Differences in data reported by various authors raise questions on the absolute dating of the main Paleogene boundaries. Ignoring established geochronometric and biostratigraphic principles only complicates the task of correlating stratigraphic units and establishing the precision of the absolute geochronologic scale. Absolute ages of younger, radiologically dated samples provides a lesser absolute error but greater relative error. It is suggested that age determinations on effusives are closer to true values (or the error is minimized), whereas interpretation on glauconites is more complicated because characteristically high argon loss in authigenic minerals seems to yield younger trending dates. With new data becoming available on continental rock units, biostratigraphic and geochronometric correlation with coeval marine facies appears to be increasingly important.