Geographical Terms A

abrasion Wearing of rock surfaces by agronomy Agric. economy, including friction, where abrasive material is theory and practice of animal hus• transported by running water, ice, bandry, crop production and soil wind, waves, etc. management. abrasion platform Coastal rock plat• aiguille Prominent needle-shaped form worn nearly smooth by abrasion. rock-peak, usually above snow-line and formed by frost action. absolute humidity Amount of water vapour per unit volume ofair. ait Small island in river or lake. abyssal Ocean deeps between 1,200 alfalfa Deep-rooted perennial plant, and 3,000 fathoms, where sunlight does largely used as fodder-crop since its not penetrate and there is no plant life. deep roots withstand drought. Pro• duced mainly in U.S.A. and Argentina. accessibility Nearness or centrality of one function or place to other functions allocation-location problem Problem or places measured in terms ofdistance, of locating facilities, services, factories time, cost, etc. etc. in any area so that transport costs are minimized, thresholds are met and acre-foot Amount of water required total population is served. to cover I acre of land to depth of I ft. (43,560 cu. ft.). alluvial cone Form of alluvial fan, consisting of mass of thick coarse adiabatic Relating to chan~e occurr• material. ing in temp. of a mass of gas, III ascend• ing or descending air masses, without alluvial fan Mass of sand or gravel actual gain or loss ofheat from outside. deposited by stream where it leaves constricted course for main valley. afforestation Deliberate planting of trees where none ever grew or where alluvium Sand, silt and gravel laid none have grown recently. down by rivers, especially when in flood or when their velocity IS checked. aftershock Vibration of earth's crust caused by minor adjustments of rocks almwind Warm Fohn type wind, after main earthquake waves have blowing s over Tatra Mountains into s passed. Poland. age-sex pyramid Graphical represen• alp High summer pasture on shoulder tation of population structure showing of mountain , especially in Switzerland, number of males and females by age where marked change of slope occurs groups. above glaciated valley. agglomerate Angular fragmented vol• altocumulus Layer of fleecy cloud, canic material cemented together by at altitude of 8,000-20,000 ft. (2,380- heat. 6,096 metres) in groups or lines, often sign ofgood weather. agglomeration Large tract of essen• tially urban and industrial land result• altostratus Mid-altitude cloud in ing from growth and physical expan• form of extensive grey sheet, usually sion of formerly separate neighbouring heralding rain associated with warm settlements. front. 627 A aluminium Geographical Terms aluminium Extracted from bauxite; Arctic Circle Parallel oflat. 66°32' N, metal of remarkable lightness, high enclosing N Polar Regions. strength and resistant to corrosion. areal differentiation Differences bet• aluminum see aluminium ween areas in terms of relief, climate, soils, vegetation, population, economy anabatic wind Local wind blowing etc. Geography is often defmed as the up-valley in afternoon, when convec• study ofareal differentiation. tion currents on mountain slopes draw air upwards. arete Narrow ridge of spur or mountain, usually above snow-line and anemometer Instrument for measur• formed at crest between two cirques. ing or recording force ofwind. arroyo Small stream channel made by aneroid barometer Instrument for occasional rainfall in arid districts measuring atmospheric pressure, com• (Latin America, sw U.S.A.). prising metallic box, almost exhausted of air, whose flexible sides expand and artesian basin Synclinal structure contract with changing air pressure. containing aquifer between two im• Such movements are magnified and permeable beds. recorded on calibrated dial. artesian well Boring put down into Antarctic Circle Parallel onat. 66°32' aquifer in artesian basin; named from s, enclosing s Polar Regions. wells ofthis type in Artois, N France. anthracite Hard, shiny smokeless coal asbestos Fibrous mineral which can of high carbon content, producing great be spun and woven into material which heat. is fire-proof, heat-resistant and of low conductivity. anticline Arch or crest of fold in rock strata. asteroids Belts of small heavenly bodies revolving in Solar System bet• anticyclone Area of high pressure ween Mars and Jupiter. with winds blowing clockwise round it in N hemisphere and anti-clockwise in s Atlantic coast see discordant coast hemisphere. Moves slowly in tem• perate lat., with winds light or variable atmosphere Envelope of air sur• near centre. Produces fme settled rounding earth, consisting of 78% weather in summer, but cold frosty nitrogen, 21 % oxygen, very small weather or fog in winter. quantities of carbon dioxide and other gases and varying quantities of water antipodes Any two places on opposite vapour. sides of earth, so that line joining them passes through centre ofearth. atoll Circular or irregularly-shaped coral reef, partly submerged to enclose apogee Part oforbit ofmoon or planet lagoon. which is farthest from earth. attrition Constant wearing-down of Appleton Layer Part of ionosphere, load of rock-material by friction when about 150 m. (240 km.) above earth, transported by running water, wind and reflecting short radio-waves back to waves. earth. aurora Luminous phenomena caused aqnifer Rock holding or allowing the by electrical discharge and visible in sky passage ofwater. in high lat. archipelago (i) sea studded with avalanche Fall of mass of snow, ice islands; (iz) group of many islands, or rock down mountainside and cap• continental or oceanic. able ofgreat destruction. 628 Geographical Terms basalt B axis (I) diameter between Nand s Awres high Sub-tropical anti• Poles, about which earth rotates; (i/) cyclone situated over E side OfN Atlan• central line of fold from which strata tic, often extending to affect Britain and dip or rise in opposing directions. wEurope. Ayala Strong, warm wind in Massif Central, France.

B

bad German, bath. Common prefix transverse to wind direction, with horns attached to German towns which are extending down-wind. spas. barkhan see barchan badlands High barren country in semi-arid regions with dry loose soils. barograph Self-recording aneroid Rain, when it falls, is heavy and washes barometer tracing ink line on moving out deep gullies so that little vegetation drum. or animal life remains. barometer Instrument for measuring Bagnio Tropical storm of Philippine atmospheric pressure, also heights, and Islands, mainly occurring between July indicating weather changes. Common• and Nov. est type employs column of liquid, usually mercury, in graduated tube. See bahada Sloping expanse of scree, also aneroid barometer gravel and sand round margins of inland basin or at foot of mountains in barrage Natural or artificial obstacle semi-arid regions, formed by coales• to flow ofstream. cence of series of adjacent alluvial cones. barrier lake L. produced by forma• tion of natural dam across valley, bajada see bahada caused by landslides, avalanches, deltas, terminal moraines, or dams of Bantu Native oftribe speaking one of vegetation, ice, lava or calcium car• 200 languages or dialects used in Africa bonate. s ofline Cameroon-L. Victoria. barrier reef (i) coral reef parallel to bar (i) unit of atmospheric pressure coast but separated from it by lagoon; equal to I m. dynes per sq. cm. At 45' (ii) coral reef wholly or partly enclosing N., in temp. ofO'C. at sea level, I bar= coral island. 29.53 ins. or750.1 mm. of mercury. It is divided into 1,000 millibars (mb.) for barrow Mound of earth or stones, weather map purposes; (ii) ridge ofsand covering anc. burial chamber, particu• and rock fragments across mouth of larly common on chalk land of SE river or entrance to bay, see off-shore England. bar, tombolo; (iii) navigational obstruc• tion where alluvium, sand and gravel barysphere Heavy central core of deposits occur in stream channels. earth below lithosphere. barchan Crescent-shaped sand dune basalt Fine-grained, dark-coloured 629 B base-level Geographical Terms igneous rock, formed of solidifIed lava beck Small rapid stream. extruded by volcanic and fIssure erup• tions: flows readily to form extensive bed-rock Solid rock of earth's surface, sheets and may solidifY to form hexago• usually covered by soil or other super• nal columns. fIcial deposits. base-level Lowest level to which bedding Arrangement of rock strata stream can erode its bed. Permanent in bands of varying thickness and base-level is the sea, but lake may character. provide temporary base-level. bedding-plane Structural feature of basic slag Blast-furnace by-product in sedimentary rocks parallel to the iron smelting, contains phosphates and original surface ofdeposition. is crushed for fertilizers. beet sugar Sugar from variety of beet basin (i) large-scale depression occu• grown in temperate zone; after sugar pied by ocean; (il) area ofland drained extraction, refuse, leaves and tops are by single river system; (iii) area pulped for cattle food, molasses and enclosed by higher land, with or with• alcohol. out outlet to sea; (iv) part ofdock system or canal ornavigable river. bench Narrow terrace, step or ledge produced by denudation, wave-cut batholith Very large intrusion of bench, step-fault, or by mining and igneous rock, usually granite, originat• quarrying. ing at great depth and extending over many miles. Upper surface may ulti• bench-mark Defmed and located mately be exposed by erosion. point of reference used in triangulation survey. bathylith see batholith berg German hill or mountain, Afri• bathyorography Map detail depict• can range. Also used in combinations ing altitude of land and depth of sea by for physical features, see bergschrund, layer-colouring. Berg wind. bathysphere (I) central core of earth; bergschrund Gap left round upper (iz) diving apparatus used for submarine rim of snowfIeld or glacier as snow or operations. ice moves downstream. bauxite Impure aluminium hydrox• Berg wind Warm, dry Fohn wind, blowing mainly in winter from s Afri• ide occurring widely in clay deposits, can Plateau to coast. chief ore ofaluminium. bight (I) wide curve or recess of coast, bayou Marshy creek or sluggish back• often between headlands; (il) large bend water in lower Mississippi and along of river. GulfCoast ofU.S.A. bill Long narrow promontory. beach Accumulation of sand and shingle along coast, occupying space billabong Backwater in temporary between low-water mark and highest flowing stream in Australia. point reached by storm waves. Bise Cold, dry N or NE wind blowing bearing Horizontal angular direction in winter in Switzerland, N Italy and s of any place or object, taken from a France. Similar to Mistral or Tramon• fIxed point. tana. bitumen Pitch or tar or asphalt. Beaufort scale Scale of wind forces ranging from 0 (calm) to 12 (hurri• bituminous coal Free-burning coal cane). Introduced by Admiral Sir with high hydro-carbon content, Francis Beaufort, 1805. includes most household and gas coals. 630 Geographical Terms bund B blackearth seechernozem usually consisting of clays, sand and stones of all shapes and sizes, probably block mountain see horst representing ground moraine of ice• sheet. blow-hole Near-vertical cleft leading from sea-cave to cliff-top, formed by bourne Temporary or intermittent hydraulic action of wave-compressed stream flowing in dry valley of chalk air; spray is sometimes blown from it country after period ofheavy rain. into air. brachycephalic Broad headed. blow-out Hollow in sandy terrain Cephalic Index> 83.1. formed by deflation (wind eddying), particularly where vegetation has been brae Sloping bank or hillside (Scot.). destroyed. In rock deserts, may develop from break in resistant surface layer. braided river channel Course of river split into complicated channels bluff Headland formed by steep because of inability to transport its slopes bordering river or lake. load. bocage Landscape ofNW France, with brash ice Accumulation of crushed small fIelds enclosed by drystone walls ice near shore, not thick enough to or low banks with hedges. hindernavigation.

