A magnetometer survey of the Balfarg henge monument, Fife, Scotland, showed a ditch as a negative anomaly of up to 200 gammas. A soil sample transect showed a corresponding susceptibility contrast (range 1.7 x 10² 1. 2 x 10³ muG cm³ Oe^-1 g^-1) and strictly ferromagnetic content contrast/induced isothermal remanence magnetization (IRM) (range 3.8 x 10⁴ - 4.4 x 10³ muG cm³ g^-1). Reversed IRM on the whole sediment, x-ray diffraction, scanning electron and optical analyses on magnetic extracts showed that the main magnetic mineral is angular asymmetrical titanomagnetite (size 3-30 mu) from which the coarser were partially and heterogeneously oxidised towards ilmenite and maghemite.