FromCoyInlet，wherethehighsummit-plaintrendsinland，aplainestimatedat350feetinheight，extendsforfortymilestotheriverGallegos。FromthispointtotheStraitofMagellan，andoneachsideofthatStrait，thecountryhasbeenmuchdenudedandislesslevel。Itconsistschieflyoftheboulderformation，whichrisestoaheightofbetweenonehundredandfiftyandtwohundredandfiftyfeet，andisoftencappedbybedsofgravel。AtN。S。Gracia，onthenorthsideoftheInnerNarrowsoftheStraitofMagellan，Ifoundonthesummitofacliff，160
feetinheight，shellsofexistingPatellaeandMytili，scatteredonthesurfaceandpartiallyembeddedinearth。Ontheeasterncoast，also，ofTierradelFuego，inlatitude53degrees20’south，IfoundmanyMytilionsomelevelland，estimatedat200feetinheight。Anteriortotheelevationattestedbytheseshells，itisevidentbythepresentformoftheland，andbythedistributionofthegreaterraticbouldersonthesurface，thattwosea-channelsconnectedtheStraitofMagellanbothwithSebastianBayandwithOtwayWater。(“GeologicalTransactions“volume6page419。)
CONCLUDINGREMARKSONTHERECENTELEVATIONOFTHESOUTH-EASTERNCOASTSOF
AMERICA，ANDONTHEACTIONOFTHESEAONTHELAND。
Upraisedshellsofspecies，stillexistingasthecommonestkindsintheadjoiningsea，occur，aswehaveseen，atheightsofbetweenafewfeetand410feet，atintervalsfromlatitude33degrees40’to53degrees20’
south。Thisisadistanceof1，180geographicalmiles——aboutequalfromLondontotheNorthCapeofSweden。Astheboulderformationextendswithnearlythesameheight150milessouthof53degrees20’，themostsouthernpointwhereIlandedandfoundupraisedshells;andasthelevelPampasrangesmanyhundredmilesnorthwardofthepoint，whereM。d’Orbignyfoundattheheightof100feetbedsoftheAzara，thespaceinanorthandsouthline，whichhasbeenupliftedwithintherecentperiod，musthavebeenmuchabovethe1，180miles。Bytheterm“recent，“Ireferonlytothatperiodwithinwhichthenowlivingmolluscawerecalledintoexistence;foritwillbeseenintheFourthChapter，thatbothatBahiaBlancaandP。S。
Julian，themammiferousquadrupedswhichco-existedwiththeseshellsbelongtoextinctspecies。Ihavesaidthattheupraisedshellswerefoundonlyatintervalsonthislineofcoast，butthisinallprobabilitymaybeattributedtomynothavinglandedattheintermediatepoints;forwhereverIdidland，withtheexceptionoftheriverNegro，shellswerefound：
moreover，theshellsarestrewedonplainsorterraces，which，asweshallimmediatelysee，extendforgreatdistanceswithauniformheight。I
ascendedthehigherplainsonlyinafewplaces，owingtothedistanceatwhichtheirescarpmentsgenerallyrangefromthecoast，sothatIamfarfromknowingthat410feetisthemaximumofelevationoftheseupraisedremains。Theshellsarethosenowmostabundantinalivingstateintheadjoiningsea。(CaptainKing“Voyagesof’Adventure’and’Beagle’“volume1
pages6and133。)Allofthemhaveanancientappearance;butsome，especiallythemussels，althoughlyingfullyexposedtotheweather，retaintoaconsiderableextenttheircolours：thiscircumstanceappearsatfirstsurprising，butitisnowknownthatthecolouringprincipleoftheMytilusissoenduring，thatitispreservedwhentheshellitselfiscompletelydisintegrated。(SeeMr。Lyell“ProofsofaGradualRisinginSweden“inthe“PhilosophicalTransactions“1835page1。SeealsoMr。SmithofJordanHillinthe“EdinburghNewPhilosophicalJournal“volume25page393。)Mostoftheshellsarebroken;Inowherefoundtwovalvesunited;thefragmentsarenotrounded，atleastinnoneofthespecimenswhichIbroughthome。
Withrespecttothebreadthoftheupraisedareainaneastandwestline，weknowfromtheshellsfoundattheInnerNarrowsoftheStraitofMagellan，thattheentirewidthoftheplain，althoughthereverynarrow，hasbeenelevated。Itisprobablethatinthissouthernmostpartofthecontinent，themovementhasextendedundertheseafareastward;forattheFalklandIslands，thoughIcouldnotfindanyshells，thebonesofwhaleshavebeennoticedbyseveralcompetentobservers，lyingonthelandataconsiderabledistancefromthesea，andattheheightofsomehundredfeetaboveit。(“Voyagesofthe’Adventure’and’Beagle’“volume2page227。AndBougainville’s“Voyage“tome1page112。)Moreover，weknowthatinTierradelFuegotheboulderformationhasbeenupliftedwithintherecentperiod，andasimilarformationoccursonthenorth-westernshores(ByronSound)oftheseislands。(IowethisfacttothekindnessofCaptainSulivan，R。N。ahighlycompetentobserver。Imentionitmoreespecially，asinmyPaper(page427)ontheBoulderFormation，Ihave，afterhavingexaminedthenorthernandmiddlepartsoftheeasternisland，saidthattheformationwasherewhollyabsent。)ThedistancefromthispointtotheCordilleraofTierradelFuego，is360miles，whichwemaytakeastheprobablewidthoftherecentlyupraisedarea。InthelatitudeoftheR。SantaCruz，weknowfromtheshellsfoundatthemouthandhead，andinthemiddleofthevalley，thattheentirewidth(about160miles)ofthesurfaceeastwardoftheCordillerahasbeenupraised。Fromtheslopeoftheplains，asshownbythecourseoftherivers，forseveraldegreesnorthwardoftheSantaCruz，itisprobablethattheelevationattestedbytheshellsonthecoasthaslikewiseextendedtotheCordillera。When，however，welookasfarnorthwardastheprovincesofLaPlata，thisconclusionwouldbeveryhazardous;notonlyisthedistancefromMaldonado(whereIfoundupraisedshells)totheCordilleragreat，namely，760miles，butattheheadoftheestuaryofthePlata，aN。N。E。andS。S。W。rangeoftertiaryvolcanicrockshasbeenobserved(ThisvolcanicformationwillbedescribedinChapterIV。
