On the basis of the magnetic susceptibilit yof the late Cretaceous to early Paleogene igneous rocks in the eastern Chugoku to western Kinki area, the zonal distribution of igneous activities has been reviewed and some data have been applied to a historica land archeologica lstudy. The San-in belt is generally recognized to be mainly composed of magnetite-series plutonic rocks. On the contrary, ilmenite-serie splutonic rocks with low magnetic susceptibilit yare extensively distributed in the belt of the study area. This observation suggests that the Cretaceous ilmeniteseries plutonism took place all over the innerzone of Southwest Japan. On the other hand, granodioriti cmasses with high magnetic susceptibilit yare distribute din the northern part of the San-yo belt composed generally of ilmenite-serie splutonic rocks. Magnetite content in igneous rocks may have affected regional industry and culture. Iron sands used for ancient iron manufacture (so-called Tatara) have been collected from magnetiteseries plutonic rocks in the San-in belt, while ilmenite-series plutonic and volcanic rocks in the San-yo belt have been quarried for buildings, ornaments, monuments, tombstones, coffins and others. Magnetic susceptibility measurements are useful to estimate the source areas for such processed stones.
