Tetrapods Lobe-finned fishes Other fish groups
Invertebrates plants Traces
       

Trace fossils represent marks that were made in sand, silt, and mud that were covered over by more sand, silt, or mud before they could be destroyed by the actions of wind or water. Most trace fossils at Blue Beach represent things like tracks, trails, tunnels, burrows, and borings.

You might be surprise to learn that most of the invertebrate traces at Blue Beach were made by creatures that are not seen in the body fossil record. Their existence at the site is indicated only by the presence of these traces. Vertebrate traces, on the other hand, can be correlated to the trace-makers much more confidently because skeletal fossils are known in great numbers here. Nonetheless, many questions still remain.

Vertebrate traces
Tetrapod footprints -The abundant footprints of Blue Beach can be assigned to at least five different types of four-legged animals: Attenosaurus, Batrachichnus, Hylopus, Palaeosauropus and Pseudobradypus. This is the oldest assemblage of footprints on Earth, and the largest Carboniferous collection, with over 2000 specimens. The tetrapod track-makers are the oldest-known members of the first groups to conquer the land. These footprints occur in over 70 different rock layers.

Fish-swimming trails – Sometimes a fish swimming along the bottom can leave a trace of its dragging fins and tail. These trails look like wavy scratch marks. They are called Undichna. More than one variety of this trace type is evidently here.

Vertebrate burrows? – Large and complex burrows known as Taenidium also occur, but nobody can say for sure what was making these. Some say it was tetrapods or fishes, others believe it was large crustaceans or even polychaete worms.

This footprint appears to have 6-toes. Called an ‘overstep’, it’s really two prints, with the hind foot stepping nearly into the front.

Invertebrate traces
Arthropod traces – A host of arthropods must have been present, judging by their trails and burrows. The surface-walkers left a variety of trails, including Cruziana, Diplichnites, Diplopodichnus, Kouphichnium and Paleohelcura. Burrow-types include Arborichnus, Limulocubichnus, and Rusophycus. At least six species were responsible, including scorpions and additional undetermined types.

Traces of worm-like animals – The most common worm-tunnels are the Palaeophycus. These cover entire surfaces of many rock layers like tangled mop-strings or spaghetti. Other forms include Planolites, ?Skolithos, and ?Gordia. Forms like Helminthoides and Helminthopsis are disputable, as they might actually be a poorly-preserved form of Palaeophycus.

Worm tunnels like Palaeophycus are very common.
Diplichnites – an arthropod trail.