ItisnotimprobablethattheheightoftheupraisedshellsattheheadoftheestuaryofthePlata，beinggreaterthanatBahiaBlancaoratSanBlas，maybeowingtotheupheavaloftheselatterplaceshavingbeenconnectedwiththedistantlineoftheCordillera，whilstthatoftheprovincesofLaPlatawasinconnectionwiththeadjoiningtertiaryvolcanicaxis。)，whichmaywellindicateanaxisofelevationquitedistinctfromthatoftheAndes。Moreover，inthecentreofthePampasinthechainofCordova，severeearthquakeshavebeenfelt(SeeSirW。
Parish’sworkon“LaPlata“page242。ForanoticeofanearthquakewhichdrainedalakenearCordova，seealsoTemple’s“TravelsinPeru。”SirW。
Parishinformsme，thatatownbetweenSaltaandTucuman(northofCordova)
wasformerlyutterlyoverthrownbyanearthquake。);whereasatMendoza，attheeasternfootoftheCordillera，onlygentleoscillations，transmittedfromtheshoresofthePacific，haveeverbeenexperienced。HencetheelevationofthePampasmaybeduetoseveraldistinctaxesofmovement;
andwecannotjudge，fromtheupraisedshellsroundtheestuaryofthePlata，ofthebreadthoftheareaupliftedwithintherecentperiod。
Notonlyhastheabovespecifiedlongrangeofcoastbeenelevatedwithintherecentperiod，butIthinkitmaybesafelyinferredfromthesimilarityinheightofthegravel-cappedplainsatdistantpoints，thattherehasbeenaremarkabledegreeofequabilityintheelevatoryprocess。
Imaypremise，thatwhenImeasuredtheplains，itwassimplytoascertaintheheightsatwhichshellsoccurred;afterwards，comparingthesemeasurementswithsomeofthosemadeduringtheSurvey，Iwasstruckwiththeiruniformity，andaccordinglytabulatedallthosewhichrepresentedthesummit-edgesofplains。Theextensionofthe330to355feetplainisverystriking，beingfoundoveraspaceof500geographicalmilesinanorthandsouthline。Atable(Table1)ofthemeasurementsisgivenbelow。Theangularmeasurementsandalltheestimations(infeet)arebytheOfficersoftheSurvey;thebarometricalonesbymyself：——
TABLE1。
GallegosRivertoCoyInlet(partlyangularpartlyestimation)350
SouthSideofSantaCruz(angularandbarometric)，355
NorthSideofSantaCruz(angularandbarometric)，330
BirdIsland，plainoppositeto(angular)，350
PortDesire，plainextendingfaralongcoast(barometric)，330
St。George’sBay，northpromontory(angular)，330
TableLand，southofNewBay(angular)，350
Aplain，varyingfrom245to255feet，seemstoextendwithmuchuniformityfromPortDesiretothenorthofSt。George’sBay，adistanceof170miles;
andsomeapproximatemeasurements(infeet)，alsogiveninTable2below，indicatethemuchgreaterextensionof780miles：——
TABLE2。
CoyInlet，southof(partlyangularandpartlyestimation)200to300
PortDesire(barometric)，245to255
C。Blanco(angular)，250
NorthPromontoryofSt。George’sBay(angular)，250
SouthofNewBay(angular)，200to220
NorthofS。Josef(estimation)，200to300
PlainofRioNegro(angular)，200to220
BahiaBlanca(estimation)，200to300
Theextension，moreover，ofthe560to580，andofthe80to100feet，plainsisremarkable，thoughsomewhatlessobviousthanintheformercases。BearinginmindthatIhavenotpickedthesemeasurementsoutofaseries，buthaveusedallthosewhichrepresentedtheedgesofplains，I
thinkitscarcelypossiblethatthesecoincidencesinheightshouldbeaccidental。Wemustthereforeconcludethattheaction，whateveritmayhavebeen，bywhichtheseplainshavebeenmodelledintotheirpresentforms，hasbeensingularlyuniform。
Theseplainsorgreatterraces，ofwhichthreeandfouroftenriselikestepsonebehindtheother，areformedbythedenudationoftheoldPatagoniantertiarybeds，andbythedepositionontheirsurfacesofamassofwell-roundedgravel，varying，nearthecoast，fromtentothirty-fivefeetinthickness，butincreasinginthicknesstowardstheinterior。Thegravelisoftencappedbyathinirregularbedofsandyearth。Theplainsslopeup，thoughseldomsensiblytotheeye，fromthesummitedgeofoneescarpmenttothefootofthenexthighestone。Withinadistanceof150
miles，betweenSantaCruztoPortDesire，wheretheplainsareparticularlywelldeveloped，thereareatleastsevenstagesorsteps，oneabovetheother。Onthethreelowerones，namely，thoseof100feet，250feet，and350feetinheight，existinglittoralshellsareabundantlystrewed，eitheronthesurface，orpartiallyembeddedinthesuperficialsandyearth。Bywhateveractionthesethreelowerplainshavebeenmodelled，soundoubtedlyhaveallthehigherones，uptoaheightof950feetatS。Julian，andof1，200feet(byestimation)alongSt。George’sBay。Ithinkitwillnotbedisputed，consideringthepresenceoftheupraisedmarineshells，thattheseahasbeentheactivepowerduringstagesofsomekindintheelevatoryprocess。
