Page:Littell's Living Age - Volume 126.djvu/41

Rh  generalizations which those at home, only acquainted with what has already been done, cannot even presage. Still there are a few points in various branches of science which it would be well that the naturalists should attend to, and which the Jeremiahs, who are never weary of crying that all is barrenness, should be aware still require solution, or more extended observations in regard to. Let us take geology. Over the north of Europe — most markedly in Great Britain — America, and in all likelihood Asia also, are found certain remarkable deposits which are believed to date from one of the latest geological epochs, viz., that known as the glacial period, and are known to have been caused by ice. These deposits are very varied, but they may be referred to three great series, viz., great beds of stiff tenacious clay, unfossiliferous, but mixed with rounded boulders most frequently scratched and ice-worn; a series of finely laminated clays, containing fossils, chiefly Arctic shells; and lastly beds of sand and gravel and boulders, rounded and angular, scattered over the country, and belonging to formations not in the immediate vicinity; indeed often far distant from the localities where these boulders and "travelled blocks" are found, showing that they may have been transported by some agency. This agency is now universally conceded to be ice in some form, most likely icebergs. Ice, again, must have been at work in forming the "glacial beds;" but whether floating ice, or some great ice-cap covering the whole country, is as yet undecided, though the preponderance of belief points to the latter as being the mode in which the ice was formed. Agassiz long ago pointed out that Scotland must have been swathed, hill and dale, mountain and valley, in such a great glacier-covering. For long he was treated with incredulity, simply because we knew of no country which at the present time was in such a condition, and therefore, reasoning on the great principles taught by Lyell, we could not accept such a hypothesis. We now know that Greenland is a country in exactly such a condition, and it is to it that we must look for an explanation of the glacial phenomena of Britain and the rest of the northern hemisphere. The naturalists, by a thorough study of glacial phenomena in that great country of glaciers, can do much to solve the questions now under discussion. In this country, and indeed in any country but Greenland, we cannot do so. Take Mr. James Geikie's "Great Ice Age," as the book which most fully — though still not so fully as it might — treats of these questions, and there is work enough for a geologist lying ready at his hand.

What is the nature of the material lying under the great ice-cap of Greenland? Is it the counterpart of the Scottish boulder-clay or till? Are the finely laminated clays forming in the Greenland ice-fjords from the mud-laden streams which flow out from beneath the glaciers the same as the brick clays of Scotland and elsewhere, as the present writer has shown to be highly probable? Again are the Greenland fjords, as are the fjords in other parts of the world, due to the wearing action of ice, when they formed the beds of great glaciers as Nordens-kjöld and I have argued? Again, the whole question hinges on the theory — not a theory, I believe, but an established fact, but still opinions differ — in regard to the eroding power of ice. In studying ice — sea and land — alone the geologist would be very fully and profitably occupied for a couple of years.

Another question for him to try and solve is this — Is Greenland rising in the north, while we know well that it is sinking in all the region south of Wolstenholme Sound? Are the terraces you find on the shores of Smith's Sound evidences of this general and gradual uprising of the shores going on, or are they only like the terraces you find on the shores of Greenland south of Melville Bay, which we know are evidences of a former uprising, not of one now going on, for at the present time I find others have shown there are indubitable signs that a gradual sinking of the coast is in progress. Mr. James Geikie — a most competent authority on all questions touching glacial deposits — suggests to me that "it would be very interesting to have determined whether the raised beaches of Greenland give any indication of changes of climate such as have been observed in these deposits in Spitzbergen. Great banks of Mytilus edulis, Cyprind islandica, and Littorina littorea, occur in that island, and none of these species are ever found living in the Spitzbergen sea. It is true