[MATTHEW] STUDIES ON CAMBRIAN FAUNAS 69 



pyge) quadriceps, a ajjecies of the Paradoxides-Dorypyge sub-fauna. 

 Furthermore D. quadriceps is said to extend up 500 feet in the limestones, 

 and at the top of the limestones is Olenoides (Zacanthoides) spinosus, a 

 common species of the Mount Stephen Fauna which, according to our 

 view, is well toward the summit of the Cambrian system. 



To us therefore it seems that the appearance of Olenellus (sens, 

 strict.) in the Cambrian Faunas of America marks the irruption of a new 

 group of forms that ousted the typical fauna of Paradoxides, which may 

 be considered to have reached its culminating point in the faunas of P. 

 Tessini and P. Davidis. These would be the conditions in Atlantic 

 North America. Further west the Olenellus Fauna appears in most 

 places to have invaded continental areas, as it is preceded by beds of 

 quartzite and sandstone ; and hence all the earlier Cambrian including 

 the Protolenus and Paradoxides Zones exhibit no faunas in those regions. 



The Newfoundland fossils described in this paper are not all new, 

 but consist partly of new species and partly of species already described, 

 on which new light has been obtained. They are arranged according to 

 their zoological standing, so far as the author has been able to appre- 

 ciate it. 



A few words descriptive of the conditions of sedimentation will not 

 be out of place, and further notes on the same subject will be found in 

 the succeeding article where the Cambrian sediments are touched on in- 

 cidentally in connection with the Etchiminian. 



Shales predominate in the Cambrian strata of Eastern Newfound- 

 land, though according to the j^ublished geological reports extensive 

 deposits of sandstones occur both in the Upper and Lower Cambi'ian ; 

 the shales of the latter are in the Protolenus Zone chiefly of a red colour, 

 but in the Paradoxides Zone mostly gray. 



At Smith Sound the most important land marks in the Lower Cam- 

 brian are the first, or basal limestone conglomerate (in the eastern basin 

 a slate conglomerate) and a second conglomerate limestone; both of 

 these are in the Protolenus Zone. Higher up in the P. eteminicus sub- 

 zone is another limestone conglomerate. 



In Conception Bay similar conditions are found, but there the basal 

 conglomerate rests on the altered rocks of the Huronian or Intermediate 

 system ; limestone accompanies this conglomerate, and in the upper 

 part of the Protolenus Zone another limestone band appears. 



The Upper Cambrian is quite different. It has no limestone beds» 

 but abounds in flaggy layers and sandstones alternating with shales. In 

 the absence of sandstone the shales become quite fine in texture and dark 

 in colour like the alum shales of Sweden. 



