building birmingham: a tour in three parts of the building...

UrbanGeologyinBirminghamNo.2

©Siddall,Schroder,Hamilton2016

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BuildingBirmingham:Atourinthreepartsofthebuildingstonesusedinthecitycentre.Part2:CentenarySquaretoBrindleyplaceRuthSiddall,JulieSchroderandLauraHamiltonThisareaofcentralBirminghamhasundergonesignificantredevelopmentoverthelasttwodecades.CentenarySquare,thefocusofmanyexercises,realisedandimagined,ofciviccentreplanningisdominatedbySymphonyHallandnewLibraryofBirmingham(byFrancineHoubenandcompletedin2013)andtheareaswestofGasStreetBasinareunrecognisabletodayfromthederelictindustrialremainsandfactoriesthatwerehereinthe1970sand80s.Nowthisregionisathrivingculturalandbusinesscentre.ThiswalkingtourtakesinthebuildingstonesusedinoldandnewbuildingsandsculpturefromCentenarySquare,alongBroadStreettoOozellsSquare,finishingatBrindleyplace.

Brindleyplace;stepsareofPortlandStoneandthepavingisYorkStone,aCarboniferoussandstone.Themainsourceonarchitecture,unlessotherwisecitedisPevsner’sArchitecturalGuide(Foster,2007)andinformationonpublicartworksislargelyderivedfromNoszlopy&Waterhouse(2007).Thisisthesecondpartinathree-partseriesofguidestothebuildingstonesofBirminghamCityCentre,producedfortheBlackCountryGeologicalSociety.ThewalkextendstheworkofShilston(1994),Robinson(1999)andSchroderetal.(2015).ThewalkstartsattheeasternendofCentenarySquare,attheHallofMemory.HallofMemoryAmemorialtothosewholosttheirlivesintheGreatWar,TheHallofMemoryhasaprominentpositionintheGardensofCentenarySquare.ItisanoctagonalbuildingintheDoricorder,withapedimentedentranceporticoandadomedroof.Itwascompletedin1925byarchitectsS.N.CookeandW.N.Twist.ThebronzesculptureisbyAlbertToft.ThemainbuildingisinwhitePortlandStone.ThisisarguablyBritain’smosticonicbuildingstoneandindeedithasbeenthestoneofchoicefortheconstructionwar



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TheHallofMemory,CentenarySquarememorialsandcommonwealthwargravesthroughouttheworld,andisthereforeafittingchoicefortheHallofMemory.PortlandStonecomesfromtheIsleofPortland,apeninsulaontheDorsetCoastwhichisnowriddledwithquarriesandundergroundminesforthestone.ThePortlandLimestonesarelateJurassicinage,depositedaround150MaintheTithonianStage(knownlocallyasthePortlandian).ThebuildingstonesareknownastheFreestoneMemberofthePortlandLimestoneFormationandaresubdividedintothethreemainbedquarriesasbuildingstone,theBasebed,WhitbedandRoach.ItisPortlandStoneWhitbedthatweseehereandthisisthemostcommonlyusedvarietyofPortlandStone.Whitbedisanooliticlimestone,andthetiny,sphericalooidsareclearlyvisibleusingahandlens.Thesetellusthatthisstoneformedasasedimentinawarm,shallowtropicalsea,wherethetidalcurrentswereabletorollsandgrainsbackwardsandforwardsastheybecamecoatedwithcalciumcarbonate.Thereisevidenceoflifeintheseastoo,intheformofshells.Thesecanbeseenasgreyfossilsstandingslightlyproudofthesurface.Themajorityofthesearespeciesofoystershells,mainlyfromLiostreasp.andthespinyoysterSpondylussp.Spinyoystershadbarbsprojectingofftheirshells,enablingthemtoanchorthemselvesinthesediment.Articulatedshellsofspinyoystersarenotuncommonhere.ThefoundationsoftheHallofMemoryareinCornishGranite.Thisisagrey,coarse-grainedgranitewithtwomicaspresent;theblackvariety,biotiteandsilverymuscovitewhichsparklesinthesunshine.Alsopresentarerandomlyorientatedwhitefeldspars,around15mminlength.ThisisprobablythevarietyofCornishGranitefromCarnsewintheCarnmenellisPluton,oneoftheplutonsoftheCornubianBatholith,whichwasintrudedattheendoftheVariscanmountainbuildingeventintheearlyPermian.ThemajorityoftheCornubiangranitesofCornwallaretwo-micagranitesandthismakesthemdistinctiveasbuildingstones.TurningnorthfromtheHallofMemoryisBaskervilleHouseandamemorialtotheeponymouslettersetterandprinter.



