228 PROGRESS OF SCIENCE IN THE CENTURY. 



may have been rhythms and changes in the action 

 of the known factors." * 



Summary. — " From Steno onward the spirit of 

 geology was catastrophic; from Hutton onward it 

 grew increasingly uniformitarian ; from the time of 

 Darwin and Kelvin it has become evolutional/' f 

 '' The Catastrophists had it all their own way until 

 the Uniformitarians got the upper hand, only to he 

 in turn displaced by the Evolutionists/' ij: 



FOUNDATION STONES OF GEOLOGY. 



Even in the later decades of the eighteenth century 

 geology as a distinct science did not exist, but its sure 

 foundations were being laid. Thus Sir Archibald 

 Geikie has rescued from undeserved oblivion (in 

 Britain at least), the name of Jean fitienne Guettard 

 (1715-1786) — "the first to construct, however im- 

 perfectly, geological maps, the first to make known 

 the existence of extinct volcanoes in Central France, 

 and one of the first to see the value of organic re- 

 mains as geological monuments, and to prepare de- 

 tailed descriptions and figures of them. To him also 

 are due some of the earliest luminous suggestions on 

 the denudation of the land by the atmospheric and 

 marine agents." ** 



Another illustrious pioneer was Nicholas Desmar- 

 est (1725-1815), who amid the labours of a life 

 devoted to fostering the industries of France, found 

 time to map the volcanic rocks of Auvergne, to work 

 out a theory of the volcanic origin of basalt, to trace 



* See J. E. Marr. Address Section C, Rep. Brit. Ass., 

 1896, p. 775. 

 t Sollas, loc. cit. 



t Geikie. Founders of Geology, 1897, p. 288. 

 ** Sir Archibald Geikie. Founders of Geology, 1897, p. 46, 



