Grinding stone?

[Virginiaguy]

I found this flat rock with a bowl shaped depression in a recently plowed field along side of the Shenandoah River in Virginia. The bottom side has depressions that match my left hand. It also has a nice fossil along the edge of the depression. Any ideas? Grinding stone of some type? Thanks for your input.

 

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[quito]

Welcome to the forum!

Tough to say for sure from what is shown. Likely natural though.

 

[mirage83]

With the texture of the depression I'd say natural.

 

[Quartzite Keith]

Looks like a water worn cobble, probably quartzite, with a dark patina from sitting in water. The smoother depression in the second picture is natural, occurring before the chunk of stone fell into the river and got tumbled eons ago. The depression shown in the first and third pictures is where a spall was struck off the cobble. The break in the rim of the depression on the bottom right of the third photo is the place the cobble was struck that dislodged the spall. That may have been intentional. When I want to make a Savannah River point, I find a quartzite cobble similar to that one and slam the edge of it down on another cobble to pop off a spall just like that. Could have also happened accidentally by machinery or mother nature, but not pecked out like if someone was intentionally making a depression to use as a mortar. If found where it doesn't belong, may have been carried there to use as a an expedient mortar.

 

[Arrow1492]

Nope. water worn or a freeze thaw fracture

 

[Virginiaguy]

Thanks to all for your replies. I will put this one in the "cool fossil" box. Much appreciated.

Bill