abstract:An early map of the extent of Lake Agassiz (by 19th century geologist Warren Upham). This map is now believed to underestimate the extent of the region once overlain by Lake Agassiz.
Theoriesrange from the extinctionof the mammoth to sudden environmentalchangescaused by a comet impactingorearth or the break of a massive freshwaterlake, lake Agassiz.