Ewwwww Yuck

I am not sure if I should report this or if it is just an obscured happening. A few weeks ago we spread the weed and seed stuff on the lawn to kill off the damn pricker weeds. GRRR. Well, the lawn being at a stage where it is still mostly dead... I was cleaning around the area we put the pool up in. You know taking misc stones, sticks and etc out of the sand lot to prep it for new sand. In the border where the sand meets the lawn... I found what looks like a molar tooth. A rather large molar.

First reaction was to put the pincher on all three horses and check their teeth. Rather scarey thing to do, considering their teeth are A LOT bigger and extend further back in the mouth then I'd expected. Well no one was missing a tooth. So, the question remains, did it come out of the soil via natural land errorison or was it something I missed last year in the sand delivery? Do I get athoritys involved or just hold the tooth as a bizare trophy? I did contact the vet and he said he would do a go behind check on the horses teeth when he comes next month for their shots.