Yamamoto et al. (1999) obtained a low-temperature geotherm typical of continental shield from a “garnet peridotite” xenolith in the Arato-yama alkali basalt. Their geotherm is, however, possibly erroneous. Their data of the “garnet peridotite” suggest discrepancies from the chemical equilibration of minerals, and the pressure obtained is too large for the depth of xenolith entrainment by alkali basalt magma. The lack of thin section descriptions is also a cause of uncertainty.