Genuflexion Geognosy secretary to the directory of finances at from the time of the fabulous Brutus, or Berlin when the French Revolution broke Brute, the Trojan, to the death of Cadout, of which he was an ardent opponent. wallader, King of Wessex, in 688. It He served alternately in the Prussian was soon translated into French, Engand Austrian civil service, and his pam- lish, and Welsh, and became a great phlets and manifestoes proved formidable source of romance to the writers of sucobstacles to the invasions of Napoleon. cessive generations. He took part in the congresses of Vienna Geoffroy St. Hilaire (zhof-rwȧ and Paris, as well as in others. Among saņ tē-lār), his various works was a life of Mary, ETIENNE, a French naturalist, born in Queen of Scots. 1772; died in 1844. He was educated Genuflexion (jen-u-flek'shun; from at the colleges of Navarre and Lemoine, the Latin genu, knee, and became a favorite pupil of Haüy. At and flectere, to bend), the act of bend- the age of twenty-one he obtained the ing the knees in worship. There are chair of zoology in the Parisian Jardin frequent allusions to genuflexion in the des Plantes. As a member of the EgypOld and New Testaments, and it would tian expedition in 1798 he founded the appear that the use was continued among Institute of Cairo, and returned about the early Christians. Genuflexion ob- the end of 1801 with a rich collection of tains, both by rule and prescription, in zoological specimens. In 1807 he was various places in the offices of the Roman made a member of the Institute, and in Catholic Church, and at different parts 1809 professor of zoology at the Faculty of the services of the Church of England. of Sciences. He devoted himself espeGenus (je'nus), in scientific classifi- cially to the philosophy of natural history. cation, an assemblage of spe- The fundamental idea brought conspicucies possessing certain characters in ously forward in all his works is, that common, by which they are distinguished in the organization of animals there is from all others. It is subordinate to only one general plan, one original type, order, tribe, and family. A single species, which is modified in particular points so possessing certain peculiar characters as to present differences of genera. This which belong to no other species, may view met with strong opposition from also constitute a genus, as the giraffe. Cuvier. Among his principal works are Geodes (je'ōdz), round hollow nodules, containing sometimes earthy matters, sometimes a deposit of agate, sometimes quartz and spars crystallized. They are found more or less in all volcanic rocks, and have been formed by water depositing their materials in the hollows of those rocks. Geodesy (je-od'e-si), the science of surveying extended to large tracts of country; the branch of applied mathematics which determines the general figure and dimensions of the earth, the variations of the intensity of gravity in different regions, etc., by means of direct observation and measurement. See Trigonometrical_ Survey. Geoffrey of Monmouth ( jef'rā; Sur le Principe de l'Unité de Composition Organique; Philosophie Anatomique; Histoire Naturelle des Mammifères, written in conjunction with Cuvier, and Notions de Philosophie Naturelle (1838). Geoffroy St. Hilaire, ISIDORE physiolo gist and naturalist, son of the preceding, was born at Paris in 1805; died in 1861. He devoted himself to natural history, and in 1824 was appointed assistant to his father at the Jardin des Plantes. He was elected to the Academy of Sciences in 1833, and afterwards became successively inspector-general of the university, member of the council of public instruction, and professor of zoology at the Academy of Sciences. One of his chief works, Histoire Générale et Particulière des Anomalies de l'Organisation chez l'Homme et les Animaux, adds valuable confirmation to the theories of his father. He was the means of founding the Acclimatization Society of Paris. Geognosy (je-og'nu-si), a term called also Geoffrey ap Arthur), an ecclesiastic and historian of the twelfth century. He sprang from the Norman settlers in Wales; became archdeacon of Monmouth, whence he was, in 1152, raised to the bishopric of St. Asaph. He died in 1154. His famous history was first published in 1128. This Chronicon sive Historia which originated among Britonum is now known to be, as the the German mineralogists, and is nearly compiler states, chiefly a translation from synonymous with geology. It is the an ancient book in the Breton tongue, science of the substances which compose discovered by Walter Calenius, an arch- the earth or its crust, their