SECTIONAL TRANSACTIONS.—C. 307 
Lewisian type’ in central Sutherland is a formidable obstacle to the view 
that Lewisian rocks of the two areas are identical. If the very strong 
evidence of the inliers is accepted, the Moines must be younger than the 
Lewisian. 
Transitional types between the Moines and Dalradians have been described 
from several localities, and elsewhere the line of separation between them 
is a structural break; thus the age of the Moines cannot be considered 
separately from the age of the Dalradians. Much more work on the genesis 
and history of the schists and on the time-relations of the various intrusions 
and injection complexes is necessary before the problem may be solved. 
Dr. J. PHEMISTER. 
Prior to the intrusion of the Carn Chuinneag complex the Moine sedi- 
ments were gently folded along east-west axes, and had possibly been 
already intruded by basic sills, in pre-Caledonian times. The Carn 
Chuinneag complex caused thermal metamorphism of the Moine sediments, 
which, in early Caledonian times, were folded isoclinally along N.N.E. to 
S.S.E. axes, and were metamorphosed into schists and granulites. Reference 
of these events to early Caledonian times is based on the argument that, 
if the Caledonian earth-movements were not responsible for the isoclinal 
folding, they had no effect in northern Scotland other than the production 
of the great overthrusts, and minor folding ; also that no parallel system 
of folding is known in the Pre-Cambrian of N.W. Scotland, except a 
very early Archzan folding of a broad, gentle type, seen in places in the 
Lewisian gneiss. The next episode was of considerable duration, and was 
mainly later than the folding, though still of early Caledonian date. To 
this episode belong the regional concordant granitic intrusions. 
In late Caledonian times the Ben Loyal syenite, the Ach’uaine Hybrid 
and Appinite Suites were intruded. 
The thrust dislocations and the minor folding and rodding along N.W. 
to S.E. axes followed ; while finally the great granitic and granodioritic 
stocks were injected, possibly continuing into Lower O.R.S. times. 
Prof. Read’s argument for the pre-Torridonian age of the Moine meta- 
morphism is considered invalid because his petrographic comparisons of 
gneisses in the Moine and Lewisian formations are drawn between rocks 
possessing different geological histories. 
Prof. C. E. TiLtey. 
AFTERNOON. 
Excursion to Methlick, Tanglanford Bridge, Ythanbank, Auchedly 
Bridge, Tarves, Craigie, Rocks of Balmedie Quarry, Belhelvie Village 
and ‘Tarbothill. Leaders: Prof. A. W. Gres and Prof. H. H. Reap. 
Saturday, September 8. 
Excursion to Potarch, Birse, Dinnet, Deecastle, Inchmarnoch, Dinnet 
Bridge, Mill of Dinnet, Ferrar, Dinnet Village, Burn o’ Vat, Ordie, Dinnet 
and Aboyne. Leader: Prof. H. H. Reap. 
Sunday, September 9. 
Excursion to Stonehaven Harbour, Dunnottar Castle, Burn of Benholm. 
Leader: Dr. R. CAMPBELL. 
