304 SECTIONAL TRANSACTIONS.—C. 
Friday, September 7. 
PRESIDENTIAL AppRESS by Prof. W. T. Gorpon on Plant life and the 
philosophy of geology (10.0). (See p. 49.) 
Discussion on The age of the Moine and Dalradian formations (11.0). 
Prof. H. H. Reap.—Introduction. 
In connection with the age-problems of the Moine Series, four different 
opinions are held :” 
(a) The Moine Series includes Lower Palzozoic rocks and received its 
metamorphic character during the Caledonian orogeny. 
(b) The Moine Series is the equivalent of the Torridonian and was 
metamorphosed in post-Cambrian times. 
(c) The Moine Series is post-Lewisian but pre-Torridonian, and its 
metamorphism is pre-Torridonian in age. 
(d) The Moine Series and its metamorphism are Lewisian in age. 
The bearing on these views of new evidence from Sutherland and else- 
where is indicated. Resemblances between Torridonian and Moine rocks 
adjacent to the post-Cambrian dislocations are due to metamorphic con- 
vergence, and indicate neither that the Moine general metamorphism is of 
post-Cambrian date nor that the Moine Series is the equivalent of the 
Torridonian. The relations and affinities of the Ben Loyal alkali-syenite of 
North Sutherland show that the general Moine metamorphism is earlier than 
the post-Cambrian movements—a conclusion confirmed by the examina- 
tion of the belt of low-grade metamorphism in the Moine Series near the 
great post-Cambrian dislocations. ‘The two metamorphisms of the Moine 
rocks may be both of Caledonian date or they may be separated by a great 
interval of time. 
In Central Sutherland, the Moine Series is invaded by metamorphosed 
ultrabasic and basic intrusions that are identical with the pre-Torridonian 
intrusions in the Lewisian Gneiss of the unmoved foreland. ‘This suggests 
that the Moine Series and its metamorphism are of pre-Torridonian date. 
Further, in that district, the Hornblendic Rocks of Durcha Type, which are 
of Lewisian facies, form an integral part of the Moine Series, and the three 
rock-groups—Moine Series, Rocks of Lewisian Type and Hornblendic 
Rocks of Durcha Type—are there one and indivisible. But the evidence 
for the inlier-character of the Lewisian Rocks of Ross-shire has still to be 
reckoned with, and the conclusion that the Moines may be of Lewisian age 
cannot be advanced till this evidence has been re-examined in full. 
Few data are available concerning age-relations in the Dalradian Series. 
The correlation of the Struan Flags with the Moines is accepted and leads 
to the conclusion that the Moines and Dalradian are transitional. ‘There 
are, however, many views opposed to this conclusion. The ‘ Lennoxian ’ 
of Gregory has no existence in North-East Scotland. With regard to the 
relations between metamorphism and folding in the Dalradian area, it is 
considered that no conclusions can be reached till detailed field and petro- 
graphical work has been done. 
Prof. E. B. Battey, M.C., F.R.S. 
The straight bedding of most of the Moine rocks shows that these are not, 
in the main, merely metamorphosed equivalents of the Applecross Group 
of the Torridonian, as the latter are intensely current-bedded arkoses. But 
