Burrow cast in Chinle Formation

[kgbudge]

Trace fossils aren't always as exciting, but I like the ones I've found.

 

This looks like a burrow cast. From the "mottled member" of the Chinle Formation, Temple Mountain, San Rafael Swell, Utah, US.

 

Posting also to check my identification. My references indicate that the mottled member at this locale is known to have lungfish burrows ... unless they're crustacean burrows. This one seems large for a crawdad (even a Triassic crawdad) but small for a lungfish.

[JohnBrian]

I don't know what yours is. But, I have, what I believe, are several infilled burrows from the Chinle. They range in size from 1/4 that of the diameter of a pencil lead to 3 times the diameter of a pencil lead. The longest is 3/4 inch. They might be just mineral oddities or maybe twigs that deteriorated and the resulting void was then filled.

 

Unfortunately, it is dark outside and the light for my microscope burned out so I have no way to photograph them at the moment.

[Rockwood]

Bivalves can leave traces that look a bit like this. They are more mobile than one might expect, and move with a slight jiggle to their walk.

[jdp]

Might also be a root cast.

[abyssunder]

I think, there are three possibilities:  borrow cast attributed to freshwater crayfish, rhizolith or sandstone-filled mudcrack. Hard to me to say. 

[kgbudge]

I couldn't get the pictures to show this well, but the thing is quite cylindrical in shape. Might be more obvious if It was removed from its matrix.