Abstract

The Middle-Upper Devonian Catskill (nonmarine) Magnafacies of southeastern New York contains rare body fossils and numerous trace fossils, many of which have not been described previously from this area. Body fossils include: Archanodon, Euestheria, Leperditia and Welleria (ostracodes), fish fragments, lingulids and plant remains; trace fossils include: large vertical meniscate burrows (interpreted as bivalve escape structures), Beaconites antarcticus, Planolites montanus, Spirophyton, Diplichnities (=Beaconichnus gouldi), Rusophycus (=Isopodichnus), other traces resembling modern arthropod trackways, and problematical structures of uncertain origin.

Trace fossils occur in all sedimentary facies but are concentrated in the deposits of specific depositional environments. The large vertical meniscate burrows occur within channel-bar and crevasse splay deposits; locally they are associated with Archanodon. Beaconites antarcticus is most common in upper point bar and levee deposits and in sandy overbank channel-fills. Diplichnites and other trackways are abundant in certain chute channel- fills, and also occur in the deposits of floodbasin ponds with the conchostracan Euestheria. This distribution indicates that organisms were concentrated in and along rivers and around areas of ponded water on the floodplain, and suggests that early terrestrial organisms required moist habitats.

Body and trace fossils are widely distributed through these deposits, indicating that terrestrial communities were developed over much of these Devonian floodplains. Some workers have argued that the early terrestrial life was most diverse near the shoreline, but in this study systematic variations were not observed in trace fossil diversity in localities proximal and distal to the paleoshoreline.