Facts seem to support the theory that before the Great Ice Age the climate of the northern part of Canada was very different from what it is now. It is very probable that a warm if not a torrid climate extended for hundreds of miles northward of the now habitable limits of the Dominion. The frozen islands of the Arctic seas were once the seat of luxurious vegetation and teemed with life. On Bathurst Island, which lies in the latitude of 76 degrees, and is thus six hundred miles north of the Arctic Circle, there have been found the bones of huge lizards that could only have lived in the jungles of an almost tropical climate. We cannot tell with any certainty just how and why these great changes came about. But geologists have connected them with the alternating rise and fall of the surface of the northern continent and its altitude at various times above the level of the sea. Thus it seems probable that the glacial period with the ice sheet of which we have spoken was brought about by a great elevation of the land, accompanied by a change to intense cold. This led to the formation of enormous masses of ice heaped up so high that they presently collapsed and moved of their own weight from the elevated land of the north where they had been formed. Later on, the northern continent subsided again and the ice sheet disappeared, but left behind it an entirely different level and a different climate from those of the earlier ages. The evidence of the later movements of the land surface, and its rise and fall after the close of the glacial epoch, may still easily be traced. At a certain time after the Ice Age, the surface sank so low that land which has since been lifted up again to a considerable height was once the beach of the ancient ocean. These beaches are readily distinguished by the great quantities of sea shells that lie about, often far distant from the present sea. Thus at Nachvak in Labrador there is a beach fifteen hundred feet above the ocean. Probably in this period after the Ice Age the shores of Eastern Canada had sunk so low that the St Lawrence was not a river at all, but a great gulf or arm of the sea. The ancient shore can still be traced beside the mountain at Montreal and on the hillsides round Lake Ontario. Later on again the land rose, the ocean retreated, and the rushing waters from the shrunken lakes made their own path to the sea. In their foaming course to the lower level they tore out the great gorge of Niagara, and tossed and buffeted themselves over the unyielding ledges of Lachine. Mighty forces such as these made and fashioned the continent on which we live. CHAPTER II MAN IN AMERICA It was necessary to form some idea, if only in outline, of the magnitude and extent of the great geological changes of which we have just spoken, in order to judge properly the question of the antiquity and origin of man in America.