CHAPTER LVI

GEOLOGY [Sidenote: The Province Geology or Sermons in Stones] Shakespeare tells us that “there are sermons in stones.” No science, except possibly astronomy, appeals more to the imagination or carries one further away from our present workaday world than geology. While geology “claims as its peculiar territory the rocky framework of the globe,” its object is, says the Encyclopaedia Britannica (Vol. 11, p. 638) “to trace the structural progress of our planet from the earliest beginnings of its separate existence through its various stages of growth down to the present condition of things.” It goes back millions and hundreds of millions of years to the first beginnings of things and unravels complicated processes by which the earth and each of the continents on it has been built up. “It follows, even into detail, the varied sculpture of mountain and valley, crag and ravine.” It shows “that the present races of plants and animals are the descendants of other and very different races which once peopled the earth. It teaches that there has been a progressive development of the inhabitants.” Dead and cold though the rocks seem, they are filled, to one who can read their secret, with the tragedy of past life. Parts of Florida are but the graves where millions of corals, now crushed into massive limestone, once lived and died; the coal of Pennsylvania tells of ferns and other terrestrial plants matted together into a bed whence they originally grew; “the snails and lizards which lived and died within a hollow tree, the insects which have been imprisoned within the exuding resin of old forests, the footprints of birds and quadrupeds, the trails of worms left upon former shores—these and innumerable other pieces of evidence” tell of the tragedies of former times and “enable the geologist to realize in some measure what the faunas and floras of successive periods have been.” The foundation for the study of the whole subject in the Britannica is the article GEOLOGY (Vol. 11, p. 638), equivalent to 125 pages of this Guide. It is by the highest authority in the world, Sir Archibald Geikie, long director general of the Geological Survey of the United Kingdom, and director of the Museum of Practical Geology, London. It deals with the general principles and gives an outline of the subject matter of the science. In particular it treats of, _The historical development of geological science_; _The cosmical aspects of geology_; _Geognosy_; _Dynamical Geology_; _Geotectonic or Structural Geology_; _Palaeontological Geology_; _Stratigraphical Geology_; _Physiographical Geology_. [Sidenote: Age of the Earth] While the student will doubtless be interested equally in each of these departments, the general reader will be especially interested in the historical development which—it is worthy of note—is almost the only concise account of geological history hitherto published in English. Especially interesting is the question, fully discussed, of the age of the earth. Lord Kelvin (Vol. 11, p. 653) declared some few years ago that the time “was more than twenty and less than forty millions of years and probably much nearer twenty than forty.” But the trend of later investigations, and especially the study of radio-activity, has led to the belief that the period must have been much longer. Sir Archibald Geikie sums up the evidence as follows (Vol. 11, p. 653): “In the present state of science it is out of our power to state positively what