BY A. MONTGOMERY, M.A. 161 
The shape of many of the valleys, and the contour of the 
hillsides suggest, however, that the present configuration of 
the surface is largely due to glacial erosion, and it is probable 
that during the ice period the valleys, already partly worn out 
by running waters, were immensely deepened and enlarged by 
the accumulation in them of glaciers. 
At the head of the Forth Valley it is very evident that 
the diabase greenstone is a horizontal sheet overlying the 
quartzites and permo-carboniferous strata, for on every hill- 
side forming the amphitheatre at the head of the valley the 
same features present themselves; first, highly inclined 
quartzites in all the deep gullies at the base of the mountains, 
the lying on these horizontal coal measures, sandstones, and 
mudstones ; then at about the same level on every peak we 
find the columnar greenstone resting on the coal measures. 
On East Mount Pelion and Barn Bluff the residual mass of 
greenstone left on the top of the sedimentary strata is very 
small, and the undisturbed coal measures are visible all round 
the peaks. Mr. Moore mentions the occurrence of coal- 
measure fossils in the moraine at Mount Sedgwick, and it 
will no doubt prove that the sedimentary strata there too 
underlie the greenstone capping. I cannot think it at all 
probable that Mr. Moore is correct in referring the con- 
glomerate containing fossils to the action of floating ice; it 
seems much more likely that it is a moraine drift derived 
from the lower beds of the carboniferous formation, which, 
further north near Barn Bluff and Cradle Mountain, consist 
mainly of conglomerates. These would supply the stones of 
granite, slate, porphyry, etc., which Mr. Moore has noticed, 
and also the fossils, and I have little doubt that when he 
comes to examine the country more thoroughly he will find 
these beds in situ under the greenstone capping. Itis hardly 
conceivable that if the conglomerate was deposited by 
floating ice in permo-carboniferous times, which is what Mr. 
Moore’s words seem to imply, that it should happen that the 
only proof of such ice action should be found in a region 
where there has been evidently severe glaciation at a much 
later date. Before accepting such a theory we should first 
have to eliminate all possibility of the conglomerate having 
been formed at the later period. Round Mount Pelion 
there is direct proof that the glaciation took place long after 
the permo-carboniferous period and after the diabase green- 
stone had covered the strata of the latter, and Mr. Moore’s 
observations of striated greenstone blocks on Mount Sedg- 
wick show the same thing. 
The first place in which I came upon plain proof of ice 
action was near Fast Mount Pelion, between a branch of 
the River Forth flowing from that mountain and from Lake 
Eyre, and another small feeder running in a deeper gully at 
