The rock didn’t necessarily seem special when 6-year-old Leo Youngdahl spotted it during a late summer Rafting and Rocks event at Schramm Park State Recreation Area near Gretna.
But it was a pretty large one, and he hoped if he turned it over, he’d find one of his favorite fossils on the underside, he said.
Instead of crinoids, though, he discovered a much rarer fossil: an ancient marine animal call…