Bohorok Hot dry wind on N coast of Brave West Winds see Roaring Sumatra during NW Monsoon (June• Forties Sept.). break in bulk Location at which bolson Basin of interior drainage in materials or products are transferred arid or semi-arid regions. Floor may from one mode oftransport to another. contain salt lake or alluvial fans round flanks ofsurrounding mountains. breaker Mass ofbroken water rushing up beach or where mass of rock lies Bora Violent, cold, dry wind blowing near surface ofsea. from N or NE into Adriatic, mostly in winter; can produce rain or snow when breccia Angular fragments of rock of depression lies to the s. any type, cemented together in matrix. Boraccia Particularly violent form of breckland Area on borders of Norfolk Bora. and Suffolk comprising heathland, thicket and bracken. bore Steep, wall-like wave in river with funnel-shaped estuaries, flowing Brickflelder Hot, dry, dusty, squally rapidly upstream on rising tide. Highest wind in SE Australia, caused by S move• at spring tides. ment of mass oftropical air, especially in summer. boreal (i) N; (ii) general term for clima• tic zone with short summers and snowy British Summer Time Period in year winters; (iii) climatic period from during which clocks are advanced one 7,500-5,500 B.C. hour ahead ofGreenwich Mean Time. Borino Weaker summer form ofBora. broad Sheet of reed-fringed shallow water beside or forming part of sluggish boss Small batholith, more or less cir• river near estuary, particularly in E cular in plan. Anglia. Boswash Name given to the urban buffer state Small, independent area extending from Boston (Massa• autonomous country between two or chusetts) to Washington (D.C.). more powerful ones. boulder cIay UnstratifIed glacial bund (/) artifIcial embankment; (iI) deposits of varying composition but main quay in some Far Eastern ports. 631 B Buran Geographical Terms Buran Cold, strong NE wind in Cent• tropical and tropical Africa, with trees ral Asia, producing blizzards in winter, scattered, forming open parkland, but but can also blow in summer. sometimes dense so as to resemble forest. burn Small stream (Scot.). bush Large uncultivated tract, over• butte Isolated flat-topped hill, usually grown with bushes and small trees, capped with resistant rock and rising usually in semi-arid regions. abruptly from plain. bushveld Type of savanna in sub- Buys Ballot's Law see Ferrel's Law c

caatinga Thorn forest or carse Level tract of fertile alluvial open woodland with scrub in arid parts lands bordering estuaries in Scotland. ofNEBrazil. cartouche Panel on map, usually cacao Evergreen tree of equatorial or decorative, containing title, scale, etc. tropical regions, with large pods con• taining beans, the source of cocoa and cash crop Crop cultivated for market. chocolate. cassava Plant with tuberous roots, caldera Large, shallow, circular cavity used as food in Central or s America. remaining after removal of former vol• canic peak by immense eruption; caste Hindu hereditary social group. sometimes contains lake. cataract (I) waterfall running over sheer caliche Impure deposits of nitrogen precipice; (it) series of rapids, as on R. salts found in deserts of Chile or Peru; Nile. valuable fertilizer in 19th cent. campos (Plural) open plains of Cent• catch crop Quick-growing crop (I) bet• ral Brazil with savanna climate and ween two main crops in a rotation; (it) between rows of main crop; (iit) in place vegetation. offailed crop. cane sugar Tall tropical or sub- tropical plant whose stem yields sugar. catchment Area served by a function, fIrm, establishment or central place. canyon Spanish, canon. (i) deep, steep-sided gorge with river at bottom, catchment area Self-contained drain• mainl y found in arid or semi-arid areas; age basin collecting all rainfall in area. (it) submarine trough on, and beyond, continental shelf. causses (I) French term used for lime• stone country in general; (it) limestone 'Cape Doctor' Strong wind blowing district in s of Massif Central, France, from plateau to coast in s Africa. resembling Yugoslavian karst. carr Fen containing reeds, shrubs and cavern Large cave or subterranean willows. chamber, naturally produced, with 632 Geographical Terms climate C entrance, from surface; common chine Narrow cleft in cliffs of soft feature of karst landscape. material, containing stream; mainly found in Hampshire and Isle ofWight. cay Low island or reef of sand and coral in Caribbean Sea. chinook American Indian 'snow• eater', dry, warm sw wind descending E Celsius scale Internationally accepted slopes of Can. or N U.S.A. Rocky name for Centigrade scale of temp. Mountains and warmed adiabatically; where 0' is melting point ofice and 100' in spring, causes swift rise in temp. boiling point of water, after inventor Anders Celsius (170 1-44). chorochromatic map Map showing non-quantitative phenomena by means Celtic fIeld Roughly sq. field, varying ofcolouring or shading. in size from half to one and a half acres, used before Saxons introduced strip• choropleth map Map showing quanti• field system. ties per unit of area by means of scaled shading or colouring (e.g. map of popu• centrality Relative importance of a lation density by parishes). settlement with regard to region it serves. cinchona Tropical evergreen tree ofs America whose bark yields quinine. central place A settlement providing goods, services, etc. for a surrounding cirque Steep-sided, flat-floored, area (catchment). horseshoe shaped rock-basin of glacial origin, marking site of cirque glacier, central place system Spatial distribu• but in post-glacial conditions often tion ofcentral places. contains smalf, deep lake. central place theory Theory of loca• cirro-cumulus 'Mackerel sky'; type of tion of settlements and functions cloud above 20,000 ft. (6,096 metres), devised by W. Christaller (1933). in lines of ripples, containing ice• crystals. Cephalic Index Mathematical index to describe shape of skull =maximum cirro-stratus Layer or veil of sheet breadth of skull -;. maximum length x cloud, above 20,000 ft. (6,096 metres), 100. See also brachycephalic, dolicho• of milky appearance, causing sun or cephalic. moon to appear with halo; marks approach ofwarm front. chaco Forest land in parts ofs Ameri• ca, see Gran Chaco. cirrus Delicate, wispy clouds at 20,000-40,000 ft. (6,096-12,192 chaparral Spanish, evergreen shrub metres), containing ice-particles. When vegetation ofNW America, resembling drawn out into 'mare's tail' indicates garigue and maquis of Mediterranean strong upper winds. Europe. citrus fruit Obtained from evergreen chernozem Russian, 'Black Earth' soil trees like grape-fruit, lemon, lime and of loose, crumbly texture, rich in orange; widely grown in sub-tropical or humus and lime, covering large areas of warm temperate regions, especially temperate lands where natural vegeta• Mediterranean climates. tion was grass, now forms great wheat growing areas ofworld. cliff High, steep face of rock mass, especially along sea coast, where chicle Gum obtained from latex of marine denudation is active. several trees in s and Central America, chiefingredient ofchewing gum. climate Total complex of weather conditions, average characteristics and chili Hot, dry s wind over N Africa. range of variation over large areas of earth's surface, considered over period china clay see kaolin of30-35 years. 633 C clinometer Geographical Terms clinometer Instrument for measuring in occlusion is colder than air mass in vertical angle between two points or for front. measuring dip ofstrata. 'Cold Pole' Term applied to point clint Low, flat-topped ridge between with lowest temp. usually referring to fIssures or grikes on surface of carboni• Verkhoyansk, NE Asia, where mean ferous limestone plateau, forming Jan. temp. is-58°F. (-50°C.). limestone pavement as result of solution. collective farming Type of agric. organization started in U.S.S.R., but cloud Mass of condensed water now practised in E Europe and SE Asia. vapour or ice-particles formed by con• Land compulsorily amalgamated into densation on atmospheric nuclei, such large holdings, run by manager and as dust, smoke particles, pollen, etc. worked by directed labour; proportion They float in masses from near ground of crops go to Govt., workers are paid a level, as mist or fog, to over 40,000 ft. share of proceeds of marketing (12,192 metres). remainder. c1use French for steep-sided valley Colombo Plan Formally put into cutting transversely across limestone operation in 1951 to improve political ridges in Savoy Al ps and Jura. and economic conditions of sand SE Asia. coal measures Geological term cover• ing series of coal seams and intervening combe (I) Small, generally narrow strata. valley; (if) glacial cirque, cwm. coast General name for zone of con• common Area of land, often unen• tact between land and sea. closed, over which members of com• munity have certain rights of access, coastline (I) general term for edge of pasture, turf-cutting, etc. land viewed from sea; (if) high-water mark of medi um tides; (iii) base ofcliffs. compass Instrument used to deter• mine direction, either by free-swinging coca Bolivian shrub whose dried magnetized needle or by rotating gyro• leaves provide stimulant when chewed. wheel. cocoa see cacao concordant coast Running parallel to general grain of relief, giving straight coconut Nut of palm from tropical and regular coastline. regions of E Indies and PacifIc Islands whose dried flesh produces oil for condensation Process whereby sub• margarine and soap; see copra stance changes from vapour to liquid, coffee Beverage produced from roast• as with cloud formation, mist, etc. ing beans ofberries produced by trees in condominium Territory governed tropical uplands. jointly by two or more countries. coir Outer covering of coconut used to make matting and cordage. cone Volcanic peak with broad base tapering to summit. col (i) high pass between two higher summits; (if) area oflower pressure bet• confluence Point where trib. joins ween two anticyclones. main stream. cold front Rear of warm sector of conglomerate Rock composed of depression, marking boundary between rounded, water-worn pebbles cement• warm air and advancing wedge of cold ed together in matrix. air; undercutting causes appreciable temp. drop and heavy showers. connectivity A measure of the number of routes connecting one place cold occlusion Where overtaking air with other places. 634 Geographical Terms crag and tail C continent (I) large, continuous mass of coral reef Reef composed of coral land; (il) mainland, as applied to limestone, see atoll, barrier reef. Europe. cordillera Mountain system compris• continental climate Climate of con• ing several ranges, broadly parallel in tinental interiors in temperate zone, trend. with seasonal extremes of temp. and low rainfall, mainly in summer. core Central mass of earth, radius about 2,160 m. (3,456 km.), probably continental drift Theory that con• consisting of metallic mass of nickel• tinental masses have changed relative iron ornife. positions. First put forward in 19th cent. and now further substantiated Coriolis Force see Ferrel's Law through palaeomagnetism. corona (I) series of coloured rings continental island One rising from surrounding sun or moon resulting continental shelf and structurally relat• from diffraction of light by water drop• ed to that continent. lets; (i/) fringe of radiant light visible round circumference of sun at total continental shelf Gently sloping mar• eclipse. gins of continent, submerged beneath sea and extending to point where con• corrasion Frictional wearing down of tinental slope begins; in general less rock surface by material moved by than 100 fathoms deep. gravity, running water, ice, wind and waves. continental slope Steep slope des• cending from continental shelf to corrie see cirque abyssal plain. corrosion Chemical solution of rock contour lines Lines on map connect• by water. ing all points at same relative elevation above or below specific datum, usually cOte (I) escarpment in France; (i/) sea-level. section ofcoast (France). contour ploughing Measure to combat coteau Name given by French ex• soil erosIOn by ploughing along slope to plorers in N America to sharp ridge of reduce run-off. hills or prominent escarpment. conurbation Area of extensive urban cotton Annual, sub-tropical shrub development where existing separate whose bolls contain fibrous material towns have expanded so as to coalesce. used to make cotton cloth; seeds are crushed for oil, cooking fat, margarine convection Transmission of heat through liquids and gases by move• and cattle food. ments oftheir particles .• cove (I) small creek or inlet or rounded convectional rain Caused by mois• bay; (i/) steep-walled, semi-circular ture-laden air being warmed, rising, opening at head ofvalley. expanding and cooling adiabatically to its dew-point. cover crop Quick-maturing crop ploughed In as fertilizer or grown as coombe see combe protective mat between main crops to reduce soil erosion. copra Dried flesh of coconut, source of coconut oil, shredded coconut and crag and tail Characteristic of glaciat• cattle food. ed area, where mass of resistant rock in path ofadvancing ice has been attacked coral Hard, calcareous substance on upstream side, to produce crag, but formed from skeletons of some marine has I?rotected land on downstream side, polyps living in warm inter-tropical leaVing a gentler slope or tail, to lee• seas. ward. 635 C crater Geographical Terms crater (I) rounded, funnel-shaped cuesta Ridge with steep scarp slope hollow at summit of volcano; (il) and gentle dip slope, see escarpment. depression caused by impact of meteorite. comec Unit for measuring river dis• cha~e; number of cu. m. per second creep Slow downward movement of passmg particular point, approx. 19m. soil under influence ofgravity, lubricat• gallons per day. ed by running water. comula-nimbus Cumulus cloud Creole Person born in w Indies but developing to immense vertical height not of aboriginal descent; initially with towering summits, sometimes implying no question of colour, now s{>reading into anvil shape, and ass0- mainly descnbes people of mixed ciated with thunderstorms, hail and blood. heavy rain. crevasse Deep fissure in glacier, with cumulus Convectional cloud, growing transverse trend where slope increases vertically from flat base to produce or longitudinal where glacier spreads white domed summits, often reaching out as valley widens. 25,000 ft. (7,620 metres). croft Small farm-holding in Scotland, reckoned to supply all family's needs in cutoff Channel cut by river across food, fuel and clothing. neck ofland at acute meander, leaving oxbow. cromlech Celtic fonn of megalithic burial chamber, with large flat stone cwm see combe resting on stone uprights. cyclone Tropical low pressure system, crust Upper (sial) and lower (sima) Similar to depression of temperate lat. layers ofearth, fonning outennost shell but smaller in extent and more violent or lithosphere, about 10-30 m. (16-48 in effect, marked by very high winds, km.) thick. torrential rain and thunder.

