THE GEOLOGY OF THE FAROE ISLANDS. 243 
time, there is something to be said for the view that the old volcanic centre may 
after all have occurred in that direction, and that owing to the sinking down 
of the central region, the dip of the great basalt plateaux has been reversed. 
Sucb enormous denudation and so many great movements of the earth’s crust 
have taken place since Miocene times, that too much stress may easily be laid 
upon the configuration of the sea-bottom, and the present dip of the strata. In 
whatever direction the centre of eruption lay the fact remains, that in the basalt- 
masses of Ferde we see only a few shreds of what must at one time have been 
a continuous plateau, occupying a much wider superficial area. The lofty 
cone or cones, if from such rather than fissures the basalts were erupted, have 
entirely disappeared—perhaps the looser and less consolidated materials of 
which they would probably be composed, having, we may suppose, contributed 
to their overthrow. This, I may remark, is the fate which has overtaken all 
the great volcanic centres of our own islands. Thus the volcanic products of 
the Old Red Sandstone, Carboniferous, and Permian formations are now 
represented chiefly by sheets of igneous rock, many of which have consolidated 
at a greater or less distance from the points of eruption. Such cones of scoriz 
and lava as may formerly have existed have been entirely demolished— 
their sites being now indicated by the hard plugs of rock that occupy the 
pipes or necks through which ashes and molten rock found a passage to the 
surface. 
V. GLACIAL PHENOMENA OF THE ISLANDS. 
1. Early Notices of Glacial Phenomena.—The earliest notice of the abraded 
and striated rocks of the Ferdée Islands occurs as already mentioned in Mr 
‘ALLAN’s paper. His description does not tell us in what direction the abrading 
agency moved ; but Ropert CuamsBers, who visited the islands forty-three years 
afterwards, and saw the roches moutonnées and striz described by ALLAN, 
was clearly of opinion that the ice had come from the north. He says, “They 
(the strize) presented themselves in abundance in several places, most strikingly 
of all within sea-mark on the shore of the quiet bay, being all directed from 
the north,” &c. Again he describes similar striz observed by him in Iceland, 
which had the same trend with those at Eide, and concludes that these facts, 
taken in connection with observations of a like kind in the north of Europe 
and America, indicate “that there has been one universal sweeping of the 
surface by ice, down to some point in latitude which remains to be deter- 
mined. The parallel channels between the Feerée Islands, all lying between 
north-west and south-east, I regard as excavations made by this wide-spread- 
ing arctic ice-sheet.” Mr Cuampers likewise noticed the glaciated rocks at 
Thorshavn, but failed to see the striz which many of them present. Again, 
