ABSTRACT
Palaeoichnologists possess a rich vocabulary of terms with which to describe occurrence and distribution of trace fossils. These terms are mainly borrowed from body fossil palaeoecology, but as bodies and traces are not biologically equivalent concepts, problems emerge with the equivalent terminologies. In fact, these terms have been used in many different ways and there is some disagreement over their definitions. In particular, there is difficulty over scale, or hierarchical ranking, of the terms.
This is the basic collective term, embracing all the trace fossils occurring within a single unit of rock. The term is equivalent to the assemblage of body fossils (e.g. Kidwell and Bosence 1991), and is non-committal as to the origin of the collection of trace fossils. Thus, the trace fossils of an assemblage may have been emplaced simultaneously as a single ecologically-related group, or they may represent several overprinted events of bioturbation. As physical transport of trace fossils is uncommon, the trace fossil equivalent of the taphocoenosis is correspondingly rare (but see Belt et al. 1983; Baird and Brett 1986; Donselaar 1989; Fiirsich et al. 1992; Hunt et al. 1994). Goldring (1991) called reworked trace fossils ichnoclasts.