D

dale Wide, open valley, particularly ofriver where deposition ofpart ofriver in N England. load exceeds rate of removal by tidal or other currents; covered by network of Dalmatian coast see concordant coast branching channels or distributaries. Date Line see International Date Line demersal fish Species living near bottom of shallow seas, caught by datum Zero from which altitudes and trawling. depths are detennined; see ordnance datum. demography Branch ofanthropology, dealing with statistics of births, deaths, deflation Removal of fine deposits of etc. dust and sand from earth's surface by wind. denudation Destructive process modifying surface of earth by all delta Alluvial tract fonning at mouth natural agencies. 636 Geographical Terms dustbowl D deposition The laying down of mater• dispersed settlement Scattered farms ial transported by all agencies; comple• and hamlets, with no concentration of mentary to denudation. population in village or larger settle• ment. depression (I) low-lying portion of earth's surface; (il) low-pressure system distributary Individual channel into in mid or high lat., formerly called which river may divide in delta, leading cyclone, now known as cyclonic to sea without rejoining main stream. depression or 'low'; has diameter of 300-2,000 m. (480-3,200 km.) with diurnal range Difference in 24 hour winds blowing round it anti-clockwise period between maximum and mini• in N hemisphere and clockwise in s. See mum value ofelement such as temp. fronts, occlusion. Doctor Popular name for Harmattan desert Area ofland with scanty vege• wind, West Africa. tation and low rainfall or low temp. Types of desert include (I) hot, Trade doldrums Equatorial belt oflow pres• Wind; (il) coastal, in lat. 15"-30·, with sure between two Trade Wind belts, cool offshore currents; (iiI) mid-Iat. of marked by light winds or calms, high continental interiors; (iv) polar. temp. and humidity. determinism Philosophy that man's dolichocephalic Long headed. Cepha• actions are essentially determined by licIndex < 75. physical condition ofhis environment. doline Shallow, saucer-shaped detritus Material shed from rock sur• depression in karst landscape. faces by disintegration. drainage (I) act of removing water dew Condensed droplets from atmos• from poorly-drained area; (il) discharge pheric vapour on surfaces cooled by of water from any area through natural nocturnal radiation. stream systems. dew-point Lowest temp, to which air drift (I) superficial deposits, usually can be cooled without causing conden• glacial; (il) horizontal passage in mine sation. following vein of ore; (iiI) slow move• ment of surface ocean water under dew-pond Small hollow of special influence of prevailing winds; (iv) sur• construction to collect water from face movement of loose material by atmospheric condensation. wind, such as snow. dike seedyke drumlin Low, oval-shaped hill of dip-slope Gentle slope ofcuesta. glacial origin, formed of boulder clay and elongated in direction ofice flow. discordant Cutting across general lines ofstructure ofland. dry farming Agric. in semi-arid parts, without irrigation, where moisture is discordant coast Running transverse conserved by mulching, maintenance to general grain of relief, giving dissect• of fme tilth and croppmg in alternate ed coastline. years so as to increase total water. dispersed city Group oflarge towns of dry valley Valley, usually in chalk or similar size found in close proximity to limestone, with no permanent flowing each other, and tending to function m a stream. complementary manner. Although the total population contained in its area is dunes Low ridges of wind-blown sufficient to support one large centre sand, found in deserts and along low• offering a full range of highest order lying coasts above high water mark. goods and services, such a centre does not exist and these functions are shared dust bowl Originally applied to parts between the constituent centres. ofsw and w U.S.A., but now refers to 637 D dust devil Geographical Terms any area where soil erosion occurs as arid areas causing dense clouds of dust result ofover-grazing or over-cropping. to rise to considerable heights. dust devil Short-lived swirling wind drke (I) mass of intrusive rock run• nm~ discordantly across landscape; (i/) resulting from convection over sandy dramage ditch or watercourse; (iiI) arti• area, lifting dust and sand but not to any ficial embankment preventing flooding great height. of low ~ound; (iv) embankment in flood plam ofriver parallel to its course; dust storm Caused by winds in semi- (v) man-made defensive earthwork.

E

0 eagre see bore equator Great circle, lat. 0 , midway between Poles, in plane perpendicular earth pillar Column of soft earth, to earth's axis. often 20-30 ft. (6-9 metres) high, pro• tected by capping of rock; product of equinox Period of year when day and sub-aerial erosion. night are of equal length all over world, occurring about March 21 and Sept. 23, earthquake Movement or tremor of when sun crosses equator. earth's crust causing series of shock waves to move outwards in all erg Arabic for sandy deserts ofSahara directions. with dunes and sand-sheets. eclipse Partial or total obscuring of erosion Wearing away of land sur• light of (I) moon, when earth comes faces by various natural agents, chiefly between it and sun; (i/) sun, when moon running water, ice, wind and waves but, comes between it and earth. unlike denudation, excludes weather• ing. ecliptic Apparent movement of sun through sky during course of year; erratic block Piece of rock carried by plane of ecliptic is tilted at angle of glacier or ice-sheet and deposited some about 66lho to earth's axis. distance from parent outcrop when ice melted. entrepOt Centre or port to which goods in transit are sent for temporary escarpment (I) see cuesta; (il) term also storge before re-export. applied to any steep slope breaking general uniformity oflandscape. environmentalism Philoso{,hy that environmental factors determme man's esker Elongated ridge or mound actions see determinism. formed from glacial and sub-glacial sands and gravels, deposited by sub• environmental perception The en• glacial streams. vironment as perceived by individuals or groups rather than as it is in reality. esparto Grasses grown in N Africa and Iberian Peninsula, used in making epicentre Point on earth's surface paper, cordage, matting and sacks. vertically above origin of earthquake shock. estancia Spanish, large farm in 638 Geographical Terms fetch F Argentina used for extensive cattle and trees in Florida and along Gulf rearing. Coast ofU .S.A. estuary Mouth ofriver where channel exfoliation Alternate heating and broadens into V -shape and tidal move• cooling of rock surfaces causing peeling ments occur. offin scales. expanded town Town outside the etang French, shallow lake in sand• metropolitan area whose expansion has dune areas, formed by beach material been purposefully accelerated by thrown up by sea. Government agencies (e.g. by fmancial assistance towards development of Etesian wind Strong N to NW wind at industries, housing) to curtail further intervals in summer in E Mediterra• expansion of metropolitan regions and nean. to alleviate over-crowding elsewhere (e.g. Basingstoke). eucalyptus Gum tree ofAustralia. extensive agriculture Method offarm• eustasy World-wide change of sea ing based on large farm units with little level, caused by Ice Age, movement of labour but with a high degree of ocean floors or sedimentation of ocean mechanization (e.g. Canadian Wheat• basins. lands). evaporation Physical process by extrusive rocks Igneous rocks reach• which substance changes from liquid to ing the surface as lava, flowing from vapour state, caused mainly by heat. fissures and then solidifying. everglades Marshy area with grasses eyot seeait

F

Fahrenheit Graduated scale of temp. fauna Animal life ofregion or geologi• where 320 is melting point of ice and cal period. 2120 boiling point of water, after A. D. Fahrenheit (1686-1736). fell Norwegian, bare, uncultivated hill or mountain in N England. fall-line Narrow belt, marked by line ofwaterfalls, where rivers descend from fen Water-logged land of reed and plateau edge to lowland, as in Fall Line peat, providing excellent agric. land mSEU.S.A. when drained, as in Fens OfE Anglia. fan Fine wind- or water-borne material, deposited in shape offan with Ferrel's Law Postulated by American low angle ofslope. scientist W. Ferrel in 1856, stating that bodies in free motion are deflected to fathom Nautical measurement of right in N hemisphere and to left in S, depth, equal to 6 ft. (1.9 metres); 1,000 (Coriolis Force) as result of earth's fathoms equal I nautical m. rotation. fault Fracture or rupture in earth's fetch Extent ofopen water over which crust, where movement has displaced wind blows, instrumental in determin• strata on each side. ing height and force ofwaves.

