Paleomagnetic analysis of samples from the original 600-m-long core from the San Agustin Plains, New Mexico, showed an unquestionable reversal stratigraphy dating the record back to at least 1.6 my. Analysis of pollen, ostracodes, and algae
of a duplicate sample section in the vicinity of the original coring site and spanning the last 18.000 yr B.P. shows a much higher resolution than the earlier results.