCE 



during which the level of the crust is undisturbed, fol- 

 lowed by short periods of active stress, when continents 

 are thrown up with volcanic suddenness, as by the throes 

 of a gigantic earthquake. But now came Charles Lyell 

 with his famous extension of the " uniformitarian" doc- 

 trine, claiming that past changes of the earth's surface 

 have been like present changes in degree as well as in 

 kind. The making of continents and mountains, he said, 

 is going on as rapidly to-day as at any time in the past. 

 There have been no gigantic cataclysmic upheavals at any 

 time, but all changes in level of the strata as a whole have 

 been gradual, by slow oscillation, or at most by repeated 

 earthquake shocks such as are still often experienced. 



In support of this very startling contention Lyell 

 gathered a mass of evidence of the recent changes in 

 level of continental areas. He corroborated by personal 

 inspection the claim which had been made by Play fair 

 in 1802, and by von Buch in 1807, that the coast-line of 

 Sweden is rising at the rate of from a few inches to sev- 

 eral feet in a century. He cited Darwin's observations 

 going to prove that Patagonia is similarly rising, and 

 Pingel's claim that Greenland is slowly sinking. Proof 

 as to sudden changes of level of several feet, over large 

 areas, due to earthquakes, was brought forward in 

 abundance. Cumulative evidence left it no longer open 

 to question that such oscillatory changes of level, either 

 upward or downward, are quite the rule, and it could 

 not be denied that these observed changes, if continued 

 long enough in one direction, would produce the highest 

 elevations. The possibility that the making of even the 

 highest ranges of mountains had been accomplished 

 without exaggerated catastrophic action came to be 

 freely admitted. 



126 