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CornishGranitewithbothmuscoviteandbiotitemica(left)andPortlandWhitbedwithoysterfossils(right).ThiscombinationofstonesisseenontheHallofMemory,BaskervilleHouse&theFirstMunicipalTradingBank.BaskervilleMemorialThisisamemorialtotheletterfounderJohnBaskerville(1706-1775)wholivedinthevicinityofwhatisnowCentenarySquarefrom1748-1775.Thefulltitleofthememorialis‘MonumenttoJohnBaskerville–IndustryandGenius’.ItisbyDavidPattenandMichaelP.Houseandrepresentsletterpunches,whichspelloutthewordVirgil;avolumeofVirgil’spoetrybeingthefirstbookthatBaskervilleprintedin1757.Thelettersandinscriptionsareinbronze,butonceagainPortlandWhitbedisusedtoconstructthemonument.Thistoohasmanybrokenfragmentsofoystershellbutalsocontainsthefloret-likeheadsofareefformingalgae,SolenoporaportlandiawhichwasendemicinthePortlandseas.FragmentsofS.portlandiaobservedherehavebrokenoffthereefandhaveaccumulatedinamongsttheshelldebris.BaskervilleHouseBaskervilleHouse,designedbyT.CecilHowittandcompletedin1940,dominatesthisendofCentenarySquare.LikeTheHallofMemory,ittooisbuiltfromPortlandWhitbedonfoundationsofCornishGranite,again,probablyCarnseworasimilartype.Indeedthiswastheintention,tocontinuethethemeofthestonesusedintheHallofMemory.Theashlarmasonryonthegroundfloorhasbeenrusticatedtogivetheappearanceofgreater‘weightiness’tothePortlandStoneinthisportionofthebuilding.TheintricatecarvingonthearmsandgarlandsabovethemaindoorwaydemonstratetheversatilityofPortlandBasebedasadecorativestone.BasebedcontainsfarfewerfossilsthanWhitbedandthiscoupledwithnostringpartingsmakesitanexcellent‘freestone’thatcanbecutandcarvedinanydirection.Abovethedoorway,theupperstoriesareinfine,smoothashlarmasonry.Theapseabovethedoorwayisfrontedbyioniccolumnsandthehalf-domehasacofferedceiling.StatueofEdwardVIIAregalstatueofKingEdwardVIIstandsattheeastendofCentenarySquare.Thespectacularplinth,adornedwithbronzesisofsandstone,whereasEdwardhimself,sadlytoohighupforcloseexamination,isinwhitemarble.AnUpperCarboniferoussandstoneisusedfortheplinth;itisamediumgrained,quartz-richsandstone,anarenite.Evidenceofliesegangbanding,canbeseenontheeast-facingsideoftheplinth.Theprovenanceofthisstoneisunknown,butmanysandstonesofthistypearesourcedfromquarriesintheMillstoneGritGroupoftheLancashireandWestYorkshirePennines.ItisnotpossibletoascertaintheprecisevarietyofmarbleusedinthesculptureofEdwardVII.Notonlyisitaboveeye-level,butallwhitemarbleslookprettymuchthesame.Howeverthisappearstobeapure



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white,withoutanygreystreaks.Themainsourceofstatuarymarbleintheearly20thCenturywasCarrarainTuscany,Italyandthisisbyfarthemostlikelyprovenanceofthestoneusedhere.Variousgradesofstatuarymarble‘statuario’wereextractedfromtheTuscanquarries.OnevarietywhichwasoftenusedbytheBritishRoyalFamilywascalled‘Campanile’;itwasaparticularlytoughmarblewhichranglikeabellwhenhitwithahammer.TurnnowtowardsthesouthernsideofCentenarySquareandBroadStreet.FirstMunicipalSavingsBankTheimposingbuildingonthesouthsideofthesquareisalsobuiltfromPortlandWhitbed.ThiswasformerlytheFirstMunicipalSavingsBank,openedin1933andalsodesignedbyT.CecilHowitt,whowentontobuildBaskervilleHouseopposite.OnceagainweseethethemeofPortlandStoneandCornishGranitebeingusedhere.Thisbuildinghasthatimpenetrablelookofabank,withfewwindowsandweighty,rusticatedmasonry.TheporticoissupportedbyIoniccolumnsandthewindowsonthegroundfloorareheavilybarred.Goodexamplesofoystershelllagscanbeobservedinthecolumnsandalsoweatheringoutontheashlarmasonry.ThefoundationsofthebankareinabrownishCornishGranite.Thetwomicascanbeseen,withthemuscovitemoreobviousonsunnydays.Veryroughlyaligned,brick-shaped‘smallmegacrysts’offeldspararesetinamatrixrichinsmoky,brownquartz.GraniteswiththesetextureswereobtainedfromtheCarnmenellisandBodminPlutonsoftheCornubianBatholith.AnothermajorfigurativesculptureonCentenarySquarestandsoppositetheLibraryofBirmingham.‘TheGoldenBoys’ThisgildedsculptureofengineersMatthewBoulton,JamesWattandWilliamMurdochisbyWilliamBloyeandRaymondForbes-Kings.Originallyinstalledin1956,thestatuewasrestoredandre-gildedin2006.TheplinthisofPortlandWhitbed,asdescribedabovefortheHallofMemory.Fragmentsoflargeoystershellscanbeseenweatheringoutoftheooliticlimestonematrix.WalknowtothewestendofCentenarySquareandtheentrancetotheInternationalConventionCentreandSymphonyHall.