639 F [lard Geographical Terms flard Swedish fjard; large open area of FOhn German, warm, dry, adiabatic water, surrounded by islands, occurring wind blowing down lee slopes of in rocky, glaciated lowlands. mountains, especially in Alps, when depression to N draws in air from fiord Norwegian fjord; drowned Mediterranean. glacial valley, being long and narrow, steep-sided and deep, apart from thres• fold Bending of strata by compressive hold near mouth. forces in earth's crust, usually along lines ofweakness. liro German, snow accumulating in layers above glacier, partially compact• force Waterfall in N England. ed by freeze and thaw action. foreshore Part of shore lying between flrth Estuary or strait or arm of sea high and low-water line of mean spring (Scotland). tides. fjard see liard fosse (I) ditch or trench round anc. earthwork; (iI) waterfall in N England, fjord see liord see force; (iiI) in U.S.A., depression bet• ween valley-glacier side and valley flash-flood Sudden, short-lived wall. torrent in semi-arid areas after inten• sive rainfall, carrying large load, free port Port where goods can be product ofdesert weathering. unloaded, held in bond and re-exported without customs payments. flax Annual plant, yielding fibre for linen and seed for linseed oil, paint and Friagem Strong, cold winter wind on cattle-cake. campos ofBrazii and E Bolivia. fleet (I) small inlet or lagoon ofbrack• fringing reef Uneven coral platform ish water behind coastline, separated attached to coast, with or without from it by sand or shingle bank; (il) lagoon intervening, sloping steeply small creek or inlet. seawards. flood-plain Hoor of river valley over front Plane of separation between which alluvium is spread in flood time. warm and cold air masses. flora Plant life of region or geological frost (I) condition of air whose temp. period. is at or below freezing point ofwater; (i/) minute crystals of ice formed from flume (I) narrow ravine or gorge; (i/) water vapour when dewpoint is below artificial channel to provide water for freezing. power or to float logs. frost-pocket Low-lying area into fluvio-glacial Effects of melt-water which cold air drains by gravity to stream issuing from glacier-front or ice• produce freezing conditions when air sheet margin. on higher slopes is still above freezing; fruit-growers avoid such areas. fog Thick mist or haze in surface layer of atmosphere resulting from conden• fumarole Italian, small vent in sation of moisture with smoke and dust surface, pouring forth steam, hydro• particles in suspension; visibility less chloric acid, sulphur dioxide and other thanO.6m.(1 km.). gases.

640 G

gap see water gap, wind gap glacio-fluvial see Fluvio-glacial garrigue French, stunted evergreen glen Long valley, steep-sided and flat• scrub separated by bare limestone rock, bottomed (Scotland). found in s France, Corsica, Sardinia and Malta. gneiss Coarse-grained crystalline rock. geest German, area of coarse sand, gravel and heath vegetation in N Ger• Gondwanaland Hypothetic single many, Netherlands, Denmark and land-mass in anc. geological times, Poland. from which present s continents were formed as outcome ofcontinental drift. geo Norse gya, a creek; long, narrow, steep-sided inlet in cliff, derives origin• gorge Steep-sided valley, deep in rela• ally from cave enlarged by marine tion to width. erosion. geosyncline Linear depression in graben German, narrow fault-trough. earth's crust, ofconsiderable width and several m. deep, product of slow, con• Gran Chaco 'Great hunting ground', tinuous down-warping of ocean floor, forest or savanna region on borders of accompanied by sedimentation of Bolivia and Paraguay. material worn away from neighbouring f!I"lISslands Region where rainfall is land masses. msuffIcient for tree growth but is less scanty and irregular than in desert geyser Icelandic geysir, '~sher' or regions; major types include tropical or 'roarer'; hot spring ejectm~ super heated steam and hot water at mtervals savanna, temperate or steppe or prairie from volcanic sources. or pampas or veld, and mountain. ghat Indian, (I) river landing place; (i/) graticule Network of parallels and mountain pass; (iii) range ofmountains. meridians drawn on map or globe. ghaut see ghat great circle Circle on earth's surface whose plane passes through centre of ghee Hindu, butter made from buffalo earth; arc of great circle provides milk. shortest distance between any two points on earth's surface. ghetto Part of urban area inhabited almost exclusively by one race or type Green Belt Planned and maintained ofpeople. wne of open country round town or separating adjacent towns, free from Ghibli Arabic, hot, dry, s sirocco building or industrial development. wind ofLibya or Tunisia. Greenwich Mean Time Standard time Gibli seeGhibli for British Isles and parts of w Europe, see British Summer Time glacier French, mass of compacted snow and ice, accumulated on ground Greenwich Meridian Prime meri• above snow-line, moving downstream dian, passing through old Royal Obser• under gravity and exerting great erosive vatory at Greenwich; long. ofa place is force. expressed E or w ofthis, up to 180·. 641 G Gregale Geographical Terms Gregale N cool-season winds ofCent• plant whose pods ripen below ground; ral Mediterranean. when crushed, these produce oil for margarine, cooking fat, other foodstuffs greywether Scattered blocks of sand• and animal fodder. stone found over parts of chalklands of S England, so-called because of their ground water Body ofwater contained resemblance to sheep. In soil, subsoil and underlying rocks above impermeable layer. grid Network of sq. covering map series, based on lines drawn parallel gryke see grike and at right angles to central axIS, from which position of any point can be guano Accumulation of bird drop• stated; see National Grid pin~ forming valuable phosphatic fertilizer. grike Deep groove, bounded by ridges or clints in area of karst landscape, Gulf Stream Warm ocean current where limestone pavement results from flowing NE from Gulf of Mexico solution. towards Europe; see North Atlantic Drift ground moraine Debris carried at base of glacier or ice-sheet and deposited as RUlley erosion Accelerated erosion of ice melts. rand by concentrated surface run-off after sudden rainstorm; major cause of groundnut Tropical or sub-tropical soil erosion.

H

haar Summer sea-fog blowing onto E Manse Towns Political and commer• coast ofN England and Scotland. cialleague ofGermanic towns. hachure Lines of shading on relief Harmattan Hot, dry NE wind, blowing map to show differences in slope. off Sahara to w African coast in Dec.-Feb. providing relief from humi• hacienda Spanish, large a~c. estate, dity on coastal plain, but dry and dusty ranch or plantation, chiefly in s inland. America. haze Obscurity in atmosphere caused haff German, shallow, fresh-water by condensation of moisture on dust or lagoon, formed by growth of spit or salt or smoke particles or by heat refrac• nehrung across river mouth, notably in tion; visibility from I to 2 m. (1.5-3 Baltic. km.). hamada Arabic, rock desert of N headland Steep crag or cliff projecting Africa, Australia, Gobi. into sea. hanging valley Trib. entering main head of navigation Farthest point up• valley from considerable height, often river reached by trading vessels. with waterfalls; common in glaciated regions, where main valley has been Heaviside Layer Section of iono• over-deepened by glacier. sphere, 60-75 m. (96-120 km.) high, 642 Geographical Terms ice-cap I highly ionized and able to reflect long horse latitudes Sub-tropical high radio-waves back to earth. pressure belts of atmosphere, over oceans in lat. 30-35°, giving calm con• Helm Strong, cold E to NE wind blow• ditions and stable weather. ing off Pennines in N England. horst German, block of earth's crust hemp Fibre-producing plant, for (I) left standing after adjacent areas have twine, string, rope, matting etc. whose sunk by faulting; (il) uplifted between flowers and leaves produce drugs and faults. whose seeds yield oil. Hevea Brasiliensis Tree, native to hot springs seethermalsprings equatorial forests of Brazil, now grown in plantations in Malaysia or E Indies; Humboldt Current Cool ocean cur• source of commercial rubber; see rent flowing N along w coast of s latex America.

hinterland (I) 'back country' of early humidity State of atmosphere with coastal settlement; (il) area served by regard to water vapour it contains; see port, taking its imports and supplying it absolute humidity, relative humidity with its exports. hoar-frost Thin deposit of ice crystals humus Vegetable mould derived from on surface cooled below freezing point decomposing organic matter in soil. by radiation. hurricane (I) tropical revolving storm hook Sand bar ending in recurved with violent cyclonic winds in Carib• spit. bean Sea and off Queensland coast; (b) wind ofForce 12 on Beaufort Scale. horizon (I) visible horizon, boundary of earth's surface, as viewed from point hydro-eiectric power Electrical where sky appears to meet earth or sea; energy obtained by harnessing water• (il) true horizon, great circle whose falls or by damming river. plane passes through centre of earth and is parallel to visible horizon; (iiI) geological horizon, plane of stratified hydrological cycle Endless inter• surface or bed; (ic) soil horizon, main change of water between sea, air and layer or zone within soil profile. land, by evaporation, condensation, precipitation, etc. hom German, pyramid peak formed by development of back-to-back hygrometer Instrument for measuring cirques on mountainside. relative humidity ofair.

I

iceberg Large mass of floating ice, those in N hemisphere mainly irrigular broken off from edge of ice-sheet or in shape, those in s are tabular. tongue of tidal glacier and floating under influence of currents and winds; ice-cap Permanent mass of ice, 643 I icefall Geographical Terms smaller than ice-sheet, covering ing spurs in upland valley where river plateaus and high-lat. islands. follows winding course. icefall Heavily crevassed part of International Date Line Imaginary glacier where it meets change ofslope of line closely following 180· meridian, valley floor. where date changes by one day as it is crossed, to make up for cumulative ice-field Large, continuous area of effect of time zone changes; westbound pack-ice. travellers lose a day, eastbound ones gain a day. ice-sheet Mass of permanent ice and snow of great thickness, covering large intrusive rocks (I) those resulting from areas, as in Antarctica and Greenland; injection of magma into existing rocks; also refers to much greater areas in past (ii) particular type of igneous rock thus glacial eras. formed; see batholith, dyke, laccolith, sill. ideographic Studying individual cases and situations; opposite nomothetic. ionosphere Part of atmosphere above stratosphere, marked by distinctive igneous rock One formed by solidifi• layers reflecting electromagnetic waves; cation of molten rock or magma; see see Appleton Layer, Heaviside Layer extrusive and intrusive rocks irrigation Artificial application of water to land in arid regions to promote incised meander Pattern of meander maintained at progressively lower plant growth. levels by downcutting of river resulting island Piece of land, smaller than from rejuvenation. continent, surrounded by water. industrial inertia Condition whereby isobar Line on map joining points of industries, once established at a central equal atmospheric pressure; figures location, remain there due to existing reduced to sea-level for comparison. investment in capital, services, etc., even though some other location may isobath Line on map or chart joining ultimately appear more attractive in submarine points ofequal depth. terms ofcertain other criteria. isochrone Line on a map joinin~ all infield Farmland immediately sur• places of equal travel time from a given rounding a farm or hamlet farmed point. intensively. outfield. See also isohyet Line on map joining points input-output analysis Analysis of the having same rainfall over given period. flows of goods or services, usually in isoneph Line on map joining points terms of their cash value, which take having same amount ofcloudiness. place between all sectors of a regional economy. Often used to predict the isopleth Line on map joining points overall effect of changes in the regional having same value for particular economy. phenomena, see isobar, etc. inselberg German, mountain rising isostasy State of equilibrium in sur• abruptly from uniformly level surface, face crust of earth, whereby equal mass esp. in semi-arid and arid climates. underlies equal surface area. isotherm Line on map or chart join• insolation Amount of radiant solar ing points having same air or sea temp. energy reaching earth's surface. isotropic surface A theoretical area of interOuve Area of land between two broad, featureless plain on which trans• rivers. port is equally available in all direc• tions, population is uniformly distri• interlocking spurs Alternate project- buted and has uniform tastes and 644 Geographical Terms key K preferences. Used as a basic assumption isthmus Narrow neck ofland between m many locational theories (such as two seas or joining peninsula to main• central place theory). land.

