148 Reports on the Geology of the State of Maine. 



they descend. This appears to be the case with the Lubec Lead 

 Mines, so far as they have been examined." 



" In Nova Scotia likewise, the most valuable beds of iron ore are found 

 in the immediate vicinity of similar rocks, while at Cape D'Or, in the same 

 province, we find an abundance of rounded (evidently once mollen) 

 masses of copper, in the mixture of trap rocks with the new red sand 

 stone." 



The hypothesis of segregation, which has recently been offer- 

 ed in explanation of the origin of metallic veins in rocks, finds 

 no support from discoveries thus far made known in Maine ; and 

 we must think that, should it continue to be received at all, its 

 application must be limited to veins contained in those rocks, 

 through which there are also abundantlj^ disseminated concre- 

 tionary masses of the same substance, at a distance from the 

 veins. The theory of igneous injection, certainly offers a more 

 unexceptionable explanation of all those veins of a contrary char- 

 acter, or whose substance is entirely foreign to the nature of the 

 rock in which they are contained ; and to oppose it on the ground 

 that the " extinct volcanoes of France afford no other metallic min- 

 eral than ' a little oligiste iron,' " (implying that if veins were form- 

 ed by igneous injection, these volcanic rocks would present them 

 to a great extent,) seems to us hardly sufficient ; for we are not to 

 infer that the metals were always in a situation to be thrown up, 

 and therefore the rocks of some epochs, whose volcanic origin is 

 undoubted, may be comparatively, or even positively, nonmetal- 

 liferous, while others of the same character may abound in met- 

 als ; at least, the objection referred to, is removed by the well 

 known fact, that various metals, such as tellurium, gold, copper, 

 iron, and antimony, are the frequent products of volcanoes not 

 yet wholly extinct. However, we are rather inclined to agree 

 with Mr. Bakewell, that these phenomena, whether caused by 

 electro-chemical agency, by sublimation, or by igneous injection, 

 are involved in much obscurity, and that the state of chemical 

 science, with the facts at present known, do not throw any cer- 

 tain light upon it. 



The other metallic minerals enumerated, beside iron, are lead, 

 zinc, molybdena, titanium, manganese, copper, bismuth, and 

 tungsten. The latter mineral, occurring in the usual form of 

 wolfram, which accompanies all the tin mines of Europe, has led 

 Dr. Jackson to anticipate the discovery of tin in Maine \ a dis- 