LauraHamilton&JulieSchroderatSymphonyHall;greySardinianGraniteandredBalmoralGranite.



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SymphonyHallSymphonyHalldominatesthewesternendofCentenarySquareandisastrikingbuilding,builtinthepost-modernstyleitispartofacomplexwhichincludestheInternationalConventionCentreandtheHyattRegencyHotel.ItwasdesignedunderaconsortiumbyPercyThomasPartnershipandRentonWoodHowardLevin.Itwasbuiltbetween1987and1991andwasnotmetwithuniversalapproval.Foster(2007)describesitas‘architecturallyahugedisappointment’;neverthelessithasfulfilleditsuseandmanyofthefacilitiesaredesignedtoahighspecification.Aswasverymuchthetrendatthetime,thebuildingiscladwithgranite,predominantlywhitewitharedstoneusedforbandsandforcolumnsontheBroadStreetfaçade.ThegreygraniteisSardinianGreyGranite,alsoknownasGrigioPerla(greypearl).ThisisaVariscanGranitefromtheBuddosoPlutonontheItalianislandofSardinia,agedaround280-290Ma.Ithasadistinctivetexture,beingslightlyporphyriticwithlargergrey-whiteplagioclasefeldsparinagroundmassofgreyquartz,blackbiotiteandasmallamountofpink,partiallykaolinised,potassicfeldspar.TheredgraniteisfromFinlandisdistinctiveandinstantlyrecognisable.ItiscalledBalmoralGraniteanditcomesfromKurpiQuarryandothers,nearTurkuinVehmaa,SWFinland.Composedofbrightredfeldsparandsmokyquartz,biotiteandhornblende,thisstoneisoneoftheso-calledrapakivigranites,avarietycalledpyterlite.Itisanancientstonetoo,over1.5billionyearsold.Industrial-scalequarryingbeganontheVehmaapeninsulain1903andthegraniteisstillactivelyquarriedtodayandremainsverypopularasanornamentalstone.FinallyonthecornerofSymphonyHallwithBroadStreet,isasmalldedicatoryplaqueadvertisinganArtsCouncilandBritishGasawardforthecomplexin1992.Theplaqueismadeofdarkgreyslatesetwitharoundelofgreenslate.ThegreyslateisprobablyWelshSlatefromtheOrdovicianSlateBeltofNorthWales,quarriedfromanumberofquarriesaroundBlaenauFfestiniog.ThegreenstoneisCumbrianGreenSlate,alsoofOrdovicianage,fromanumberofquarriesworkingtheSeathwaiteFellFormationintheLakeDistrict.TurnrightontoBroadStreetandcrossovertothecomplexofbuildingsaroundRegencyWharf.

Sculpture:InnerSpiritThispublicartworkisinstalledinawalkwaytoRegencyWharf,betweentheRegencyHyattHotelandWetherspoon'spub.Entitled‘InnerSpirit’itisbysculptorAmandaBrisbaneandwaserectedin2001.Thesculptureiscomposedofacolumnofblueglassroundels,flankedbymonolithicslabsofWelshHeatherSlate.Theslabsofstonearefreshfromthequarryandhavenotbeenfurtherworkedfollowingextraction.Theyhavenaturallybrokenalongthecleavageandjointplaneswhichformplanarsurfaces.Thejointsurfacesaredistinguishedbythefine,feather-likeridgesontheirsurfacesandthissculpturewillhaveinteresttostructuralgeologists.Thisfeatureisindeedknownasplumosestructureandformsasjointspropagatethrougharock.Thedirectionofpropagationgoesinthedirectionofthefeather,fromitsoriginatthebaseofthe‘feather’untilwerunoutofrocktofractureatthetipofthe‘feather’.OnthelargeslabofInnerSpirit,jointpropagationisfromtoptobottomasindicatedbythearrowonthephotograph(left).



