Imagine this: You have an idea for a stunning flower garden and you get to work digging, only to come across something you never thought you would — a fossil. It's seemingly a worthwhile find; however ...

To find out, I took it to London’s Natural History Museum, where Susannah Maidment, a senior researcher and fossil expert, examined it. “Yeah, it’s a fossil, for sure,” she said. “It’s got a rounded ...