Walking Rock ??????

Okay - I have seen some odd things before - but look what was in MY garden this morning - it was a walking rock!!! Mom said I was being silly and that it wasn't a rock - but a tortoise. I say if it looks like a rock, feels like a rock then it is a rock - just that this one had a head and legs!!! And what was it doing in MY yard - that is what I want to know? I didn't give permission for any walking rock to go strolling through - doesn't it need a permit or something to do that? Mom and "she who is never seen" (dad's daughter) then got into a discussion about whether it is a tortoise or a turtle. Mom says this is a tortoise as it doesn't live in water (there isn't even any ponds around here !) "She who is never seen" says it is a box turtle. Mom just shook her head and said "well you might call it a turtle but technically it is a tortoise ! YOU ARE BOTH WRONG - is what I said - it's a walking rock ! In the end we all agreed to disagree - though EVERYONE KNOWS I am RIGHT ! We took the walking rock over to my favorite park and let him go there - we were worried if he stayed around our neighborhood he might get run over by a car or a lawn mower although personally I doubt a rock could get damaged! So what do you think. Rock, Tortoise or Turtle? Remember you can click on the photo's to see them bigger. We did find this information on the walking rock http://www.naturalheritage.com/citizen-science/past_projects/box_turtle/turtlebasics.aspx