must be the lowest limit of the age of the earth, but we cannot assume it to be less, and it may possibly have been much more than one hundred millions of years.” [Sidenote: Geological Formations] The general reader will find of interest, too, the table (Vol. 11, p. 670) representing the geological record or order of succession of the formations of the earth’s crusts from the earliest Archean, through Cambrian, Silurian, Devonian and Carboniferous to the Post-glacial or Human of to-day. A separate article is to be found on each of these different formations, namely: ARCHEAN (Vol. 2, p. 360); CAMBRIAN (Vol. 5, p. 86); SILURIAN (Vol. 25, p. 109); DEVONIAN (Vol. 8, p. 124); CARBONIFEROUS (Vol. 5, p. 309); PERMIAN (Vol. 21, p. 176); TRIASSIC (Vol. 27, p. 258); JURASSIC (Vol. 15, p. 567); CRETACEOUS (Vol. 7, p. 414); EOCENE (Vol. 9, p. 661); OLIGOCENE (Vol. 20, p. 81); MIOCENE (Vol. 18, p. 565); PLIOCENE (Vol. 21, p. 846); PLEISTOCENE (Vol. 21, p. 835); Recent, Post-glacial or Human under article QUATERNARY (Vol. 22, p. 718). Full local geological information is found in geographical articles. See, for instance, in the article UNITED STATES, the section on _Geology_ (Vol. 27, pp. 624–632), by Professors R. D. Salisbury and T. C. Chamberlin of the University of Chicago; the section _Geology_ in the article ENGLAND (Vol. 9, pp. 415–416), by H. R. Mill, editor of _The International Geography_; the section _Geology_ in the article AFRICA (Vol. 1, pp. 323–325), by Walcot Gibson, author of _Mineral Wealth of Africa_, etc. These special treatments are accompanied by sketch maps. Similarly, the articles on each of the different states of the Union has a section giving information on the geology, the flora and fauna, the climate, and the geography of the state. And in such articles on geographic topics as GREAT SALT LAKE, NIAGARA, by G. Karl Gilbert, and GRAND CANYON, by R. S. Tarr, there is valuable geological information. Other important articles which the reader should consult are PETROLOGY (Vol. 21, p 323), equivalent to 40 pages of this Guide, largely illustrated, by Dr. J. S. Fleet, petrographer to the Geological Survey of Great Britain; MINERALOGY (Vol. 18, p. 509), equivalent to 25 pages of this Guide, by L. J. Spencer, editor of the _Mineralogical Magazine_; MINERAL DEPOSITS (Vol. 18, p. 504), equivalent to 15 pages of this Guide, by James F. Kemp, professor of geology of Columbia University, and geologist to the United States and New York Geological Surveys; CRYSTALLOGRAPHY (Vol. 7, p. 569), equivalent to 60 pages of this Guide, also by L. J. Spencer; MINING (Vol. 18, p. 528), equivalent to 40 pages of this Guide, by Henry Smith Munroe, professor of mining, Columbia University, New York; PALAEONTOLOGY (Vol. 20, p. 579), profusely illustrated, equivalent to 35 pages of this Guide, by Prof. Henry Fairfield Osborn of Columbia University, and president of the American Museum of Natural History of New York; PALAEOBOTANY (Vol. 20, p. 524), profusely illustrated, equivalent to 100 pages of this Guide, written by three of the leading geological writers of the day: Dr. D. H. Scott, president of the Linnean Society, author of _Studies in Fossil Botany_; A. E. Steward, professor of botany of the University of Cambridge; and Clement Reid, author of _Fossil Flora of Tegelen_. Of more popular interest are the three articles, Earthquake, Seismometer and Volcano. The article EARTHQUAKE is in two parts. The first (Vol. 8, p. 817) is an historical