I had the pleasure of visiting a well known collector in SW Wisconsin a few weeks ago. His home is almost as nice as any museum I have ever visited. He showed us some beautifully crystalized stromatolites that were collected in SE Minnesota. Hints were given as to where to find such specimens. So naturally, I had to find myself an example. I am just not sure if these are just geological and not biological. I hate to question a very knowledgeable man, but obviously I am. Opinions are welcomed.
Mike