Was hiking on a trail beside the Encampemnt river ( southern Wyoming ). Found a fist sized black rock ( basalt I think )It was in the shape of a paralellogram. I am used to the rounded edges of rocks from tumbling , but I think the shape is quite uniqe on this one. Kinda cool I think.

That's a scary canyon! I went up it about 10 years ago and found numerous mulie carcasses that were just bone and hair piles. I HATED walking under ledges along the trail after that. Lions freak me out far more than bear. The fishing and the bighorns made it worth it, though. Did you post a picture of the rock?

No don't have that sofisticated of a rig.

Have hiked that trail from where it begins in Colorado .15.8 miles.It is a wilderness area. I am going back and check out the rocks.

I saw a photo of oddly geometric rocks on the internet. Interesting .

without seeing the rock, it is hard to say but the Devils Tower is in Wyoming I think. It is a columnar basalt that forms polygon as it cools. Another place off the coast of Scotland has that. Could be a chunk of that basalt stuff.

No basalt formations that I've ever seen along the Encampment River where Bill 03 hiked it. It's almost at the opposite corner of Wyoming from Devils Tower! The wilderness area portion is over the line in Colorado.

Bill, do you have a photo?

I wish I did .

No basalt formations ? Interesting . Encampment river flows out of Colorado. Mayhaps .... I had stopped to water the dogs in the river A very long time ago I had a course in geology in college. May not know what basalt is anymore.