Here is a new fossil for you to identify. I haven’t put up anything like it before, so you can rule out any of the usual candidates. I will put up the answer next Monday unless some early bird beats me to it. Good luck.
Home » Paleontology » Fossils of Arkansas » Fossil Monday, A New Segment
paleoaerie 
That’s either a serpulid worm cluster or some burrows.
You have an excellent eye for worm fossils. They are rare in Arkansas and almost never reported, but they turn up occasionally. I’ll write more about them later.
I find them to be very beautiful fossils and it’s too bad that not many are known from the landmass of Appalachia.
P. S.
I wanted to inquire about the exact age of “Arkansaurus fridayi” for a paper I’m writing, as I’m sure you would know. I would be really thankful if you could help me out!
They are interesting fossils, aren’t they? I am only recently acquainted with them myself. I was looking through the list of fossils found in the state and realized that was the only group for which I had never seen a specimen of any kind that I knew about, so I decided to take a look.
According to the Rebecca Hunt 2003 paper, Arkansaurus came from the upper Trinity Group dated to approximately 120 million years. Here’s the full reference for that paper. It is also the most complete study that has been undertaken for the fossils to date.
Hunt, ReBecca K., Daniel Chure, and Leo Carson Davis. “An Early Cretaceous Theropod Foot from Southwestern Arkansas.”Proceedings Journal of the Arkansas Undergraduate Research Conference 10 (2003): 87–103.
Thanks so much for the information. I had no idea the “A. fridayi” holotype was so old (I originally thought it was from the Albian-Cenomanian border). This will be really helpful to my work. Cheers.
*I think.