 Complete the following phrase:  The history of the formation of the Cascade Mountains dates back millions of years ago to the late Eocene Epoch. Geological events occurring many years ago created the diverse topography and drastic elevation changes over the Cascade Range leading to various climate differences. During the Pleistocene period dating back over two million years ago, glaciation advancing and retreating repeatedly scoured and shaped the landscape. With the North American Plate overriding the Pacific Plate, episodes of volcanic igneous activity occurred. The lateral blast from the 