National Goegraphic scans bottom of great lakes see what they conclude.

[jaxsprat]

Did you know that five thousand years ago the Great Lakes were actually five different lakes, not even connected! This is a National Geographic DOC.called Draining the Great Lakes, If you have about 42 minutes of free time, check it out at the link below. At about 4 min 16 seconds in check out the very large transducer they lower into water to scan lake bottoms-That's one heck of a transducer for sure. Also the part about the ancient hunting grounds under Lake Huron at 13:00 minutes in. Wasn't real sure if post goes here. Very Interesting, makes u wonder how your lake was formed.

http://m.youtube.com/watch?v=Vz-fS4yppA4