So we may see the meadows beside the lower Yukon, green pasture starred with flowers, bushed, wet, mosquito-stricken range for the bearded Celtic pony, utterly unlike the sun-baked golden steppe of the Dun horse. We must cast back to earlier times when Bering Land was clouded, torrid, range for ancestors of our modern horses, the pasture which changed the brown tapir of Brazil into the skewbald tapir of Malaya. At that time pre-glacial America had seven species of three-toed horse-ancestors, some of which may have ranged westward across Bering Land into Asia, and there given birth to the stock of the Old World. With the onset of the Great Ice Age the growing weight of the American Ice-cap seems to have strained the loose skin of the Earth, which, in the Columbia Basin cracked, pouring forth floods of lava to overwhelm a region nine hundred miles in length, eight hundred wide. {24} A series of rock waves folded, forming the coast or island ranges from California northward and culminating in the stupendous Alps of St. Elias. There gathered a lesser Ice-cap, pouring its glaciers down the Alaskan and British Columbian fjords. It was this barrier of ice which put an end to all migrations of animals. The Alps of St. Elias closed the path-way between those two groups of continents which so far had been the common breeding ground for beasts and men. Within the narrowed breeding ground of the Americas the horse together with the camel, and many other species, became extinct. [Sidenote: The deluge] Old Bering Land had become sub-Arctic, the home of the Mammoth, a maned roan elephant. Then the Pacific flooded the plains of the Lower Yukon, and formed the shoals of Bering Sea. Both in Asia and in America faint memories remain of a drowned world. In Assyria and in British Columbia the legend tells us of a hero, and of rescued folk in a fleet of three hundred canoes. So the two groups of continents were finally cut apart at Bering Straits. And now a ring of flaming craters girdles the Pacific, the fit finale to a tremendous drama. {25} PART V. THE MARKINGS OF THE HORSE. [Sidenote: Markings] Darwin wrote of the probable "descent of all existing races from a single dun-coloured, more or less striped primitive stock to which our horses occasionally revert." The stories of the Great Ice Age and of Bering Land have shown us a variety of swiftly changing climates in which the original three-toed dun striped ancestors begat a special type of horse for each kind of habitat. The high lands and high latitudes, the low lands and low latitudes, the tall grasses, the short grasses, the open woodlands, the northern downs and valleys, bred each their special type of the wild horse.