Note 2 — THE CHANGING WORLD in which Prehistoric Men Lived

This is a complicated affair and I do not want to bother you with its details. Both the alpine and the continental ice sheets seem to have had minor fluctuations during their main phases, and the advances of the later phases destroyed many of the traces of the earlier phases. The general textbooks have tended to follow the names and numbers established for the Alps early in this century by two German geologists. I will not bother you with the names, but there were four major phases. It is the second of these alpine phases which seems to fit the traces of the earliest of the great continental glaciations. In this book, I will use the four-part system, since it is the most familiar, but will add the word alpine so you may remember to make the transition to the continental system if you wish to do so.