Exploration of the lake bottom near a prehistoric mining site on Lake Michigan revealed an ancient land bridge and river channel exposed during a period of low water levels 8,000-10,000 years ago.
A documentary DVD and teacher's guide are available.
Drowned coastlines of the prehistoric Great Lakes are being explored for sinkholes, underwater springs and other features
These shores were exposed during extreme low water
conditions some 10,000 years ago. In 2005 we explored one of these underwater sinkhole springs (click to view report & video)