1036 REPORT— 1885. 
power, and to form the great dam stretching more than four miles across the valley 
ot the Spean, though aided on the other side of the Caledonian Canal by the ice 
from the glen. 
The country which fed this glacier of the Cour consists of about eleven square 
miles of surface, with a peak 4,000 feet high. It does not seem to possess such a 
position so that a great glacier should continue to flow from it when the other 
glens adjoining had lost their glacier-producing power. 
The drainage outlet of 700 miles of mountainous country within which the 
roads are is at Corron Ferry. It is narrow, contracted, and the ice would be 
jammed back during the intense period of glaciation, and a portion forced over the 
Col in Glen Spean into the Spey. 
The roads consist of the usual glacial stuff from the hill sides. Neither sea shore 
nor lake shingle shells, water sorted sands nor silts, are met with. Some material 
run from the hill sides before vegetation covered the surface may be seen. 
What, then, were the causes which led to the formation of those roads? The 
resting of the ice of the glaciers at certain levels after the great glaciation ceased, 
and when the ice in these glens of Gloy, Roy, and Spean found its way outward 
by the lowest level. The lateral moraines so formed when the supply of ice was 
sufficient to maintain their movement seaward are now the roads. 
Thus, in Glen Gloy, No. 1, the road and several somewhat similar terraces, as 
shown in Sir Henry James Vance’s work on the roads, would be formed by the ice 
after it had ceased to flow over the col into Glen Roy. 
No. 2, in Glen Roy, after the ice ceased to flow into the Spey. 
No. 3, after no more ice flowed into Glen Spean from Glen Roy, by the col Glen 
Glaister ; also several other shelves or terraces seen in the district. 
And No. 4, in Glens Roy and Spean, would be forming so long as the Gulbein, the 
Treig, the Laire, and the Cour supplied sufficient quantity of ice to maintain the 
glaciers in these valleys at the levels where the roads now are. 
10. Further Evidence of the Extension of the Ice in the North Sea during the 
Glacial Period. By B. N. Peacu, F.R.S.E., and J. Horne, F.R.S.£. 
The authors briefly summarised at the outset the results of their investigations 
regarding the glacial phenomena of Shetland and Orkney, which point to the 
conclusion that they were glaciated by land ice that moved from the North Sea 
towards the Atlantic, while at a later period they were subjected to a purely local 
glaciation. 
They then proceeded to call attention to certain observations of Dr. Traill, on 
the glacial phenomena of North Ronaldshay, which is situated at the extreme 
north-east corner of the Orcadian group, and, like the other isles, is composed of 
Old Red Sandstone and mainly of the characteristic flagstone series. In the red 
boulder clay an assemblage of stones foreign to Orkney was obtained, consisting 
of diorite, gabbro, granite with various kinds of metamorphic foliated rocks, 
volcanic tuff like that of the Ochils, chalk and chalk flints. With few exceptions 
these foreign blocks might have been derived from the basin of the Moray Firth 
and the surrounding high ground. Numerous smoothed and striated fragments of 
marine shells were also met with in the boulder clay. These phenomena are 
identical with those found in the boulder clay of the other Orcadian islands, and 
they point to the conclusion that the northern limits of Orkney must have been 
glaciated by ice from Scotland moving in a westerly direction. 
Reference was also made to the results obtained by Dr. John Murray while ex- 
ploring the ‘ Wyville Thomson Ridge,’ in the summers of 1880 and 1882, the 
surface of which seems to be covered with boulder clay or moraine matter. The 
stones dredged from the northern part of the ridge consist of metamorphic rocks 
and Old Red Sandstone, which might have been derived from Shetland, while more 
than half of the blocks from the south end are composed of flagstones of the 
Orlmey and Caithness flagstone series. From the distribution of the boulders, 
some of which are well striated, it is evident that the ice must have moved west- 
