428 PROCEEDINGS OP THE GEOLOGICAL SOCIETY. [May 10, 



base of the St. John series is known to be on the horizon of the 

 Potsdam, while the middle and superior portion probably represents 

 the Calciferous or the Llandeilo of Britain (and perhaps higher 

 formations), it does not seem likely that Professor C. H. Hitchcock's 

 surmise will be substantiated. He says, " It would not be strange 

 if the name Cambrian, which was applied to both these belts of 

 mica-schist in New Brunswick many years ago, and is now generally 

 discarded, should ultimately prove to be their correct appellation." 



In the alternations of arenaceous and dark-coloured clay-slate 

 with intercalated quartzite, this formation, which is also auriferous, 

 resembles the gold-bearing series of the Atlantic coast of Nova 

 Scotia, long ago recognized as Lower Silurian by Dr. Dawson *. If 

 both prove to be on the same horizon geologically as the St. John 

 series, namely, the lower part of the Lower Silurian, our knowledge 

 of the age and relations of the older metamorphic rocks of Acadia 

 will be placed on a firmer basis than heretofore. 



So far as our knowledge goes, they differ from cotemporaneous 

 deposits to the westward in being conformable to the Huronian 

 series ; and also in the rarity of calcareous and magnesian sediments, 

 there seeming to be little else than shales of various degrees of fine- 

 ness, flagstones, and quartzites. 



V. Upper Silurian. 



The strata noticed under this head may prove to be in part either 

 above or below the horizon I now place them in ; for they are for the 

 most part highly metamorphosed, and organic remains are rare. 



They cover an area of about seventy mUes long and twenty wide, 

 stretching north-eastwardly from Passamaquoddy Bay, and including 

 the highest eminences in the southern counties. 



The evidence bearing upon their age may be summed up as 

 follows : — 



1st. Dr. Dawson, to whom a suite of the metamorphic rocks was 

 submitted, remarks — 



" In comparing them with Nova Scotia I have no hesitation in 

 saying that they are unlike our Atlantic-coast series, which I 

 believe to be Lower Silurian ; but they are very like the rocks of the 

 Cobequid Mountains, and of the inland hUls of east Nova Scotia, 

 which I believe to be Middle and Upper Silurian." 



2nd. There is a district in the south-east part of Maine, about 

 twenty mUes wide, occupied by Upper Silurian rocks, which extend 

 through the islands of Passamaquoddy Bay into New Brunswick. 



3rd. Fragments of shale occur in the " drift " at St. John, holding 

 CTionetes, Pterinea or Avicula, ClidopJiorus, Oriliis, Mhynchonella?, 

 Leptodomus ?, &c., which appear to have been derived from a band 

 of grey shales on the north-west side of the supposed Upper SUurian 

 district. 



It would thus appear that the highest and most broken tracts in 

 this and the neighbouring province are composed of the metamorphic 



* See also ' Can. Nat.' vol. v. p. 134. 



