The realm of ichnology, its strengths and limitations

Ichnology is the study of aU manner of gouges, scrapes, and traces made by living or ancient organisms. At first glance, these oddities might seem to offer little encouragement for serious study. But many looks later, a surprisingly sophisticated body of information begins to emerge, most of it unavailable from any other source. Fossils that once were dismissed simply as "indirect evidence of ancient life" or "secondary sedimentary structures" now are proving to be invaluable in interpreting many forms of ancient life and the associated sedimentological and environmental conditions. Trace fossils are preserved in numerous places where body fossils are not, and they document several behavioral, ecological, and sedimentological traits that body fossils cannot. Even where both are present in representative quantities and are associated with physical sedimentary structures, trace fossils can yield information that is basic and valuable in its own right, broadening a picture that otherwise is needlessly (and at times misleadingly) narrow. By the same token, trace fossils are inherently less useful than body fossils and physical sedimentary structures in many circumstances, and may yield obscure or ambiguous information in others. The question, then, is not simply which line of evidence to use in a given study, but rather, how all the evidence available can be brought to bear in that study. The actual situation is that, more often than not, trace fossils have been relegated to a minor role in paleoecology, sedimentology, and facies analysis where, if utilized, they could have made a very substantial contribution.