Oichnus simplex Bromley, 1981

Emended diagnosis: Sedilichnus having a simple cylindrical or subcylindrical form, axis more or less perpendicular to the substrate surface. The distal ends of the pits terminate within the substrate; those of the partially penetrating holes are flat or slightly concave (after Bromley, 1981).

Diagnosis – (After Bromley, 1981, p. 60.) “Circular to subcircular holes of biogenic origin bored into hard substrates. The holes may pass right through the substrate as a penetration, where the substrate is a thin shell; or end within the substrate as a shallow to deep depression or short, subcylindrical pit.”
Description – Circular to oval, vertically oriented borings. The majority of these borings do not totally penetrate the substrate. Diameters vary between 70-350 μm.

Diagnosis: Oichnus having a simple cylindrical or subcylindrical form, axis more or less perpendicular to the substrate surface. Where the substrate is not penetrated right through, the distal end is flattened hemispherical.

Diagnosis: Oichnus having a simple cylindrical or subcylin-drical form, axis more or less perpendicular to the substrate sur-face. Where the substrate is not fully penetrated, the distal end is flattened hemispherically (after Bromley, 1981, p. 60),