A Man would see but little of the reality of the world if he shut himself up in his house, and only gazed out from the same window; he would learn little more if he contented himself with alternately gazing upon the scenes passing around him, from the windows of every storey. So a geologist, in limiting himself to the study of the rock-masses of a circumscribed area, would never, by the utmost perseverance, in going continually over the same ground, attain to a perfect understanding of the subject of his study. He must go abroad, either in his own person or equivalently, by making himself acquainted with the travels and labours of others. Our knowledge of the ancient conditions and relations of the oldest rock-masses would not be complete if we limited our investigations to those isolated patches in our own country, which, however important, are still only a part of that great whole, more important traces of which are to be met in regions far away. Thus those very old—indeed, primitive sedimentary rocks, represented in the British Isles in a fragmentary manner, as by the younger or bedded gneiss of the Scottish Highlands, assume in Canada and the Arctic regions proportions of great extent, and consequently, of far greater value. Far back in the obscurity of the past, as must be placed the birth-time of these primitive land-masses, we seem, in our first investigations, plunged in interminable ignorance, like the explorers of some vast subterranean cave in impenetrable darkness.