262 DR JAMES GEIKIE ON 
filled up of course before the ice could overflow that island. This indicates a 
mass of ice not less than 2200 or 2300 feet in thickness. In Suderée, again, the 
upper surface of the ice attained a height of 1400 feet, which we may take as 
the thickness of the stream that flowed out of Trangjisvaagfiord and Howebuet. 
We cannot wonder then that the shallow seas which separate the Feerde Islands 
were completely filled up, nor that the outflow of ice from Suderée should have 
been controlled by that coming towards it from the north. The direction of 
the strize and voches moutonnées at the head of Qvalbéefiord agrees with that of 
the glaciation in the west of Sandde, and seems to point to a general movement 
of the mer de glace towards the south-west. Probably all the ice that lay to 
the west of Skuée and the two Dimons flowed in this direction, while that which 
lay to the east of these islands participated in the south-easterly movement. 
How far out to sea the ice-sheet extended can only be conjectured, but 
judging from the thickness it attained upon the islands, and in the sounds and 
fiords, it may well have reached what is now the 100-fathoms line, where it 
would break away in bergs. Like the greater mers de glace of Europe and 
North America, it tells a tale of excessive evaporation and precipitation, and 
one ceases to marvel at the thickness attained by the ice-sheets of those vast 
continental regions when one sees the indisputable evidence of a very consider- 
able sheet of glacier-ice having covered even so limited an area as that of the 
Ferée Islands. 
11. Origin of Erratics and Morainic Débris.—The large erratics which 
are scattered over hill-tops and hill-sides were doubtless deposited by the mer 
de glace during its final dissolution ; and the erratics and loose morainic débris 
that occur in the valleys mark out, in like manner, the gradual disappearance 
of those local glaciers that still occupied the hollows of the islands after the 
higher grounds had been relieved of their icy coverings. I have mentioned 
the fact that valley-moraines are much less numerous than one might have 
expected, when the shattery character of the igneous rocks is kept in mind. 
It is true that considerable quantities of loose morainic-like débris are fre- 
quently scattered over the bottoms of the valleys, but well-marked mounds of 
morainic origin appear to be of rare occurrence. We saw some in the valley 
leading down to Westmannshavn, and some of the mounds in the Saxen valley 
may be moraines, but such of them as were exposed in section proved to be 
roches moutonnées buried under their own ruins. It is difficult to account satis- 
factorily for this scarcity of moraine mounds, more especially when we remember 
that in other countries, such as Scotland, North of England, Wales, Ireland, 
Norway, Switzerland, &c., where the rocks as a rule are less easily acted upon 
by the weather, distinct valley-moraines are yet more or less abundantly met 
with. The following considerations, however, may help to explain the apparent 
anomaly. 
