Figure 4. Columns showing magnetic polarities determined from Zijderveld diagram analysis of samples, magnetic polarity zones, nannofossil zones, and nannofossil datums at Site 994. Solid circles and zones = normal polarity, open circles and zones = reversed polarity, parenthesis = less certain polarity interpreted from Type Y samples, bars = unsuccessful analyses of Type Z samples, and diagonal zones = undetermined. The nannofossil data are from Okada (Chap. 33, this volume).