Trace fossils are the burrows, trails and tracks of animals passing over or through the sediment, and are inexplicably rare throughout the inlier. Simple burrows are often associated with ash beds, but these cannot be usefully classified. A few specimens of trilobite trails (Cruziana) have been doubtfully reported, but they are remarkably scarce. Occasional borings into the skeleton of bryozoans and brachiopods at Llandegley Rocks are also known, but have not been studied in detail. No other identifiable traces have yet been reported.

Although it is usually impossible to assign an animal species to a particular trace, they are very useful in recording the activity of organisms that otherwise would not fossilize. Arthropod trails in particular can be very indicative of a certain group, while worm trails can at least offer some insight into diversity and abundance. In other words, they’re not glamorous, but like everything else, they’re worth recording.

This is the one group that I’ve gotten nowhere with the drawings of yet – partly because it’s such a difficult group, with arbitrary divisions, and partly because trace fossils are so frustratingly rare in the Builth Inlier. This will, one day, be remedied. Honest.

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To be drawn:

[2]Cruziana sp. ?

[1]‘dumbbell’

[2]indet. boring sp. A

[2]indet. boring sp. B

[1,2,4]indet. simple burrows

[2]micromorphic Palaeodictyon?

[2]nematode trails?

[2]scratches (trilobite?)

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