482 Canadian Record of Science. 
of genera with those of Scandinavia, and here as there, 
exhibit a very decided paleontological break at the summit 
of the Paradoxides beds. Hence Dr. Hicks was justified in 
dividing the Cambrian groups of strata into Upper and 
Lower, accordingly as they were above or below this horizon. 
Having seen how the Cambrian faunas are related to each 
other in Europe, we may now examine their succession in 
the eastern half of North America. 
To Mr. C. D. Walcott is due the credit of having deter- 
mined the relation of the Olenellus fauna in this region to 
the rest of the Cambrian system. 
The clearest succession of the lower members carrying 
unmistakable forms of this fauna is that which he has lately 
examined in Newfoundland. Combining the genera found 
there with those of the Champlain and Hudson valleys we 
find tbe following :— 
OLENBLLUS. * Zacanthoides. 
Msonacis. * Olenoides. 
* Paradoxides (Shaler)  Bathynotus. 
Avalonia (n. gen. not yet described.) 
* Ptychoparia. * Protypus. 
* Agraulos. * Microdiscus. 
* Solenopleura. * Agnostus. 
Of these thirteen genera it will be observed that two- 
thirds pass to the Paradoxides beds, and of the remainder, 
Avalonia is not described, and Mesonacis is by Scandinavian 
paleontologists regarded as congeneric with Olenellus. There 
is thus a much closer connection between this fauna and that 
which follows it, than there is between the latter and the 
faunas of the Upper Cambrian. - Moreover, the embryonic 
and larval stages of Paradoxides and Olenellus show that 
these genera are closely related. 
We have very little knowledge as yet of the way in 
which the Paradoxides fauna was related to that which fol- 
_lows it, since both in Newfoundland and Acadia the next 
zone has yielded very scanty remains of trilobites. Perhaps 
the Mt. Stevens section where the genus Paradoxides has 
been found? will yield the required information. In New- 
1 See this journal, vol. 11, No. 1. (Jan. ’89.) 
