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  Minnesota's Geology - Richard W. Ojakangas - Google Books

  http://books.google.de/books?id=ZiBS4yhTt2wC&pg=PA49

  Have you ever wondered how the Mississippi River was formed? Or why shark teeth have been found in the Iron Range of the Upper Midwest? Towering mountain ranges, explosive volcanoes, expansive glaciers, and long-extinct forms of both land and sea life were…

• 

  Minnesota's Geology - Richard W. Ojakangas - Google Books

  http://books.google.de/books?id=ZiBS4yhTt2wC&pg=PA55

  Have you ever wondered how the Mississippi River was formed? Or why shark teeth have been found in the Iron Range of the Upper Midwest? Towering mountain ranges, explosive volcanoes, expansive glaciers, and long-extinct forms of both land and sea life were…

• 

  Minnesota's Geology - Richard W. Ojakangas - Google Books

  http://books.google.de/books?id=ZiBS4yhTt2wC&pg=162

  Have you ever wondered how the Mississippi River was formed? Or why shark teeth have been found in the Iron Range of the Upper Midwest? Towering mountain ranges, explosive volcanoes, expansive glaciers, and long-extinct forms of both land and sea life were…

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