Richard W. Ojakangas 
Roadside Geology of Minnesota [EPUB ebook] 

You may have heard that Minnesota’s ten thousand lakes are the hoofprints of Paul Bunyan’s ox, Babe. ‘Don’t you believe it!’ writes Richard Ojakangas, author of the newly released Roadside Geology of Minnesota. 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 Minnesota was at the active edge of the fledgling North American continent for several billion years.
If you’ve ever wondered where all those lakes came from, or how the iron range formed, or why southern Minnesota crop land is so fertile, then pick up a copy of the Roadside Geology of Minnesota by Richard W. Ojakangas. The latest addition to the acclaimed Roadside Geology series, this book will steer you over glacial moraines and till plains to some of the state’s unparalleled geologic features, such as the Morton Gneiss, once thought to be the oldest rock on Earth; the St. Peter Sandstone, one of the purest sandstones in the world; the banded iron-formation, the source of iron for the Great Lakes steel industry; and the ancient shorelines of Glacial Lake Agassiz, one of the largest glacial lakes that ever existed in North America.