Wewillnowbrieflyconsiderthissubject：ifwelookattheexistingcoast-line，theevidenceofthegreatdenudingpoweroftheseaisverydistinct;for，fromCapeSt。Diego，inlatitude54degrees30’tothemouthoftheRioNegro，inlatitude31degrees(alengthofmorethaneighthundredmiles)，theshoreisformed，withsingularlyfewexceptions，ofboldandnakedcliffs：inmanyplacesthecliffsarehigh;thus，southoftheSantaCruz，theyarebetweeneightandninehundredfeetinheight，withtheirhorizontalstrataabruptlycutoff，showingtheimmensemassofmatterwhichhasbeenremoved。Nearlythiswholelineofcoastconsistsofaseriesofgreaterorlessercurves，thehornsofwhich，andlikewisecertainstraightprojectingportions，areformedofhardrocks;hencetheconcavepartsareevidentlytheeffectandthemeasureofthedenudingactiononthesofterstrata。Atthefootofallthecliffs，theseashoalsverygraduallyfaroutwards;andthebottom，foraspaceofsomemiles，everywhereconsistsofgravel。IcarefullyexaminedthebedoftheseaofftheSantaCruz，andfoundthatitsinclinationwasexactlythesame，bothinamountandinitspeculiarcurvature，withthatofthe355feetplainatthissameplace。If，therefore，thecoast，withthebedoftheadjoiningsea，werenowsuddenlyelevatedoneortwohundredfeet，aninlandlineofcliffs，thatisanescarpment，wouldbeformed，withagravel-cappedplainatitsfootgentlyslopingtothesea，andhavinganinclinationlikethatoftheexisting355feetplain。Fromthedenudingtendencyofthesea，thisnewlyformedplainwouldintimebeeatenbackintoacliff：andrepetitionsofthiselevatoryanddenudingprocesswouldproduceaseriesofgravel-cappedslopingterraces，risingoneaboveanother，likethosefrontingtheshoresofPatagonia。
Thechiefdifficulty(forthereareotherinconsiderableones)onthisview，isthefact，——asfarasIcantrusttwocontinuouslinesofsoundingscarefullytakenbetweenSantaCruzandtheFalklandIslands，andseveralscatteredobservationsonthisandothercoasts，——thatthepebblesatthebottomoftheseaQUICKLYandREGULARLYdecreaseinsizewiththeincreasingdepthanddistancefromtheshore，whereasinthegravelontheslopingplains，nosuchdecreaseinsizewasperceptible。
Table3belowgivestheaverageresultofmanysoundingsofftheSantaCruz：——
TABLE3。
Undertwomilesfromtheshore，manyofthepebbleswereoflargesize，mingledwithsomesmallones。
Column1。Distanceinmilesfromtheshore。
Column2。Depthinfathoms。
Column3。SizeofPebbles。
1。，2。，3。
3to4，11to12，Aslargeaswalnuts;mingledineverycasewithsomesmallerones。
6to7，17to19，Aslargeashazel-nuts。
10to11，23to25，Fromthree-tofour-tenthsofaninchindiameter。
12，30to40，Two-tenthsofaninch。
22to150，45to65，One-tenthofaninch，tothefinestsand。
Iparticularlyattendedtothesizeofthepebblesonthe355feetSantaCruzplain，andInoticedthatonthesummit-edgeofthepresentseacliffsmanywereaslargeashalfaman’shead;andincrossingfromthesecliffstothefootofthenexthighestescarpment，adistanceofsixmiles，I
couldnotobserveanyincreaseintheirsize。Weshallpresentlyseethatthetheoryofaslowandalmostinsensibleriseoftheland，willexplainallthefactsconnectedwiththegravel-cappedterraces，betterthanthetheoryofsuddenelevationsoffromonetotwohundredfeet。
M。d’Orbignyhasargued，fromtheupraisedshellsatSanBlasbeingembeddedinthepositionsinwhichtheylived，andfromthevalvesoftheAzaralabiatahighonthebanksoftheParanabeingunitedandunrolled，thattheelevationofNorthernPatagoniaandofLaPlatamusthavebeensudden;forhethinks，ifithadbeengradual，theseshellswouldallhavebeenrolledonsuccessivebeach-lines。ButinPROTECTEDbays，suchasinthatofBahiaBlanca，wherevertheseaisaccumulatingextensivemud-banks，orwherethewindsquietlyheapupsand-dunes，bedsofshellsmightassuredlybepreservedburiedinthepositionsinwhichtheyhadlived，evenwhilstthelandretainedthesamelevel;any，thesmallest，amountofelevationwoulddirectlyaidintheirpreservation。IsawamultitudeofspotsinBahiaBlancawherethismighthavebeeneffected;andatMaldonadoitalmostcertainlyhasbeeneffected。Inspeakingoftheelevationofthelandhavingbeenslow，Idonotwishtoexcludethesmallstartswhichaccompanyearthquakes，asonthecoastofChile;andbysuchmovementsbedsofshellsmighteasilybeuplifted，eveninpositionsexposedtoaheavysurf，withoutundergoinganyattrition：forinstance，in1835，arockyflatofftheislandofSantaMariawasatoneblowupheavedabovehigh-watermark，andwasleftcoveredwithgapingandputrefyingmussel-shells，stillattachedtothebedonwhichtheyhadlived。IfM。d’Orbignyhadbeenawareofthemanylongparallellinesofsand-hillocks，withinfinitelynumerousshellsoftheMactraandVenus，atalowlevelneartheUruguay;ifhehadseenatBahiaBlancatheimmensesand-dunes，withwater-wornpebblesofpumice，ranginginparallellines，onebehindtheother，upaheightofatleast120feet;ifhehadseenthesand-dunes，withthecountlessPaludestrinas，onthelowplainneartheFortatthisplace，andthatlonglineontheedgeofthecliff，sixtyfeethigherup;ifhehadcrossedthatlongandgreatbeltofparallelsand-dunes，eightmilesinwidth，standingattheheightoffromfortytofiftyfeetabovetheColorado，wheresandcouldnotnowcollect，——Icannotbelievehewouldhavethoughtthattheelevationofthisgreatdistricthadbeensudden。Certainlythesand-dunes(especiallywhenaboundingwithshells)，whichstandinrangesatsomanydifferentlevels，mustallhaverequiredlongtimefortheiraccumulation;
