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CHALK , the name given to any soft, pulverulent, pure See also:- WHITE
- WHITE, ANDREW DICKSON (1832– )
- WHITE, GILBERT (1720–1793)
- WHITE, HENRY KIRKE (1785-1806)
- WHITE, HUGH LAWSON (1773-1840)
- WHITE, JOSEPH BLANCO (1775-1841)
- WHITE, RICHARD GRANT (1822-1885)
- WHITE, ROBERT (1645-1704)
- WHITE, SIR GEORGE STUART (1835– )
- WHITE, SIR THOMAS (1492-1567)
- WHITE, SIR WILLIAM ARTHUR (1824--1891)
- WHITE, SIR WILLIAM HENRY (1845– )
- WHITE, THOMAS (1628-1698)
- WHITE, THOMAS (c. 1550-1624)
white See also:limestone. The word is an old one, having its origin in the Saxon cealc, and the hard See also:form " See also:kalk " is still in use amongst the See also:country folk of See also:Lincolnshire. The See also:German Kalk comprehends all forms of limestone; therefore a See also:special See also:term, Kreide, is employed for chalk—French craie. From being used as a See also:common name, denoting a particular material, the word was subsequently utilized by geologists as an appellation for the Chalk formation; and so prominent was this formation in the eyes of the earlier workers that it imposed its name upon a whole See also:system of rocks, the Cretaceous (See also:Lat. creta, chalk), although this See also:rock itself is by no means generally characteristic of the system as a whole.
The Chalk formation, in addition to the typical chalk material —creta scriptoria—comprises several See also:variations; argillaceous kinds—creta marga of Linnaeus—known locally as maim, See also:marl, clunch, &c.; and harder, more stony kinds, called rag, freestone, rock, hurlock or harrock in different districts. In certain parts of the formation layers of nodular flints (q.v.) abound; in parts, it is inclined to be sandy, or to contain grains of See also:glauconite which was originally confounded with another See also:green See also:mineral, See also:chlorite, hence the name " chloritic marl " applied to one of the subdivisions of the chalk. In its purest form chalk consists of from 95 to 99% of See also:calcium carbonate (carbonate of See also:lime); in this See also:condition it is composed of a See also:mass of See also:fine granular particles held together by a somewhat feeble calcareous See also:cement. The particles are mostly the broken tests of See also:foraminifera, along with the debris of echinoderm and molluscan shells, and many See also:minute bodies, like coccoliths, of somewhat obscure nature.
The earliest attempts at subdivision of the Chalk formation initiated by Wm. See also:Phillips were based upon lithological characters, and such a See also:classification as " Upper Chalk with Flints," " See also:Lower Chalk without Flints," " Chalk marl or See also:Grey chalk," was generally in use in See also:England until W. See also:Whitaker established the following See also:- ORDER
- ORDER (through Fr. ordre, for earlier ordene, from Lat. ordo, ordinis, rank, service, arrangement; the ultimate source is generally taken to be the root seen in Lat. oriri, rise, arise, begin; cf. " origin ")
- ORDER, HOLY
order in 1865:
Upper Chalk, with flints
chalk rock
Lower Chalk chalk with few flints
chalk without flints
Totternhoe See also:- STONE
- STONE (0. Eng. shin; the word is common to Teutonic languages, cf. Ger. Stein, Du. steen, Dan. and Swed. sten; the root is also seen in Gr. aria, pebble)
- STONE, CHARLES POMEROY (1824-1887)
- STONE, EDWARD JAMES (1831-1897)
- STONE, FRANK (1800-1859)
- STONE, GEORGE (1708—1764)
- STONE, LUCY [BLACKWELL] (1818-1893)
- STONE, MARCUS (184o— )
- STONE, NICHOLAS (1586-1647)
stone
marl
In See also:France, a similar system of classification was in See also:vogue, the subdivisions being craie See also:blanche, craie tufan, craie chlorites, until 1843 when d'See also:Orbigny proposed the term Senonien for the Upper Chalk and Turonien for the Lower; later he divided the Turonien, giving the name Cenomanien to the lower portion. The subdivisions of d'Orbigny were based upon the fossil contents and not upon the lithological characters of the rocks. In 1876 Prof. Ch. See also:Barrois showed how d'Orbigny's classification might be applied to the See also:British chalk rocks; and this See also:- SCHEME (Lat. schema, Gr. oxfjya, figure, form, from the root axe, seen in exeiv, to have, hold, to be of such shape, form, &c.)
scheme has been generally adopted by geologists, although there is some divergence of See also:opinion as to the exact position of the See also:base See also:line of the Cenomanian.
