Trace fossils Nereites
, Helminthopsis, Cruziana, Lockeia, Cochlichnus, Arenicolites, Archaeonassa, Aulichnites, Phycodes and Planolites are found.
The determined ichnotaxa are: Chondrites isp., Helminthoraphe flexuosa, Multina minima, Nereites irregularis, Ophiomorpha annulata, Ophiomorpha rudis, Paleodictyon strozzii, Planolites isp., ?Squamodictyon isp., and Taenidium crassum (Fig.
The trace-fossil assemblage of the Ezkaba Sandstone Formation, the older unit considered in this work, is characteristic of the deep-sea Nereites ichnofacies, as revealed by the presence of graphoglyptids (Uchman and Wetzel, 2011; Wetzel and Uchman, 2012).
vertebralis), supporting the differentiation of the Ophiomorpha rudis ichnosubfacies of the Nereites ichnofacies.
and Helminthorhaphe flexuosa) suggests the Paleodictyon ichnosubfacies of the Nereites ichnofacies or a mixed Paleodictyon-Ophiomorpha rudis ichnosubfacies ichnoassemblage.
Gordia, Helminthopsis, and Planolites are widespread and common in three ichnofacies: Cruziana, Mermia, and Nereites
. Palaeophycus is restricted to the Cruziana, is the genus attributed to this ichnofossil.
Similar examples (Nereites
) occur in the Mississippian Hartselle Sandstone of Alabama in an estuarine paleoenvironment.
These trace fossils suggest a Nereites
ichnofacies indicative of a deep-water environment (Gingras et al.
Four groups were originally identified (the Skolithos, Cruziana, Zoophycos, and Nereites ichnofacies--following Bromley 1996, we do not italicize ichnofacies).
However, in the marine realm, Bromley and Asgaard (1991) considered the Nereites ichnofacies to comprise a Zoophycos ichnofacies, and one or more as yet unnamed graphoglyptid ichnofacies.
Buatois and Mangano (1998) considered it the nonmarine equivalent of the Cruziana-, Zoophycos-, and Nereites ichnofacies in its environmental context, whereas Bromley (1996) considered it only equivalent to the Nereites ichnofacies.
ichnofacies from the Ordovician-Silurian Welsh basin.