Have you ever toured Lizard Mound Park?
http://www.co.washington.wi.us/landuse/lizard%20mound.html
No, I haven't. It is probably not more than 15 miles from where I live, and I've never heard of it. I'll be sure to check it out as soon as it gets a little warmer! I have some strange mounds on my land, too; but I thought they were the previous owners's dogs! LOL.