the fossils
petoskey stone
Hexagonaria · each eye was one live polyp


The tell
Big six-sided cells, each with a dark center and fine lines radiating out from it like a tiny sun. Those radiating lines are the tell, not the size: a small-celled petoskey is still a petoskey. Wet one cell and look for spokes. Spokes mean petoskey. Plain-walled tubes with no spokes mean charlevoix.
Dry, a petoskey often looks like a plain gray stone. Wet it. That is why everyone photographs them at the waterline.
What it gets mistaken for
- charlevoix
- chain coral
- stromatoporoid
- bryozoan
- honeycomb coral
The facts
- also called(petoskey stone) · each eye was one live polyp
- age~385 million yrs
- where it turns upup north best · statewide in gravel
- the field markwet it · six-sided cells, each with a dark eye
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