It is sandstone. Definitely peculiar. There is a perfect bird on it. The bird looks like a pelican. Pelicans migrate to the lake he lives near (Oklahoma). However, the lake was only put there in the 50's. So.......... Never seen anything like it before. The two most interesting 'artifacts' are squared in black. Same type of shapes, same arrangement, just flipped from each other. I don't know what it is. I vote NO for treasure marker and a big fat MAYBE for trail marker.
Natives crawled the mountain where this came from. We find their stuff up there all the time. Ol' buddy let me take the pics. Wouldn't let me take the stone. The guy he got it from said there were a lot more where that one came from. A sampling would be nice but, the guy ain't talking.
The rock is out of place. Set down in ol' buddy's front yard for the shoot. Maybe an early Indian Picasso? Who knows?