The variation of low-field magnetic susceptibility with low temperature (between -77¿K and -300¿K) observed for a vertical columnar basalt from central Mexico shows a rare pattern for continental basalt -i.e. susceptibility decreases with temperature to about 40-70% of room-temperature value, and then increases up to about 60-100% of 77¿K. These results combined with other rock-magnetic measurements, including AF and thermal demagnetization, IRM experiments, Lowrie-Fuller tests, thermomagnetic analysis, and optical and SEM observations suggest the presence in the columnar basalt of predominantly single domain and pseudo-single domain titanomagnetites with composition around TM60, and a small amount of very fine-grained particles.