480 Canadian Record of Science. 
reason the Swedish paleontologists regard this fauna as 
belonging to the Lower Silurian. But it evidently corres- 
ponds to the Tremadoc fauna, which by English paleon- 
tologists is reckoned to the Cambrian; and late discoveries 
in America show that Mileus, Niobe, &c., also are truly 
Cambrian. 
In Wales, which has given its name to the Cambrian 
system, the succession of the faunas, their unity and their 
relative importance are much the same as in Sweden and 
Norway, but these features are obscured by the use of 
different names for some of the genera. 
Mr. Robert Htheridge’s catalogues in the Geology of 
North Wales are the basis for the comparisons made here. 
In them the genus Conocoryphe (as used by Mr. Salter) is 
made to serve for a number of Scandinavian and other 
genera. The figures of many of the species in this work 
are very imperfect, but for the purposes of this comparison 
the species in Conocoryphe may be distributed to Conocoryphe, 
Ctenocephalus, Liostracus, Ptychoparia, Solenopleura, Huloma, 
Parabolina, Parabolinella (?) Conocephalites and Dicello, 
cephalus. 
In Wales the first fauna has produced no trilobites unless 
Conocoryphe viola belongs here. The second Cambrian fauna 
has a full representation as follows :— 
PARADOXIDES. Ctenocephalus. 
Plutonia (sub gen. of Paradoxides. ) 
Anopolinus (c.f, Centropleura.) Carausia. 
Solenopleura.- Conocoryphe. 
%* Liostracus (or Ptychoparia.) Erinnys (c.f. Harpides.) 
Holocephalina. Microdiscus. 
Arionellus. * Agnostus. 
Here there are twelve genera of which two only extend 
upward to higher horizons. 
The third fauna (Lower Lingula flags) has the following 
genera: 
OLENUS. * Huloma. 
* Parabolina. * Agnostus. 
