318 THEORIES OF ORE DISPOSITION HISTORIC AX,LY CONSIDERED. 



rendered to geology at Edinburgh, in Scotland, by James Hiitton, 

 who, like so many of the eminent geologists of the world, had been 

 educated as a physician. Plutton, like Werner, taught mainly through 

 his lectures, neither of them finding time for much writing, so that 

 the doctrines of either have become known to posterity mainly 

 through the jDublications of their pupils. 



Each of these great teachers aimed to discard theory and to build 

 their respective systems on a basis of ascertained facts, but in the then 

 existing condition of geological investigation certain fundamental 

 conceptions had to be assumed from the interpretation given to as yet 

 imperfectly studied j^henomena. With minds like theirs, strong in 

 the courage of their convictions, an inter})retation once fairly rea- 

 soned out and accepted became an established fact, and thus it came 

 about that through a dilTerence in their premises their respective sys- 

 tems Avere diametrically opposed and gave rise to the great controversy 

 between Neptunists and Plutonists, which for nearly fifty years di- 

 vided the scientific world of Europe into two antagonistic schools. 

 Werner assumed that the earth had once been surrounded by an ocean 

 of water at least as deep as the mountains are high, and that from this 

 ocean there were deposited by chemical precipitation the solid rocks 

 which now form the dry land. He entirely ignored the internal heat 

 of the globe in its influence on crystalline rocks, on ore deposits, and 

 as a cause of the dislocations of stratified rocks. Hutton, on the 

 other hand, while not ignoring the agency of water in the formation 

 of the sedimentary rocks, ascribed to subterranean heat and the ex- 

 panding power it exercised their final consolidation, their disturbed 

 condition, and the changes produced in the older rocks, to Avhich Lyell 

 later gave the name of metamorphism. 



Neither made any distinction between dikes and mineral veins, but 

 while Hutton supposed fissures and openings to have been formed 

 from time to time which reached through the external crust down to 

 the hot nucleus, and that both were formed by molten matter forced 

 up through them toward the surface, Werner, on the other hand, 

 taught that they were contraction fissures which were filled by ma- 

 terial held in suspension or in solution; that a primeval ocean once 

 covered them, and hence they must have been filled from above. 



In general matters Hutton's reasoning and observations were both 

 broader and more logical than AVerner's, and his views have hence 

 proved more enduring, but he had little, if any, personal knowledge 

 of ore deposits. A\\>rner made their study an important feature 

 of the geologist's training, and his principal })ul)lication was entitled 

 "A New Theory of Vein Formation.'" .Vlthough this work was the 

 only important one exclusively devoted to the subject, owing to the 

 fatal defects in his geological premises, it contributed little to the per- 

 manent advancement of that branch of the science, and it nuiy even 



