134 ROYAL SOCIETY CF CANADA 



cycle does uot agree with the systematic divisions adopted in Europe. 

 Practically it is impossible to map these two bands separately from the 

 rest of the St, John terrane, owing to the rarity of fossils and the close 

 litho logical resemblance between bands c and d, one Cambrian and the 

 other Ordovician, and also the thinness of the Ordovician. 



The Silurian Cycle. 



Betnveen the cycle last described and this there was a great hiatus, 

 for there is no trace of the Upper Ordovician in all this region. "While 

 the great Trenton limestone, and Lorraine shales were being deposited 

 in the more <?entral part of the continent and along the valley of the 

 St. Lawrence, the region of Acadia appears to have been above the sea; 

 or at least there are no marine deposits in any part of it, -w-ihich by thair 

 organic remains show that the sea covered any part of the land at this 

 time. Such being the case we are prepared to look for shore deposits 

 as those which shall usher in the beginning of a new cycle of depression. 



When free from the irregularities due to the proximity of shores 

 or to volcanic ejections, this cycle is found to consist in southern New 

 Brunswick of the following members: — 



1. Quartzites or coarse slates Medina horizon. 



2. Black argillites or shales Clinton " 



3. Dark gray argillites or shales Niagara " 



4. Pale gray argillites or shales L. Helderberg " 



A shallow water and a thin phase of this cycle is seen in the Mas- 

 carene series in the S.W. of New Brunswick which consists of ^ : 



FEET. 



1. Hard gray feldspathic slates and argillites 400 



2. — Black and dark gray silicious beds, with distinctly alternating 



bands of colour; obscure remains of plants 620 



3. Gray sandy flags and argillites, with gray sandstones 350 



4. Greenish and reddish sandstones and argillites 310 



5. Dark red felsite, effusive 300 



1,980 



Here the cycle appears to have been cut short by the rising of the 

 lajîd, for a Niagara fauna has been found in the equivalent of the 

 third member, and the fourth and fifth are largely made tip of volcanic 

 effusives, and so may have accumulated rapidly. 



^Rep. Proff. Geol. Surv. Can., 1870-71, p. 145. 