J

jarrah Eucalyptus tree ofsw Austra• joran Cold, dry wind blowing at night lia, resembling mahogany and very from Jura Mountains to L. Geneva. durable in water. jungle Wild, uncultivated land; now jet stream Hi~ altitude air move• widely used to refer to tropical forest ment ofstrong wmds in narrow belt. with dense undergrowth. joint Plane of division in rock mass, jute Fibre from bark ofplant grown in usually transverse to bedding-plane, Bengal and used in making sacks, caused by tension or compression. carpets, etc.

K

kame Hummocky deposits of sand kars; proper name for rugged limestone and gravel laid down by melt-water plateau of NW Yugoslavia, but used along edge of ice-sheet, usually parallel generally to describe areas of carboni• to ice-front. ferous lImestone with typical pheno• mena of limestone pavements, sink kaolin Hydrated silicate of alumina holes, underground drainage, caverns, derived mamly from decomposed gran• gorges, etc. ites; known as china clay, used in manu. ofpottery, china and paper. katabatic wind Cold wind, blowing downhill, usually at night, caused by Karaburan Hot NE wind in Central gravity flow of dense air from upper Asia, sweeping up clouds of sand, the slopes, chilled by radiation. lighter particles being carried great dis• tances and ultimately deposited as kay seecay loess. kettle hole Circular hollow in glacial karri w Australian eucalyptus, pro• drift, caused by melting oflarge block of viding very hard timber. ice separated from glacier. karst Italian, carso, Serbo-Croat, key seecay 645 K Khamsin Geographical Terms Khamsin Arabic, hot, dry, sirocco kopje Afrikaans, prominent, small, wind ofEgypt and SE Mediterranean. isolated hill in s Africa. kloof Afrikaans, deep, narrow ravine kraal Afrikaans, village, cattle-pen or or mountain pass in S Africa. enclosure in Africa, surrounded by thorn fence. knot (I) nautical measurement of speed, 1 nautical m. per hour; (il) kyle Gaelic, channel or sound or junction of two or more ridges in fold strait between mainland and island or mountain system. between two islands.

L

labour coefficient Ratio of labour with joints widened by solution to form cost to all other inputs or outputs of c1ints and grikes. productive process. lapse-rate Rate of temp. decrease in laccolith Intrusive mass of magma atmosphere with increase in height. forced up a pipe and spreading laterally Environmental lapse-rate approx. in lenticular form, causing arching of -21°F. (6"e.) per 3,250 ft. (1,000 the overlying strata. metres). lacustrine Pertaining to a lake. laterite Red soil consisting of decom• posed and weathered igneous rocks, ladang Slash and bum shifting agric. found as soil horizon in tropical practised in SE Asia. climates. lagoon (I) sheet ofsalt water separated latex Milky fluid of rubber tree from open sea by sand or single bank; (Hevea Brasiliensis), extracted by tap• (il) sheet ofwater between off-shore reef ping bark to provide raw matenal for and mainland; (iiI) sheet ofwater within manu. natural rubber. an atoll. latitude Angular distance N or of lake Extensive sheet ofwater enclosed s by land, occupying hollow in earth's Equator ofany poiht along a meridian. surface. lava Molten rock or magma extruded land and sea breezes Resulting from onto surface of earth and subsequently unequal heating of land and water solidifYing. masses. By day, with land heated more rapidly, sea-breeze blows on-shore; by leaching Removal of soluble salts night, land-breeze blows off-shore as from upper layers of soil by water per• land loses heat by radiation. colation in humid climates. landes French, wastelands; proper least cost location Location at which name of lowlands of sand-dunes and costs of production of any economic lagoons in sw France. activity are at a minimum compared with costs at all other possible lapies French, bare limestone surface locations. 646 Geographical Terms lynchet L Levanter Spanish, mild and humid E zone between high and low water wind affecting SE Spain, Balearics and marks. Straits of Gibraltar when depressions form in w Mediterranean. llanos Spanish, tropical grasslands or savanna ofGuiana Plateau, S America. Leveche Spanish, hot, dry S wind blowing from Morocco to Spain when load Material transported by natural E-moving depressions enter Mediter• agent as part ofdenudation process, but ranean. applied mostly to river. levee (I) broad low ridge of alluvium loam Soil consisting of a friable, built up by river in flood to form bank; permeable mixture of clay, sand and (il) artificial embankment along river to humus. check flooding. locational analysis Analysis of the location of human and economic ley Area of cultivated grass or clover activity. in an arable rotation. location theory Attempt to isolate and liana Climbing plant, rooted in analyse theoretically those factors ground, usually in tropical forests. which influence the location of econo• micactivity. libeccio Italian, strong w wind of Corsica, most frequent in summer. loch Scottish, lake or long narrow arm ofsea. light-year Distance light travels in I year at rate of 186,326 m. loess German, fme-grained, friable, (298,123 km.) per second, i.e. porous dust, usually removed from arid approximately 5,878,310,400,000 m. regions by wind and deposited fmally in (9,405,296,000,000 km.). broad sheets, as in Asia, Central Europe and N America. lignite Low-grade type of coal, longitude Angular distance of a place midway between peat and sub• E orw ofprime meridian. bituminous coal in carbon content, mainly used in thermal-electric genera• longitudinal coast see concordant tors. coast limestone pavement see clint longshore drift Drift of material along a beach as result of waves breaking at limon French, superfIcial deposit of angie to shore. fme material, often wind-blown and resembling loess, found in Belgium and lough (Irish), see loch the Paris Basin. lucerne see alfalfa lithosphere Solid crust ofearth. lyncl!et Man-made terrace on hill• side, parallel to contours, part of anc. littoral (I) relating to sea-shore; (i/) cultivation practice.

647 M

maelstrom Dutch (I) whirlpool; (ii) marine terrace Shoreline above pre• powerful eddy in tidal current in sent sea-level. restricted channel, as Maelstrom in Lofoten Islands, Norway. marketing principle Theoretical spatial arrangement ofsettlements, sug• Maestrale (Italian) see Mistral gested by W. Christaller (1933), where• by the supply of goods from central magma Molten material under earth's places to other settlements involves the crust, from which igneous rocks are least transport cost. formed. market location Location chosen by magnetic pole Two extremities of firm, industry etc. which is nearer to its earth's magnetic fiC;ld, lying in polar major market(s) than to its raw mater• regions, indicated by free-swinging ials, suppliers, etc. magnetic needle in compass. marl (I) mixture of clay and calcium• maize Cereal crop, originating in New carbonate; (i/) geological name of parti• World, grown in sub-tropical and warm cular types o(rock. temperate climates, mainly used to fatten livestock; known as corn in massif French, (I) compact mount• U.SA ainous area with relatively uniform characteristics and clearly defmed mar• mallee Dense scrubby growth of gins; (i/) mountain group, as Mont dwarf eucalyptus in SE and sw Aust• Blanc massif. ralia. mangrove Tree with short trunk and mate tea Made from dried leaves of S maze of aerial roots, forming almost American evergreen shrub. impenetrable obstacle. Mangrove swamps are found mainly in tropical meander Curve in course of river and sub-tropical regions, close to river moving slowly across flat country. -mouths. Mediterranean climate Warm tem• manila hemp Plant grown largely in perate climate ofw margins of contin• Philippines for its fibre, used in making ents in lat. 30-40°, with hot, dry, sunny rope and fabrics. summers and mild, moist winters. manioc see cassava megalith Large stone or stones, erected singly or in circles as monu• mantle (I) layer ofi~eous rock, some ments, mainly Neolithic. 1,800 m. (2,880 km.) thick, lying bet• ween crust and core ofearth; (i/) surface megalopolis Very large urbanized accumulation of soil and weathered metropolitan area. Orisinally applied rock, or regolith. to the Boston-Washmgton region maquis French, low scrub ofMediter• U.S.A. see also Boswash. ranean area, characterized by dense xerophytic vegetation, found mainly in Melanesia Group of islands in w S France, Italy (macchia) and Corsica. Pacific. marin Moist, warm SE wind over coast melt-water Water formed from melt• ofs France in spring and autumn when ing snow or ice, as in melt-water stream depressions enter Gulfof Lyons. ofglacier. 648 Geographical Terms moraine M menhir Single upright stone of Neo• where soil is too poor for wheat and lithic origin, markingburial place. rainfall insufficient for rice, as in Africa and India. Mercator projection Cylindrical pro• jection used by German Mercator for millibar One-thousandth ofa bar. world map of 1569. Meridians oflong. and parallels of lat. are all shown as mirage Optical illusion caused by straight lines, causing distortion of refraction of light, particularly in hot shape in high lat. deserts. mere Small lake usually circular, misfit river One too small for present common in Cheshire where removal of valley, either as result of river capture, underground salt deposits causes subsi• change ofclimate, or glaciation. dence. mist Obscuring of ground layers of meridian Line of long. part of Great atmosphere by condensation of water Circle. Prime Meridian IS Greenwich particles, reducing visibility to bet• Meridian (0°). ween 0.6 and I.2m.(1 and 2 km.).

