296 THE CANADIAN NATURALIST. [Jan. 



These insects are the first ever found in rocks older than the 

 Carboniferous. 



These rocks, consisting chiefly of hard shales and sandstones, 

 having been ascertained to be Devonian, there still remained an 

 immense thickness of underlying rocks of uncertain age. In the 

 upper member of these rocks, the same active observers already 

 mentioned have observed a rich primordial fauna, embracing species 

 of Conocephalites, Paradoxides, Microdiscus, andAgnostus, as well 

 as an Orthis, and a new type of Cystidians. These fossils are 

 regarded by Mr. Hartt and Mr. Billings as of the age of Barrande's 

 " Etage C," and as marking a new and older period of the " Silurian 

 Primordial" than any other as yet recognized in America, with the 

 exception of the slates holding Paradoxides in Massachusetts, and 

 the similar slates of the "Older Slate Formation" of Jukes, in 

 Newfoundland. Descriptions of these fossils, by Mr. Hartt, will 

 be published in the edition of " Acadian Geology" now in press. 

 It is proposed to call this series, represented in New Brunswick by 

 the St. John slates, the Acadian Series. 



Below these primordial beds are highly metamorphosed rocks, 

 at least 9,000 feet in thickness, which have afforded no fossils. 

 A portion of these, consisting principally of conglomerate and 

 trappean beds, is regarded by Messrs. Matthew and Bailey as 

 of the age of the Huronian. The remainder, containing much 

 gneiss and a bed of crystalline limestone, they regard as Lau- 

 rentian. If this view is correct, and it certainly seems to be 

 probable, these rocks, thus rising through the oldest members 

 of the Lower Silurian, and forming a stepping-stone between the 

 Laurentian of Newfoundland and that of New Jersey, show that 

 the foundations of the north-east and south-west line of the east 

 side of North America were already laid in the Laurentian period. 

 Still, it is not here, but farther west, that we are to look for the 

 dividing line between the great inland Silurian basin of America, 

 and that of the Atlantic coast ; the latter has been pointed out by 

 Professor Hall and Sir. W. E. Logan, as remarkably distinguished 

 by the predominance of mechanical sediments, and by a develop- 

 ment of the lower rather than the upper members of the Lower 

 Silurian. 



To ascend from these rocks to the Carboniferous, — recent labors 

 of Mr. Davidson, Mr. Hartt, and the author, had led to the division 

 of the Lower Carboniferous into successive subordinate stagehand 

 to the determination of most of the marine fossils, and also to the 



