you trade them to hikers that are underground for an assortment of items.
fossils, shards, stones, plates, spheres
You can find fossils in the Underground Tunnels, or underground. Just dig for them as you would spheres.
you can dig it up underground
its underground. you can dig it up.
In the underground
you have to dig it up when you are underground
Dig for it underground. Its rare but it is possible to dig one up
You gotta dig it up (underground.)
You can find it somewhere or you can go underground and dig it up.
Go underground and dig one up.
go underground and dig one up
i believe you go underground and dig it up.