Can you guess what this is?
Hint: It's very old.
Another photo below, if you can't guess from this one.
UPDATE: Claire nailed it, right off! No, it's not petrified poop. I don't think Oxford likes to acknowledge the existence of poop, much less place it on display at their Museum of Natural History. I happened to be there with a geologist, who gave me the poop on dino eggs. Most of them are found in China, but this collection, she told me, was better than the one on display at the museum in Beijing.
I'll try to write more about the museum later. It's well worth a visit if you're in the area.