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Thevarietyofslateusedhereisdarkpurpleincolourandisthevarietyknownas‘HeatherSlate’.Ithasnumeroussmall,palegrey-greenreductionspots.ThismakesthisinstantlyrecognisableasslatederivedfromtheCambrianSlateBeltofNorthWaleswhichrunsSW-NEfromNantlle,throughLlanberistoBethesda.TheslateisLowerCambrianinageandhasbeenmetamorphosedtogreenschistfacies,duringwhichitwassubjectedtohomogeneousstrainwhichdevelopedastrongcleavage.ThishasmadethisstoneWorld-famousasaroofingslate.Thecolourisimpartedbyironandtitaniumoxidesandreducedformsofironoxidesinthespots.TheonlyactivequarryproducingthisslateisPenrhynnearBethesdaandthisisthereforethelikelyoriginofthisstone.Thequarryhasbeeninproductionsincethe13thCenturyandiscurrentlyoperatedbyWelsh//Slate.NextdoortoInnerSpiritisaratherdrab-lookingbuilding,housingthelocalbranchofthepublichousechainWetherspoon's.Wetherspoon’s:TheSolomanCutlerThis(typically)largehostelryisnoarchitecturalgem,withlargeglassfrontagesandceramiccladdingontheBroadStreetfaçade.ThepubstandsonthesiteofPearce&Cutler’sGlassworks,foundedbySolomanCutlerin1854.Thewindowlessblockattheeasternendofthebuildingiscladinwhatappears,atfirstglance,tobeconcrete.Howeveritisfacedwithanivory-colouredooliticlimestone.Closerinspectionshowsthatthisstoneisveryworthyofclosergeologicalexamination.Itisrichinfossildebris,mainlysectionsthroughbivalveshellsandechinoidspinesandtheooidsarejustvisibletothenakedeye.ThisisoneoftheMiddleJurassicLimestonesofthePortugueseLusitanianBasin.AverylargenumberofsimilarstonesarequarriedintheregionaroundSantaréminEstremadura,andthisisprobablyCandeeirosLimestonefromPortodeMos.

FossildebrisinCandeeirosLimestoneonWetherspoon’sTheSolomanCutlerpub.Thesocleofthisbuildingisalsoofgeologicalinterest(thoughshouldbeexaminedwithcaution,itscleanlinesscannotbeconfirmed…).Itisametamorphicrock,VerdeCandeias,agreengneiss-migmatite.Thisistheoldestrockwewillencounteronthiswalk,being2.75billionyearsold.ItisquarriedfromtheCampoBeloMetamorphicComplexinMinasGerais,Brazil,partoftheSãoFranciscoCraton.Theserocksareorthogneissesderivedfrom3billionyearoldprotoliths.Themajormineralsarequartz,plagioclaseandpyroxeneandthegreencolourisimpartedbychloriteandepidote.CrossovertheroadtotheCelebrityRestaurant.



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CelebrityRestaurantThedoorwayofthisIndianRestaurantisthemainpointofgeologicalinteresthere.Likemanyofthebuildingsinthisarea,thisisbrickbuilt.HoweverthereisagrandVictorianentranceindressedstone.ThesmallcolumnsarePeterheadGranite.Thesearealittleweatheredandarelosingtheirhighpolish,howeverthemedium-grainedmosaicofgreyquartzandpinkfeldspar,withflecksofbiotiteisobviouswhenlookingclosely.Alsolookoutfortheroundedenclavesofafinergrained,moremaficigneousrock,whicharecharacteristicofthisstone.PeterheadisaCaledonian,post-tectonicgranite,intrudedat406Ma.Itisquarriedonthecoast,NorthofAberdeenandwasoneofthemostpopulardecorativestonesoftheVictorianera.Abuff-coloured,Carboniferoussandstoneisusedforthedressingsaroundthedoorway,thefoundationsandthedelicatecarvinginthearch.Thestoneiscross-beddedandthesestructurescanbeseenintheblocksflankingthekeystoneofthearch.LikethestoneusedontheplinthofEdwardVII,thesestonesarehardtoprovenanceoutoftheirgeologicalcontextandwithoutfurtherarchitecturaldocumentation.ItcouldbeDarleyDaleStoneoroneofthemanyothersandstonessourcedinNorthWales,theMidlandsorNorthernEngland.ContinuealongBroadStreetuntilyoureachOneBrindleyplaceonthecornerofOozellsStreet.OneBrindleyplaceThisbuilding,markingtheentrancetotheBridleyplace/OozellsSquaredevelopmentisoccupiedbyDeutscheBank.Asaconsequenceithasavigilantsecurityteamandthekeenurbangeologistwoulddowellnottoloiterhere.ItwasdesignedbyAnthonyPeakeAssociatesandconstructedbetween1994-5.Themaingeologicalinterestisthepavingunderthecolonnadeonthegroundfloor.Amedium-grainedtogritty,palebrownsandstonehasbeenusedforflagstones.Itshowsgoodexamplesofcurrentcross-beddingandthereisahighcarboncontent,bothasdisseminatedmaterialandlargerfragmentsofplantfossils.