structure, deacon of Oxford. It contains a pre- position, relative situation and propertended genealogy of the kings of Britain ties. Geographical Societies Geography Geographical Societies--grof graphical knowledge. They seem to have i-kal) are explored all the shores of the Mediterassociations formed with the view of ranean, and at an early period to have obtaining and disseminating geographical passed the Pillars of Hercules (by the knowledge. Of these, the first was founded Strait of Gibraltar), and visited to some in Paris in 1821; the second, the Royal extent the Atlantic shores of Europe and Geographical Society of England, in 1830; Africa, extending their voyages as far the American Geographical Society at north as Britain, and as far south as New York in 1852, and others elsewhere the Tropic of Capricorn. In the Homeric at various dates. The National Geographic poems (which may be regarded as repSociety, founded at Washington in 1888, resentative of the ideas entertained by has an enormous membership, number- the Greeks about the commencement of ing considerably over 100,000 due to the circulation of its richly illustrated monthly magazine. the ninth century B. C.) the earth is supposed to resemble a circular shield surrounded by a belt of water which Geography e-og-ra-fi; from the was the source of all other streams. The Greek ge, earth, and world of Herodotus (born 484 B.C.) graphō, I write), the science which treats extended from the Atlantic to the westof the world and its inhabitants, giving ern boundary of Persia, and from the an account of the earth as a whole, and Red Sea or Indian Ocean to the amber of the divisions of its surface, natural lands of the Baltic. The Indian expeand artificial, describing the different dition of Alexander the Great (330 B.C.) countries, states, provinces, islands, cities, greatly enlarged the ancient knowledge etc. It may be regarded as embracing of Northern and Eastern Asia. About several departments or branches. Mathe- 320 B.C. Pytheas, a seaman of Massilia matical Geography is that branch of the (ancient Marseilles), a Greek colony, general science which is derived from the sailed along the western coasts of Spain application of mathematical truths to and Gaul, visited Britain, and, pursuing the figure of the earth, and which de- his voyage, discovered an island, hencetermines the relative positions of places, forward famous as Ultima Thule, which their longitudes and latitudes, the differ- is supposed to have been Iceland. Eraent lines and circles imagined to be tosthenes (276-196 B.C.) first used drawn upon the earth's surface, their parallels of latitude and longitude, and measurement, distance, etc. Physical constructed maps on mathematical prinGeography treats of the physical condition ciples. He considered the world to be of the earth, its great natural divisions a sphere revolving with its surrounding of land and water, the atmosphere, and the movements of oceanic and aërial currents; the geological structure of the earth; and the natural products of the earth, vegetable and animal. It is concerned chiefly with general laws and principles, as they are manifested upon a grand scale, and in the organic kingdom with the existence of groups of animals and plants. This branch approaches at various points the sciences northern and eastern portions the most of geology, hydrology, meteorology, botany, zoology, and ethnology. Political Geography embraces the description of the political or arbitrary divisions and limits of empires, kingdoms, and states; and treats of their government, laws, social organizations, etc. Commercial Geography has to do with the distribution of the products of the earth or the workship between different nations. atmosphere on one and the same axis, and having one center. The Geography of Strabo, a Greek of Pontus, written about the beginning of the Christian era, embodies all that was known of the science at that period. The countries lying round the Mediterranean were known with tolerable_accuracy, but the Atlantic shores of Europe were very vaguely comprehended, while of the erroneous notions prevailed. Pomponius Mela, an early Roman geographer, wrote about the time of the Emperor Claudius. He divided the world into two hemispheres, the Northern or known and the Southern or unknown; the former comprising Europe N. of the Mediterranean and w. of the Tanais (Don); Africa s. of the Mediterranean and w. of the Nile; and Asia. The next famous geographer The earliest idea of the earth formed is Ptolemy, who lived at Alexandria by mankind seems to have been that it about_the_middle of the second century was an