andhenceIdonotdoubtthatthelast100feetofelevationofLaPlataandNorthernPatagoniahasbeenexceedinglyslow。
IfweextendthisconclusiontoCentralandSouthernPatagonia，theinclinationofthesuccessivelyrisinggravel-cappedplainscanbeexplainedquiteaswell，asbythemoreobviousviewalreadygivenofafewcomparativelygreatandsuddenelevations;ineithercasewemustadmitlongperiodsofrest，duringwhichtheseaatedeeplyintotheland。Letussupposethepresentcoasttoriseatanearlyequable，slowrate，yetsufficientlyquicktopreventthewavesquiteremovingeachpartassoonasbroughtup;inthiscaseeveryportionofthepresentbedoftheseawillsuccessivelyformabeach-line，andfrombeingexposedtoalikeactionwillbesimilarlyaffected。Itcannotmattertowhatheightthetidesrise，eveniftofortyfeetasatSantaCruz，fortheywillactwithequalforceandinlikemanneroneachsuccessiveline。Hencethereisnodifficultyinthefactofthe355feetplainatSantaCruzslopingup108feettothefootofthenexthighestescarpment，andyethavingnomarksofanyoneparticularbeach-lineonit;forthewholesurfaceonthisviewhasbeenabeach。Icannotpretendtofollowoutthepreciseactionofthetidal-wavesduringariseoftheland，slow，yetsufficientlyquicktopreventorcheckdenudation：butifitbeanalogoustowhattakesplaceonprotectedpartsofthepresentcoast，wheregravelisnowaccumulatinginlargequantities，aninclinedsurface，thicklycappedbywell-roundedpebblesofaboutthesamesize，wouldbeultimatelyleft。(OntheeasternsideofChiloe，whichislandweshallseeinthenextchapterisnowrising，Iobservedthatallthebeachesandextensivetidal-flatswereformedofshingle。)Onthegravelnowaccumulating，thewaves，aidedbythewind，sometimesthrowupathincoveringofsand，togetherwiththecommoncoast-shells。Shellsthuscastupbygales，would，duringanelevatoryperiod，neveragainbetouchedbythesea。Hence，onthisviewofaslowandgradualrisingoftheland，interruptedbyperiodsofrestanddenudation，wecanunderstandthepebblesbeingofaboutthesamesizeovertheentirewidthofthestep-likeplains，——theoccasionalthincoveringofsandyearth，——andthepresenceofbroken，unrolledfragmentsofthoseshells，whichnowliveexclusivelynearthecoast。
SUMMARYOFRESULTS。
Itmaybeconcludedthatthecoastonthissideofthecontinent，foraspaceofatleast1，180miles，hasbeenelevatedtoaheightof100feetinLaPlata，andof400feetinSouthernPatagonia，withintheperiodofexistingshells，butnotofexistingmammifers。ThatinLaPlatatheelevationhasbeenveryslowlyeffected：thatinPatagoniathemovementmayhavebeenbyconsiderablestarts，butmuchmoreprobablyslowandquiet。Ineithercase，therehavebeenlonginterveningperiodsofcomparativerest，duringwhichtheseacorrodeddeeply，asitisstillcorroding，intotheland。(IsayCOMPARATIVEandnotABSOLUTErest，becausetheseaacts，aswehaveseen，withgreatdenudingpoweronthiswholelineofcoast;andtherefore，duringanelevationoftheland，ifexcessivelyslow(andofcourseduringasubsidenceoftheland)，itisquitepossiblethatlinesofcliffmightbeformed。)Thattheperiodsofdenudationandelevationwerecontemporaneousandequableovergreatspacesofcoast，asshownbytheequableheightsoftheplains;thattherehavebeenatleasteightperiodsofdenudation，andthattheland，uptoaheightoffrom950to1，200feet，hasbeensimilarlymodelledandaffected：thattheareaelevated，inthesouthernmostpartofthecontinent，extendedinbreadthtotheCordillera，andprobablyseawardtotheFalklandIslands;thatnorthward，inLaPlata，thebreadthisunknown，therehavingbeenprobablymorethanoneaxisofelevation;andfinally，that，anteriortotheelevationattestedbytheseupraisedshells，thelandwasdividedbyaStraitwheretheRiverSantaCruznowflows，andthatfurthersouthwardtherewereothersea-straits，sinceclosed。Imayadd，thatatSantaCruz，inlatitude50degreesS。theplainshavebeenupliftedatleast1，400feet，sincetheperiodwhengiganticbouldersweretransportedbetweensixtyandseventymilesfromtheirparentrock，onfloatingicebergs。
Lastly，consideringthegreatupwardmovementswhichthislonglineofcoasthasundergone，andtheproximityofitssouthernhalftothevolcanicaxisoftheCordillera，itishighlyremarkablethatinthemanyfinesectionsexposedinthePampean，Patagoniantertiary，andBoulderformations，Inowhereobservedthesmallestfaultorabruptcurvatureinthestrata。
GRAVELFORMATIONOFPATAGONIA。
Iwillheredescribeinmoredetailthanhasbeenasyetincidentallydone，thenature，origin，andextentofthegreatshinglecoveringofPatagonia：
