Up to the end of the last glaciation, we prehistorians have a relatively comfortable time schedule. The farther back we go the less exact we can be about time and details. Elbow-room of five, ten, even fifty or more thousands of years becomes available for us to maneuver in as we work backward in time. But now our story has come forward to the point where more exact methods of dating are at hand. The radioactive carbon method reaches back into the span of the last glaciation. There are other methods, developed by the geologists and paleobotanists, which supplement and extend the usefulness of the radioactive carbon dates. And, happily, as our means of being more exact increases, our story grows more exciting. There are also more details of culture for us to deal with, which add to the interest. CHANGES AT THE END OF THE ICE AGE The last great glaciation of the Ice Age was a two-part affair, with a sub-phase at the end of the second part. In Europe the last sub-phase of this glaciation commenced somewhere around 15,000 years ago. Then the glaciers began to melt back, for the last time. Remember that Professor Antevs (p. 19) isn’t sure the Ice Age is over yet! This melting sometimes went by fits and starts, and the weather wasn’t always changing for the better; but there was at least one time when European weather was even better than it is now. The melting back of the glaciers and the weather fluctuations caused other changes, too. We know a fair amount about these changes in Europe. In an earlier chapter, we said that the whole Ice Age was a matter of continual change over long periods of time. As the last glaciers began to melt back some interesting things happened to mankind. In Europe, along with the melting of the last glaciers, geography itself was changing. Britain and Ireland had certainly become islands by 5000 B.C. The Baltic was sometimes a salt sea, sometimes a large fresh-water lake. Forests began to grow where the glaciers had been, and in what had once been the cold tundra areas in front of the glaciers. The great cold-weather animals--the mammoth and the wooly rhinoceros--retreated northward and finally died out. It is probable that the efficient hunting of the earlier people of 20,000 or 25,000 to about 12,000 years ago had helped this process along (see p. 86). Europeans, especially those of the post-glacial period, had to keep changing to keep up with the times.