Includes bibliographical references and indexes.

The problem of the diversity of igneous rocks / G. Malcolm Brown -- Silicate liquid immiscibility in magmas / Edwin Roedder -- Fractional crystallization and partial fusion / D.C. Presnall -- Crystallization in silicate systems / Arnulf Muan -- The reaction principle / E.F. Osborn -- Fractional crystallization of basaltic magma / Ikuo Kushiro -- The liquid line of descent and variation diagrams / Ray E. Wilcox -- Glass and the glassy rocks / I.S.E. Carmichael -- Rocks whose compostion is determined by crystal accumulation and sorting / T.N. Irvine -- Effects of assimilation / A.R. McBirney -- The formation of siliceous potassic glassy rocks / David B. Stewart -- Melilite-bearing rocks and related lamprophyres / H.S. Yoder, Jr. -- The fractional resorption of complex minerals and the formation of strongly femic alkaline rocks / David R. Wones -- Further effects of fractional resorption / E.D. Jackson -- The importance of volatile constituents / C. Wayne Burnham -- Petrogenesis and the physics of the earth / P.J. Wyllie -- Partitioning by discriminant analysis: a measure of consistency in the nomenclature and classification of volcanic rocks / F. Chayes.