butIdonotmeantoaffirmthatallofthisshingle，especiallythatonthehigherplains，belongstotherecentperiod。Athinbedofsandyearth，withsmallpebblesofvariousporphyriesandofquartz，coveringalowplainonthenorthsideoftheRioColorado，istheextremenorthernlimitofthisformation。Theselittlepebbleshaveprobablybeenderivedfromthedenudationofamoreregularbedofgravel，cappingtheoldtertiarysandstoneplateauoftheRioNegro。Thegravel-bedneartheRioNegrois，onanaverage，abouttenortwelvefeetinthickness;andthepebblesarelargerthanonthenorthernsideoftheColorado，beingfromoneortwoinchesindiameter，andcomposedchieflyofratherdark-tintedporphyries。
AmongstthemIherefirstnoticedavarietyoftentobereferredto，namely，apeculiargallstone-yellowsiliceousporphyry，frequently，butnotinvariably，containinggrainsofquartz。Thepebblesareembeddedinawhite，gritty，calcareousmatrix，verylikemortar，sometimesmerelycoatingwithawhitewashtheseparatestones，andsometimesformingthegreaterpartofthemass。InoneplaceIsawinthegravelconcretionarynodules(notrounded)ofcrystallisedgypsum，someaslargeasaman’shead。Itracedthisbedforforty-fivemilesinland，andwasassuredthatitextendedfarintotheinterior。Asthesurfaceofthecalcareo-
argillaceousplainofPampeanformation，onthenorthernsideofthewidevalleyoftheColorado，standsataboutthesameheightwiththemortar-
likecementedgravelcappingthesandstoneonthesouthernside，itisprobable，consideringtheapparentequabilityofthesubterraneanmovementsalongthissideofAmerica，thatthisgraveloftheRioNegroandtheupperbedsofthePampeanformationnorthwardoftheColorado，areofnearlycontemporaneousorigin，andthatthecalcareousmatterhasbeenderivedfromthesamesource。
SouthwardoftheRioNegro，thecliffsalongthegreatbayofS。Antonioarecappedwithgravel：atSanJosef，IfoundthatthepebblescloselyresembledthoseontheplainoftheRioNegro，butthattheywerenotcementedbycalcareousmatter。BetweenSanJosefandPortDesire，IwasassuredbytheOfficersoftheSurveythatthewholefaceofthecountryiscoatedwithgravel。AtPortDesireandoveraspaceoftwenty-fivemilesinland，onthethreestep-formedplainsandinthevalleys，Ieverywherepassedovergravelwhich，wherethickest，wasbetweenthirtyandfortyfeet。Here，asinotherpartsofPatagonia，thegravel，oritssandycovering，was，aswehaveseen，oftenstrewedwithrecentmarineshells。
Thesandycoveringsometimesfillsupfurrowsinthegravel，asdoesthegravelintheunderlyingtertiaryformations。Thepebblesarefrequentlywhitewashedandevencementedtogetherbyapeculiar，white，friable，aluminous，fusiblesubstance，whichIbelieveisdecomposedfeldspar。AtPortDesire，thegravelrestedsometimesonthebasalformationofporphyry，andsometimesontheupperorthelowerdenudedtertiarystrata。
Itisremarkablethatmostoftheporphyriticpebblesdifferfromthosevarietiesofporphyrywhichoccurhereabundantlyinsitu。Thepeculiargallstone-yellowvarietywascommon，butlessnumerousthanatPortS。
Julian，whereitformednearlyone-thirdofthemassofthegravel;theremainingpartthereconsistingofpalegreyandgreenishporphyrieswithmanycrystalsoffeldspar。AtPortS。Julian，Iascendedoneoftheflat-
toppedhills，thedenudedremnantofthehighestplain，andfoundit，attheheightof950feet，cappedwiththeusualbedofgravel。
NearthemouthoftheSantaCruz，thebedofgravelonthe355feetplainisfromtwentytoaboutthirty-fivefeetinthickness。Thepebblesvaryfromminuteonestothesizeofahen’segg，andeventothatofhalfaman’shead;theyconsistofpalervarietiesofporphyrythanthosefoundfurthernorthward，andtherearefewerofthegallstone-yellowkind;
pebblesofcompactblackclay-slatewereherefirstobserved。Thegravel，aswehaveseen，coversthestep-formedplainsatthemouth，head，andonthesidesofthegreatvalleyoftheSantaCruz。Atadistanceof110milesfromthecoast，theplainhasrisentotheheightof1，416feetabovethesea;andthegravel，withtheassociatedgreatboulderformation，hasattainedathicknessof212feet。Theplain，apparentlywithitsusualgravelcovering，slopesuptothefootoftheCordilleratotheheightofbetween3，200and3，300feet。Inascendingthevalley，thegravelgraduallybecomesentirelyalteredincharacter：highup，wehavepebblesofcrystallinefeldspathicrocks，compactclay-slate，quartzoseschists，andpale-colouredporphyries;theserocks，judgingbothfromthegiganticbouldersinthesurfaceandfromsomesmallpebblesembeddedbeneath700
feetinthicknessoftheoldtertiarystrata，aretheprevailingkindsinthispartoftheCordillera;pebblesofbasaltfromtheneighbouringstreamsofbasalticlavaarealsonumerous;therearefewornoneofthereddishorofthegallstone-yellowporphyriessocommonnearthecoast。
Hencethepebblesonthe350feetplainatthemouthoftheSantaCruzcannothavebeenderived(withtheexceptionofthoseofcompactclay-
slate，which，however，mayequallywellhavecomefromthesouth)fromtheCordillerainthislatitude;butprobably，inchiefpart，fromfarthernorth。
