THEORIES OF ORE DISPOSITION HISTORICALLY CONSIDERED. 819 



he questioned whether it (Hd not retard it, since throuiih the great 

 weiglit of the autlior's name it remained a standard work in (lerniany 

 long after many of liis peculiar geological theories had been dis- 

 canU-d. Its merit lay less in the novelty of the views advanced, most 

 of which had already been put forth 1)V one or another of liis j)rede- 

 cessors, than in the logical way in which they were j)resented. 



The principal ])oints with regard to the origin of ore dei)osits 

 which may be considered as fairly Avell established by Werner's 

 teachings are that they are the Hlling of fissures and cracks of later 

 formation than the inclosing rocks, and consist of foreign material 

 subsequently introduced, largely in aqueous sohition. As to the 

 fissures themselves, while a certain systematic arrangement had been 

 noted in their directions, aiul the fact that, where by intersection, 

 one had l)een shifted or faidted by another, inferences as to tlieir 

 relative age might l)e drawn, little definite conception was appar- 

 ently had as to their origin l)eyond the general suggestion that they 

 might be the result of subsidence oi- of contraction of the rock masses 

 in which they occur. 



Any important ad\ain'e over these rather crude conceptions was 

 Iiai"dly to l)e looked for until very decided ])rogress had been made in 

 the broad general theories of geology, and this })rogress was neces- 

 sarily very slow. Although the period of reasoning from facts of 

 nature to generalizations had connuenced, the tendency to pure 

 speculation was not yet extinct, and resulted in many remarkable 

 theories, such as that put forth by Professor Oken, of Jena, who, 

 in his text-book of Natural Philosophy (ISODK assumed that the 

 earth was a polyeder formed according to tlu» laws of crystallo- 

 graj)hy, and that veins or fissures resulted from the loss of the 

 water of crystallization. For the genesis of ores, dai-kness, earthy 

 water, and air are necessai'y ; hence there can be no ore in the interior 

 of the earth, since no air reaches it, etc. Or, again, that of Rreislak, 

 the Italian geologist (1811), who put forth a phitonic earth theory 

 which supposed that Avhile the rocks were still in a molten condition 

 the metals had a tendency to sej)arate under the influence of specific 

 gravity and of certain chemical and physical aflinities. and localized 

 tliemsehcs in veins without entirely separating from their country 

 rock. This is appai'ently the first enunciation of the modern theory 

 of magmatic segregation. The metallic grains in placei's he supposed 

 to have been granulated like slag on coming in contact with water. 



The peculiar views of Werner naturally held sway longer in (ler- 

 manj'' than elsewhere, yet it Mas his favorite pupils that were first 

 led, in their widening fields of observation, to abandon his theory 

 that basalt is of aqueous origin, though altered by the heat produced 

 through the combustion of neighboring beds of coal. 



Von Buch, for a long time the leadinir geologist of ( Jermanv. was 



