Cambrian Rocks in Acadia. eee iy 
nearly related genera ; to the former there is considerable 
resemblance, but the thorax and pygidium of the latter are 
of a different port. He also remarks of the rocks in China, 
in which this genus is found,' that there is, so far, no hori- 
zon in Europe to which, with confidence, they can be paral- 
leled; but adds that there are some observations [which 
lead to the view] that the slates with Dorypyge belong to 
the horizon of the Scandinavian Ceratopyge limestone. 
Species of other genera occurring with the Chinese Dorypyge 
have been compared by Dr. Dames with those of the Potsdam 
sandstone in Wisconsin, especially with those of the central 
portion of that formation. These sandstones are regarded 
by Walcott as younger than the Georgian series; so in the 
associated genera there is nothing to lead to the supposition 
that Dorypyge marks an older horizon than the Ceratopyge 
Jimestone and shale. Dr. Brogger also admits that Dames 
places together the Chinese limestone with Dorypyge and 
the Ceratopyge limestone of Sweden.” 
As for Olenoides (proper) of Meek, we see in it a much 
closer relation to Parabolina of the European Cambrian 
beds than can be observed in Dorypyge. To judge by the 
sections of the Cambrian rocks in Western North America, 
given by Mr. Walcott, the genus belongs to a somewhat 
higher horizon than Olenellus and Dorypyge, a conclusion 
which may also be gathered from the species of other 
genera associated with it. Olenoides may be considered as 
having its representatives in Europe in the upper part of 
the Olenus Zone. 
Another consideration which militates against the greater 
antiquity of the Georgian Series is the presence in it of 
several genera of trilobites as Protypus, Bathyuriscus and 
Asaphiscus,’ in which the size of the head-shield, thorax and 
pygidium are nearly equal. Such genera predominate in 
' Cambrian trilobites of Liau-tung, China, p. 33. in Richthofen’s 
China, vol. iv. 
* On alderen, &c., p. 
*Compare Nilevs and Niobe of the Tremadoe and Ceratopyge 
beds, with these genera, 
