Many ages ago in North America there was no spring or summer or autumn, but only winter all the time; there were no forests or fields or flowers, but only ice and snow, which stretched from the Arctic Ocean to Maryland. Sometimes the climate would grow a little warmer, and then the great glaciers would shrink toward the north, and then again it would grow cold, while the ice crept southward; but finally it became warmer and warmer until all the southern part of the country was quite free from the ice and snow, which could then only be seen, as it is now, in the Polar regions.