BIBLIOGRAPISY  .—Most

text-books of geology treat of petrology in more or less detail (see GEOLOGY : § Bibliography) . Elementary hooks on petrology include F . H . Hatch, Petrology (5th ed., London, 1909) ; L . V . Pirsson, Rocks and Rock-minerals (New York, I908); J . D . Dana, Handbook of Mineralogy and Petrography (12th ed., New York, 19o8); A . Harker, Petrology for Students (4th ed., Cambridge, 19o8); G . A . J . Cole, Aids to Practical Geology (6th ed., London, 1909) .

For rock minerals consult J . P . Iddings, Rock Minerals (New York, 1906); A . Johannsen, Determination of Rock forming Minerals (New York, 1908); E . Hussak and E . G .

Smith, Determination of Rock-forming Minerals (2nd ed., New York, 1893) ; N . H. and A . N . Winchell, Optical Mineralogy (New York, 1909) . On the classification and origin of rocks see A . Harker, Natural History of Igneous Rocks (London, 1909) ; J .

P . Iddings, Igneous Rocks, (New York, 19o9) ;

Cross, Iddings, Washington and Pirsson, Quantitative Classification of Igneous Rocks (Chicago, 1902) ; C . Van Hise, Metamorphism (Washington, 1904); A . P . Merrill, Rocks, Rock-weathering and Soils (London, 1897) ; C . Doelter, Petrogenesis (Brunswick, 1906); J . H . L . Vogt, Silikatschmelzlosungen (Christiania, 1903) ; F . Fouque and A . Michel Levy, Synthese des mineraux et des roches (Paris, 1882) . The principal authorities on the analysis and chemical composition of rocks are J .

Roth, Beitrage zur Petrographie (Berlin, 1873–1884) ; A . Osann, Beitrage zur chemischen Petrographie (Stuttgart, 1903) ; H . S . Washington, Manual of the Chemical Analysis of Rocks (New York, 1904) and Chemical Analyses of Igneous Rocks (Washington, 1904) ; F . W . Clarke, Analyses of Rocks (Washington, 1904) ; Max Dittrich, Anleitung zur Gesteinsanalyse (Leipzig, 1905) ; W . F . Hillebrand, Analysis of Silicate and Carbonate Rocks (Washington, 1907) . The great systematic treatises on Petrology are F . Zirkel, Lehrbuch der Petrographie (2nd ed., Leipzig, 1894, 3 vols.) ; H . Rosenbusch, Mikroskopische Physiographie (4th ed., Stuttgart, 1909, 2 vols.) Useful German handbooks include: E . Weinschenk, Polarisationsmikroskop, Gesteinsbildendc Mineralien and Gesteinskunde (2nd ed., Freiburg, 1907, &C.); R .

Reinisch, Petrographisches Praktikum (2nd ed., Berlin, 1907); H . Rosenbusch, Elemente der Gesteinslehre (3rd ed., Stuttgart, 1909) ; A . Grubenmann,

Die krystallinen Schiefer (Berlin, 1907) ; F . Loewisson Lessing, Petrographisches Lexikon (1893 and 1898, also a Fr. ed., 1901) ; F . Rinne, Praktische Gesteinskunde (2nd ed., Hanover, 1905) . The principal French works are E . Jannettaz, Les Roches (3rd ed., Paris, 1900) ; F . Fouque and A . Michel Levy, Mineralogie micrographique (Paris, 1879) ; A .. Michel Levy and A . Lacroix, Les Mineraux des roches (Paris, 1888) ; A . Lacroix, Mineralogie de la France (I., II., Paris, 1893) ; and Les Enclaves des roches eruptives (Macon, 1893) .

British petrography is the subject of a special work by J . J . H . Teal ! (London, 1888) . Much information about rocks is contained in the memoirs of the various geological surveys, and in Quart . Journ. of the Geol . Soc. of London, Mineralogical Magazine, Geological Magazine, Tschermak's Mineralogische Mittheilungen (Vienna), Neues Jahrbuch fur Mineralogie (Stuttgart), Journal of Geology (Chicago), &c . (J . S .