merino Sheep with long-stapled, Mistral French, strong, cold, dry N high-quality fleece, native to Spain and wind blowing from Central France to N Africa, but now abundant in s Africa Mediterranean, especially down lower and Australia. Rhone Valley. mesa Spanish, small tableland MohoroviCic Discontinuity Discon• capped with resistant rock, denuded tinuity between earth's crust and remnant offormer plateau. mantle, greatly affecting speed of earth• quake waves. Lies a{'prox. 20 m. (32 meseta Extensive inland plateau km.) deep under contments, but 4-6 m. forming about three-quarters ofSpain. (6-10 km.) under oceans. mesosphere (I) layer of atmosphere Mollweide projection Equal-area pro• between stratosphere and ionosphere; jection with central meridian as a (il) obsolete name for mantle. straight line half scale-length of Equator. metamorphism Alteration in rock structure resulting from increase in heat monadnock Residual mountain rising or pressure or both combined. above peneplain; named after Mount Monadnock, New Hampshire, U.S.A. meteor Body of matter travelling through space, being heated by friction monsoon From Arabic word for with atmosphere, hence 'shooting season, referring particularly to reversal stars'. of pressure systems and winds over Arabian Sea and neighbouring land meteorite Body of stone and iron masses. Now applied generally over which has survived passage through Asia, and also used to describe 'the atmosphere to land on earth. rains' ofthe monsoon season. meteorology Scientific study of montana Spanish, forested slopes OfE atmosphere. Andes in equatorial lat. Micronesia Groups ofPacific Islands, moon Sole natural satellite of earth, mainly volcanic, between Equator and revolving round it in one sidereal 400 N and 130° and 1800 E. month of approx. 271f4 days. Contri• butes to gravitational forces responsible midnight sun Phenomenon of polar for earth's tides. lat. observed about mid-summer, when sun does not set in 24 hour period. moraine French, (I) masses of boulder-clay and stones carried and millet Species ofgrain grown in places deposited by glacier; (il) arrangement of 649 M mortlake Geographical Terms this material to form particular land• mud-volcano Ejection of hot water form. and mud from volcanic vent, producing short-lived cone, as in Sicily, Iceland mortlake see ox-bow lake and New Zealand. mountain Landform of marked eleva• tion, bounded by steep slopes and rising mulga Dense thicket of acacia-scrub to prominent ridges or peaks. on margins of central desert of Aust• ralia. mud-flat Area of fine silt, usually covered and uncovered by tides, found muskeg Water-logged land of N and in sheltered estuaries or behind bars NW Canada, with characteristic vegeta• and spits. tion cover ofsphagnum moss.

N

nappe French, over-thrust mass of nehrung German, spit enclosing or rock in near-horizontal fold. almost enclosing a haff.

National Grid Rectangular system of Nevados Cold wind blowing down lines printed on Ordnance Survey valley from Andes to high valleys of maps, providing method of precise Ecuador. reference to points on it by means of numbered co-ordinates. neve French, accumulation area of firn. national park Area set aside for pre• servation of scenery, vegetation, wild Newlyn see Ordnance Datum life and historic objects, for scientific purposes and for general public. new town Town created and deve• loped as result of deliberate govern• ment planning to relieve over-crowding natural gas Free hydrocarbons in and population pressure in large cities gaseous state, usually associated with crude mineral oils. (e.g. Crawley, Skelmersdale). nife Mass of nickel-iron believed to natural region Region defmed in comprise core ofearth. terms of physical characteristics (relief, climate, vegetation, etc.). nimbo-stratus Low thick cloud, dark grey, from which continuous rain falls. nautical mile Unit of distance used in navigation, equal to 6,080 ft. (1,853 nimbus General term for clouds from metres) or length of 1 minute of arc on which rain is falling. Great Circle. nivation Rotting or disintegration of DaZe Promontory or headland. rocks beneath and round margins of patch of snow by chemical weathering neap tides Tides of low amplitude, and alternate freeze-thaw action. about time of first and last quarters of moon. nodal point (settlement) see node 650 Geographical Terms Ordnance Datum 0 node Settlement upon which sur• Norther Cold dry wind over N Ameri• rounding settlements are dependent for can continent. goods, services, etc. or upon which lines ofcommunication converge. Nor'-Wester Fohn wind in s Island of New Zealand. nomad Member of social group con• tinually changing habitation to find nucleated settlement Locational pat• food for human and animal needs. tern of rural settlement where houses and farmsteads are clustered together in nomothetic Studying generalities hamlets or villages; opposite dispersed rather than individual cases, so as to settlement. develop laws, principles, etc. opposite nuee anlente French, mass of hot gas, ideographic. superheated steam and incandescent volcanic dust, producing glowing Norte (I) cold dry wind of Central avalanche down flank of volcanic America; (il) cold winter wind of E mountain. Spain. nullah Indian, normally dry water• North Atlantic Drift Movement of course becoming temporary stream surface water of N Atlantic E from after heavy rains. Grand Banks, Newfoundland. nunatak Eskimo, prominent rock• North East Trades Trade winds ofN peak projecting above surface of ice• hemisphere. sheet in Greenland and Antarctica. o

oasis Area in desert made fertile by oceanic islands Those of volcanic or presence of water sufficient for per• coral formation unconnected with any manent plant growth and human settle• continent. ment. oceanography Study of oceans, occlusion Overtaking of one front by including nature of water, its move• another in atmospheric depression. See ments, temp. and depth, as well as its cold front, warm front. flora and fauna. ocean Great body of sea-water sur• odometer Wheel used by surveyors to rounding land-masses and covering record distance traversed. over 70% ofearth's surface. ofI-shore bar Bar formed off coast of low-lying mainland. ocean currents Movements of surface water of the oceans, mainly clockwise onion-weathering . see exfoliation in N hemisphere and anticlockwise in s. They are labelled warm or cool accord• opencast mining Form of excavation ing to their temp. relative to the waters where mineral deposits lie near surface. to which they flow. Ordnance Datum Mean sea-level Oceania Islands of Pacific and seas calculated from hourly tidal observa• surrounding them. tions at Newlyn, Cornwall, from which 651 o ore Geographical Terms all heights on offIcial British maps are outlier (I) outcrop of rock whose derived. surface is completely surrounded by older rocks; (iz) small isolated hill lying ore Mineral containing one or more beyond main scarp and formed of same metals in suffIcient quantity to warrant material. mining. outport Port near mouth of estuary, orogenesis Phase of mountain build• affording deeper water and closer prox• ing, when rock material is compressed, imity to open sea than previous river forming folds. port. orography Description or depiction outwash plain Alluvial plain formed ofrelief. by melt-water stream from glacier. orrery Working model of sun, moon, earth and planets to show relative overspill Population from urban area movementsofthese bodies. moved to new settlement area because of overcrowding, slum clearance and outcrop Portion of rock stratum pro• population pressure. jecting above earth's surface. ox-bow lake Surviving portion of outfield Land beyond infIeld, normal• former meander; also called cut-off or ly extensive in use esp. in Saxon times: mortlake. p

Pacific coast see concordant coast name of mountain complex in Central Asia. packet port One from which regular specifIed daily sailings occur, carrying pampa Extensive monotonous plain cargo, mail and passengers. in Argentina-Uruguay; now used to describe temperate grasslands of s pack-ice Masses of ice floating on sea America. to form almost continuous cover with little open water. Pampero Dry, cold s to sw wind over Argentina-Uruguay. paddy Rice, either whole plant or grain in outer husk. Papagayo Spanish, dry, cold NE wind paddy field Flooded rice fIeld. affecting Mexican coasts. palaeomagnetism Study of past 'parallel roads' Series of wave-cut ter• magnetism of rocks, thus of earth's races on valley sides thought to mark magnetic fIeld, enabling geologists to former glacial lake levels. gauge amount of movement of contin• ents in past. paramo Spanish, high, bleak plateau ofAndes between puna and snowline. pamir (i) poor grassland of high plateau in Central Asia; (il) proper parish (I) ecclesiastical unit in care of 652 Geographical Terms polders P single priest; (il) smallest local govt. piedmont glacier Mass of ice where sub-division in Britain. several glaciers converge at base of mountain. pass Color gap through mountain range. pike Mountain peak. paternoster lakes Series of rockbasin pitch (I) inclination of axis offold; (il) lakes in former glacial valley. resinous substance formed in distilla• tion ofcoal tar. peat Partially decomposed vegetation accumulated under waterlogged condi• plain Extensive area ofrelatively level tions and used as fuel or for horti• country at low altitude. cultural purposes. planetary winds General atmospheric peda)fer Soil in humid climates where circulation producing series oflat. wind leaching has removed calcium com• pounds, leaving aluminium and iron. belts. pediment Large, gently sloping rock• p~on Minute floating or drifting platform at base of mountain slope in orgamsms of plant and animal life arid or semi-arid region. found in oceans, lakes and ponds. pedocal Soil in dry climate where plantation (I) estate in tropical regions, leaching has not removed calcium usually employing scientific methods compounds. and providing paid labour to produce cash crops for temperate regions; (il) pelagic Belonging to open sea, bet• areas of trees planted for commercial ween littoral and abyssal regions. purposes. peneplain LandscatJe evolved in last plateau French, large, elevated, rela• stage of cycle of erOSIOn, presenting an tively level area ofland, often bounded extensive, almost level plain. by steep slopes. peninsula Elongated projection of playa Spanish, basin of inland drain• land into sea or lake. age in arid regions, containing shallow, fluctuating lake, often saline. perched block Boulder carried by glacier and left balanced on rock sur• plucking Tearing action of glacier ice race afterice has melted. on rock surface. perigee Part of orbit of moon or plug Mass ofacid lava occupying vent planet which is closest to earth. of dormant or extinct volcano, usually exposed by denudation. permafrost Permanently frozen soil, sub-soil or bed-rock. plutonic rocks Igneous rocks cooled slowly deep in earth's crust, thus highly petroleum Mixture of hydro-carbons crystallized. found in earth in liquid, gaseous or solid form. podsol Russian, leached soil of cool, phosphates One of three main ele• humid climatic regions, where natural ments needed by plants and used as vegetation is coniferous or sandy heath. fertilizer. polar front Line of discontinuity, phylloxera Aphid, highly destructive marking meeting of polar and tropical ofgrape-vine. air masses. physical planning Planning of land polders Dutch, land near or below sea use (not to be confused with economic level and reclaimed by draining and planning). construction ofdykes. 653 P poles Geographical Terms poles (I) geographic; Nand s extremi• prevailing wind One which, in any ties of earth's axiS; (il) magnetic; poles given area, blows most frequently from ofearth's magnetic fIeld. a specifiC direction.

Polynesia Islands of PacifIc, approx. primary industry Activities involved lying between long. 120'w and 170'w. in collecting or winning natural resources. (e.g. mining, forestry, fIshing, Ponente Cool w wind on coast of agriculture). Corsica and Mediterranean. population lapse rate Rate at which Prime Meridian Generally accepted population density decreases within as Greenwich Meridian, from which all Increased distance from city, town, etc. longitude is measured E and w. population potential (I) Maximum prismatic compass Magnetic compass population that can be maintained at a with prism, allowing observer to read reasonable living standard in relation to bearing ofdistant object. resources available in given region. (il) Mathematical measure of total size of Probabilism Philosophy that there are population found within given distance several possible courses of action open ofa given location. to man within his environment of which some are more probable than portage Carrying a boat, with its con• others. tents, overland where a natural inter• rupation to navigation occurs. projection Geometrical method used by cartographers to represent the possibilism Philosophy that environ• curved earth's surface on a plane. ment offers a number of possible courses ofdevelopment which man can promontory Headland or cliff or crag take without serious consequences ensuing. projecting into sea. pot-hole Circular hole in rocks of Puna s American, high, bleak plateau river bed, caused by scouring action of ofs America with cover ofcoarse grass, water laden with pebbles; incorrectly at altitude of 12,000-16,000 ft. used for swallow-hole in limestone (3,658-4,877 metres). districts. pumice Surface scum ofvolcanic lava, prairie Extensive tract of temperate solidifIed to cellular rock. grassland in N America. Purga see Buran precipitation Deposition of atmos• phenc moisture on earth's surface, as puy French, small volcanic cone, dew, hail, sleet, snow. frequent in Auvergne, France. pressure see atmosphere pyramid peak see hom

654 Q

qllll:llt. P!,!rsian, underground channel quartz Crystalline silica or silicon fOflmgatIOn water. oxide, essential element ofgranite. quagmire Bog which shakes under quebracho Very hard wood found in weight ofman or beast. Gran Chaco ofArgentina or Paraguay.

