Harv,
Been there, done that. Here in Middle Tennessee, we have the expression of a thing called the "County Rock". Thats the rock you hit that the whole county is sitting on. A few years back, I had this "small" little rock poking out of the ground in my back yard. It was just high enouph to be annoying with the lawn mower deck. My neighbor across the street has a large Ford backhoe, so I decide to borrow it for a couple of minutes (yah, right) and pop the "small" rock out of of my yard. Well, needless to say 2 hours later and a hole 12' wide and 10' deep, alas, I have gotten the rock out. It was in 3 pieces, laying vertical, just below the suface of my lawn. The hoe had a terrible time trying to get these rocks out. Estimated each piece weighed around 5 to 7 thousand pounds! After that, any "small rocks I found in my yard, I just took a hammer and chisel and knocked the top off of them.