I'm looking for information about these rocks.

[Jason Stallings]

[minnbuckeye]

They have the general look of the Ordovician bryozoa called Prasapora. But unfortunately I do not see the finer diagnostic features that would confirm this possibility. So I lean towards rocks, not fossils. 

[TqB]

Possibly the trace fossil Conostichus.

[minnbuckeye]

@TqB Conostichus is a new name to me. They look surprisingly similar to Prasapora from a distance! Did they occur back in the Ordovician? @Jason Stallings, do you know the formation these specimens came from?

[Jason Stallings]

I found them on different job sites around the fort Smith area. I don't know anything thing else about them.  Over the years I've collected these. Thanks for any information. Here's another larger one.

 

[TqB]

1 hour ago, minnbuckeye said:

@TqB Conostichus is a new name to me. They look surprisingly similar to Prasapora from a distance! Did they occur back in the Ordovician? @Jason Stallings, do you know the formation these specimens came from?

A cursory search finds this paper with possible Ordovician specimens.

Middle Ordovician Trace Fossils…Eastern Canada

 

And this blog has Arkansas (Ozarks) specimens but doesn't give an age. 

https://arkansasgeological.wordpress.com/2016/10/06/geo-pic-of-the-week-conostichus-trace-fossils/