THE SCIENTIFIC PERIOD 11 



disturbed condition, and the changes produced in the older rocks, to 

 which 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 material held in suspen- 

 sion 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 Werner's, and his views have hence proved 

 more enduring, but he had little, if any, personal knowledge of ore de- 

 posits. Werner made their study an important feature]of the geologist's 

 training, and his principal publication was entitled "A new theory of 

 vein formation." Although this work was the only important one ex- 

 clusively devoted to the subject, owing to the fatal defects in his geolog- 

 ical premises, it contributed little to the permanent advancement of that 

 branch of the science, and it may even be questioned whether it did not 

 retard it, since through the great weight of the author's name it remained 

 a standard work in Germany long after many of his peculiar geological 

 theories had been discarded. Its merit lay less in the novelty of the 

 views advanced, most of which had already been put forth by one or 

 another of his predecessors, than in the logical way in which they were 

 presented. 



The principal points with regard to the origin of ore deposits which 

 may be considered as fairly well established by Werner's teachings are 

 that they are the filling of fissures and cracks of later formation than the 

 enclosing rocks, and consist of foreign material subsequently introduced, 

 largely in aqueous solution. As to the fissures themselves, while a cer- 

 tain systematic arrangement had been noted in their directions, and the 

 fact that, where by intersection, one had been shifted or faulted by an- 

 other, inferences as to their relative age might be drawn, little definite 

 conception was apparently had as to their origin bej^ond the general sug- 

 gestion that they might be the result of subsidence or of contraction of 

 the rock masses in which they occur. 



Any important advance over these rather crude conceptions was hardly 

 to be looked for until very decided progress had been made in the broad 

 general theories of geology, and this progress was necessarily very slow. 

 Although the period of reasoning from facts of nature to generalizations 

 had commenced, the tendency to pure speculation was not yet extinct, 

 and resulted in many remarkable theories, such as that put forth by Pro- 



