124 The Founders of Geology LECT. 



he called the "highly probable conjecture that most, if 

 not all, volcanoes arise from the combustion of under- 

 ground seams of coal." 1 The coal might be set on 

 fire by spontaneous combustion, and the most vigorous 

 volcanoes would be those starting on the thickest masses 

 of coal. In order to support this belief, it was necessary 

 to furnish evidence of the existence of deposits of coal 

 around volcanoes. And much research and ingenuity 

 were displayed in collecting all the known examples. Not 

 only coal, but every kind of natural inflammable substance 

 was pressed into service, and made to do duty as fuel for 

 the subterranean fires. 



It was also obviously needful to maintain that volcanoes 

 must be comparatively modern phenomena. We are told 

 that "it was only after the deposition of the immense 

 repositories of inflammable matter in the Floetz-trap that 

 volcanoes could take place ; they are therefore to be con- 

 sidered as new occurrences in the history of nature. The 

 volcanic state appears to be foreign to the earth." 2 



The similarity of basalt to many undoubtedly volcanic 

 rocks had long been noticed, and could not escape the 

 observant eyes of Werner. But he did not therefore 

 infer basalt to be of volcanic origin. He had already estab- 

 lished, as one of the indisputable canons of geognosy, 

 that basalt was precipitated from chemical solution in 

 a universal ocean. The way in which he accounted for 

 the resemblance between basalt and lava must be regarded 

 as a signal proof of his ingenuity. He announced that 

 volcanoes not only occur where there are seams of coal, but 



1 See the paper just cited in Hopfner's Magaz. iv. (1789), p. 240. 

 2 Jameson's Geognosy, p. 96. 



