Two species of Cruziana are common in North Wales.
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C. Semireplicata is prevalent at Cwm Ceunant, it is of Upper Cambrian age.
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C. Furifera is prevalent at Arenig, it is considered to be of Arenig (Lower Ordovician age)
Unfortunately photographs are not very good at showing the difference, semireplicata's leg marks are much clearer. The changing pattern, presumably caused by evolutionary changes means that these trace fossils can be used for stratigraphy.