Geological Society of London. 381 
mediate between those of Plesiosaurus and Pliosaurus, but was 
retained provisionally in the former genus. Although a direct link 
in the chain connecting the two genera, P. philarchus was not 
regarded as an ancestor of Pliosaurus, since teeth undistinguishable 
from those of the latter genus occur in the Coralline Oolite. 
Finally it was concluded that the evidence brought forward was 
sufficient to render necessary the abolition of the name Pliosauride, 
and the inclusion of Plesiosaurus and Pliosaurus in a single family. 
3. “On the Hozoic and Paleozoic Rocks of the Atlantic Coast of 
Canada in comparison with those of Western Europe and the Interior 
of America.” By Sir J. W. Dawson, LL.D., F.R.S., F.G.S. 
The author referred to the fact that since 1845 he had contributed 
to the Proceedings of the Geological Society a number of papers 
on the geology of the eastern maritime provinces of Canada, and it 
seemed useful now to sum up the geology of the older formations 
and make such corrections and comparisons as seemed warranted by 
the new facts obtained by himself, and by other observers of whom 
mention is made in the paper. 
With reference to the Laurentian, he maintained its claim to be 
regarded as a regularly stratified system probably divisible into two 
or three series, and characterized in its middle or upper portion by 
the accumulation of organic limestone, carbonaceous beds, and iron- 
ores on a vast scale. He also mentioned the almost universal pre- 
valence in the northern hemisphere of the great plications of the 
crust which terminated this period, and which necessarily separate 
it from all succeeding deposits. He next detailed its special develop- 
ment on the coast of the Atlantic, and the similarity of this with 
that found in Great Britain and elsewhere in the west of Europe. 
The Huronian he defined as a littoral series of deposits skirting 
the shores of the old Laurentian uplifts, and referred to some rocks 
which may be regarded as more oceanic equivalents. Its characters 
in Newfoundland, Cape Breton, and New Brunswick were referred 
to, and compared with the Pebidian, etc.,in England. The questions 
as to an Upper Member of the Huronian or an intermediate series, 
the Basal Cambrian of Matthew in New Brunswick, were discussed. 
The very complete series of Cambrian rocks now recognized on 
the coast-region of Canada was noticed, in connexion with its equi- 
valency in details to the Cambrian of Britain and of Scandinavia, 
and the peculiar geographical conditions 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 represented largely by 
bedded igneous rocks, the latter by the remarkable series named by 
Logan the Quebec Group, which was noticed in detail in connexion 
with its equivalents further west, and also in Europe. 
The Silurian, Devonian, and Carboniferous were then treated of, 
and detailed evidence shown as to their conformity 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, 
