LAMARCK'S WORK IN GEOLOGY 95 



upon a scientific basis." And not only did Rousseau 

 make botany fashionable, but Goldsmith wrote from 

 Paris in 1755 : "I have seen as bright a circle of 

 beauty at the chemical lectures of Rouelle as gracing 

 the court of Versailles." Petit lectured on astron- 

 omy to crowded houses, and among his listeners were 

 gentlemen and ladies of fashion, as well as profes- 

 sional students.* The popularizers of science during 

 this period were Voltaire, Montesquieu, Alembert, 

 Diderot, and other encyclopaedists. 



Here should be mentioned one of Buffon's contem- 

 poraries and countrymen ; one who was the first true 

 field geologist, an observer rather than a compiler or 

 theorist. This was Jean E. Guettard (1715-1786). 

 He published, says Sir Archibald Geikie, in his valu- 

 able work. The Founders of Geology, about two hun- 

 dred papers on a wide range of scientific subjects, 

 besides half a dozen quarto volumes of his observa- 

 tions, together with many excellent plates. Geikie 

 also states that he is undoubtedly entitled to rank 

 among the first great pioneers of modern geology. 

 He was the first (175 1) to make a geological map of 

 northern France, and roughly traced the limits of his 

 three bands or formations from France across the 

 southeastern English counties. In his work on " The 

 degradation of mountains effected in our time by 

 heavy rains, rivers, and the sea,"f he states that the 



'^France under Louis XV. , p. 360. 



f See vol. iii. of his Miinoires stir differentes Parties des 

 Sciences et des Arts, pp. 209-403. Geikie does not give the date 

 of the third volume of his work, but it was apparently about 1771, 

 as vol. ii. was published in 1770. I copy Geikie's account of Guet- 

 tard's observations often in his own words. 



