Page:Quarterly Journal of the Geological Society of London, vol. 33.djvu/1059

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ON THE ACTION OF COAST-ICE ON AN OSCILLATING AREA.
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49. On the Action of Coast-Ice on an Oscillating Area. By Prof. John Milne, F.G.S., of the Imperial College of Engineering, Tokio, Japan. (Read June 20, 1877.)

[Abridged.]

[In this paper the author commenced by discussing those theories which have been proposed to account for glacial markings by the assumption of a polar ice-cap. He argued that even if such vast sheets of ice as are accepted by many geologists could have produced the grooves and other markings, and the drift deposits ascribed to their agency, the action of the sea during subsequent submergence and upheaval of the regions where these phenomena are displayed would certainly have effaced all such traces of ice-action. Other objections might also be raised to the hypothesis of great ice-sheets; and he thought it desirable to consider fully "whether other agents may not have shared the work with which they have been credited." He proceeds as follows:—]

Excepting glacier-action, which will generally have taken place in elevated regions, I think it can be shown that the modelling and scratching has in many instances been produced by an agent the existence of which is certain, and which acted under conditions favourable to the preservation of its work. Such an agent is coast or floe-ice acting on a rising area.

Examples of the work done, and being done, by such an agent under the stated conditions I shall take from Newfoundland, Labrador, and Finland. Every year the shores of these countries are surrounded by a fringe of ice. During the process of freezing and at other times, by various causes, such as tides, currents, wind, the driving in of pack-ice from the sea, this is forced up and down upon the shore on which it rests. By actions such as these, which extend sometimes 100 yards back above high water, the shore line is scratched, scoured, and rounded. Boulders and angular stones travel along the coast, and are often deposited in banks and lines far removed from the cliffs or mountain masses from which they were originally detached. These actions are perhaps best seen upon the small islands which form archipelagos along the shores of all those countries to which I have referred.

Lying well out from the east coast of Newfoundland there is an island called Funk Island, which, through the action of the floe-ice by which it is annually invaded, has, I believe, received not only the ordinary marks due to the moulding of ice, but also its contour as a whole. It is about half a mile in length, very low and flat, and is situated right in the stream of arctic ice coming south from Baffin's Bay and Labrador. The northern end of this island, which has every year to face the pressure of the vast fields of ice which are borne down upon it, is visibly worn down and covered with erratic boulders, whilst the opposite extremity is a low but abrupt cliff.