R

radial drainage Pattem of streams open, unfenced area of grazing in High flowing outwards down sides ofuplifted Plains of U.S.A.; (iii) difference bet• dome or volcanic cone. ween highest and lowest values oftemp. or pressures, at given place, over given radiation Process by which body period of time; (iv) limit of habitat of emits radiant energy. plant or animal.

radiation ~0If Layers of fog forming rapid Area of broken, fast-flowing over low-lYIng areas during settled water in river, where slope of bed weather. increases or where gently dipping band ofhard rock crosses bed. radiosonde French, self-recording instrument carried to high altitudes by rattan Stem oflong, flexible climbing balloon, for transmitting meteorologi• palm used in Indonesia for ropes, nets, cal data back to earth. baskets, mats, etc. rain Condensed atmospheric mois• raw material Substance forming basis ture falling in separate drops. ofmanu. product. rain gauge Instrument consisting of reef (I) rock or coral formation of funnel leading to collecting vessel, care• considerable extent, at or just above fully sited clear of obstructions and with rim of funnel I ft. (30 cm.) low-water mark; (iI) vein of metal or above ground. ore. rain shadow Area of comparatively reg Arabic, extensive area of stony low rainfall on lee side of mountain desert in Sahara, from which flOe sand area. has been blown. raised beach Beach lifted by earth regIme French, (I) seasonal fluctua• movements to form narrow coastal tion in volume of river or glacier; (il) plam, often bounded by inland cliffs. seasonal pattern ofclimatic changes. range (l) line of mountains or hills; (il) regionalism Feeling of regional iden- 655 R regolith Geographical Terms tity or consciousness held by the rift valley Narrow trough between region's inhabitants. parallel faults or between series of step• faults. regolith Greek, regas, blanket; lithos, stone; layer of disintegrated rock frag• rime Accumulation of ice-crystals ments below top-soil but above bed• extending to windward of exposed rock. objects when frost, fog and wind occur simultaneously. rejuvenation Revival of erosive acti• vity, usually by river, resulting from fall rip Turbulence in sea or river where in sea-level or local uplift ofland. tidal streams meet or enter shallows. relative humidity Ratio of amount of river Large body of fresh water flow• water vapour present in air to amount ing with perceptible current in defmite needed for saturation at same temp. channel or course towards sea, lake, marsh,etc. relief Configuration ofearth's surface. river capture Cutting-off of up{>Cr remote sensing Gathering ofin forma• waters of one stream by neighbounng tion by aerial survey (aerial photo• river system with greater erosional graphs, satellite recording, etc.). power. resurgence Emergence of under- Roaring Forties Uninterrupted ground stream from cave. stretch of ocean S oflat. 40·s where N to w winds blow with great strength and rhyne or rhine Artificial drainage constancy. channel of Somerset Levels leading to larger channels or Drains. roche moutonnee French, rock-mass projecting from floor of glacial valley, ria Spanish, funnel-shaped indenta• smooth and rounded on upstream side, tion of coast caused by submerging of but rough and angular on downstream estuary or lower part of river valley, side. generally where rock-structure is at right angles to coast. rubber Substance, derived from latex, obtained by tapping bark of tree found rice Chief cereal crop of Monsoon originally in Amazon basin. and SE Asia, usually grown in flat, swampy fields. run-otr Surface discharge of water from rainfall or snowmelt. Richter scale Used for measuring earthquake magnitude from instru• rural-urban fringe Transitional zone mental records, running from 0 to over of edge of urban area where urban land 8·0. uses (mainly housing, cemeteries and industrial estates) mix with mainly Riding One of three former adminis• intensive rural land uses (e.g. market trative districts ofYorkshire. gardening).

656 s

saddle Broad, flat ridge between two savannaorsavannahorsavana Tropi• summits. cal grasslands, with scattered trees and bushes and tall grasses, resulting from saeter Norwegian, (I) farm on Norwe• marked precipitation regime. gian alp, used only in summer; (il) upland pasture in Norway. scar Rock-face of cliff, common in carboniferous limestone OfN England. ~brush Scrub vegetation in semi• and areas ofw OfN America. scarp Steep face or slope ofcuesta. salina Spanish, salt-encrusted surface schist Fine-grained metamorphic ofplaya. rock. salinity Percentage of dissolved salts scree Debris of rock, broken off by contained in sea water. frost-shattering and forming steep slope at base ofhill or mountain. saltation Transport of solid material in series ofhops (/) along bed of stream; scrub Vegetation of stunted trees, (il) by wind action in deserts. bushes and brushwood on poor soils in semi-arid regions. salt-flat Horizontal stretch of saIt• crust, formerly bed of salt-lake, tem• sea-breeze Diurnal movement of air, porarily orpermanentIy dried out. from sea to land, caused by differential heating. salting Marsh rich in salt, often suit• able for grazing. sea-level (I) level which surface of sea would assume if uninfluenced by tides Samoan or Samum or Simoon Per• or waves or swell; (i/) mean level bet• sian, warm, dry, descending wind in ween high and low tide at any place. Persia; see FOhn. seasons Divisions ofyear, determined sand Gritty particles, mainly of by earth's position relative to sun. quartz, fmer than gravel but coarser than silt. secondary industry Activities pro• cessing the products of primary indus• sand-dunes see dunes tries to manufactured goods. Santa Ana Spanish, hot, dry, dusty wind from N or NE, descending from sedentary agriculture Cultivation Sierra Nevada in California, doing practised by a settled farmer in one much damage to orchards by desic• place; opposite shifting agriculture. cation. sedimentary rocks Those formed of sanen Large sandstone block, found materials deposited in layers by water in S Britain, left after erosion of con• or wind, made up of remains of pre• tinuous bed ofwhich it formed part. existing rocks, and of vegetation and animal deposits. satellite town One associated with a larger town but separated from it by seif dunes Arabic, long dunes aligned stretch of open land and dependent on across desert in direction of prevailing it for goods and services (e.g. Slough, wind, forming steep-sided ridges England, is a satellite town ofLondon). extending many m. 657 S seismology Geographical Terms seismology Study and interpretation sila2e Layers of grass, clover or ofearthquakes. alfaffa, compressed in pit or silo, usually with addition of molasses and selvas Portuguese, rain-forest found used as fodder. in areas of heavy rainfall with high temp. all year. sill (l) near-horizontal sheet of igneous rock, formed from magma serac French, pillars of ice in icefall intruded between bedding-planes; (i/) where glacier reaches steep slope. submarine ridge separating adjacent ocean basins; (iii) rock ridge at entrance sericulture Culture ofsilk-worms. to fIord. serir Arabic, stony deserts ofEgypt or silt Loose sedimentary material, Libya, covered by sheets of angular coarser than clay and finer than sand, gravel. laid down in water. shadoof or shadouf or shaduf Arabic, sima Thick, heavier layers of earth's device for raising water from well. crust, below sial, composed largely of silica and magnesia and forming large Shamal Arabic, dry, dusty NW wind part ofocean floors. over plains ofIraq in summer. sink hole (I) solution hole or hollow or sheet flood Hood resulting from shaft in limestone or chalk country; (il) violent rainfall! where water pours hollow down which surface water dis• down slopes WIthout forming indivi• appears. dual channels. Sirocco Italian, s to SE wind blowing shield Large continental block from Sahara as hot, dry wind over N remaining relatively stable since early Africa coast, but reaching Malta, Sicily geological times. and S Italy as warm humid wind. shieling Summer pasture, often with sisal Tropical plant with long fleshy rough dwelling, in Scottish highlands. leaves, whose fibres are used in making twine. shifting cultivation Primitive method used by nomadic peoples in tropics, site Actual area occupied by town. whereby forest areas are cleared by burning, cultivated for a few years, then situation Location oftown in relation abandoned. to its surroundings. shire Large territorial division of skerry Low island, often forming Anglo-Saxon Britain, largely corres• series off-shore and parallel to coast, as ponding to county divisions introduced in Scandinavia. by Normans. slag see basic slag shoreline see coastline siump Mass-movement involving shott Arabic, shallow, brackish salt• shearing of rocks, usually causing land• lake in N Africa. slips where massive rocks overlie clays sial Outer and lighter shell of earth's or shales. crust, composed largely of silica and alumina. slurry How ofwet mud. sidereal time Time measured by smallholding Small unit of agric. apparent diurnal movement ofstars. land, intensively farmed by small• holder without paid labour, common sierra Spanish, high range of mount• in NW Europe. ains with serrated peaks, found mainly in Spain, N, Central and s America. smog Radiation fog over a town, 658 Geographical Terms stalactite S

