I found this when i was 9 or 10.
It's half of a rotary Quern, used for grinding wheat into flour. Seeing as i found it beside a ringfort I'd like to think it's a few thousand years old but probably not. While I'm in the humour I must see if I can mail the pic to a museum and get it dated.
Here is one in action
http://indigo.ie/~skerries/1ina3.html