SouthwardoftheSantaCruz，thegravelmaybeseencontinuouslycappingthegreat840feetplain：attheRioGallegos，wherethisplainissucceededbyalowerone，thereis，asIaminformedbyCaptainSulivan，anirregularcoveringofgravelfromtentotwelvefeetinthicknessoverthewholecountry。ThedistrictoneachsideoftheStraitofMagellaniscoveredupeitherwithgravelortheboulderformation：itwasinterestingtoobservethemarkeddifferencebetweentheperfectlyroundedstateofthepebblesinthegreatshingleformationofPatagonia，andthemoreorlessangularfragmentsintheboulderformation。ThepebblesandfragmentsneartheStraitofMagellannearlyallbelongtorocksknowntooccurinFuegia。
IwasthereforemuchsurprisedindredgingsouthoftheStraittofind，inlatitude54degrees10’south，manypebblesofthegallstone-yellowsiliceousporphyry;IprocuredothersfromagreatdepthoffStatenIsland，andotherswerebroughtmefromthewesternextremityoftheFalklandIslands。(Atmyrequest，Mr。KentcollectedformeabagofpebblesfromthebeachofWhiteRockharbour，inthenorthernpartofthesound，betweenthetwoFalklandIslands。Outofthesewell-roundedpebbles，varyinginsizefromawalnuttoahen’segg，withsomelarger，thirty-eightevidentlybelongedtotherocksoftheseislands;twenty-sixweresimilartothepebblesofporphyryfoundonthePatagonianplains，whichrocksdonotexistinsituintheFalklands;onepebblebelongedtothepeculiaryellowsiliceousporphyry;thirtywereofdoubtfulorigin。)Thedistributionofthepebblesofthispeculiarporphyry，whichIventuretoaffirmisnotfoundinsitueitherinFuegia，theFalklandIslands，oronthecoastofPatagonia，isveryremarkable，fortheyarefoundoveraspaceof840milesinanorthandsouthline，andattheFalklands，300mileseastwardofthecoastofPatagonia。TheiroccurrenceinFuegiaandtheFalklandsmay，however，perhapsbeduetothesameice-agencybywhichthebouldershavebeentheretransported。
WehaveseenthatporphyriticpebblesofasmallsizearefirstmetwithonthenorthernsideoftheRioColorado，thebedbecomingwelldevelopedneartheRioNegro：fromthislatterpointIhaveeveryreasontobelievethatthegravelextendsuninterruptedlyovertheplainsandvalleysofPatagoniaforatleast630nauticalmilessouthwardtotheRioGallegos。Fromtheslopeoftheplains，fromthenatureofthepebbles，fromtheirextensionattheRioNegrofarintotheinterior，andattheSantaCruzcloseuptotheCordillera，IthinkithighlyprobablethatthewholebreadthofPatagoniaisthuscovered。Ifso，theaveragewidthofthebedmustbeabouttwohundredmiles。Nearthecoastthegravelisgenerallyfromtentothirtyfeetinthickness;andasinthevalleyofSantaCruzitattains，atsomedistancefromtheCordillera，athicknessof214feet，wemay，I
think，safelyassumeitsaveragethicknessoverthewholeareaof630by200miles，atfiftyfeet！
Thetransportalandoriginofthisvastbedofpebblesisaninterestingproblem。Fromthemannerinwhichtheycapthestep-formedplains，wornbytheseawithintheperiodofexistingshells，theirdeposition，atleastontheplainsuptoaheightof400feet，musthavebeenarecentgeologicalevent。Fromtheformofthecontinent，wemayfeelsurethattheyhavecomefromthewestward，probably，inchiefpartfromtheCordillera，but，perhaps，partlyfromunknownrockyridgesinthecentraldistrictsofPatagonia。Thatthepebbleshavenotbeentransportedbyrivers，fromtheinteriortowardsthecoast，wemayconcludefromthefewnessandsmallnessofthestreamsofPatagonia：moreover，inthecaseoftheonegreatandrapidriverofSantaCruz，wehavegoodevidencethatitstransportingpowerisverytrifling。Thisriverisfromtwotothreehundredyardsinwidth，aboutseventeenfeetdeepinitsmiddle，andrunswithasingulardegreeofuniformityfiveknotsanhour，withnolakesandscarcelyanystillreaches：nevertheless，togiveoneinstanceofitssmalltransportingpower，uponcarefulexamination，pebblesofcompactbasaltcouldnotbefoundinthebedoftheriveratagreaterdistancethantenmilesbelowthepointwherethestreamrushesoverthedebrisofthegreatbasalticcliffsformingitsshore：fragmentsoftheCELLULARvarietieshavebeenwasheddowntwiceorthriceasfar。ThatthepebblesinCentralandNorthernPatagoniahavenotbeentransportedbyice-agency，asseemstohavebeenthecasetoaconsiderableextentfarthersouth，andlikewiseinthenorthernhemisphere，wemayconclude，fromtheabsenceofallangularfragmentsinthegravel，andfromthecompletecontrastinmanyotherrespectsbetweentheshingleandneighbouringboulderformation。