immense disc, in the center of which their own land was situated, surrounded by the ocean, and covered by the sky as with a canopy. The Phoenicians were the first people who made any great progress in extending the bounds of geo A.D. In Europe, Spain and Gaul were now correctly delineated, together with the southern shores of Britain. Northern Germany and the southern shores of the Baltic were pretty well known, as also some portion of Russia in the neighbor Geography Geological Surveys hood of that sea, and the southern part knowledge certain and precise in respect of European Russia. In Asia it was to a great part of the continent. The considered certain that there were wide interior of Australia has been explored regions inhabited by nomadic tribes by Sturt, Eyre, Leichhardt, Burke, Wills, called Scythians, while from the far east King, McDouall Stuart, etc. The opening came some vague reports of China. The up of the African interior was materially Geography of Ptolemy remained the advanced by the explorations of a host of acknowledged authority during the whole travelers, including Bruce, Park, Denof the middle ages. From his time up ham, Clapperton, the Landers, Burton, till the thirteenth century no advance Speke, Grant, Baker, Barth, Livingstone, was made in geographical knowledge until Rohlfs, Schweinfurth, Cameron, Stanley, Marco Polo opened up new fields of in- etc., and now is almost as well known quiry. The account of his travels first as that of Europe and America. Within made known to Europe the existence of the present century great advances have Japan and of many of the East Indian been made in Arctic geography, the site islands and countries. Then followed of the North Pole having been reached the discovery of America in 1492, and in 1909 and that of the South Pol from this time forward the progress of 1911. The progress which has mark discovery was extremely rapid. In 1497 recent discovery has been materially asthe Cape of Good Hope was doubled by sisted by the governments of various counVasco da Gama, four years after its dis- tries, and by the numerous geographical covery by Bartholomew Diaz. Within societies formed during the nineteenth thirty years from the date of the first century. The scientific study and teachvoyage of Columbus the whole of the ing of geography are becoming more and east coast of America from Greenland more recognized to be of high importance, to Cape Horn had been explored. In and in both at present Germany takes the 1520 Magellan passed the straits which lead. See also Geographical Societies, bear his name, and his vessel, crossing the articles on the different countries, the Pacific and Indian Oceans, returned and such articles as Earth, Climate, etc. to Europe by way of the Cape of Good Geok Tepe (gök-te'pe), a town and Hope, being the first that had circumnavigated the globe. The west coast of America was explored as far as the Bay of San Francisco about the middle of the sixteenth century. At the same time discovery in the east advanced with rapid strides. Within twenty years of Gama's arrival in India the coasts of East Africa, Arabia, Persia, and Hindustan had been fortress of Central Asia, oasis of the Akhal-Tekke-Turkomans, lon. 58° E., lat. 38° N. In 1879 the Russians under General Lomakine were defeated here with heavy loss, but in January, 1881, it was stormed by General Skobeleff after a three weeks' siege, when about 8,000 fugitives were massacred, no quarter being given. explored, and many of the islands of the Geological Surveys tive efforts (je-ol-oj'i-kal). great Archipelago discovered. The expeditions of Willoughby and Frobisher in have been made by the states of this 1553 and 1576, of Davis in 1585, of country to obtain a just idea of their Hudson in 1607, and of Baffin in 1616, geological conditions, the first movement though they failed in their object of find- being made by North Carolina in 1823, ing a N. W. passage to India, materially followed by Massachusetts in 1830, and by enlarged our knowledge of the Arctic 11 more states in the succeeding decade, regions. By the middle of the seven- while by the end of the century nearly all teenth century the Dutch, under Tasman the states had entered upon a systematic and Van Diemen, made the Australasian investigation of their rocks and minerals. Islands known to the world. Late in Pennsylvania, New York, New Jersey, the following century Captain Cook and some of the Eastern states did this added largely to geographical knowledge work with a large degree of completeness. by his survey of the Pacific and its The United States government early eninnumerable islands. The