ABSTRACT
There were at least four different glaciations. They were originally characterized in the Alps by means of moraines, tills, and river terraces, by the geologists Penck and Bruckner. The four glaciations are: Gunz, Mindel, Riss and Wurm. During the glacial phases most of the Alpine mountain arc was covered by a continuous ice sheet, out of which the highest peaks rose as nunataks. The size of the Alpine ice sheet was small in comparison with the tremendous Scandinavian land ice, which extended southwest, south and east from its centre in the Scandinavian mountains. In North America there is a sequence of four different glaciations, perhaps corresponding to those in the Alps. The glaciations alternate with warm phases, the interglacials. Obviously there were at least three, but actually the number of interglacials is greater. There is a late Villafranchian interglacial, the Tiglian, which apparently antedates the Gunz.
