Abstract
Andesites and olivine-basalts of Takamatsu District, Setouchi volcanic zone carry numerous xenocrysts derived from the acidic plutonic rocks which constitute the basement of the volcanoes., The contamination between these xenoliths and the andesites and olivine basalts is discussed particularly in reference to the selective diffusion in magma., The writer reached the conclusion that the so-called autoliths in these volcanic rocks are the products of diffusion-differentiation due to contamination.,
