Trilobite tracks and other trace fossils from the Upper Cambrian of North Wales

Trace fossils are recorded from eight localities within Upper Cambrian (Ffestiniog Stage) strata in North Wales. Trilobite furrows (Cruziana), resting impressions (Rusophycus), walking and striding tracks (Diplichnites), sideways grazing tracks (Dimorphichnus) and swimming grazing marks (Monomorphichnus, gen. nov.) are described, largely on the basis of over 500 collected specimens, and are figured together with examples of other trace fossil genera including Rouaultia, Phycodes and Monocraterion. The trilobite traces are used to investigate the varied methods of locomotion of the animais. They also indicate the morphology of some of the trilobite hard and soft parts from which it is inferred that most of these traces were probably made by a population consisting of a small number of closely allied species of trilobites belonging to the Olenid family.