Читать книгу The Romance of Modern Geology. Describing in simple but exact language the making of the earth with some account of prehistoric animal life онлайн

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At last, after many of these swallow-like retreats and advances, the warmer climate at length came to stay, and the ice retreated farther and farther to the north. It still remained among the mountains, so that we might describe the glaciers of the Alps and of the Canadian Rockies as the last relics existing to-day of the great Ice Age of the past. The retreat to the Arctic Circle left many other relics behind it, the great lakes, for example, like Winnipeg and Manitoba, and the Great Salt Lake of Utah. All were once mightier sheets, because during the Ice Age their waters were held back. Other smaller lakes formed by the dumping-heaps or terminal moraines of the glaciers still exist, and are especially noticeable in Finland. During the later stages of the Ice Age the level of the land was lower than it is now in Western Europe. When the ground began to rise—in slow upheavals with long pauses for rest—it left its impress in raised beaches, which can be seen on both sides of Scotland and on the Norwegian coast. The climate grew gradually milder, the animals and the plants followed in the train of the retreating ice, and even the traces of man's existence began to appear. The change was not sudden; it was so gradual that the Ice Age slipped as imperceptibly as its own glaciers into the age in which Man's activities in Europe began.