Unknown imprint in stone

[Dale from Utah]

Greetings everyone, my first post.  I've attached a couple of photos of a rock I found recently that shows (to my untrained eye) what appears to be rows of raised bumps from some type of biological material.  Or, maybe it is the result of something tunneling under mud or sand.  Here's the data:  found in the United States in the state of Utah, in Cache county, at the base of Little mountain, which is 2 miles north of the town of Newton.  This area was under several hundred meters of water during the time of Lake Bonneville but I suspect that this example predates that era.  The stone is textured on only one surface.  The bumps are only 1 or 2 mm in height and I had to photograph the piece using low angle light in order to show the texture.  The surface of the stone isn't perfectly flat but rather has some slight ridges and depressions and the imprint details follow those contours.  Any thoughts as to what this may be, or what caused it, would be greatly appreciated.  Thanks.

[Darktooth]

Welcome to the forum from New York! 

 

[ynot]

Welcome to TFF!

Looks like it could be an algal mat.

[westcoast]

2 hours ago, ynot said:

Welcome to TFF!

Looks like it could be an algal mat.

That was my first thought also. Could be. However it almost looks too regular for algal mat. Also it appears to within a single sandstone bed, I would be looking for some fine silty  laminations. Could be small scale load casts or dewatering structures but again no heterolithic layering is apparent in this piece.  Another option is some piece of very poorly preserved plant material but I'm not convinced of that either. 

[supertramp]

if not of biological origin, 
they coul be interlaminar markings known as "polygonal casts" or "pendent structures" (for the italian "rigonfiamenti squamiformi")

picture from "Sedimentografia" - F. Ricci Lucchi - ciao

 

 

[Dale from Utah]

Thank you very much for welcoming me to the forum and for your insights on the stone, I really appreciate it.  Dale

[abyssunder]

I'd try to lean toward a possible ichnological content of the specimen, suggesting a graphogliptid aspect, maybe something in the line of Paleodictyon.

[Dale from Utah]

Thanks abyssunder, I visited the field site again yesterday since it is only 20 minutes from my house.  I found this stone about 5 meters from the example I posted earlier.  It is similar and maybe even more close to being something like Paleodictyon.  Thank you again for your suggestion!

[westcoast]

These almost look like dissolution features.... Intriguing!

[abyssunder]

Intriguing, I agree. It's clearly visible that the second specimen has etched surfaces, probably due to the weathering factors, also it's rounded all around the margins, but I can't exclude the possibility of ichnos stated before. Trying to compare the specimen with some of the ones figured below, I can see similar features, also I could be wrong.

 

excerpt from P. Monaco. 2008. Taphonomic Features of Paleodictyon and Other Graphoglyptid Trace Fossils in Oligo-Miocene Thin-Bedded Turbidites, Northern Apennines, Italy. Palaios 23: 667-682

 

[westcoast]

I agree with @abyssunderthat Paleodictyon is a strong candidate.

[DeepTimeIsotopes]

Looks like interference ripples in sand

https://www.google.com/search?q=interference+ripples+sand&prmd=isvn&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjKkfrGu4LfAhUHrYMKHd-WDfMQ_AUoAXoECA0QAQ&biw=375&bih=559#imgrc=OVu0iuzMcbARrM

 

This forms when two primary water currents wash over the same area at different times. It frequently occurs in sand. 

[ynot]

48 minutes ago, UtahFossilHunter said:

Looks like interference ripples in sand

I agree with this ID.