Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/943

 the most northern Danish post, and the most northerly abode of civilized man. Circumstances have only allowed of its being noted so far 1.

Hr. Neilssen told me that he considered that Disco Island, opposite Claushavn, was rising, because the glaciers were on the increase. I think that if there is no more evidence than this for that supposed fact, we may lay it aside as erroneous, because the glaciers are undoubtedly increasing by the increase of the interior mer de glace on the island, and by the regular descent which they are making to the sea.

I have made an attempt to estimate the rate of fall ; and though we have no certain data, yet I believe that it does not exceed five feet in a century, if so much ; so that none of us will live to see Greenland overspread by the sea. Here I may point out what seems to be a fallacy in the reasoning of those authors who write about the denuding power of rivers, and calculate that such and such a country will be overwhelmed by the sea in so many millions of years. Whatever the land loses by denudation the sea gains; and therefore the two forces keep pace with each other. We thus see in Greenland two appearances: (1) In the interior what Scotland once was ; (2) on the coast what Scotland now is. We will therefore proceed in conclusion to point out some of the similarities in the latter light.

IV. Application of the Facts regarding Arctic Ice-action as explanatory of Glaciation and other Ice-remains in Britain.

Scattered over Scotland and the northern portion of England, and part of Ireland, are blocks of stone and grooved boulders on the top of high hills, or down in valleys. These boulders generally take the line of valleys. All over the country, also, is found a coarse clay or earth, mixed with boulders, rocks, &c, pell-mell, and above it another, finer clay, also with boulders, but stratified, and in many localities abounding with fossil shells, these shells being species now living in the Arctic Sea. I need hardly remind the reader that this is the Boulder-clay, the Northern drift, or by whatever other name it is known. In the eastern counties of England it consists of gravel with fragments of various rocks ; in the midland counties, of dark tenacious clay or "till," with boulders; and wherever found, these clays &c. are almost always local; i.e. they partake in character of the district over which they lie, in colour, texture, and admixture of the underlying formations. In addition, the rocks are grooved, and the sides and tops of the hills are worn and furrowed as if by some body passing over them. Further than this I do not require to introduce the subject; for it is abundantly well known to all geologists, and its origin is an endless subject of controversy. What my opinion of the origin of these clays &c. is, is already

1 In the ' Report of the British Association' for 1869 (Exeter Meeting), I have given a summary of the foregoing observations.