314 Canadian Record of Science. 
Ptychopariz which I do not make out clearly, from Mr. 
Walcott’s notes, as of this horizon, but which probably be- 
long here (P. Piochensis, and P. coronata) and these have 
a still closer resemblance to Anomocare. Olenellus and 
Olenoides may be considered as the representives of the 
Paradoxides family at this horizon, but the two last genera 
on the list find their representatives in Europe at a higher 
horizon than the Paradoxides zone, even as high as the 
summit of the Cambrian. 
This remarkable grouping of genera, which it is stated 
gradually gave place to the Upper Cambrian fauna, would 
lead one to suppose that the introduction and removal of 
successive groups Of marine forms in the West, during the 
Cambrian age, was governed by other conditions than those 
which prevailed in the better known regions around the 
North Atlantic Ocean. 
In his former paper on the classification of the Acadian 
Cambrian Rocks, the writer considered the Olenellus fauna 
as a whole, but when the later phase of this fauna ig re- 
moved, the evidence for the rest, i.e., the Olenellus-Dorypyge 
phase, is in favour of its greater antiquity than the Parad- 
oxides beds. 
The great range of Olenellus in the west, as shown by Mr. 
Walcott’s work, is unusual for a trilobite, but is parallelled 
by that of Calymene Blumenbachii in the Ordovician and Silur- 
ian and by other trilobites.* It is quite compatible with 
this feature, that the Olenellus-Dorypyge or older phase of 
the Olenellus fauna should also have a wide geographical 
range: accordingly, we find it spread all across the Ameri- 
can continent, and although we do not know of the occur- 
rence of Olenellus in Asia, its companion, Dorypyge, has 
been found in Northern China. Dr. F. Schmidt has de- 
scribed from a limestone on the Jenisei river, in Siberia, a 
trilobite which, by its form, agrees with the genus Dorypyge. 
Other Cambrian fossils are described in the same paper. 
1 Protypus senectus is also credited with a wide vertical range, but 
the examples figured are so defective that more than one genus 
may be included under the name. 
