176 The Founders of Geology LECT. 



matters, proclaimed as late as 1810 his belief that De 

 Saussure overthrew the doctrine of central fire, or of a 

 source of heat within the earth's interior, demonstrated 

 granite to be the first-formed rock, and proved it to have 

 been formed in strata deposited in water. 1 Nobody before 

 Button's time had been bold enough to imagine a series of 

 subterranean intrusions of molten matter. Those who 

 adopted his opinion on this subject were styled Plutonists, 

 and were looked upon as a section of the Vulcanists, but 

 as carrying out their doctrines to still greater extravagance, 

 "attributing to the action of fire widely -diffused rocks 

 which nobody had till then ever dreamt of removing from 

 the domain of water." 2 



According to the Huttonian theory, fissures and openings 

 have from time to time arisen in the external crust of 

 the earth, and have reached down to the intensely hot 

 nucleus. Into these the molten material has ascended, 

 forming veins of whinstone underground, and, where it has 

 reached the surface, issuing there in the form of lava 

 and the other phenomena of volcanoes. Every geologist 

 recognizes these generalizations as part of the familiar 

 teachings of modern geology. 



We have seen that Werner made no distinction, as 

 regards origin, between what we now call mineral veins 

 and the dykes and veins of granite, basalt, or other 

 eruptive rocks. He looked upon them all as the results of 

 chemical precipitation from an ocean that covered the 

 rocks in which fissures had been formed. Hutton, in like 

 manner, drew no line between the same two well-marked 



1 Cuvier. "Eloge de De Saussure," filoges, i. p. 427. 

 2 Cuvier, op. cit. ii. p. 363. 



