Eozoic and Paleozoic Rocks. 231 | 
The very complete series of Cambrian rocks now recog- 
nized on the coast-region of Canada was noticed, in connec- 
tion with its equivalency in details to the Cambrian of 
Britain and Scandinavia, and the peculiar geographical con- 
ditions implied in the absence of the Lower Cambrian over 
a large area of interior America. 
In the Ordovician age a marginal and submarginal area 
existed on the east coast of America. The former is repre- 
sented largely by bedded igneous rocks, the latter by the 
remarkable series named by Logan the Quebee Group, 
which was noticed in detail in connection with its equiva- 
lents further west, and also in Europe. 
The Silurian, Devonian, and Carboniferous were then 
treated of, and detailed evidence shown as to their conform- 
ity to the types of Western Europe rather than to those of 
America, 
‘ In conclusion, it was pointed out that though the great 
systems of formations can be recognized throughout the 
Northern Hemisphere, their divisions must differ in the 
maritime and inland regions, and that hard and fast lines 
should not be drawn at the confines of systems, nor widely 
different formations of the same age reduced to an arbitrary 
uniformity of classification not sanctioned by nature. It 
was also inferred that the evidence pointed to a permanent 
continuance of the Atlantic basin, though with great 
changes of its boundaries, and to a remarkable parallelism 
of the formations deposited on its eastern and western 
sides. 