account telling of the extent and damage done by many earthquakes, including the terrible San Francisco earthquake of April 18, 1906, and that of Calabria and Sicily, December 28, 1908, by F. W. Rudler, president of the Geologists’ Association; the other part (Vol. 8, p. 820), by Dr. J. Milne, late professor of geology in the Imperial University of Tokio, deals with the physical theory of earthquakes. The article VOLCANO (Vol. 28, p. 178), equivalent to 45 pages of this Guide, is by F. W. Rudler, and gives us the reasons for and the history of volcanic disturbances. It is of interest both to the scholar and to the casual reader. Thus we learn that “while Herculaneum was buried beneath a flood of mud swept down from Vesuvius” in 79 A.D., Pompeii “was overwhelmed in great measure by loose ashes, capable of removal with comparative ease.” Nearly everyone of middle age remembers the famous eruption of Krakatoa in 1883 and the famous sunsets of that year. Concerning this the Britannica article tells us (p. 180): Enormous quantities of dust ejected from Krakatoa in 1883 were carried to prodigious distances, samples having been collected at more than a thousand miles from the volcano; whilst the very fine material in ultramicroscopic grains which remained suspended for months in the higher regions of the atmosphere seems to have enjoyed an almost world-wide distribution, and to have been responsible for the remarkable sunsets at that period. The article DUST (Vol. 8, p. 713), by John Aitken, inventor of the machine for counting particles of dust, explains the mechanical causes of this suspension. Besides there is much concrete information about volcanoes in articles on volcanic regions: for instance, on volcanoes in the possessions of the United States, see articles HAWAII, ALASKA, PHILIPPINES. The student should read also the articles on the different minerals, many of them long and important and all by well-known authorities. Thus the article DIAMOND (Vol. 8, p. 158), illustrated, equivalent to 20 pages of this Guide, is by Henry Alexander Miers, editor of the _Mineralogical Magazine_. Besides dealing with the general character of this stone, the article pays particular attention to diamond mining in South Africa, the text being illustrated by plates showing the Kimberley and DeBeers workings. The article GEM (Vol. 11, p. 560), is equivalent to 25 pages of this Guide. The article GEM, ARTIFICIAL (Vol. 11, p. 569) is by the well-known chemist and physicist, Sir William Crookes. It tells of the changes induced by radioactive emanations and of the artificial production of the diamond, ruby, sapphire, Oriental emerald, amethyst and topaz. The reader will be interested, too, in the article LAPIDARY AND GEM CUTTING (Vol. 16, p. 195), by Dr. George F. Kunz, gem expert for Messrs. Tiffany & Co., New York. There are special biographical articles in the Britannica on all the well-known geologists, and in these articles special stress has been laid on the part played by the subject of the memoirs in promoting the science. This is well shown, for instance, in the articles AGASSIZ (Vol. 1, p. 367); HUTTON (Vol. 14, p. 16) and LYELL (Vol. 17, p. 158). Geology, by its study of earth deposits, age of rocks, etc., and by its estimate of the date of certain extinct animals like the mammoth and hairy elephant, or of the time when certain animals, e.g., the elephant and reindeer, were found in parts of the world where they no longer occur, is