Lookingtothegravelonanyoneofthestep-formedplains，Icannotdoubt，fromtheseveralreasonsassignedinthischapter，thatithasbeenspreadoutandleveledbythelong-continuedactionofthesea，probablyduringtheslowriseoftheland。Thesmoothandperfectlyroundedconditionoftheinnumerablepebblesalonewouldprovelong-continuedaction。Buthowthewholemassofshingleonthecoast-plainshasbeentransportedfromthemountainsoftheinterior，isanotherandmoredifficultquestion。Thefollowingconsiderations，however，showthattheseabyitsordinaryactionhasconsiderablepowerindistributingpebbles。Table3aboveshowshowveryuniformlyandgraduallythepebblesdecreaseinsizewiththegraduallyseawardincreasingdepthanddistance。(Imaymention，thatatthedistanceof150milesfromthePatagonianshoreIcarefullyexaminedtheminuteroundedparticlesinthesand，andfoundthemtobefusibleliketheporphyriesofthegreatshinglebed。Icouldevendistinguishparticlesofthegallstone-yellowporphyry。Itwasinterestingtonoticehowgraduallytheparticlesofwhitequartzincreased，asweapproachedtheFalklandIslands，whicharethusconstituted。InthewholelineofsoundingsbetweentheseislandsandthecoastofPatagoniadeadorlivingorganicremainsweremostrare。Ontherelationsbetweenthedepthofwaterandthenatureofthebottom，seeMartinWhiteon“SoundingsintheChannel“pages4，6，175;alsoCaptainBeechey’s“VoyagetothePacific“
chapter18。)Aseriesofthiskindirresistiblyleadstotheconclusion，thattheseahasthepowerofsiftinganddistributingtheloosematteronitsbottom。AccordingtoMartinWhite，thebedoftheBritishChannelisdisturbedduringgalesatdepthsofsixty-threeandsixty-sevenfathoms，andatthirtyfathoms，shingleandfragmentsofshellsareoftendeposited，afterwardstobecarriedawayagain。(“SoundingsintheChannel“pages4，166。M。Siaustates(“EdinburghNewPhilosophicalJournal“volume31page246)，thathefoundthesediment，atadepthof188metres，arrangedinripplesofdifferentdegreesoffineness。TherearesomeexcellentdiscussionsonthisandalliedsubjectsinSirH。DelaBeche’s“TheoreticalResearches。”)Groundswells，whicharebelievedtobecausedbydistantgales，seemespeciallytoaffectthebottom：atsuchtimes，accordingtoSirR。Schomburgk，theseatoagreatdistanceroundtheWestIndianIslands，atdepthsfromfivetofifteenfathoms，becomesdiscoloured，andeventheanchorsofvesselshavebeenmoved。(“JournalofRoyalGeographicalSociety“volume5page25。ItappearsfromMr。ScottRussell’sinvestigations(seeMr。Murchison’s“AnniversaryAddressGeologicalSociety“1843page40)，thatinwavesoftranslationthemotionoftheparticlesofwaterisnearlyasgreatatthebottomasatthetop。)
Thereare，however，somedifficultiesinunderstandinghowtheseacantransportpebbleslyingatthebottom，for，fromexperimentsinstitutedonthepowerofrunningwater，itwouldappearthatthecurrentsoftheseahavenotsufficientvelocitytomovestonesofevenmoderatesize：
moreover，Ihaverepeatedlyfoundinthemostexposedsituationsthatthepebbleswhichlieatthebottomareencrustedwithfull-grownlivingcorallines，furnishedwiththemostdelicate，yetunbrokenspines：forinstance，intenfathomswateroffthemouthoftheSantaCruz，manypebbles，underhalfaninchindiameter，werethuscoatedwithFlustraceanzoophytes。(Apebble，oneandahalfinchsquareandhalfaninchthick，wasgivenme，dredgedupfromtwenty-sevenfathomsdepthoffthewesternendoftheFalklandIslands，wheretheseaisremarkablystormy，andsubjecttoviolenttides。Thispebblewasencrustedonallsidesbyadelicatelivingcoralline。Ihaveseenmanypebblesfromdepthsbetweenfortyandseventyfathomsthusencrusted;onefromthelatterdepthoffCapeHorn。)Hencewemustconcludethatthesepebblesarenotoftenviolentlydisturbed：itshould，however，beborneinmindthatthegrowthofcorallinesisrapid。Theview，propoundedbyProfessorPlayfair，will，I
believe，explainthisapparentdifficulty，——namely，thatfromtheundulationsoftheseaTENDINGtoliftupanddownpebblesorotherloosebodiesatthebottom，suchareliable，whenthusquiteorpartiallyraised，tobemovedevenbyaverysmallforce，alittleonwards。Wecanthusunderstandhowoceanicortidalcurrentsofnogreatstrength，orthatrecoilmovementofthebottom-waterneartheland，calledbysailorsthe“undertow“(whichIpresumemustextendoutseawardasfarastheBREAKING
wavesimpelthesurface-watertowardsthebeach)，maygainthepowerduringstormsofsiftinganddistributingpebblesevenofconsiderablesize，andyetwithoutsoviolentlydisturbingthemastoinjuretheencrustingcorallines。(Imaytakethisopportunityofremarkingonasingular，butverycommoncharacterintheformofthebottom，inthecreekswhichdeeplypenetratethewesternshoresofTierradelFuego;namely，thattheyarealmostinvariablymuchshallowerclosetotheopenseaattheirmouthsthaninland。Thus，Cook，inenteringChristmasSound，firsthadsoundingsinthirty-sevenfathoms，theninfifty，theninsixty，andalittlefartherinnobottomwith170fathoms。Thesealersaresofamiliarwiththisfact，thattheyalwayslookoutforanchorageneartheentrancesofthecreeks。
See，also，onthissubject，the“Voyagesofthe’Adventure’and’Beagle’“
volume1page375and“Appendix“page313。ThisShoalnessofthesea-
channelsneartheirentrancesprobablyresultsfromthequantityofsedimentformedbythewearandtearoftheouterrocksexposedtothefullforceoftheopensea。Ihavenodoubtthatmanylakes，forinstanceinScotland，whichareverydeepwithin，andareseparatedfromtheseaapparentlyonlybyatractofdetritus，wereoriginallysea-channelswithbanksofthisnatureneartheirmouths，whichhavesincebeenupheaved。)