ConvolutelaminationsandblackplantdebrisatOneBrindleyplace.Thereisalsosubstantialironstaining.Theoriginofthisstoneisunknown,butthereisastrongprobabilitythatitisfromtheUpperCarboniferousofthePennines.LikelycontendersareFletcherBankStonefrom



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Halifax,geologicallyfromtheMillstoneGritGroupandknownforitsdriftedplantfossils,oralternativelyavarietyofRoughRockfromtheCoalMeasureswhichisquarriedinanumberoflocationsaroundHuddersfieldandRossendale.FollowthecolonnadealongOozellsStreettoOozellsSquare.OozellsSquareThesquarehasbeenremodelledaspartoftheBrindleyplaceredevelopmentunderthedirectionofTownshendLandscapeArchitects.ThecentrepieceofOozellsSquareisasculpturalinstallationbyPauldeMonchaux(1998)calledWaterFeature.Thisiscomposedofsixgranitebenchesandagranitearch.Arillcutsdiagonallyacrossthesquareandthisinstallationissurroundedbycherrytrees.DeMonchauxhasanespecialinterestinstoneandthematerialsheusesareintegraltohiswork.ThesevensculptureshereareconstructedfromDeLankGranitefromStBrewardinCornwall.Itisatwo-micagranitefromtheBodminpluton(297Ma)andhasacharacteristic‘silver-grey’appearance.DeLankistheonlyremainingquarryintheCornubianBatholithstillextractingdimensionstone.Therillisedgedinablackdolerite.ThisismostprobablyNeroZimbabwewhichisoneofthefewblackstonesavailable.Itiswidelyusedaskerbstonesandpolishedascladding.ThestoneisquarriedinMashonaland,easternZimbabwe,fromaseriesofsillsintruded1.87billionyearsago.Composedpredominantlyofplagioclase,pyroxeneandhornblende,itisalsoveryrichinmagnetitewhichpromotestheobservedblackcolour.

OozellsSquareThenewofficedevelopmentsinOozellsSquareandBrindleyplacearemainlybrickbuilt,reflectingtheconstructionmaterialsofthefactories,workshopsandwarehouseswhichoncestoodhere.OnebuildingofthattimehasbeenpreservedandthatistheoldOozellsStreetSchooldesignedinaveryBirminghamversionoftheVictorianGothicstylebyarchitectsMartin&Chamberlainandcompletedin1877.IthassubsequentlybeenrestoredandrefurbishedbythefirmLevittBernsteinandsince1997ithasbeentheIkonGallery.Thisphaseofredevelopmentreinstatedthetower(designedtotheoriginalplans)whichhadbeenremovedinthe1960s.Stoneisusedasdressingsassociatedwiththewindows.Beautifullycarvedfoliagecanbeseeninthegapsbetweenthewindowarchesonthesecondregister.Againthestoneisunknown.Itisadarkbrown-redincolourandcouldbeoneoftheTriassicsandstonesoftheMidlandsortheNorthofEngland.



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Thepavingherecontinuestobeofgeologicalinterest.Althoughmuchofthesquareiscoveredingravel,reclaimedcobblestoneshavebeenusedinpatchesandagoodplacetolookforthemiswheretheOozellsStreetwalkwayleavesOozellsSquareheadingtowardsBrindleyplace.Awidevarietyofstoneswereusedforcobblesduringthe18thand19thcenturiesandquarryindustrieswerebuiltuparoundthesupplyofcobblesandkerbstonesforthegrowingnetworksofcitystreets.ThegranitesofJerseyanddioritesofGuernseywereprimarilyusedforthispurpose.ClosertoBirmingham,igneousrocksquarriedintheBlackCountryandtheeastMidlandswerealsocommonlyused.Theoriginsofallthestonesseenherearenotpossibletodetermine,especiallythegranites,butthecharacteristicfeaturesofthemainstonesusedaredescribedbelow.MountsorrelGranodioritecomesfromCharnwoodinLeicestershire,geologicallyfromtheOrdovicianintrusionsoftheMountsorrelGranodioriteComplex.Itisamedium-grainedgranite,withzoned,redandwhitefeldspar,hornblende,quartzandbiotite.Thequarry–oneofthelargestinEurope–isstillworkedtodayforaggregate.MarkfielditealsocomesfromtheCharnwoodareaofLeicestershire,butisderivedfromthesuiteofNeoproterozoicSouthCharnwoodDiorites.ItisquarriedatCliffeHill,MarkfieldandGrobyQuarries.Ithasaverydistinctiveappearance,amedium-graineddiorite,speckledredandgreen.Itiscomposedofgreenhornblendeandpinkorthoclase,withminorepidoteappearingasbrightgreenpatches.ItiscommonlyseenascobblestonesalongwithMountsorrelGranodiorite.