where sulphur dioxide is present and South East Trades Trade winds of S soot acts as nuclei for condensation. hemisphere. snout Lower end of valley glacier, Southerly Burster Strong, dry wind with melt-water stream issuing from bringing unusually low temp. from cave. polar regions to S Australia. snow Precipitation as ice-crystals. soya bean Seeds rich in protein, from pods of leguminous plant, once indi• snow-line Lower limit of permanent genous to China, now common in snow-cover. U.S.A. and Europe. soil Topmost layer of earth, compris• spa (I) mineral spring; (il) town where ing disin.ted rock, decayed organic mineral springs used for medicinal matter, livmg organisms, water and air. purposes. soil erosion Removal ofsoil by action spate Sudden flood, usually in ofwind or water more rapidly than soil• mountainous areas, resulting from forming processes can replace it; heavy rainfall or sudden snow-melt. usually the result of over-cropping, over-grazing, dry farming or ploughing speleology Science of cave explora• up and down steep slopes. tion and study ofcaves. soke Former small administrative sphagnum Bog-moss of tundra region in Britain (Soke of Peter• regions. borough). sphere ofintluence seecatcbment Solano Spanish, hot and oppressive SE wind bringil1$ occasional rain in spiUway Outflow channel draining summer to SE SpaIn. lake dammed up by ice-sheet. solar system Group ofcelestial bodies spinifex Australian desert grass with revolving round sun, including planets, spiny sharp-pointed leaves. asteroids and satellites. spit Long, narrow tongue of sand or solar time Time reckoned by appar• gravel projecting from land into sea or ent motion ofsun, recorded by sundial. across estuary mouth. solfatara Italian, vent giving off spot-height Precise point where sulphurous gases from volcano height above given datum is marked on approaching extinction. map. solitluction Downhill flow of surface spring-line Line of springs where deposits saturated with water, especial• water-table intersects surface. ly ifthaw sets in at surface when ground beneath is still frozen. spring tides Those of considerable amplitude, about times of new and full solstice Time during summer or moon. winter when sun is vertically above point marking its farthest distance N or stack Tall pillar of rock, detached S ofequator, i.e. the two tropics. from headland by wave action. solution Form of weathering where staithe Elevated stage from which rock is dissolved by chemical action. wagons may discharge coal into ships. sound (I) passage between two land stalactite Icicle-shaped mass of car• areas; (il) large inlet. bonate of lime, deposited by percolat• ing water and hanging from roof of sounding Recorded depth ofwater. cave. 659 S stalagmite Geographical Terms stalagmite Stump-shaped mass of stratus Thin, uniformly grey cloud carbonate of lime, found on cave floor sheet, found up to 8,000 ft. (2,438 by deposition of water dripping from metres). roof. striation Scratching and grooving of steppe Temperate grasslands of rocks by glacial action. mid-lat. of Eurasia. subsoil Partially decomposed rock storm-beach Accumulation of coarse between top-soil and bed-rock. material well above high-water mark, produced by very powerful storm• sucld Arabic, thick mass of floating waves. vegetation on upper Nile. storm-surge Rapid rise in level of sea Sumatra Squally wind in Malacca above predicted tidal heights, caused by Straits, occurring suddenly, often at strong on-shore winds. night, during sw monsoon. Surazo Cold wind of s Brazil in anti• strait Narrow stretch of water linking cyclonic conditions ofwinter. two adjacent sea areas. surf Mass of breaking water when strandtlat Wave-cut platform otT large wave approaches reef or steeply• coast OfN Norway. shelving shore. stnta Layers or beds of sedimentary swallow-hole see sink hole rock. swash Mass of foaming water rushing strath Broad, flat-floored valley in up beach as wave breaks. Scotland. swell (I) regular undulating move• stratocumulus Continuous sheet of ment ofwaves in open ocean when they uniform dark grey cloud below 8,000 ft. do not break; (il) gently sloping eleva• (2,438 metres). tion rising from sea-floor, but still well below ocean surface. stratosphere Layer of atmosphere above troposphere, where temp. ceases syncline Strata downfolded into form to fall with increasing height. oftrough by compressive forces.

T

tableland Broad, level-topped upland tank Artificial pool or lake used in rising abruptly from lowland. India or Sri Lanka to store irrigation water. taiga Russian evergreen softwood forests of N continents where tree tarn Small pool or lake in mountain• ~wth is slow, tree shapes give stability ous areas, usually located in cirque. In wind and snow and needle leaves reduce transpiration. tea Small evergreen shrub of tropical monsoon lands, whose leaves are talus see scree picked and processed to form beverage. 660 Geographical Terms truncated spur T tectonic Related to internal forces which mean time of meridian near building up features ofthe earth's crust. centre of zone is used as standard for whole zone. temperature Degree of heat or cold within atmosphere, measured on tombolo Italian, sand or shingle bar thermometric scale. linking island with mainland. terminal moraine Crescent-shaped tor Isolated mass of rock, usually ridge of drift material and broken rock granite, weathered into prominent deposited by valley glacier at successive shapes; common in Devon or Corn• stages ofretreat. wall, England. terrace (I) flat surface along valley tornado (I) extremely violent whirl• side, marking former river level; (ii) wind, of short duration but very des• embanked area along contour on steep tructive, affecting Mississippi basin; (il) sloping land, to prevent soil erosion. thundery squalls producing torrential rains over w Africa coasts. terrace cultivation System where soil on steep slopes is retained by walls; trade winds Those blowing from sub• often employs irrigation. tropical high pressure cells to low pres• sure area of equatorial lat., noted for terra rossa Italian, reddish clay soils constancy offorce or direction. developed by chemical weathering in karst country under semi-arid condi• Tramontana Italian or Spanish, cold, tions. dry N wind blowing down from mountains in w Mediterranean basin. territorial waters Coastal waters over which bordering state retains jurisdic• transhuDruiDCe Seasonalmovementof tion; originally 3 m. (5 km.) WIde, now animals and man to new pastures, often extended, to claimed, up to 12,50 usually at different altitude. and even 200 m. (19,80,320 km.). transpiration Loss ofwater-vapour by tertiary industry Activities providing plants through leaves. services for primary and secondary industries (transport, finance, insur• transport principle Theoretical ance, etc.). arrangement of settlements, where transport costs are significant so that as thermal spring One with water temp. many important places as possible lie over 68°F. (20°C.) normally found III on one route between larger towns. areas ofactive or recent vulcanism. transverse coast see discordant coast thermometer Instrument for measur• ingtemp. tropic One of parallels oflat. (23'1t N and s of Equator) marking limits ofarea threshold population Minimum size where sun may be directly overhead. of population necessary to make a single establishment of any function troposphere Lower layers of atmos• economically viable. phere, where temp. fall with increasing altitude. thrust-fault Reverse fault at very low angle, where upper beds are pushed trough (I) elongated trench or ocean forward over lower ones. deep; (iI) glacial valley; (iii) depression between crests of two successive waves; tide Periodic vertical movement of (iv) narrow belt oflow pressure between sea-level in response to gravitational two areas ofhigh pressure. forces ofsun or moon. trough-end Abrupt slope at head of till see boulder clay glacial valley. time zone Long. division within truncated spur Former interlocking 661 T tse-tse-fly Geographical Terms spur of river valley, now cut away by tumulus see barrow glacier, causing straightening ofvalley. tundra Lapp, zone of stunted vegeta• tse-tse Oy Small blood-sucking fly of tion, often marshy, in N hemisphere, Africa whose bite causes sleepmg• between polar snow and ice and N sickness in man and is often fatal to limits oftree growth. cattle. twilight zone Area of town in decay tsunami Japanese, large-scale waves because oflack of amenities, poor con• caused by submarine earthquakes, dition of buildings, etc. capable oftravelling vast distances very fast and causing considerable damage typhoon Smal, intense tropical storm when surging ashore. ofChina Sea and w Pacific margins. u

underground drainage Feature of building by outward expansion of areas of well-jointed rocks, as in town, often leading to development of carboniferous hmestone, where water conurbation. flow may be directed below ground in distinct channels, from sink-hole to urstromtiIer German, broad, shallow resurgence. troughs eroded by melt-water from front of continental ice-sheet, notably urban field Sphere of influence of in NW Europe, where they often town. contain parts of present post glacial river courses. urban mesh Locational arrangement ofcentral places. U-shaped valley Glaciated valley with flat floor, steep sides and straight urban renewal Planned renovation of course; may contain ribbon lake or buildings, services and facilities in an mis-fit river. urban area. uvala Depression in karst landscape, urban sprawl Unplanned spread of large than doline. v

valley Elongated depression between variation Magnetic angle by which hills or mountains, usually containing magnetic compass needle deviates from river. true N for given point on earth's surface. 662 Geographical Terms wheat W veld Afrikaans, open grassland of s volcanic eruption Ejection of solid or Africa, ranging from high veld above liquid or gaseous material from interior 5,000 ft. (1,524 metres) through middle ofearth on to its surface. veld to bushveld in low country. volcano Hill or mountain, with vent ventifact Pebble polished and faceted through which lava, gas, steam and by wind-blown sand. cinders are expelled. V-sbaped valley Term for valley vicuiia Native animal of s America eroded by river. providing limited supplies of very flOe, soft wool. vulcanicity All processes in which molten material is forced into earth's viticulture Cultivation ofthe vine. crust or onto the surface. w

wadi Arabic, steep-sided rocky ravine in U.S.A., term to describe catchment in arid regions, usually dry except when area ofsingle river system. heavy rains produce short-lived torrent waterspout Intense, rapid moving low pressure system over seas, producing warm front Front of warm sector of pillar ofwater, common in tropics. depression, marking boundary where advancing warm air rises over cold air water table Upper surface of zone of to produce broad belt ofrain. saturation in permeable rocks. The level varies seasonally with the amount warm occlusion Where overtaking ofprecipitation and percolation. cold air is not as cold as air-mass in front. wattle Type ofAustralian acacia. washIand Embanked lowland border• wave-aJt bench Rock-shelf produced ing river, where excess water is collect• at base ofcliffby wave action. ed in flood-time. weather Condition of atmosphere at waterfall Steep fall of river water given place and time. marking sudden change in gradient of river. weathering Disintegration and decay ofrocks in situ by climatic elements. water-gap Narrow passage through ridge, cut by river. westerlies Prevailing winds of tem• perate lat., blowing from sub-tropical water-power Originally referred to high pressure cells to low pressure power generated by river turning mill• zones in lat. 35-65". wheel, now synonymous with hydro• electric power. wheat Widely cultivated cereal, most commonly grown extensively in tem• watershed (I) line of separation bet• perate grasslands, but intensively in NW ween two adjacent drainage basins; (i/) Europe. 663 W whirlwind Geographical Terms whirlwind Rapidly revolving stonn tion of winds blowing from each car• round centre of low pressure, product dinal point. oflocal heating. wine Product of fennented grape Williwaw Violent squall in Straits of juice, though can be made from variety Magellan. ofother fruits. Willy-willy Intense cyclonic stonn winterbourne Intermittent stream in encountered offNW Australian coast. chalk areas, generally fiowinll only in winter when water table is highest. At wind Horizontal current of moving other times it represents a dry valley. air. wold Open hilly country in chalk or wind-gap Gap in ridge of hills, origin• limestone regions of Britain, such as ally caused by river erosion but now dry Cotswolds and Yorkshire Wolds. as result ofriver capture. wood pulp Major softwood ~roduct wind-rose Diagram of radiating lines, for making paper, artificial silk and indicating by their length the propor- cellulose paints. x

xerophyte Type of plant adapted to arid conditions. y

yarn Plant whose thick tubers fonn lands where rocks ofdiffering resistance staple food of w Africa and s Sea run parallel to prevailing winds. Islands. yazoo Deferred junction of trib. yardangs Wind-scoured ridges of stream, resulting from migration of rock resulting from erosion in desert meanders in main river.

664 z

zenith Point in heavens vertically with depression over Argentina or above observer. Uruguay. zeggen German, tabular mass ofresis• zone of assimilation Area which is tant rock, up to 100 ft. (30 metres) high, bein~ developed for business and retail whose protective capping makes it actiV1ty on edge of present central stand out from softer rocks removed business district. by differential erosion, mainly in arid areas. zone of discard Area which is being vacated by business and retail activities zonda Warm, humid wind associated on edge ofcentral business district.

665