It is probable that little remained but the Algonkian shales and limestones when the Ice Age sent southward the first of its three great invasions. Doubtless already there were glaciers there of sorts, but the lowering temperatures which accompanied the ice-sheets developed local glaciers so great of size that only a few mountain-tops were left exposed. It was then that these extraordinary cirques were carved. There were three such periods during the Ice Age, between which and after which stream erosion resumed its untiring sway. The story of the ice is written high upon Glacier's walls and far out on the eastern plains. IV Into this wonderland the visitor enters by one of two roads. Either he leaves the railroad at Glacier Park on the east side of the continental divide or at Belton on the west side. In either event he can cross to the other side only afoot or on horseback over passes. The usual way in is through Glacier Park. There is a large hotel at the station from which automobile-stages run northward to chalets at Two Medicine Lake, the Cut Bank Valley, and St. Mary Lake, and to the Many Glacier Hotel and chalets at Lake McDermott. A road also reaches Lake McDermott from Canada by way of Babb, and Canadian visitors can reach the trails at the head of Waterton Lake by boat from their own Waterton Lakes Park. Those entering at Belton, where the park headquarters are located, find chalets at the railroad-station and an excellent hotel near the head of Lake McDonald. There is also a comfortable chalet close to the Sperry Glacier. To see Glacier as thoroughly as Glacier deserves and to draw freely on its abundant resources of pleasure and inspiration, one must travel the trails and pitch his tent where day's end brings him. But that does not mean that Glacier cannot be seen and enjoyed by those to whom comfortable hotel accommodations are a necessity, or even by those who find trail-travelling impossible. Visitors, therefore, fall into three general classes, all of whom may study scenery which quite fully covers the range of Glacier's natural phenomena and peculiar beauty. The largest of these classes consists of those who can travel, or think they can travel, only in vehicles, and can find satisfactory accommodations only in good hotels. The intermediate class includes those who can, at a pinch, ride ten or twelve miles on comfortably saddled horses which walk the trails at two or three miles an hour, and who do not object to the somewhat primitive but thoroughly comfortable overnight accommodations of the chalets. Finally comes the small class, which constantly will increase, of those who have the time and inclination to leave the beaten path with tent and camping outfit for the splendid wilderness and the places of supreme magnificence which are only for those who seek.