Featured What type of tool and approx. age?

A little background: As I shared earlier, my mom and her sister grew up on a farm that has been in our family for over 150 years. I know my Grandfather played with the indian children prior to his father purchasing the farm when they lived in the little town near by.
I found this item out in our field when I, a kid that grew up in Anaheim, CA, was asked to go out and pick rocks that "grew up out of the ground" over the winter. Thinking this was like the time I was sent out to hunt Skypes with a pillow case, I said I wasn't falling for it. Then they offered me 5 cents a rock for all each of the rocks I picked, that were bigger than my head, so out I went. And that's when I found this. Any takers on what this is?

 

now yer rockin !!!!!!

Native ax head......

 

Full-grooved ground-stone axe head (with a broken bit.)

Native American, Early Archaic. (way old)

 

I'm betting it broke and got dumped, like a lot of modern tools. Given the way the edges have worn down, old may not be the word for it.