REVIEWS — ACADIAK GEOLOGY. 43 



rous period. Satisfactory proofs of the posterior age of another 

 portion, are entirely due to Mr. Dawson's researches. The only 

 debateable point that remains for future elucidation, affects the 

 question as to whether these newer strata belong to the Permian or 

 to the Triassic epoch. The author's opinion referring them to the 

 former, is probably the correct one. In Nova Scotia, this upper for- 

 mation is chiefly limited to the inner coast of the Bay of Pundy ; 

 but it appears to occupy, on the other hand, the entire area of Prince 

 Edward's Island. At Walton, near the mouth of the Shubenac- 

 adie, X. S., Mr.Dawson met with it resting in slightly inclined beds on 

 the upturned edges of the lower strata ; and he gives in his book, 

 from one of his earlier papers communicated to the Geological So- 

 ciety, an exceedingly interesting section illustrative of this want 

 of conformability between the two formations. The new red sand- 

 stone in Nova Scotia is every where traversed by extensive outbursts 

 of trap belonging to the same geological period. Cape Blomidon, 

 Cap d'Or, and other bold and picturesque headlands of the Bay of 

 Pundy, are thus constituted. These trap localities offer to the 

 mineralogist a rich harvest of zeolitic and other specimens. As in 

 the older trap of Lake Superior, native copper is also present, but 

 in comparatively small and unimportant quantities. Pollowing Dr. 

 Jackson and others, Mr. Dawson attributes the origin of the copper 

 to deposits from solutions by electro-chemical action : although he 

 states at the same time, " why this deposit should have occurred 

 in trap rock does not appear very obvious" ; and, furthermore— 

 " when we take a piece of native copper from Lake Superior or Cap 

 d'Or, with the various calcareous and silicious minerals which accom- 

 pany it, nothing can be more difficult than to account on chemical 

 principles for these assemblages of substances, either by aqueous or 

 igneous causes." There can be no doubt that the precipitation of 

 metallic copper by natural voltaic agencies is a phenomenon of actual 

 occurrence ; and, looking, amongst other circumstances, to the small 

 amount of copper present in the trap of Nova Scotia, we might be 

 justified, were further considerations kept ovit of view, in adopting 

 the author's conclusions for that particular locality. But, with re- 

 gard to the origin of the Lake Superior copper, occurring in such 

 vast and apparently inexhaustible masses in the more ancient trap 

 of that district, we hold the opinion of Agassiz and other observers, 

 to be the true one, viz. — that, like the igneous rock with which it is 

 so intimately blended, the copper is itself of igneous origin. If we 

 allow the copper to be an igneous product, its occurrence in these 

 igneous rocks of different geological ages, and in widely-remote 

 localities — as in the Silurian trap of Lake Superior, the Triassic or 



