Oh Evelyn, you beat me to the punch! :^)

I used to have a huge collection of these fossil corals. It's called Petoskey Stone (obviously not its scientific name) and is the state stone of Michigan (my home state.)

I think my mother used to clean out my closet periodically & throw away my stone collection. And when we moved from Michigan to the west coast, my husband refused to ship my rock collection (we were so poor, we couldn't afford to pay for the extra weight) and I donated it to a high school teacher who was an amateur rock hound and geology nut.

I miss my Petoskey stones!! :^(
Luann