102 TRANSACTIONS OF THE. [MAR. 17, 
Taking these faunas and these deposits as the standard, we 
regard the arrangement and division of the Cambrian faunas 
set forth by Messrs. Salter and Hicks many years ago as pre- 
senting the most natural arrangement of the Life Zones of this 
System. By this arrangemement the Cambrian is divided into 
two great sections, the lower holding the “ Great Oleni” (Para- 
doxides, Olenellus, ete.), the upper the depauperated forms, 
Olenus (proper), Peltura, etc. Under this arrangement of the 
Cambrian System we have the following faunas of trilobites 
(descending order). 
In Scandinavia. In Wales. 
Ceratopyge Fauna, Upper Tremadoc, 
Upper Cambrian. < Peltura Fauna, ,Lower Tremadoc, 
Olenus Fauna. Lingula Flags. 
Te Crain: ( Paradoxides Fauna, Menevian and Solva, 
( Olenellus Fauna. Caerfai Group. 
Each of these faunas is well characterized and the three mid- 
dle ones have several sub-zones. This arrangement in sub-zones 
has not been shown to exist in the Olenellus Zone, but as there 
is such a variety of forms grouped under Olenellus in its com- 
prehensive sense, it it quite probable that such sub-zones exist. 
One advantage of the localization of the study of the Cam- 
brian in Southern New Brunswick is that it has enabled us to 
point out the existence of several sub-zones in the fauna which 
there came in before Paradoxides, but which apparently is not 
the Olenellus Fauna, since this genus does not occur, and the 
species associated with Olenellus are also mostly wanting. 
A knowledge of the grand zones of life in the Cambrian of the 
Atlantic coast of America have been developed by slow degrees. 
The Paradoxides zone was first made known, many years ago, on 
the discovery of P. Harlaniin Massachusetts; this was followed 
soon after by the discovery of the same genus in Newfound- 
land, and after some years in New Brunswick. 
Next in order was the Olenellus Zone, though for many 
years its true position was misunderstood, and it was deter- 
mined for America only when Mr. Walcott found it in subordi- 
nate position to the Paradoxides Zone at Manuel Brook, in New- 
foundland.* 
*The writer had previously determined this to be a Pre-Paradoxides Zone (and gave 
the name of ‘“‘ Horizon of Agraulos strenuus’’) from specimens sent him by Mr. J. P. 
Howley, the present director of the Geological Survey in that island. Atthat time the 
zone Was not known to contain any representative of the genus Olenellus. Trans. 
Roy. Soc. Can., Vol. iv., sec. iv., p. 148. 