The accompanying table shows the classification now adopted in England, with the zonal fossils and the See also:continental names of the substages:
Since Prof. Barrois introduced the zonal system of subdivision (C. See also:Evans had used a similar scheme six years earlier), our know-ledge of the See also:English chalk has been greatly increased by the See also:work of See also:Jukes-See also:- BROWNE
- BROWNE, EDWARD HAROLD (18,1–1891)
- BROWNE, ISAAC HAWKINS (1705-1760)
- BROWNE, JAMES (1793–1841)
- BROWNE, MAXIMILIAN ULYSSES, COUNT VON, BARON DE CAMUS AND MOUNTANY (1705-1757)
- BROWNE, PETER (?1665-1735)
- BROWNE, ROBERT (1550-1633)
- BROWNE, SIR JAMES (1839–1896)
- BROWNE, SIR THOMAS (1605-1682)
- BROWNE, WILLIAM (1591–1643)
- BROWNE, WILLIAM GEORGE (1768-1813)
Browne and See also:- WILLIAM
- WILLIAM (1143-1214)
- WILLIAM (1227-1256)
- WILLIAM (1J33-1584)
- WILLIAM (A.S. Wilhelm, O. Norse Vilhidlmr; O. H. Ger. Willahelm, Willahalm, M. H. Ger. Willehelm, Willehalm, Mod.Ger. Wilhelm; Du. Willem; O. Fr. Villalme, Mod. Fr. Guillaume; from " will," Goth. vilja, and " helm," Goth. hilms, Old Norse hidlmr, meaning
- WILLIAM (c. 1130-C. 1190)
- WILLIAM, 13TH
William See also:- HILL
- HILL (0. Eng. hyll; cf. Low Ger. hull, Mid. Dutch hul, allied to Lat. celsus, high, collis, hill, &c.)
- HILL, A
- HILL, AARON (1685-175o)
- HILL, AMBROSE POWELL
- HILL, DANIEL HARVEY (1821-1889)
- HILL, DAVID BENNETT (1843–1910)
- HILL, GEORGE BIRKBECK NORMAN (1835-1903)
- HILL, JAMES J
- HILL, JOHN (c. 1716-1775)
- HILL, MATTHEW DAVENPORT (1792-1872)
- HILL, OCTAVIA (1838– )
- HILL, ROWLAND (1744–1833)
- HILL, SIR ROWLAND (1795-1879)
Hill, and particularly by the laborious studies of Dr A. W. Rowe. Instead of employing the mixed assemblage of animals indicated as See also:zone fossils in the table, A. de Grossouvre proposed a scheme for the See also:north of France based upon ammonite faunas alone, which he contended would be of more See also:general applicability (Recherches sur la Craie Supe'rieure, See also:Paris, 1901).
The Upper Chalk has a maximum thickness in England of about r000 ft., but See also:post-cretaceous erosion has removed much of it in many districts. It is more See also:constant in See also:character, and more typically chalky than the lower stages; flints are abundant, and harder nodular beds are limited to the lower portions, where some of the compact limestones are known as " chalk rock." The thickness of the See also:Middle Chalk varies from about See also:loo to 240 ft.; flints become scarcer in descending from the upper to the lower portions. The whole is more compact than the upper See also:stage, and nodular layers are more frequent—the " chalk rock " of See also:Dorset and the Isle of See also:Wight belong to this stage. At the base is the hard " See also:Melbourne rock." The thickness of the Lower Chalk in England varies from 6o to 240 ft. This stage includes See also:part of the " white chalk without flints," the " chalk marl," and the "grey chalk." The Totternhoe stone is a hard freestone found locally in this stage. The See also:basement See also:bed in See also:Norfolk is a pure limestone, but very frequently it is many with grains of See also:sand and glauconite, and often contains phosphatic nodules; this facies is See also:equivalent to the " See also:Cambridge See also:Greensand " of some districts and the "chloritic marl "of others. In See also:Devonshire the Lower Chalk has become thin sandy calcareous See also:series.
The chalk can be traced in England from Flamborough See also:Head in See also:Yorkshire, in a See also:south-See also:westerly direction, to the See also:coast of Dorset; and it not only underlies the whole of the S.E. corner, where it is often obscured by See also:Tertiary deposits, but it can be followed across the Channel into See also:northern France. Rocks of the same See also:age as the chalk are widespread (see CRETACEOUS SYSTEM); but the variety of limestone properly called by this name is almost confined to the Anglo-Parisian See also:basin. Some chalk occurs in the See also:great Cretaceous deposits of See also:Russia, and in See also:Kansas, See also:Iowa, See also:Nebraska and S. Dakota in the See also:United States. Hard white chalk occurs in See also:Ireland in See also:Antrim, and on the opposite See also:shore of See also:Scotland in See also:Mull and Morven.
