474 THE CANADIAN NATURALIST. [Vol. vlii. 



The volcanic members of these series are also often very irregular 

 in distribution, and there is little to distinguish them from each 

 other, even when their ages may be very different. These cir- 

 cumstances oppose many difficulties to the classification of all 

 the pre-Devonian rocks of Nova Scotia and New Brunswick, 

 difficulties as yet very imperfectly overcome." 



In New Brunswick and in Eastern Maine it appears that the 

 Upper Silurian rocks of the " Mascarcne " series are capped by 

 felsites, chloritic schists, and agglomerates of great thickness, 

 and having the aspect of Huronian rocks, while in Eastern Nova 

 Scotia similar rocks appear in the lower part of the Upper 

 Silurian. All that part of the Lower Silurian period intervening 

 between the Quebec group and the Utica shale of the interior 

 continental areas seems to have been characterised by the depo- 

 sition of similar volcanic beds, constituting with a group of over- 

 lying metalliferous slates, the " Cobequid series" of the author, 

 and resembling much more the Skiddaw and Borrowdale forma- 

 tions of England than the familiar rocks of the New York system. 



Below these however are fossiliferous beds of true Cambrian 

 age. In Cape Breton there have recently been recognised by 

 Mr. Fletcher, fossils indicating an Upper Cambrian group, 

 probably of the horizon of the Lingula flags. Below this is the 

 Acadian series so rich in Conocoryphe, Paradoxidcs and other 

 forms characterising the Middle or Lower Cambrian ; and the 

 author now regards the auriferous quartzites and slates of the 

 Atlantic coast of Nova Scotia as equivalent to the lowest Cam- 

 brian or Longmynd rocks of England. Some portions of this 

 Atlantic coast series, which are associated with intrusive masses 

 and dykes of granite, and which appear as gneisses and mica 

 schists, have been described as Huronian or Lauren tian ; but 

 the author regards this as an error and considers that they are 

 merely metamorphosed portions of the slates and quartzites. 



Distinguishable from all these in New Brunswick, and also in 

 Cape Breton and probably in Western Nova Scotia, are the 

 Huronian and Laurentian systems. In the close of the work an 

 attempt is made to present in a tabular form the equivalency of 

 the older rocks in Acadia and in Great Britain. This is of 

 course somewhat provisional, but may serve to aid comparisons. 