Antarctic tered upon similar work, sending out continent was discovered in 1840 by numerous expeditions, and a United American, English, and French expedi- States Geological Survey was organized tions, and the northwest passage round in 1879, which diligently continued the North America was found by McClure in work, its field of operations embracing 1850. The travels of Humboldt, Spix the whole country. Great Britain was and Martius, Lewis and Clark, Fremont, the first country in Europe to engage in and others have made us acquainted a similar work, beginning in 1832. It with the general features of the American has been followed by nearly all the councontinent. In Asia numerous travelers tries of Europe and by its several have contributed much to render our colonies. Geology Geology (j-ol'o-ji; Gr. ge, the earth, logos, a discourse) is the science which treats of the history of the earth, as ascertained by the study of its exterior or crust, investigating the successive changes which have taken place in the rock-masses composing it, their relations, structure and origin, and discussing also the main features of the animal and vegetable life of the past as bearing on the earth's history. The present condition and conformation of the earth is the result of vast changes in the past and of agencies working through Section of River Terraces, showing Successive Geology ashes, others of old lavas, others of masses of matter which were introduced in a melted state from below among the strata. Granite is the most important and widely-spread of the igneous rocks, and is generally regarded as the fundamental rock of the earth's crust. Rocks that have been melted are known to be igneous by their structure, and also by the effects they have produced on the strata with which they are associated. Shales, sandstones, etc., are often hardened, bleached, and even vitrified at the points of junction with greenstone, basaltic, and felspathic dykes, or old lava beds, and the same kind of alteration takes place on a greater scale when large masses of igneous rocks have been intruded on the strata. That the rocks which form the crust of the earth had the same general origin with the igneous rocks and sedimentary strata now forming has been well estabimmense periods of time, and the same lished, and that there is a regular sucor similar agencies may still be seen at cession of strata from the older to the work producing similar changes. Thus newer, the oldest being normally lowerrocks, both aqueous and igneous, are still most, the newest uppermost, is also well being formed. The former receive their ascertained. A corresponding succession name from owing their origin mainly in regard to the animal and vegetable to water, which acts both chemically and life of former ages has also been proved mechanically on the crust of the earth, by the fossils that accompany the sucin wearing down rocks and soils and cessive strata. This superposition of carrying the débris often to considerable strata and the succession of life in time distances. The sediments thus carried to are two cardinal doctrines in geology. sea, or into lakes and estuaries, are Observation and experiment alike estabspread abroad in the water, and form lish the doctrine of superposition. Thus stratified deposits, which in course of at the edges of the strata on which time solidify into rock. With sufficient London stands the rocks known as the time all land would thus be eventually Woolwich and Reading beds are seen to degraded beneath the sea, were it not lie on the chalk. Far within these edges that the loss is compensated by disturb- well-sinkers are aware that often after ance and elevation of land always slowly sinking several hundred feet through the taking place over great portions of the London clay the chalk is reached. In continents and islands of the world. Such like manner proceeding westward across disturbances have produced strange phe- the middle of England, it is found that nomena among the stratified rocks, which may be contorted, tilted up, dislocated, or otherwise changed in their original arrangement. The strata resulting from aqueous deposits are consolidated (petrified) chiefly by pressure and chemical decomposition and recomposition. Some formations are many thousands of feet in thickness. Contraction of the crust of the earth due to radiation of the heat of the earth into space has also had immense effects, the result being that over broad areas rocky masses have been contorted and compressed to a great degree, and mountain ranges upheaved. SECTION OF SUBMARINE PLAIN. and skerries by the waves, and reduced to a platform below the level of the sea (s s) on which the gravel, sand, and mud (d) produced by the waste of the coast may accumulate. 