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Fossiling in February

The APS made a return visit to the Pennsylvanian Age rocks of Walker County, Alabama on a gorgeous February day. We had a good group of about 15 enthusiasts, many joining us for the first time. The day was spectacular with deep blue skies and bright sun at a low winter angle (really good for hunting trackways!), it was cold to start with temps right around freezing but warming up to near 50 degrees by the time most were worn out and heading home. The freezes of winter have done a good job killing off the the vegetation that had covered the site at the end of summer. This was the first time the club had visited the site since the fall and there had been lots of rain and freezes to expose and crack some of the more productive rocks. A number of great fossils were found and folks had a really good time.

This site remarkably continues to produce exceptional plant fossils, exquisite invertebrate trackways, and world-class tetrapod trackways, along with other fossils. The following is a sampling of exceptional fossils found on this trip.

Plants including seed ferns and there reproductive pods:

Next some truly wonderful invertebrate trackways and burrows:

A terrific sinusoidal fish swimming trace (Undichna):

And the early tetrapod trackways that truly make this site world class:

This next group of vertebrate tracks going from left to right shows the variation in trackways that can be found at the site based on depth in the sediment. In other words, the first trackway reflects the exact or nearly exact surface where the tetrapods foot contacted the mud. In this first pic, the footprints are ill-defined and the tail drag is present. As you move to the next photos the mud layers are deeper and deeper and show less and less of the footprints only reflecting where the most pressure was exerted down through the mud layers. In pics 2-4 the pad of foot fades away and the last picture all you have left are the ends of the digits preserved.

Finally, here is an odd one (there are always oddities from the site). I believe this is a smudgy attenosaurus tetrapod footprint (impression and counter-impression), however I am open to any ideas!

Hope to see everyone out in the field in the coming months!

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