You may have heard that Minnesota�s ten thousand lakes are the hoofprints of Paul Bunyan�s big blue ox, Babe. �Don�t you believe it � writes author Dick Ojakangas. Though the lakes, which formed at the end of the most recent ice age, may be Minnesota�s most famous features, the glaciated countryside disguises a much longer history of volcanoes and plate collisions�not surprising when you learn that...