Economic Products of the Chalk.—Common chalk has been frequently used for rough See also:building purposes, but the more important building stones are " See also:Beer stone," from Beer Head in Devonshire, " See also:Sutton stone " from a little north of Beer, and the " Totternhoe stone." It is burned for lime, and when mixed with some form of See also:clay is used for the manufacture of cement; chalk marl has been used alone for this purpose. As a manure, it has been much used as a dressing for clayey See also:land. Flints from the chalk are used for road See also:- METAL
- METAL (through Fr. from Lat. metallum, mine, quarry, adapted from Gr. µATaXAov, in the same sense, probably connected with ,ueraAAdv, to search after, explore, µeTa, after, aAAos, other)
metal and See also:concrete, and have been employed in building as a facing for walls.
Phosphatic nodules for manure have been worked from the chloritic marl and See also:Cam-See also:bridge Greensand, and to some extent from the Middle Chalk. The same material is worked at Ciply in See also:Belgium and See also:Picardy in France. Chalk is employed in the manufacture of carbonate of soda, in the preparation of See also:carbon dioxide, and in many other chemical processes; also for making paints, crayons and tooth-See also:powder. See also:Whiting or See also:Spanish white, used to See also:polish See also:glass and metal, is purified chalk prepared by triturating common chalk with a large quantity of See also:water, which is then decanted and allowed to See also:deposit the finely-divided particles it holds in suspension.
Chalk Scenery.—Where exposed at the See also:surface, chalk 'produces rounded, smooth,
Chalk Marl
Zonal fossils used in See also:Britain. Stages. N. France S.E. and
and S. France.
Belgium.
A.. -Ostrea lunata (Norfolk) Danian? u x
B. Belemnitella mucronata (Trimingham) a c n a
Actinocamax quadratus Upper Chalk 'C u
=Inoceramus lingua in Yorkshire Senonian a p o
Marsupites, Craie blanche a~ a ^
`Marsupites testudinarium I w 4a. 0)
Uintacrinus a d a'
Micraster See also:cor-anguinum w .Ey. A.
cor-testudinarium U a
Holaster planus, Chalk rock .a? 3
a 0
ca a
c a
~
ch
Terebratulina gracilis Middle Chalk
Rhynchonella Cuvieri,Melbourne rock Turonian
Craie marneuse
Actinocamax plenus Lower Chalk.
Holaster subglobosus, Totternhoe stone. Chalk Marl and
Schloenbachia varians. Cambridge Green-
sand
Cenomanian
Craie glauconieuse
grass-covered hills as in the See also:Downs of See also:southern England and the Wolds of Yorkshire and Lincolnshire. The hills are often intersected by clean-cut dry valleys. It forms fine cliffs on the coast of See also:Kent, Yorkshire and Devonshire.
Chalk is employed medicinally as a very mild astringent either alone or more usually with other astringents. It is more often used, however, for a purely See also:mechanical See also:action, as in the preparation hydrargyrum cum creta. As an antacid its use has been replaced by other drugs.
See also:Black chalk or See also:drawing See also:slate is a soft carbonaceous schist, which gives a black streak, so that it can be used for drawing or See also:writing. See also:- BROWN
- BROWN, CHARLES BROCKDEN (1771-181o)
- BROWN, FORD MADOX (1821-1893)
- BROWN, FRANCIS (1849- )
- BROWN, GEORGE (1818-188o)
- BROWN, HENRY KIRKE (1814-1886)
- BROWN, JACOB (1775–1828)
- BROWN, JOHN (1715–1766)
- BROWN, JOHN (1722-1787)
- BROWN, JOHN (1735–1788)
- BROWN, JOHN (1784–1858)
- BROWN, JOHN (1800-1859)
- BROWN, JOHN (1810—1882)
- BROWN, JOHN GEORGE (1831— )
- BROWN, ROBERT (1773-1858)
- BROWN, SAMUEL MORISON (1817—1856)
- BROWN, SIR GEORGE (1790-1865)
- BROWN, SIR JOHN (1816-1896)
- BROWN, SIR WILLIAM, BART
- BROWN, THOMAS (1663-1704)
- BROWN, THOMAS (1778-1820)
- BROWN, THOMAS EDWARD (1830-1897)
- BROWN, WILLIAM LAURENCE (1755–1830)
Brown chalk is a See also:kind of See also:umber. Red chalk or reddle is an impure earthy variety of See also:haematite. See also:French chalk is a soft variety of steatite, a hydrated See also:magnesium silicate.
The most comprehensive See also:account of the British chalk is contained in the See also:Memoirs of the See also:Geological Survey of the United See also:Kingdom, " The Cretaceous Rocks of Britain," vol. ii. 1903, vol. iii. 1904 (with bibliography), by Jukes-Browne and Hill. See also " The White Chalk of the English Coast," several papers in the Proceedings of the Geologists' Association, See also:London, (I) Kent and See also:Sussex, xvi. 1900, (2) Dorset, xvii., 1901, (3) See also:Devon, xviii., 1903, (4) Yorkshire, xviii., 1904. (J. A.
End of Article: CHALK
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