an important adjunct to the science of anthropology, especially in the question of the antiquity of man. On this see the section of antiquity of man in the article ANTHROPOLOGY (Vol. 2, p. 114), and, in general, the chapter in this Guide on _Anthropology and Ethnology_. From one point of view geology is only a branch of geography and the student of geology should consult the elaborate article on GEOGRAPHY in the Britannica, especially all parts dealing with physical geography or physiography. For a clue to this part of the book see the chapter in this Guide on _Geography_. The following is a list of the more important articles on Geology in the Encyclopaedia Britannica: LIST OF ARTICLES IN THE ENCYCLOPAEDIA BRITANNICA OF SPECIAL INTEREST TO STUDENTS OF GEOLOGY Abich, O. W. H. von Abraum salts Acadian Acmite, or Aegirite Agalmatolite Agate Agglomerate Agricola, Georg Aikin, Arthur Alabaster Albertite Albian Albite Alexandrite Allophane Allport, Samuel Alluvium Almandine Alquifou Alunite, or Alumstone Amazon Stone, or Amazonite Amber Amblygonite Amethyst Amianthus Amphibole Amphibolite Amygdaloid Analcite Anatase Andalusite Andesine Andesite Anglesite Anhydrite Ankerite Annabergite Anning, Mary Anorthite Ansted, David Thomas Anthracite Apatite Aphanite Aplite Apophyllite Aptian Aquamarine Aragonite Archean System Archiac, vicomte d’ Arenig Group Argentite Argyrodite Asbestos Assise Asteria, or Star-stone Atacamite Atherstone, W. G. Augite Autunite Aventurine, or Avanturine Avonian Axinite Aymestry Limestone Azurite, or Chessylite Bagshot Beds Baily, William Hellier Bain, Andrew Geddes Bajocian Bakewell, Robert Bala Series Barrande, Joachim Barrett, Lucas Barrois, Charles Barton Beds Barytes Barytocalcite Basalt Basin Batholite Bathonian Series Bathvillite Bauxite Bed Beecher, C. E. Belt, Thomas Bembridge Beds Benett, Etheldred Benitoite Bernician Series Beryl Beryllonite Beudant, François S. Beyrich, H. E. von Bigsby, J. J. Binney, E. W. Biotite Bismuthite Bitumen Blanford, W. T. Blende, or Sphalerite Bloodstone Boase, Henry Samuel Bole Bomb Bone Bed Bonney, Thomas George Boracite Born, I. von Borolanite Bort, or Boart Bostonite Boucher de Crévecoeur de Perthes, J. Boué, Ami Boulder Boulder Clay Bournonite Bovey Beds Bowerbank, J. S. Bracklesham Beds Bradford Clay Brander, Gustavus Breccia Breislak, Scipione Bristow, H. W. Brocchi, G. B. Brochant de Villiers, A. J. F. M. Brochantite Brodie, P. B. Brogger, W. C. Bromlite Brongniart, Alexandre Bronn, Heinrich Georg Bronzite Brookite Brucite Brückmann, Franz Ernst Buch, Baron von Buckland, William Bunter Bytownite Cainozoic Cairngorm Calamine (Smithsonite) Calcite Callovian Cambrian System Cancrin, F. L. von Caradoc Series Carbonado Carboniferous System Carnelian Cassiterite Cat’s-eye Cave Celestine Cerargyrite Cerussite Chabazite Chalcedony Chalk Chalybite Charnockite Childrenite Chlorite Chromite Chrysoberyl Chrysocolla Chrysolite Chrysoprase Cinnabar Cinnamon Stone Clarke, William B. Clay Clay-with-Flints Clinoclastite Clintonite Close, Maxwell H. Cobaltite Colemanite Columbite Concretion Conglomerate Connellite Conybeare, W. D. Copalite, or Copaline Cope, Edward D. Copper-glance Copper-pyrites, or Chalcopyrite Coprolites Corallian Cornbrash Corundum Cotta, Bernard von Covellite Crater Credner, C. F. H. Cretaceous System Crocidolite Crocoite Croll, James Crosskey, Henry W. Cryolite Crystallite Crystallography Culm Cumming, Joseph G. Cuprite Cyanite Dacite Dalradian