1, Land cut into caves, tunnels, sea-stacks, reefs, the Chalk rests on the Greensands, the Igneous rocks also form a considerable Greensands on the Upper Oolites, the portion of the visible crust of the earth, Lower Oolites on the Lias, the Lias on though much smaller in amount than the New Red marl, and so on through those of sedimentary origin. Some of the lower members of the geological series igneous rocks consist of beds of volcanic of English rocks. Similar conditious Geology Geology may be found in all other countries, the in one of which was found a structure superposition of strata being widely evi- believed by Dawson, Carpenter, and dent. Each great group of rocks con- others to be a foraminifer and called sists of several subdivisions called for- Eozoon Canadense. It is now, however, mations, and each group, and even to generally believed to be a mineral proda considerable extent minor subdivision, uct, In the Outer Hebrides and on the is characterized by the presence of dis- west coast of the North Highlands, rocks tinct assemblages of organic remains. occur of highly metamorphic gneiss, The successive appearance of such remains, which constitutes the succession of life in time, was the great discovery of Wm. Smith, made more than a century ago. The main rock-systems into which the earth's crust is divided, and which are based on the characteristics of the organic remains contained in them, are shown in the following table in ascending order: which are probably of Laurentian age. The term Pre-Cambrian or Archæan is now applied to these rocks in the British area; they crop out also in North and South Wales, in the Malvern Hills, and in Charnwood Forest in Leicestershire. No fossils have yet been observed in these rocks. The Huronian Rocks of North America are possibly intermediate in age between the Laurentian and the rocks next mentioned. Cambrian.-These rocks come next in Post-Tertiary (Recent-Alluvium, Peat, etc. succession to the Laurentian strata. The or Quaternary Pleistocene. Pliocene. Miocene. Oligocene. term Cambrian has been used differently by different geologists. The purple grits and slates to which the term Cambrian was restricted by Murchison form the greater part of the group of hills in Wales that lie east of Cardigan Bay; they are also well seen in Carnarvon or Archæan, Lau-1 rentian, or Fundamental Gneiss. Eozoic Igneus rocks also are associated in different localities with the systems named in the foregoing table. In the small area of Great Britain a more complete series of rocks exists than in any other part of the earth's surface of equal dimensions-so far as is known, The greater part of the European series is, indeed, nearly complete in England and Wales alone; and since the days of William Smith, the British rocks, from this early and complete study, have generally been the types to which formations in other parts of the world were referred. Archæan, Pre-Cambrian, or Laurentian Rocks.-The Laurentian are the oldest known of the sedimentary rocks. They are metamorphic (that is, changed from their original structure), and mostly gneissic in character, and were for long classed as granitic and igneous rocks till their true nature was shown by Sir William Logan. They occupy vast tracts of country in Labrador and Canada, consisting there of two divisions. Lower and Upper Laurentian. The gneiss of the lower division is interstratified with several thick banks of crystalline limestone, Normal Faults. shire, where the celebrated slate quarries of Penrhyn and Llanberis lie in Cambrian strata. Parallel strata, known by the same name, are found abundantly in other parts of the earth. Many of the beds are destitute of fossils, but these occur in certain localities down to the lowest beds of the system, and include brachiopods, trilobites, and other low organisms. The Silurian Rocks were first worked out in detail in South Wales and the bordering counties by Sir Roderick Murchison, and an account of them published in the year 1839 in his Silurian System. They are divided by geologists into the Lower and Upper Silurian. The former comprises in ascending order the Lingula beds (so named from a characteristic fossil shell), the Tremadoc slate, the Llandeilo flags, and the Caradoc or Bala beds. The Lingula flags (Potsdam sandstone of the United States) rest conformably on and in fact pass by gradations into the Cambrian rocks. Above them lie the Llandeilo flags of North Wales, named from the town of Llandeilo in Carmarthenshire, where they |