PKOF. HALL'S COMPARISON OF FOSSILS. 383 



Sir William Logan yields to the palfeontological evidence, and says, "there must be a break." He gives 

 up the evidence of structural sequence which he had before investigated and considered conclusive; and 

 having heretofore relied upon the opinion of the distinguished Geologist of Canada in regard to a region 

 of country to which my own examinations had not extended, I have nothing left me but to go back to 

 the position sustained by palaeontological evidence. Let us for a moment examine this palfeontological 

 evidence. 



The identifications of the fossils of the Quebec group, certainly show a remarkable agreement between 

 the trilobites of this group and those of the Potsdam sandstone in the occurrence of six species of 

 Dikellocephalus and one of Menocephalus ; while the occurrence of many others is in agreement, or not 

 incompatible, with the fauna of the Potsdam and calciferous sandstones. The comparative values of the 

 trilobitic faunas of this group and of the primordial zone of Europe, as established by Barrande, is better 

 shown in a tabular form which I here append : 



The Crustacean fauna of the primordial zone of Europe. 



Paradoxides, 



Olenus, 



Peltura, 



Conocephalus, 



Ellipsocephalus,* 



These genera are all limited to the fauna primordiale, and none of the other 

 European genera of trilobites are known in this fauna. 



Hydrocephalus, 



Sao, 



Arionellus, 



Agnostus, Of the first and second fauna. 



Amphion, Placed with doubt in the first fauna, and is well developed in the second fauna. 



The Crustacean fauna of the Quebec Group. 



Conocephalus. ) n f ., . ,. , 



A -mpllim ( Genera of the primordial zone. 



Arionellus, 



Agnostus, A genus passing from the first to the second fauna. 



Bathyurus, Quebec group. 



Asaphus, Of the second fauna. 



Illaenus, Of the second and third fauna. 



Amphion, Of the second fauna; and doubtfully of the first fauna in Sweden. 



Ceraurus=: Chierurus, Of the second and third Silurian faunas, and of the Devonian fauna . 



We have therefore, in the Quebec group, two established genera of the primordial zone; one Agnostus, 

 which passes from the primordial to the second fauna; one, Amphion, cited as doubtful in the first fauna 

 in Sweden, and known to be in the second; and three Asaphus, Illcenus and Chierurus, which begin 

 their existence in the second fauna. Of these, Asaphus begins and ends in the second; Illaenus begins 

 with the second and continues to the third; while Ceraurus= Chierurus begins in the second, extends 

 through the third Silurian, and appears in the Devonian fauna. 



Bathyurus is a new genus, and as yet has no stratigraphical value in comparisons. Those which I 

 have described as Olenus have proved to be not true Oleni ; and though much resembling that genus, are 

 nevertheless distinct; and I have proposed the names Barrandia and Bathynotus for the two forms, f 

 These have yet no stratigraphical value, except so far as their relations to establish genera may aid in that 

 direction. 



The genera Dikellocephalus and Menoccphalus are of the Potsdam group; and so far the Quebec group 

 is in parallelism with the Potsdam and calciferous strata. 



* Not Elliplocephalus of Emmons. 

 t Thirteenth Annual Report of the Regents of the University of N. Y., on the State Cabinet of Natural History, Albany, December, 1860 . 



