In the Miyamori district of the Kitakami mountains, small amphibolite masses are located at the margin and within the ultramafic intrusive. They were probably formed under the conditions corresponding to the epidote amphibolite and amphibolite facies. They can hardly be interpreted to form at the present position, because they are not isofacial with their surrounding rocks. These amphibolites may be not the products of thermal metamorphism by the Miyamori ultramafic intrusive at deeper levels, but the fragments of the basement complex which is expected to be widely distributed beneath the Paleozoic formations in the Kitakami mountains.