Seventy-six samples from the type Bastendorff Formation exposed near Coos Bay, Oregon, were examined to determine if significant calcareous plankton were present. Planktonic foraminifera and/or calcareous nannofossils are recorded from 24 of those samples.

Planktonic foraminiferal zones believed present are the Globigerinatheka semiinvoluta and Globorotalia cerroazulensis s.l. Zones of Bolli and Zones P15, P16, and P17 of Blow.

Nannoplankton zones recognized are the Chiasmolithus oamaruensis and Isthmolithus recurvus Subzones of Bukry; these are considered equivalent to Zone NP18 and Zones NP19 and NP20 of Martini, respectively.

The middle and upper parts of the Bastendorff—assigned by Tipton to the provincial uppermost part of the Narizian Stage and the Refugian Stage, respectively, on the evidence of benthic foraminiferal distribution—are of late Eocene age based on calcareous plankton.