Untitled Sighting

On friday July 30th we had a cement pad poured to form the base for a new dog kennel. Sometime beween friday evening and saturday late afternoon something very large left a footprint in the middle of that 12 foot by 24 foot cement pad. I have taken pictures of it and it is now embeded permanantly in that cement. I was hoping I could send you the pictures and you could tell me if you know what left the footprint. It is not a human print nor any animal print that I have ever seen. There was no one at home at the time it was left, as I was out of town for the weekend, and nobody but the family knew the cement was being poured. I am looking for some sort of reassurance that it was not something dangerouse that left the print as I live in a very rural area.