Wadsworth.] 204 [May 7» 



one cause — the action of percolating waters (whether thermal or 

 not) in collecting the copper disseminated through the old bas- 

 altic lavas and concentrating it in whatever suitable recep- 

 tacles existed in the lavas and their associated conglomerates, 

 and in the fissures traversing them. Here the theory of "Lateral 

 secretion" applies, not only to the copper, but to its associated 

 gangue and amygdaloidal minerals. 1 



At Cape D'Or, on the Bay of Fundy, native copper occurs in 

 relations similar to those observed on Lake Superior. Here, how- 

 ever, are found only the basaltic rocks (melaphyrs and diabases), 

 and the copper is disseminated in part through them, and in part 

 occurs in veins. As at Lake Superior the rocks are more or less 

 amygdaloidal, and the preceding explanation is used here to 

 account for the origin and concentration of the copper ; which, 

 however, has not been found at Cape D'Or in sufficient amounts 

 to warrant exploitation. 



The copper ores of Newfoundland, in the vicinity of Notre Dame 

 Bay, are chiefly the yellow sulphide (chalcopyrite) associated with 

 pyrite and quartz. These ores occur in connection with argillaceous 

 and chloritic schists cut through by dikes and irregular masses of 

 old basaltic rocks (melaphyrs and diabases), in all of which the 

 ores are either disseminated or form gash veins. The theory of 

 their origin adopted by the writer is as follows. During the 

 eruptive activity, but after the principal portion of the basalt, if 

 not all, had been extraversated, the action of percolating thermal 

 waters on the eruptive rock and its adjacent fissured and broken 

 sedimentary rocks led to the concentration and deposition of the 

 copper ore, iron pyrites, and quartz in the places in which they 

 are now found. As in the preceding cases the copper is supposed 

 to have been brought up from the earth's interior by the basalt, at 

 which time the ore was finely disseminated through the lava 2 , and 

 subsequently concentrated. 



Copper ore occurs on Waugh's River in Nova Scotia about 

 three miles from Tatamagouche Harbor, an inlet on the south 

 side of Northumberland Strait. The country rock is a sandstone 

 composed of granitic detritus, and contains clay, fragments of 

 lignite, and other carbonaceous materials. Associated with this 



1 Bull. Mus. Comp. Zool., 1880, vn, 76-157; Proc. Bost. Soc. Nat. Hist. 1880, xxi, 

 91-103. 



2 Am. Journ. Sci., 1884, XXVlll, 91-104. 