Dana, James D. Danburite Datolite Daubeny, Charles G. B. Daubree, G. A. Davidson, Thomas Dawson, Sir John W. Dechen, E. H. K. von De la Beche, Sir H. T. Delesse, A. E. O. J. Deluc, Jean Andre Demantoid Des Cloizeaux, Alfred Descloizite Deshayes, G. P. Deslongchamps, J. A. E. Desmarest, Nicolas Desnoyers, J. P. F. S. Desor, P. J. E. Devonian System Diabase Diallage Diamond Diaspore Dick, Robert Diluvium Diopside Dioptase Diorite Dolerite Dolomieu Dolomite Dopplerite Drift Dufrenoy, O. P. A. P. Dumont, André Hubert Dumortierite Duncan, Peter Martin Durocher, J. M. E. Earth pillar Earthquake Eclogite Egerton, Sir P. de M. Ehrenberg, C. G. Eichwald, K. E. von Elaterite Elie De Beaumont Emerald Emery Emmons, Ebenezer Enniskillen, 3rd earl of Enstatite Eocene Epidiorite Epidosite Epidote Erubescite Erythrite Escher von der Linth Esker Etheridge, Robert Ettingshausen, Baron Euclase Fall-line Farey, John Faujas de Saint-Fond Fault Favre, Jean Alphonse Felsite Felspar Fitton, William Henry Flint Fluor-spar Flysch Fold Forbes, David Forchhammer, J. G. Foster, Sir C. le Neve Fouque, F. A. Fournet, J. J. B. X. Fox, Robert Were Franklinite Freestone Freieslebenite Fulgurite Fuller’s Earth Fumarole Gabbro Galena Garnet Gaudry, Jean Albert Gault Geikie, Sir Archibald Geikie, James Geinitz, H. B. Gem Geology Gesner, Abraham Geyser Giebel, C. G. A. Gilbert, Grove K. Gilsonite Glacial Period Glauconite Gneiss Godwin-Austen, R. A. C. Goldfuss, G. A. Goniometer Göthite, or Goethite Granite Granulite Graphite Gravel, or Pebble Beds Green, A. H. Greenockite Greenough, G. B. Greensand Greisen Greywacke Griffith, Sir Richard J. Groth, P. H. von Guettard, J. E. Gumbel, K. W. von Guyot, A. H. Gypsum Haast, Sir J. F. J. von Haematite Haidinger, W. K. von Hall, James Hall, Sir James Halleflinta Harkness, Robert Harmotome Hatchettite Hauer, F. von Haughton, Samuel Hausmann, J. F. L. Hayden, F. V. Hebert, Edmond Heddle, M. F. Heer, Oswald Heim, A. von St. Gallen Helmersen, Gregor von Hemimorphite Henslow, John Stevens Henwood, William Jory Heulandite Hicks, Henry Hiddenite Hitchcock, Edward Hochstetter, F. C. von Holocene Hone Hopkins, William Hornblende Horner, Leonard Hornes, Moritz Hornfels Hulke, J. W. Humite Hunt, Robert Hunt, T. Sterry Hutton, James Hyacinth Hypersthene Idrialin Ijolite Ilmenite Iolite Itacolumite Jade Jameson, Robert Jargoon Jarosite Jasper Jet Joints Jones, T. Rupert Jukes, J. B. Jurassic System Kaolin Karrer, Felix Karsten, K. J. B. Kayser, F. H. E. Kenngott, G. A. Keuper Kidd, John Kimeridgian King, Clarence Kirwan, Richard Kjerulf, Theodor Kobell, W. X. F. von Koenig, K. D. E. Koksharov, N. I. von Koninck, L. G. de Kunzite Labradorite Laccolite Lacroix, A. F. A. Lamprophyres Lapilli Lapis Lazuli Lapparent, A. A. C. de Lapworth, Charles Lasaulx, A. C. P. F. von Laterite Laumont, F. P. N. G. de Lava Leadhillite Le Conte, Joseph Lehmann, J. G. Lepidolite, or Lithia-Mica Lesley, J. Peter Leucite Lévy, A. M. Lewis, Henry Corvill Lias Lignite Limburgite Limestone Limonite Lindstróm, Gustaf Liroconite Lister, Martin Llandeilo Group Llandovery Group Llwyd, Edward Loess Logan, Sir William E. London Clay Lonsdale, William Lory, Charles Ludlow Group Lyell, Sir Charles McCoy, Sir Frederick Macculloch, John Maclure, William Magnesite Magnetite Malachite Mallet, Robert Manganite Mantell, G. A. Marble Marcasite Marcou, J. B. Marl Martin, William Meek, F. B. Meerschaum Melaconite Mesozoic Metamorphism Metasomatism Meteorite Meyer, C. E. H. von