New find today

[kodpkd]

If this is stone, it's very strange.   Found in NE colorado near the WY border.

Edited December 7, 2021 by kodpkd

[Ludwigia]

Yes, I think that you're right in that this is a very strange stone. Not seeing a fossil here at any rate.

[Rockwood]

I suspect that the strangeness is the result of weathering. The lighter color being the weathered material. There may be a certain amount of texture in the rock, caused by some kind of deformation during deposition, which the process accentuates. 

[kodpkd]

I was thinking the formation is similar to a geode.

[Auspex]

Mineralogically, it resembles siderite, limonite, or a similar iron carbonite to me. It is an interesting piece.

[kodpkd]

Found in the same area.

[Rockwood]

This is a common problem. It could be trace fossils, but I don't see anything conclusive.

[kodpkd]

I don't think the big rock is any kind of fossil,,,,,, just limonite.

[Lone Hunter]

Funny that I see a resemblance to the chain fossil in another post.