New paleomagnetic data from southern Mexico provide a magnetostratigraphic framework to correlate mammal-bearing continental sections of the Suchilquitongo Formation to the Early Miocene part of the geomagnetic polarity time scale. A total of 127 paleomagnetic samples were collected from 40 horizons belonging to two sections. The sequence is characterized by a succession of cream to light pink to gray, thin- to medium-bedded tuffaceous sandstones and siltstones, partly silicified limestones, and a dominantly light green ignimbrite deposited in a fluviolacustrine environment. Remanent magnetization generally has been characterized by two components, a present-day field component with low-unblocking temperatures up to 350°C and a characteristic component with unblocking temperatures up to 580°–610°C. The characteristic component is interpreted as primarily based on antipodal populations of remanence data. Six sites at the top of the section (⁠inclination =40.5°⁠, declination =11.3°⁠, α95=1.4⁠, and K=471⁠) have a mean paleomagnetic direction rotated clockwise about 17° with respect to the expected Miocene direction derived from the North American polar wander curve (⁠inclination =354°⁠, declination =30°⁠). According to biochronologic age, the magnetostratigraphic results from the mammal-bearing sedimentary-type section in the Suchilquitongo area can be correlated with chron C5Dn-C5Cn3n at approximately 17.61–16.55 Ma. An age of about 17 Ma is proposed for the fossiliferous level, corresponding to an Early Miocene age.

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