Mica Mica-schist Microcline Micropegmatite Miller, Hugh Miller, W. H. Millerite Millstone Grit Mimetite Mineral deposits Mineralogy Miocene System Mispickel Mocha Stone Mofetta Mohs, Friedrich Mojsisovics von Mojsvar, J. A. G. E. Moldavite Molybdenite Monazite Monzonite Moonstone Morris, John Münster, Georg, count zu Murchison, Sir R. I. Muschelkalk Muscovite Mylonite Napoleonite Natrolite Naumann, G. A. C. F. Neck Neocomian Nepheline Nepheline-syenite Nephelinites Neumayr, Melchior Newberry, J. S. Niccolite Nicholson, H. A. Nicol, James Nitre Noeggerath, J. J. Obsidian Oldham, Thomas Oligocene System Oligoclase Olivenite Olivine Omalius d’Halloy, J. d’ Onyx Oolite Opal Oppel, C. A. Orbigny, A. D. d’ Ordovician System Orthoclase Osborn, H. F. Oxfordian Ozokerite, or Ozocerite Palaeozoic Parisite Parkinson, James Peach, C. W. Pegmatite Pendleside Series Pengelly, William Peperino Peridot Peridotite Perlite Permian System Perovskite Petalite Petrology Pharmacosiderite Phenacite Phillips, John Phillips, William Phillipsite Phlogopite Phonolite Phosgenite Phosphates Phosphorite Phyllite Picrite Pictet, de la Rive, F. J. Pitchblende, or Uraninite Pitchstone Plagioclase Pleistocene System Pliocene System Plot, Robert Plumbago Pneumatolysis Pollux, or Pollucite Porphyry Portlandian Portlock, J. E. Powell, J. W. Pre-Cambrian Prehnite Prestwick, Sir Joseph Prévost, Constant Proustite Psilomelane Pumice Purbeckian Puy Pyrargyrite Pyrites Pyrolusite Pyromorphite Pyrope Pyrophyllite Pyroxene Pyroxenite Pyrrhotite Quartz Quartzite Quartz-porphyry Quarternary Quenstedt, F. A. von Rammelsberg, K. F. A. Ramsay, Sir Andrew C. Rath, Gerhard von Reading Beds Realgar Renard, A. F. Renevier, Eugène Retinite Reusch, Hans Henrik Reuss, A. E. von Rhaetic Rhodochrosite Rhodonite Rhyolite Rock Rock-crystal Roemer, F. A. Rogers, H. D. Rome de l’Isle, J. B. L. Roth, J. L. A. Rubellite Ruby Russell, Israel Cook Rutile Rutley, Frank Salt Salter, John William Sand Sandberger, K. L. F. von Sandstone Sapphire Sard Sardonyx Satin-spar Savi, Paolo Scapolite Scheelite Schists Schlotheim, Baron von Schorl Scolecite Scoria Scrope, G. J. Poulett Sedgwick, Adam Seismometer Selwyn, A. R. C. Sénarmont, H. H. de Serpentine Sharpe, Daniel Sill Sillimanite Silurian System Sinter Slate Smaltite Smith, William Smithson, James Smyth, Sir W. W. Sodalite Soffioni Solfatara Sorby, Henry C. Speeton Beds Sphene Spherulites Spinel Spodumene Spratt, Thomas A. B. Stalactites Stannite Staurolite Steno, Nicolaus Stephanite Stibnite Stilbite Stoliczka, Ferdinand Stone Stoppani, Antonio Stratigraphy Strickland, Hugh E. Strontianite Studer, Bernhard Suess, Edward Sunstone Syenite Sylvanite Sylvite Symonds, William S. Szabó von Szentmiklos Tachylytes Talc Tate, Ralph Tchihatcheff, P. A. de Tertiary Tetradymite Tetrahedrite Theralite Thorianite Thorite Tonalite Topaz Torbernite Torell, Otto Martin Torridonian Tourmaline Trachyte Trass Tremolite Triassic System Tridymite Trimmer, Joshua Tuff Turquoise Vanadinite Variolite Variscite Veins Verneuil, P. E. P. de Vesuvianite Vivianite Vogt, Karl C. Volcano Waagen, W. H. Wachsmuth, Charles Wad Walcott, Charles D. Waltershausen Wavellite Wealden Webster, Thomas Wenlock Group Werner, A. G. Whiteaves, J. F. Whitney, J. D. Willemite Witherite Wolframite Wollastonite Wood, S. V. Woodward, John Woodward, Samuel Woolwich-and-Reading Beds Wright, Thomas Wulfenite Yoredale Series Zoelites Zincite Zircon Zirkel, Ferdinand Zittel, Karl A. von Zoisite