66 ROYAL SOCIETY OF CANADA 



Of the Lower Cambrian gênera here cited which is 19" ; in the Peltura 

 Fauna it is reduced to 15'7 ; while in the Mount Stephen Fauna it becomes 

 14-2. A more notable difference shows in number of joints of the thorax, 

 this in the genera of the Paradoxidcs Beds is 15, in the Peltura Fauna 

 11, but in the Mount Stephen Fauna 9. 



If we are to be governed by faunal distinctions without regarding 

 the stratigraphy, it api)ears to the present writer, that this fauna of 

 Mount Stephen may be claimed to be of even of later origin than the Pel- 

 tura Fauna. 