Leftandcentre,MountsorrelGranodiorite,right,Markfieldite.Thecobblesare~10cmsquare.Whinstoneisagenericnamefordarkgrey,fine-grainedigneousrocks,doleritesandbasalts,whichwerequarriedforroadstone,cobblesandkerbs.ThenamecomesfromtheGreatWhinSill,andtheword‘whin’mayrefertothesoundtherockmadewhenitwashitwithahammer.WhinstoneswerequarriedfromtheWhinSillaswellasthecontemporaneous(~295Ma)sillsanddykesoftheMidlandValleyofScotland.TheTertiaryClevelandDykeofnorthYorkshirehasalsofurnishedparticularlyblack,finegrainedwhinstone,sometimeswithlath-shapedplagioclasefeldsparphenocrysts.RowleyRagisalocalwhinstonethatwasusedforcobbles.Itisderivedfromaseriesofquarries,knownas‘TheQuacks’aroundRowleyRegisintheBlackCountryandcomesfromtheRowleyRegisMicrogabbro(dolerite)whichisasmalllopolithicintrusionwhichformspartoftheLateCarboniferousBrierleyHillClusterofintrusions.Itisafine-grainedolivinedolerite.ItisdifficulttodistinguishfromothervarietiesofWhinstone,butitisdarkgreywith,sometimes,abrownishpatina.ItwaswidelyusedforcobblestonesinBirminghamandsurroundingareasbutdevelopedareputationforacquiringapolishwhichcausedhorsestoskidandthereforewentoutofuse.



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TreforGraniteisfromNorthWales.LikeMountsorrelandMarkfieldite,itwasmainlyquarriedforcobblestones,buthadtheaddedvalueofbeingoneofthefewstoneswiththeperfectpropertiesformakingcurlingstones(itwasthechosensourcefortheSaltLakeCityWinterOlympicsstones).TherearetwovarietiesofTreforGranite,adarkgreyvarietyandapink-palegreyvariety.Bothhaveabundant,small,whiteplagioclasephenocrysts.BothstonesarequarriedatTreforontheLleynPeninsulafromseparateintrusionsinthe450MaGarnforigneouscomplex.

ReclaimedcobblesinOozellsSquare.DarkgreycobblesareWhinstones,andsomemaywellbeRowleyRag.ThethreepalegreyandpinkstonesatthetoprightareTreforGranite.ThetworedstonesareMountsorrelGranodiorite.CentralSquare,BrindleyplacePlanningforthedevelopmentofBrindleyplace,whichencompassesthelargeCentralSquare,OozellsSquareandBrunwsickSquarebeganin1987.TheCityCouncilinviteddeveloperstobidforaschemebasedoncommercial,leisureandculturalopportunitiesandtoopenupthecanalsasareasforwatersideactivities.However,thesitechangedhandsanumberoftimesandiscurrentlyownedbyHinesGlobalREIT.Planningpermissionwasobtainedin1992andbuildingbeganon6thSeptember1993.ThearchitectsforthecomplexwerePorphyriosAssociates,Allies&Morrison,StantonWilliamsandSiddellGibson,withTownshendoverseeingthelandscapearchitectureoftheopenspaces.Asbrickdominatesasthemainmaterialusedforthebuildings,wewillfocusonthesquareanditsfountain.ThesinuousstepsattheeasternendofthesquareareconstructedfromPortlandStoneWhitbed.Thisfaciesofthestoneissparselyfossiliferous,buttherearesomegoodexamplesofTrigoniasp.bivalves(withmuchoftheshellmaterialpreserved)onthenortheastendofthesteps.LookcarefullyandyoumayalsofindtheoddexampleofAptyxiellaportlandica,thegastropodknownasthe‘PortlandScrew’.



