The Tari-Misaka ultramafic complex is located in the Sangun zone of the so-called Inner zone of southwest Japan. The Sangun zone is basically composed of metamorphosed or unmetamorphosed Paleozoic formations, onto which many ultramafic complexes had been emplaced by thrusts from the north. The Sangun metamorphism belongs to a high-pressure intermediate type. The complex has been intruded by Cretaceous granitic rocks. The main ultramafic complexes of this area are aligned from east-northeast to west-southwest. The Tari-Misaka ultramafic complex is located near the west-southwest end of this alignment. The complex is emplaced within unmetamorphosed Paleozoic sediments which have been fragmented and thermally metamorphosed by later granitic intrusions. The complex has also undergone one strong thermal metamorphism from two granite intrusions. The ultramafic rocks are concentrically arranged in five mineral zones within the complex, i.e., chrysotile-lizardite (unmetamorphosed), antigorite, olivine + talc, olivine + anthophyllite, and olivine + orthopyroxene toward the contact with the granitic intrusions. The ultramafic rocks are also strongly serpentinized; the degree of serpentinization is usually more than 90 percent. Small lenticular and podlike bodies of mafic to felsic rocks (hornblende-clinopyroxene gabbros, diorites, and albitites) are present throughout the complex. Some of them have fine-grained rims which are probably chilled margins. Pyroxenites are rare.