264 Canadian Record of Science. 



selves elsewhere mostly in the Upper Cambrian. The 

 Oleni are of a more primitive type than those of the North 

 of Europe, and notwithstanding the presence of so many 

 Upper Cambrian forms the whole assemblage appears to be 

 Lower Cambrian. 



It is to be noticed that nowhere in the South of Europe 

 have we recovered the representatives of the later Paradox- 

 ides of the north of Europe, or even of P. Tessini, except 

 in Bohemia, the Bohemian representative species being 

 P. JBohemicus. A similar gradation can be traced on the 

 western side of the Atlantic where the equivalent of the 

 Tessini fauna appears in Acadia, but is not known in Mas- 

 sachusetts ; while in Newfoundland the later Davidis sub- 

 fauna is present in addition to the earlier Paradoxides. Can 

 this deficiency of the later species of Paradoxides in the 

 more southerly district be due to conditions of temperature 

 of the sea, and would a sufficiently high temperature exclude 

 the genus entirely ? If so the Paradoxides of the northern 

 seas may have been cotemporary with the Olenelli, Cono- 

 cephalites and Anomocara of the warmer oceans, and it 

 would be necessary with this landmark gone to reconstruct 

 for the southern areas, the succession of Cambrian faunas 

 from the earliest Olenelloid types to Dicellocephalus and its 

 cotemporaries . 



The Utica slate of a later age contains a fauna in many 

 respects analogous to that of the Paradoxides beds of the 

 Atlantic coast of America, but spread over an area on that 

 continent further to the west, and extending to more south- 

 ern latitudes. It is spread from Labrador to Virginia and 

 as far west as Michigan and Ohio. The Trlarthri of the 

 Utica slate represented the Paradoxides of the earlier time, 

 and the black bituminous slates of the Utica, the similar 

 alum bearing slates of the Cambrian. The Arctic current 

 which now flows southward along the Atlantic coast has a 

 course corresponding to that of the belt of country along 

 which at the present clay the outcrops of the Paradoxides 

 beds and the Utica shale are 4 found. 



A diagrammatic view of the distribution and succession 