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YorkStoneisusedtopavethesquare.Thistermisgeneric,referringpredominantlytoflaggysandstonesextractedfromtheUpperCarboniferousPennineLowerCoalMeasuresGroup.IncidentallythesedonotcomefromYork,butfromtheSouthPenninesLancashire-Yorkshireborder.AgainexamplesofCarboniferoussandstones,thesearefluvialinnatureandthereforequartzarenites,withvaryingamountsofmica,fossilplantmaterialanddispersedcarbon.Coarseandfinegrainedexamplesareusedheretogoodeffect.Thesamecoarse-grainedvarietyseenatOneBrindleyplaceisusedhere,cutinawaythatitalmostresemblesplanksofwood.TheseareseeninradiatingstripsaroundtheglasscoffeeshopinthecentreoftheSquare(seefrontispiece).Afountainislocatedintheeasterncornerofthesquare.ThistooiswalledbybenchesofPortlandStone.HoweverthepoolissurroundedbyapolishedkerbofEmeraldPearlLarvikite.Thisisadarkcolouredvarietyofthiswell-knownbuildingstone,withitscharacteristic‘schillerescent’feldspars,whichflashsilver-blue.ThisstonecomesfromLarvikinNorwayandisquarriedfromanigneousringcomplexintrudedintotheOsloGrabenriftsystemat290Ma.TherapakivigraniteBalticBrownisusedforpavingaroundtheedgesofthefountain.ThisstonecomesfromalargenumberofquarriesintheenormousWiborgBatholithwhichissituatedinFinlandbutstraddlestheborderwithRussia.Intruded1.5billionyearsago,thisstoneiswellknownforitsdistinctive‘ovoids’ofpinkpotassicfeldspar,whichareoftenrimmedbydark-greenplagioclaseandsetinamatrixofsmokyquartz,hornblendeandbiotite.ThefinallocationisBrunswickStreet,leadinguptoBrunswickSquare.BrunswickStreet

StreetfurnitureandpavingonBrunswickStreet.BrunswickStreetismainlyusedfortaxiaccesstotheCentralSquareofBrindleyplace.Itiscobbledwithred,reclaimedcobblestoneswhicharepredominantlyMountsorrelGranodiorite,withtheoccasionalblockofMarkfielditeandWhinstone,asdescribedforOozellsSquareabove.



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YorkStoneisusedforthepavements,thisisanexamplewithspectacularliesegangbanding,aformofironstainingproducedthroughaseriesofcomplexchemicalreactionsingroundwaterspercolatingthroughtherock.TheseflagsarederivedfromaseriesofquarriesintheUpperCarboniferousPennineLowerCoalMeasuresGroup.Granitecubesareusedforstreetfurniture.UnfortunatelytheprovenanceofthesestonesisunknownbutitispossiblethattheyhavecomefromeithertheIberianPeninsulaorChina,theseareasbeingthemainsuppliersofgranitetotheUKbuildingindustry.Thisisagreymediumtocoarse-grainedgranitewithbrickshapedphenocrystofpalepinkpotassicfeldspar,inamatrixdominatedbygreyquartzandwhitefeldspar.Thiswalkendshere.ToreturntoCentenarySquare,itisbesttoretraceyourstepsbackthroughCentralSquareandcrossthecanaltoentertheICCandwalkthroughthepublicatriumtotheCentenarySquareentrance.References

BrindleyPlace:http://www.brindleyplace.com/wp-content/uploads/The-History-of-Brindleyplace.pdf

Foster,A.,2007,Birmingham.PevsnerArchitecturalGuides.,YaleUniversityPress,Newhaven&London.,326pp.

Noszlopy,G.T.&Waterhouse,F.,2007,Birmingham:PublicSculptureTrails.,LiverpoolUniversityPress,Liverpool.,191pp.

Robinson,E.,1999,Birmingham:AGeologicalWalk,September1999.

Schroder,J.K.,Schroder,J.&Robinson,E.,2015,BuildingStonesDetectiveTrail.,UniversityofBirminghamLapworthMuseumofGeology.,2pp.

Shilston,P.,1994,BuildingStonesofBirminghamCityCentre,ESTAconferenceFieldWorkshopHandbook,BirminghamUniversity,BlackCountryGeologicalSociety;RevisedbyJulieSchroder2016.,7pp.

IndexofStonesandfurtherreadingBalmoralGranite(SymphonyHall)Selonen,O.,Ehlers,K.,Luodes,H.&Karell,F.,2011,MagmaticconstraintsonlocalizationofnaturalstonedepositsintheVehmaarapakivigranitebatholith,southwesternFinland.,BulletinoftheGeologicalSocietyofFinland,Vol.83,25–39.BalticBrown(BrindleyPlacefountain)Müller,A.,2007,RocksExplained1:RapakiviGranites.,GeologyToday,23(3),114-120.CandeeirosLimestone(Wetherspoon's)Gonçalves,P.A.,MendonçaFilho,J.G.,Mendonça,J.O.&Flores,D.,2014,ThepresenceofzooclastsandzoomorphsinthecarbonateCandeeirosformation(Arrudasub-basin,LusitanianBasin,Portugal):paleoenvironmentalevidence.,ComunicaçõesGeológicas,101,439-442.CarboniferousSandstone(StatueofEdwardVII,CelebrityRestaurant,OneBrindleyplace,Brindleyplace)CornishGranite(HallofMemory,BaskervilleHouse,FirstMunicipalSavingsBank)Bristow,C.M.,2013,ThegeologyofthebuildinganddecorativestonesofCornwall,UK.,in:Cassar,J.,Winter,M.G.,Marker,B.R.,Walton,N.R.G.,Entwisle,D.C.,Bromhead,E.N.&Smith,J.W.N.(eds)StoneinHistoricBuildings:CharacterizationandPerformance.GeologicalSociety,London,SpecialPublications,391&supplementaryData.



