146 Proceedings of the Royal Society 
may be impossible at present to determine. But there seems strong 
reason to believe that the whole valley in this quarter was originally 
filled with detrital matter, which has since been carried away by 
the action of streams and rivers, except at a few places. 
2. A question of considerable difficulty arises here in connection 
with the ancient glaciers which undoubtedly existed in Scot- 
land. 
Take, for example, Flichity Valley. If it was filled with a 
glacier which pressed on its sides, and carried down debris to form, 
moraines, and the huge boulders which now lie on that debris, at 
what period did this glacier exist? Was it before or after the 
submergence of the country? If it was after the emergence, is it 
not likely that all the drift deposits of sand and gravel now on its 
sides would have been scoured out, and all traces of the terraces 
obliterated ? 
On the other hand, if the glacier existed before the submergence, 
is it likely that the moraines, in that valley, in Lochaber, and 
other parts of Scotland, would have retained so distinctly their 
prominent features? Would they not have been planed down by 
submarine currents? 
It is, however, a circumstance in favour of the existence of 
glaciers before the submergence, that the stride on rocks, which, 
these glaciers are supposed to have produced, are often covered 
over by thick beds of sediment. 
The Committee abstain from venturing farther upon theoretical 
ground. They allude to these questions only because the facts 
already ascertained, and more of which they will search for if they 
are re-appointed, seem calculated to throw upon these questions 
important gleams of light. 
III. Work still before the Committee. 
1. The Committee think that as so much information has been 
obtained from the east half of Scotland, it would be desirable to 
obtain similar information from the west half. 
It is manifest from the Beports, that in the sea lochs of the 
west coast, there are houlders of large size, and in most interesting 
positions. 
They are also particularly anxious to have as many particulars 
