THE DISTRIBUTION OF ANCIENT VOLCANIC ROCKS. 1/ 



tor's Brook, Georgeville, Blue Mountain and East River of St. 

 Mary's. These are quite like the Cape Breton and Cape Porcu- 

 pine rocks, and carry copper, as they do in South Mountain, Pa., 

 and on Lake Superior. He gives the age of these eruptions as 

 probably pre-Cambrian, although at Arisaig they may be of any 

 age older than Medina. Similar volcanic eruptions occur in all 

 strata up to the base of the Carboniferous.^ In his last report 

 covering Pictou and Colchester counties, the same author 

 describes Cambro-Silurian porphyries, agglomerates, fragmental 

 felsites, breccias and amygdaloids from Moose and Sutherland 

 rivers. A dyke-like mass of volcanic breccia occurs on Sam 

 Cameron's brook. Similar volcanic products are also very 

 apparent in the Devonian of these two counties, among the most 

 interesting of which are the syenitic granites overlaid by thick 

 volcanic deposits at the east end of the Cobequid Hills, as 

 described by Dawson.^ The well-known traps of northwestern 

 Nova Scotia, along the Bay of Fundy, which furnish the beauti- 

 ful zeolites and other minerals, are of Triassic age. 



In New Brunswick and the Gaspe Peninsula, old volcanic 

 rocks, like those of Newfoundland and Nova Scotia, are exten- 

 sively developed. Ells and Low mention amygdaloidal traps and 

 porphyries cutting various strata of Gaspe, up to and including 

 the Devonian. 3 Felsitic rocks, similar to those which are better 

 known further to the south, are rather vaguely mentioned by 

 Robb in northern New Brunswick."* Ells, in his report on the 

 same region in 1879—80, clearly describes as volcanic both acid 

 and basic rocks. A vast area of felsite, petrosilex, porphyry 

 and breccia, like that near St. Johns, is developed in the upper 

 Nipisiguet river and lake Nictor. Another like it extends 

 from the upper Upsalquitch river along Jacket river to the 

 bay of Chaleur, while great masses of basic volcanics (amyg- 



^Ib., 1886, P. 



=^ Acadian Geology, 1878, suppl., p. 79. 

 Report of the Geol. Survey of Canada, new ser., Vol. 5, 1890-91, P. pp. 147-166. 



3 lb., 1882-83-84, E. and F. 

 '*Ib., 1870-71, p. 245. 



