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 0 have Sceneas-brieht 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 encyclopzdists. 
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, Zhe 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 (1751) 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,’+ he states that the 
* France under Louts XV., p. 300. 
+See vol. iii, of his A/émotres sur differentes Parties des 
Sctences 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, 
