ROCK...NO ROLL

One thing my county is rich in is rocks...thanks to the last wave of glacial activity to move through this area some 10-12,000 years ago.  Our native bedrock is sedimentary limestone laid down when Wisconsin and Minnesota were covered by shallow seawater during the Silurian Period some 450 million years ago.
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The sharp-eyed among you will notice that this is not sedimentary stone but rather igneous.  There is no native igneous rock in this area but, thanks again to glacial activity, lots of granite rock was pushed down here from the Canadian Shield many miles to the north..  This layer of rock is among the oldest on Earth being some 2 to 4 Billion years old.  We have all sorts of if in Wisconsin even through out of place from its origin...and it ranges in size from small pebbles to boulders the size of a house.  This fragment is about a meter long.
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My 8th grade history teacher (circa 1957) was so old the rumor was that she didn't teach history as much as she just reminisced.  She might have witnessed the volcanic birth of this rock.
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BEST IN LARGE.