419 



December 5, 18G0. 



The President in the Chair. 



Prof. W. B. Rogers made some remarks on the paleo- 

 zoic rocks of Dennis River in Maine, as compared with 

 those of certain parts of Nova Scotia recently described 

 by Prof. Dawson in the supplement to the Acadian 

 Geology. 



Among the specimens from the former locality, Prof. Rogers 

 had found Galymene Blumenbachii, Discina tenuilamellata, Cor- 

 nulites Jlexuosus, Tentaculites distans, Atrypa reticularis, an 

 Avicula apparently identical with A. Honey mani, and a Chonetes, 

 closely resembling C. Nova Scotica, all of which are mentioned by 

 Prof. Dawson as occurring in the rocks at Arisaig and New 

 Canaan, in Nova Scotia. Along with these forms are Beyrichia 

 lata, Spirifer sulcatus, Leptcena rugosa, Orthis elegantula, Mbdio- 

 lopsis ovatus, and others, the whole constituting a group sugges- 

 tive of an Upper Silurian age. As the specimens at this locality 

 are mostly in the condition of casts more or less distorted by 

 cleavage, some of the above identifications may hereafter require 

 correction, but enough is clearly made out to show the near cor- 

 respondence of these Silurian groups of Maine with those of Nova 

 Scotia. 



Viewing the different localities in connection with one another, 

 and with the recently discovered Trilobite beds of Eastern Mas- 

 sachusetts and Newfoundland, it would seem probable that we 

 have here parts of an extensive paleozoic area, of which the 

 greater portion is submerged beneath the adjacent expanse of 

 the Atlantic. 



Prof. W. B. Rogers commented on the view recently put forth 

 by M. Barrande in regard to the existence of a primordial 

 fossiliferous group in North America extending through a great 

 thickness of strata below the Potsdam sandstone, and on the re- 



