St. Helens started its growth in the Pleistocene 37,600 years ago, during the Ape Canyon stage, with dacite and andesite eruptions of hot pumice and ash.(p214) Thirty-six thousand years ago a large mudflow cascaded down the volcano;(p214) mudflows were significant forces in all of St. Helens' eruptive cycles. The Ape Canyon eruptive period ended around 35,000 years ago and was followed by 17,000 years of relative quiet. Parts of this ancestral cone were fragmented and transported by glaciers 14,000-18,000 years ago during the last glacial period of the current ice age.(p214)