i Guettard and the later Schools 43 



aqueous fluid, and that there is no reason to regard it as 

 due to igneous fusion." 1 



We may gather how little was then known of the 

 characters of modern lavas when Guettard was ignorant of 

 the occurrence of columnar structure among them. 2 He 

 was as hopelessly wrong in regard to the origin of basalt, 

 as he was with respect to the nature of volcanic action. 

 How this error originated will appear in an examination of 

 the controversy to which basalt gave rise. But the most 

 interesting feature in the passage just cited from Guettard 

 is not his mistake about basalt, but his clear enunciation 

 of his belief in its deposition from aqueous solution, for he 

 thus forestalled Werner in one of the most keenly disputed 

 parts of his geognosy. 



I know nothing more whimsical in the history of geo- 

 logy than that the same man should be the parent of two 

 diametrically opposite schools. Guettard's observations in 

 Auvergne practically started the Vulcanist camp, and his 

 promulgated tenets regarding basalt became the watchword 

 of the Neptunists. 



The notable Frenchman, of whose work I have now at- 

 tempted to give an outline, must have been a singular figure 

 as he moved about among his contemporaries. Endowed 

 with a healthy constitution, he had strengthened it by travel, 

 and by a hard and sober life. At last he became liable 

 to attacks of a heavy lethargic sleep, during one of which 

 his foot was burnt. The long and painful healing of the 

 wound he bore with stoical patience, though often convinced 

 of the uselessness of the remedies applied. " I see quite 



1 Op. tit. p. 268. 



2 We shall find that this ignorance continued for many years after 

 Guettard's time, and was characteristic of the Wernerian school. 



