Notices of Memoirs—S.W. Highlands of Scotland. 119 
of the plant is known in the North Wales Exposure.” I am afraid 
that I cannot agree with this suggestion; on the contrary I think 
that any conclusion, based on the occurrence of isolated fragments of 
plant-remains in the Lower Carboniferous rocks might be most 
misleading, and might result in serious errors in correlation. 
Thus in the present instance 4A. Vanuxemi occurs at Meathop and 
at two horizons in the Shap district in beds which, as I have shown, 
belong to the C 1 horizon of the Bristol area, while in North Wales 
abundant remains of this species occur according to Messrs. Hind and 
Stobbs in S 2, an horizon very much higher in the series; lastly, this 
species was originally described from the Upper Devonian of New 
York. After all, this is only in keeping with what we have been led 
to expect from the study of the relative duration of terrigenous and 
marine floras and faunas elsewhere, for instance the Laramie and 
overlying formations in America. 
NOTICES OF MBEMOTRS. 
Prozsiems or THE Sovrn-Western Hicuianps or Scornanp. Abstract 
of the Presidential Address to the Glasgow Geological Society by 
Professor J. W. Grecory, D.Sc., F.R.S., F.G.S., January, 1910. 
f¥VHE Southern Highlands of Scotland consist of a complex series of 
eneisses, schists, crystalline limestones and quartzites, trending 
across Scotland approximately from south-west to north-east. These 
metamorphic rocks are bounded abruptly to the south by the Highland 
Boundary Fault, which brings them against Upper Palzeozoic rocks. 
Their northern boundary is less regular and is generally the junction 
with the Moine Gneiss, the rock which occupies so much of the 
Northern and Central Highlands. The schists and the associated 
rocks between the Moine Gneiss and the Boundary Fault may 
be conveniently grouped together, under the name proposed by 
Sir Archibald Geikie, as the Dalradian System. 
The most important difficulty in the interpretation of these rocks is 
the uncertainty as to which is the upper and which the lower end of 
the succession. According to Nicol, the southern members are the 
youngest, and there is a descending series to the north. This view is 
contradicted by many obvious facts in the field geology; the view is 
therefore widely held that Nicol’s order must be reversed and that the 
beds on the southern margin are the oldest. ‘The serious difficulty in 
the second view is that the southern rocks are much less altered than 
the northern, and this theory therefore involves some measure of 
selective metamorphism. Several ingenious interpretations have been 
advanced to overcome this difficulty. The author of the address, 
however, held that both views as to the order of the succession are 
correct in parts. 
The Dalradian System is intermediate in age between the Torridon 
Sandstone above and the Caledonian and Lewisian Gneisses below. 
That it is pre-Torridonian seems to follow from the evidence in Islay 
and Colonsay; that it is post-Caledonian is shown by its superposition 
upon the Moine Gneiss in several localities, as north of Ben Lui and in 
Glen Tilt; in the latter, the evidence collected by Mr. Barrow appears 
