Frosty February Trip to Walker County
Updated: Mar 4, 2021
There was quite a bit of excitement building since January to get back out to the strip mine site in Walker County as some large slabs were turned up by a bulldozer the month prior. A lot of rain in the first half of February had done and excellent job washing off the newly turned material, as we had hoped. The morning started out cold with temperatures in the 20s, but with no wind and bright sun, it was surprising pleasant. The cold posed an issue initially as the slabs were frozen in place (this was a first for me at this site), but by the afternoon the bright sun had warmed the air into the 50s and the earth loosened its grip. We had a large crowd of 30+ APS members and guests, likely due to the pre-trip enthusiasm expressed by Ashley! The day did not disappoint! There were lots of amazing finds and at least one find that we will likely hear more from in the future. Stay tuned APS members.
Enough of the prologue though, lets get to some of the fossils. These fossils represent Pennsylvanian Age fossils dating back around 310 million years ago. The fossils found here represent flora and fauna of the wet coal swamps and tidal plain that would have been in proximity of an ancient sea. Occasionally that sea invaded the area for periods introducing rock layers containing marine fossils which were discovered on this trip. We will start with those. The first set of images include rusophycus, brachiopods in matrix, and a likely section of a coiled cephalopod.
Of course coal swamps had plants, a wide variety of plant fossils were found including fern fossils and sections of lycopod trees, and many other plant fossils. The next set of pictures includes a fern pollen organ (whittleseya elegans), a really cool stump, a 310 million year old stick, and a lovely stigmaria!
The next group of photos are invertebrate trackways which also showed up in a lot of variety and sizes this trip. Some of these trackways can be beautiful in their detail. Some are very characteristic to modern day analogs but some from this site can be quite hard to attribute to current fauna. Here are a group of some of the incredible variety found on this trip. From top left to bottom right, there is a diplichnites? (myriapod trackway) running by a fern leaf, an arthropod trackway, treptichnus (feeding burrows), arborichnus (feeding trace?), stiaria? (monuran insect), and two small invertebrate trackways (???).
There were also quite a few vertebrate trace fossils found to include this terrific Undichna fossil seen below. These fossils are created by fish fins making contact to the bottom. In this case you the fish was swimming at near constant speed making a perfect sinusoidal pattern in the silty bottom.
Finally, the last set are some of the vertebrate trackways discovered on this trip. These range from small reptiles and amphibians to quite large animals with footprints on the order of human prints. The details of some of these trackways are incredible and contribute greatly to the overall significance of the site. Without further delay here are some examples of the vertebrate tracks and trackways that were found. There are several nice examples of both reptilian and amphibian trackways below. The relatively large tracks below in the bottom left are of attenosaurus sublensis and in the bottom right is an amphibian trackway with several very nice manus prints. The manus or hand prints are considerably smaller than the pes prints and only have four toes. Also, note the small bulbous ends of the toes characteristic of amphibians.
The weather and the fossil gods were kind, and it is always good to get out fossil collecting with APS friends from literally across the entire state. Thank you to Ike, Glen, Robert, Prescott, Ricky, Bill, and Jim for providing pics for the blog!