A few years ago, I was wandering through Snake Den looking for art subjects. I started noticing that large boulders and outcrops with striking shapes often were surrounded by piles or rows of stones. An online search of "stone structures" led me to Larry Harrop's blog, and to the realization that the mysterious structures had some aesthetic or spiritual significance to the Native Americans who built them.
Here is an example. A few weeks ago, I noticed this large outcrop, which looks like granite boulders joined eons ago by the lava which flowed between them. The lava cooled into layers, which resemble flowing drapery.
Here are a couple of landmarks from an old native trail, now Route 44 through Rhode Island. The first is a large boulder on bedrock in Smithfield. The second is a pedestal boulder on a small hill on private property next to 44 in Harmony. Our roads are built on a secret landscape.