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CumbrianGreenSlate(SymphonyHallplaque)Lott,G.&Parry,S.,2012,Strategicstonestudy:abuildingstoneatlasofCumbria&theLakeDistrict.,EnglishHeritage.,17pp.http://www.bgs.ac.uk/mineralsuk/buildingStones/StrategicStoneStudy/EH_atlases.htmlDeLankGranite(OozellsSquare)Bristow,C.M.,2013,ThegeologyofthebuildinganddecorativestonesofCornwall,UK.,in:Cassar,J.,Winter,M.G.,Marker,B.R.,Walton,N.R.G.,Entwisle,D.C.,Bromhead,E.N.&Smith,J.W.N.(eds)StoneinHistoricBuildings:CharacterizationandPerformance.GeologicalSociety,London,SpecialPublications,391&supplementaryData.EmeraldPearlLarvikite(BrindleyPlacefountain)Heldal,T.,Meyer,G.B.&Dahl,R.,2014,Globalstoneheritage:Larvikite,Norway.,in:Pereira,D.,Marker,B.R.,Kramar,S.,Cooper,B.J.&Schouenborg,B.E.(eds)GlobalHeritageStone:TowardsInternationalRecognitionofBuildingandOrnamentalStones.GeologicalSociety,London,SpecialPublications,407,http://dx.doi.org/10.1144/SP407.14,14pp.Markfieldite(OozellsSquare&BrunswickStreetcobblestones)Horton,A.&Harald,J.,2012,Strategicstonestudy:abuildingstoneatlasofLeicestershire.EnglishHeritage.,33pp.http://www.bgs.ac.uk/mineralsuk/buildingStones/StrategicStoneStudy/EH_atlases.htmlCarney,J.,2005,OldCliffeHillandWhitwickquarries,CharnwoodForest.,MercianGeologist,16(2),138-141.MountsorrelGranodiorite(OozellsSquarecobblestones,BrunswickStreetcobblestones)Horton,A.&Harald,J.,2012,Strategicstonestudy:abuildingstoneatlasofLeicestershire.EnglishHeritage.,33.http://www.bgs.ac.uk/mineralsuk/buildingStones/StrategicStoneStudy/EH_atlases.htmlNeroZimbabwe(OozellsSquare)Price,M.T.,2007,DecorativeStone:TheCompleteSourcebook.ThamesandHudson,p.235.PeterheadGranite(CelebrityRestaurant)Stephenson,D.&Gould,D.,1995,BritishRegionalGeology:TheGrampianHighlands.4thEdition.BritishGeologicalSurvey,HMSO.,124-143.PortlandStone(HallofMemory,BaskervilleMemorial,BaskervilleHouse,TheGoldenBoys,FirstMunicipalSavingsBank,BrindleyplaceCentralSquaresteps)Hackman,G.,2014,StonetobuildLondon:Portland’slegacy.,FollyBooksLtd.,MonktonFarleigh.,311pp.RowleyRag(OozellsSquarecobblestones)Cutler,A.,2010,FromthedepthsoftheEarth:DiscoveringtheAncientPastoftheRowleyHills.,BlackCountryGeologicalSociety;http://bcgs.info/pub/local-geology/geological-leaflets-and-guides/rowley-hills-leaflet/SardinianGreyGranite(SymphonyHall)Puccini,A.,Xhixha,G.,Cuccuro,S.,Oggiano,G.,Kaçeli-Xhixha,M.,Mantovani,F.,Alvarez,C.R.&Casini,L.,2014,RadiologicalcharacterizationofgranitoidoutcropsanddimensionstonesoftheVariscanCorsica-SardiniaBatholith.,EnvironEarthSci.,71,393–405.TreforGranite(OozellsSquarecobblestones)Bendall,C.,2004,TreforGranite.,WelshStoneForumNewsletter,2,p.2.VerdeCandeias(Wetherspoon's)



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Siddall,R.,Schroder,J.K.&Hamilton,L.,2016,BuildingBirmingham:Atourinthreepartsofthebuildingstonesusedinthecitycentre.;Part2:CentenarySquaretoBrindleyPlace.,14pp.

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