Today's Geo Quiz rocks.

The rocks we're looking for in our quiz today are actually "bluestones."

One place you can find clusters of craggy bluestones is in the Welsh countryside.

We're thinking of one particular site in the county of Pembrokeshire.

“It's in the Preseli Hills, it's an incredibly atmospheric spot, they're quite high hills, they're very exposed, it can get very cold up on the top, and they're very distinctive, you can see them from many miles back, you can see them out to sea in the English Channel and the Irish Sea.”

This archaeologist believes the massive stones used to build Stonehenge came from this lofty site.

Get out your GPS or your old archeology class notes ... whatever you need to come up with the name of this rocky site.

We'll consult a Stonehenge expert for the answer here...