For methods of investigation:—E. Weinschenk, Petrographic Methods, trans. R. W. Clark (1912) ; A. Johannsen, Manual of Petrographic Methods (1914) ; A. Holmes, Petrographic Methods and Calculations (1921) ; H. Rosenbusch, Mikroskopische Physzographze, 5th ed. by E. A. Wiilfing (1921-25).
For rock minerals:—J. P. Iddings, Rock Minerals, 2nd ed. (191I) ; H. Rosenbusch, Mikroskopische Physiographie, 5th ed. by 0. Miigge (1925-27) ; E. S. Larsen, The Microscopic Determination of the non-opaque Minerals, Bull. U.S.G. Survey, No. 679 (1921) ; N. H. and A. N. Winchell, Elements of Optical Mineralogy, Pt. II., 2nd ed. by A. N. Winchell (1927).
On the classification of igneous rocks see especially L. Milch, Die Systematik der Eruptiven gesteine I. II., Fortschritte der Mineralogie, vols. on their geographical distribution see M. Stark, Petrographische Provinzen, Fortschritte der Mineralogie, vol. 4 (1914) P. Niggli, Der Taveyannarsandstein und die Eruptivgesteine der jung mediterranen Kettengebirge, Schweiz. Min. Petr. Mitt., vol. 2 (1922) ; C. R. Burri, Chemismus und provinziale Verhdltnisse der jungeruptiven Gesteine des pazifischen Ozeans und seiner Umrandung, Ibid., vol. 6 (1926).
The classical works on rock synthesis include F. Fouque—A. Michel Levy, Synthese des Mineraux et des Roches (1882) ; J. H. L. Vogt, Silikatschmelzlosungen, I. (1903) , II. (1904). The principal authorities
on the analysis and chemical composition of rocks are H. S. Washing ton, Manual of the Chemical Analysis of Rocks, 3rd ed. (1919) ; W. F. Hillebrand, Analysis of Silicate and Carbonate Rocks, Bull. U.S.G., Survey No. 700 (1919) ; H. S. Washington, Chemical Analyses of Igneous Rocks, Prof. Paper U.S.G. Survey, No. 99 (1917). See also Cross, Iddings, Pirsson and Washington, Quantitative Classifica tion of Igneous Rocks (1902), for a chemical classification of igneous rocks.
Books devoted to physicochemical petrology, include above all H. Boeke, Grundlagen der physikalisch-chemischen Petrographie, 2nd ed. by W. Eitel (1923). See also P. Niggli, Die Leichtfiiichtigen Bestandteile im Magma (1920) ; O. H. ErdmannsdOrffer, Grundlagen der Petrographie (1924) ; W. Eitel, Physikalisch-chemische Mineralogie und Petrologie (1925) ; R. H. Rastall, Physicochemical Geology (1927). For experimental work on silicate mixtures see especially the papers published by the workers of the Geophysical Laboratory, Carnegie Institution, Washington, principally in American Journal of Science, Journal of Geology (1905, etc.).
Much information on rocks is contained in the memoirs of the various geological surveys and in Quart. Journ. Geol. Soc. of London, Mineralogical Magazine, Geological Magazine, American Journal of Science, Journal of Geology, American Mineralogist, Neues Jahrbuch fur Mineralogie (Stuttgart), Tschermak's Mineralogische Mittheilungen (Vienna), Fortschritte der Mineralogie (Berlin), etc. (C. E. T.)