638 THE LOWER SILURIAN PERIOD. 



Brought forward 2300 



5. Black carbonaceous shales, resembling 3 b, but finer and 



softer 450 



6. a. Shales and flags like 2 a and b : Lingula, a Conchifer, 



Coprolites, Worm-burrows, and Crustacean markings 700 (?)"> 

 b. Gray and ferruginous sandstones and beds of coarse >1100 (?) 



shale : Lingula ...... V 400 ) 



7. Black carbonaceous shales, finely laminated . . . 650 





4500 " 



Westward of the St John River, the rocks of this series extend 

 through Carlton, but soon diminish in thickness and disappear. To 

 the eastward they are prolonged in a band skirting the older (sup- 

 posed Huronian rocks) to Loch Lornond, where they disappear along 

 the line of outcrop proceeding from St John, but reappear on the other 

 side of a synclinal, and extend with opposite dips nine miles farther 

 to the eastward. Their whole extension in this district is about thirty 

 miles, with a breadth of about four miles. Farther details will be 

 found in Professor Bailey's Report. 



Though thus limited in their distribution, these beds are in the 

 highest degree important in a geological point of view, as their fossils 

 establish for the first time on the American Continent a series of 

 fossiliferous beds older than the Potsdam sandstone, hitherto sup- 

 posed by American geologists to be our oldest Palaeozoic group ; and 

 corresponding with the older Lingula flags of Wales, and with Bar- 

 rande's " Etage C." in Bohemia. These fossils also contribute to 

 affix the same age to the Paradoxides slates of Newfoundland, and 

 of Braintree, Massachussets. In other words, they add a new forma- 

 tion to the Palaeozoic period in America. This formation has as yet 

 been known as the St John group ; but I think this name unsuitable, 

 both on account of the number of places known as St John, and on 

 account of the variety of formations occurring near St John in New 

 Brunswick, and would therefore propose for the group now under 

 consideration, characterized by Paradoxides, Conocephalites, etc., 

 and the oldest known member of the Palaeozoic of America, the name 

 Acadian Group, by which I hope it will be known to geologists 

 in whatever part of America it may be recognised. 



In the northern part of New Brunswick a broad belt of metamor- 

 phic rocks with granite bands extends from the south shore of the 

 Bay de Chaleur westward of Bathurst in a south-west direction 

 to the sea-coast of Maine. These rocks were denominated " Cambrian " 

 by Dr Gesner and Dr Robb, but by more recent observers are regarded 

 as Lower Silurian, principally on the ground of difference in mineral 

 character from the Huronian rocks and similarity to those of the 





