Fossil shell from Fort Myers/Lehigh

Someone’s digging in their garden and found this shell a couple of feet down. Who knows how it got there? Most of the other shells found here have been tiny. This one is a honkin’ five inches! Maybe it’s part of some "fill" that might have been dumped here. Or maybe it’s left from a time when Florida wasn’t Florida yet but just another shallow part of the place where the Atlantic, the Carribbean and the Gulf meet…

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