Available compositional data for magmatic epidotes (Naney, 1983; Zen and Hammarstrom, 1984; Barth, unpublished data) suggest no significant solid solution beyond the epidote-clinozoisite binary.
1990, Andrew P. Barth, Chapter 3: Mid-crustal emplacement of Mesozoic plutons, San Gabriel Mountains, California, and implications for the geologic history of the San Gabriel terrane, J. Lawford Anderson (editor), The Nature and Origin of Cordilleran Magmatism, Memoir 174: The Nature and Origin of Cordilleran Magmatism, The Geological Society of America, page 36