362 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [March 13, 



posit are few and not very decisive. The character of the fissui'e in 

 which the vein is contained, leaves little doubt that the metamorphism 

 of the containing rocks was complete or nearly so before its forma- 

 tion. If, as seems most probable, these rocks be of Silurian age, 

 and if, as the lower carboniferous conglomerates testify, their meta- 

 morphism occurred before the commencement of the carboniferous 

 deposits, we have a limitation of the age of the vein, at least in one 

 direction. On the principles stated in my paper on the Colouring 

 Matter of Red Sandstones*, the metamorphosed carbonate of iron of 

 this deposit might have produced on aqueous deposits, formed con- 

 temporaneously with or subsequent to its metamorphism, effects in 

 relation to colour similar to those which I have supposed to result 

 from the decomposition of sulphuret of iron. The carboniferous beds 

 at the base of the hills, however, do not present any greater amount 

 of the peroxide of iron than the same beds in other locahties ; and 

 are indeed, in comparison with those of the opposite side of the Bay 

 of Fundy, rather deficient in this respect. The carboniferous beds of 

 the northern side of the hills are indeed more highly coloured by red 

 oxide of iron than those of the south side. Another fact bearing on 

 the age of this deposit, is the occurrence, in other parts of the syenitic 

 metamorphic group, of slender veins of specular iron ore and ankerite 

 in altered lower carboniferous rocks. If these small veins be of the 

 same age with the great vein of the Cobequid hills, the latter must 

 be of later date than the beginning of the carboniferous period. 

 These small veins are, however, at too great a distance from that 

 now under consideration to allow any actual connection to be traced. 

 On the whole, it seems probable that the filling of this vein is of later 

 date than the Silurian period, and it may possibly have been poste- 

 rior to the carboniferous epoch. 



In the eastern extremity of the Cobequid hills, and in the group 

 of hills connected with Mount Thom, small metalliferous veins have 

 been found in various places. From the ^dcinity of the northern 

 branch of the Salmon River I have received specimens of specular 

 iron and brown hsematite, contained in quartz-rock similar to that of 

 the Cobequid hills, and similar specimens are found in different parts 

 of Mount Thom. From the south branch of Salmon River I have 

 received, from small veins in slate of the syenitic system, specimens 

 of copper pyrites containing 31-6 per cent, of copper. This pyrites 

 is associated with sulphate of barytes ; and in the same locality there 

 are veins of ankerite, containing disseminated crystals of copper 

 pyrites. Near the salt springs at the West River of Pictou, veinlets 

 of specular iron occur in altered lower carboniferous beds. In brooks, 

 emptying into the West River and the upper part of the Middle River, 

 both specular iron and ankerite occur in slender strings. Such ap- 

 pearances are indeed very common in all that tract of metamorphic 

 country lying to the south of the Pictou carboniferous district. In 

 the vicinity of the East River of Pictou, however, there are other de- 

 posits of iron ore which must not be confounded with these veins of 

 the metamorphic rocks. One of these is the conformable bed of per- 



* 1848. Quart. Journ. Geol. Soc. vol, v. p. 25. 



