Inferred from the integration of the data of Okada and Thierstein (1979, doi:10.2973/dsdp.proc.43.117.1979) with this study. In this study, the zonal boundaries are located at the LO or HO of the zonal markers, independent of their frequency. Although in the text Okada and Thierstein (1979) indicated that they relied on the HOs and LOs of markers to delineate zonal boundaries, location of these latter in their range chart (their table 3B) does not follow from this. This table gives the actual LOs and HOs of marker species given by Okada and Thierstein. Significant discrepancies in their data occur for the NP4/NP5 zonal boundary, located between samples 43-384-10-3,49-50 and 43-384-10-2,119-120, whereas the LO of F. tympaniformis is shown between 43-384-10-5,54-55 and 43-384-10-4,55-56. The former position is consistent with the data presented here. Lesser discrepancies include the delineation of the NP6/NP7 zonal boundary between 43-384-8-3, 124-125 and 43-384-8-4,49-50 with respect to the LO of D. mohleri, and that of the Discoaster nobilis Zone (Zone CP7 of Okada and Bukry, 1980 = upper Zone NP8) between 43-384-7-5,59-60 and 43-384-7-6,49-50 compared to the LO of D. nobilis between 43-384-7-6,109-110 and 43-384-7-CC