Hitchcock's treptichnid trace fossils (Jurassic, Massachusetts, USA): conflicting interpretations in the " Age of Fucoids "

Edward Hitchcock was one of the most influential 19 th century ichnologists. In a career that lasted nearly three decades, he established 31 invertebrate ichnogenera for Early Jurassic traces from the Hartford and Deerfield Basins of Connecticut and Massachusetts, some of which are in widespread use today. Upon reexamining some of Hitchcock's specimens, we have identified a number of fossils that are similar to the well-known ichnogenus Treptichnus. Modern ichnologists generally interpret non-marine occurrences of these burrows as the traces of larval insects. In some instances, Hitchcock ascribed his fossils to the activities of annelids or larval insects, and his descriptions of their mode of formation are similar to those presented in much more recent works. However, he also interpreted some treptichnids as algal/ plant fossils. We suspect that his varied interpretations reflect differences in morphology and preservation among specimens. Hitchcock worked in the 19 th century, a time known as the " Age of Fucoids " , and his comments also reflect the prevailing uncertainty on trace fossil origins."