Type
Zone
Age range
0.42–0.18 Ma
Pleistocene
Chibanian
Buccinosphaera invaginata
Collosphaera tuberosa
Stylatractus universus
0.430.420.410.400.390.380.370.360.350.340.330.320.310.300.290.280.270.260.250.240.230.220.210.200.190.180.17