'200 The American Geologist. September, i«97 
In tho f^eologit'ul section several important petrographical papers were 
presented. Messrs. Barlow and Ferrier illustrated the structure of a 
small area of granite which they had recently studied, with a series of 
lantern slides showing a peculiarly increasing amount of chemical met- 
amorphism and at the same time a slowly rising rate of movement among 
the particles of the rock. Mr. Miller spoke of the presence of very small 
amo\]nts of nickel in some of the Canadian iron ores, and discussing the 
merits and demei'its of the titaniferous ores he suggested that pospibly 
some of the useful properties attributed to the titanic iron might be ra- 
ther due to the small amount of nickel contained in them. 
Mr. J. B. Tyrrell laid before the section an account of the recent work 
of the Dominion survey on the ditferent ice-sheets of Canada. He said 
that evidence showed that the earliest to form was the Cordilleran on 
the Rocky mountains and that its ice spread over the plains to the east 
carrying drift outward from that range as a centre in all directions. On 
the retreat of the Cordilleran glacier the Keewatin ice-sheet advanced 
from the region west of Hudson bay and overspread all the north-cen- 
tral part of the country, extending down far into the United States. 
This was subject to several recessions and befoi-e its final retreat the 
thii-d ice- mass advanced from the Labradorian region and became con- 
terminous with the Keewatin, holding behind their united points the 
glacial lake Agassiz. Finally both receded and the post-glacial period 
began. 
Mr. John Milne gave a most interesting summary of his recent report 
on the volcanoes of Japan, to summarize which here is quite impossible. 
Many of the details given were also announced in the evening lecture, 
which will be mentioned later. 
Mr. Seward of Cambridge discussed the relation of the Carboniferous 
genera Bennettites and Williamsonia, and from a study of their struc- 
ture and a comparison with other forms had been led to the conclusion 
that the two really form but one genus. 
Prof. Fairchild gave at length a view of the condition of the surface 
geology round the region of the finger lakes of New York, giving the 
views of the geologists who have written upon the subject and sketch- 
ing the glacial history of the region. 
Prof. F. D. Adams followed with a petrographical paper discussing the 
nature of some of the gneisses and gneissic rocks of the Grenville series 
of Canada. He showed the close agreement in ultimate analysis between 
some of them and certaiTi shales and argued that the former were only 
highly metamorphosed forms of the latter. 
In an address illustrated with lantern slides, Dr. E. VV. Claypole 
sketched^the palaeozoic geography of the eastern United States and in 
a series of maps showed the varying forms of the continents and seas 
as Siku'ian and Devonian times passed by. The principal feature was 
an elevation of the southern portion, which progressed through Silur- 
ian and Devonian times until it came to an end and an opposite motion 
set in during the upper Devonian sub-era. 
The evening lectures constitute a very interesting and useful part of 
