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June Hunt for Carboniferous Trackways


I, personally, was very excited that the Alabama Paleontological Society (APS) hit the field again on 26 June in what has been a very active 2021, albeit a small group of about 8-10 members and guests. It was warm, but not too bad for almost July in Alabama, and it was not too horribly humid either (thank goodness!). The mimosa trees, in full bloom, framed the edges of the fossil collecting area. The site continues to be quite productive since it was given a very good turn by the state this past spring and so far the weeds have not completely overtaken things this year. There continues to be plenty of material to split even after literally 100s of collector-days have been spent on the site since the last turn. Please enjoy the many fossil pictures from this past trip provided by several members of the APS.


Given the fossils from this location are Pennsylvanian age and date to ~310 million years ago, the first set of tracks highlighted from this trip were an unexpected discovery. They are rare (for this site) dinosaur tracks and were found by APS member Rick. These were made by modern derived descendants of the avian dinosaurs that survived the end Cretaceous mass extinction approximately 65 million years ago. Clearly these prints demonstrate similarity to other theropod dinosaurs. These avian dinosaur prints were made by a modern dinosaur occasionally spotted near the site in small groups, commonly referred to as wild turkeys (haha!!).

Back to the actual fossils....


Plants

The first group of photos represent some of the fossil plants (pic 1 is mariopteris) to include fern leaves and fronds and the fern seed pod triganocarpus.

Invertebrate Traces and Trackways

There were some really wonderful invertebrates represented in this trips finds. The first group are Kouphichnium, which are associated with horseshoe crabs and similar. Like all the trackways, they can appear differently depending on the depth of the layer in which they are preserved and the condition of the strata at the time of preservation. The first two are close to the surface and the latter photo only shows the characteristic "y" shape deeper impression from the end of the appendages. Notice the plant fossil, a seed fern pollen organ whittleseya elegans, along the right edge of the picture.

The next set of pictures represent insect trackways, specifically stiaria (associated with monuran insects) and diplichnites (associated with myriapod insects, e.g. centipedes and millipedes). Notice in the last picture the diplichnites trackway oriented from top to bottom crosses a tetrapod surface trackway running from left to right.

We will close out the invertebrates with a variety of interesting and several rare fossils from this site. The first picture is a terrific rusophycus (along with other traces and burrows), next is a likely insect burrow called arenicolites longistriatus (also includes treptichnus apsorum burrows). The next two fossils are not trackways or burrows, the first is a small bivalve with both valves present and then a section of cephalopod(?). Finally, the last picture is a "what is it?" fossil. On the left half of the plate there are a series of "check marks" that are probably some kind of trace along with many other traces to include arborichnus on the same plate.

Vertebrates

The first up in the vertebrate tracks this time is a nice fish swimming trace, undichna, created when fish fins carved into the soft muddy bottom as the fish swam by often captured as sinusoidal waves.

Finally, no trip to this amazing sight is complete without finding tetrapod trackways and again the site yielded some of these amazing gems.

Until next time, keep looking at the rocks in Alabama. You never know what you may find!

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