The Llanfallteg Formation is a

geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

in Wales. It preserves

fossils A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

dating back to the

Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. ...

period. It predominantly consists of ash containing siltstones, as wells as ash fall deposits and tuffs. It likely dates to the

Darriwilian The Darriwilian is the upper stage of the Middle Ordovician. It is preceded by the Dapingian and succeeded by the Upper Ordovician Sandbian Stage. The lower boundary of the Darriwilian is defined as the first appearance of the graptolite species ...

based on graptolites. The local graptolite fauna includes '' Didymograptus artus'' and '' Glossograptus armatus.'' The local trilobite fauna includes agnostids, phacopids and asaphids.

References

* Geologic formations of England Ordovician System of Europe Ordovician Wales Ordovician southern paleotemperate deposits {{England-stub Fossiliferous stratigraphic units in Wales

See also

References