Theseaactsinanotheranddistinctmannerinthedistributionofpebbles，namelybythewavesonthebeach。Mr。Palmer，inhisexcellentmemoironthissubject，hasshownthatvastmassesofshingletravelwithsurprisingquicknessalonglinesofcoast，accordingtothedirectionwithwhichthewavesbreakonthebeachandthatthisisdeterminedbytheprevailingdirectionofthewinds。(“PhilosophicalTransactions“1834page576。)Thisagencymustbepowerfulinminglingtogetheranddisseminatingpebblesderivedfromdifferentsources：wemay，perhaps，thusunderstandthewidedistributionofthegallstone-yellowporphyry;andlikewise，perhaps，thegreatdifferenceinthenatureofthepebblesatthemouthoftheSantaCruzfromthoseinthesamelatitudeattheheadofthevalley。
IwillnotpretendtoassigntotheseseveralandcomplicatedagenciestheirsharesinthedistributionofthePatagonianshingle：butfromtheseveralconsiderationsgiveninthischapter，andImayadd，fromthefrequencyofacappingofgravelontertiarydepositsinallpartsoftheworld，asIhavemyselfobservedandseenstatedintheworksofvariousauthors，Icannotdoubtthatthepowerofwidelydispersinggravelisanordinarycontingentontheactionofthesea;andthateveninthecaseofthegreatPatagonianshingle-bedwehavenooccasiontocallintheaidofdebacles。IatonetimeimaginedthatperhapsanimmenseaccumulationofshinglehadoriginallybeencollectedatthefootoftheCordillera;andthatthisaccumulation，whenupraisedabovethelevelofthesea，hadbeeneatenintoandpartiallyspreadout(asoffthepresentlineofcoast);andthatthenewly-spreadoutbedhadinitsturnbeenupraised，eateninto，andre-spreadout;andsoonwards，untiltheshingle，whichwasfirstaccumulatedingreatthicknessatthefootoftheCordillera，hadreachedinthinnerbedsitspresentextension。BywhatevermeansthegravelformationofPatagoniamayhavebeendistributed，thevastnessofitsarea，itsthickness，itssuperficialposition，itsrecentorigin，andthegreatdegreeofsimilarityinthenatureofitspebbles，allappeartomewelldeservingtheattentionofgeologists，inrelationtotheoriginofthewidely-spreadbedsofconglomeratebelongingtopastepochs。
FORMATIONOFCLIFFS。
(DIAGRAM7——SECTIONOFCOAST-CLIFFSANDBOTTOMOFSEA，OFFTHEISLANDOF
ST。HELENA。
Heightinfeetabovesealevel。
Depthsinfathoms。
Verticalandhorizontalscale，twoinchestoanauticalmile。Thepointmarked1，600feetisatthefootofHighKnoll;pointmarked510feetisontheedgeofLadderHill。Thestrataconsistofbasalticstreams。
Sectionlefttoright：
HeightatthefootofHighKnoll：1，600attopofstrata。
HeightontheedgeofLadderHill：510attopofstrata。
Bottomatcoastrockyonlytoadepthoffiveorsixfathoms。
30fathoms：bottommudandsand。
100fathomsslopingmoresharplyto250fathoms。)
Whenviewingthesea-worncliffsofPatagonia，insomepartsbetweeneighthundredandninehundredfeetinheight，andformedofhorizontaltertiarystrata，whichmustoncehaveextendedfarseaward——oragain，whenviewingtheloftycliffsroundmanyvolcanicislands，inwhichthegentleinclinationofthelava-streamsindicatestheformerextensionoftheland，adifficultyoftenoccurredtome，namely，howthestratacouldpossiblyhavebeenremovedbytheactionoftheseaataconsiderabledepthbeneathitssurface。ThesectioninDiagram7，whichrepresentsthegeneralformofthelandonthenorthernandleewardsideofSt。Helena(takenfromMr。
Seale’slargemodelandvariousmeasurements)，andofthebottomoftheadjoiningsea(takenchieflyfromCaptainAustin’ssurveyandsomeoldcharts)，willshowthenatureofthisdifficulty。
If，asseemsprobable，thebasalticstreamswereoriginallyprolongedwithnearlytheirpresentinclination，theymust，asshownbythedottedlineinthesection，oncehaveextendedatleasttoapoint，nowcoveredbytheseatoadepthofnearlythirtyfathoms：butIhaveeveryreasontobelievetheyextendedconsiderablyfurther，fortheinclinationofthestreamsislessnearthecoastthanfurtherinland。Itshouldalsobeobserved，thatothersectionsonthecoastofthisislandwouldhavegivenfarmorestrikingresults，butIhadnottheexactmeasurements;thus，onthewindwardside，thecliffsareabouttwothousandfeetinheightandthecut-offlavastreamsverygentlyinclined，andthebottomoftheseahasnearlyasimilarslopeallroundtheisland。How，then，hasallthehardbasalticrock，whichonceextendedbeneaththesurfaceofthesea，beenwornaway？AccordingtoCaptainAustin，thebottomisunevenandrockyonlytothatverysmalldistancefromthebeachwithinwhichthedepthisfromfivetosixfathoms;outsidethisline，toadepthofaboutonehundredfathoms，thebottomissmooth，gentlyinclined，andformedofmudandsand;
outsidetheonehundredfathoms，itplungessuddenlyintounfathomabledepths，asissoverycommonlythecaseonallcoastswheresedimentisaccumulating。Atgreaterdepthsthanthefiveorsixfathoms，itseemsimpossible，underexistingcircumstances，thattheseacanbothhavewornawayhardrock，inpartstoathicknessofatleast150feet，andhavedepositedasmoothbedoffinesediment。Now，ifwehadanyreasontosupposethatSt。Helenahad，duringalongperiod，goneonslowlysubsiding，everydifficultywouldberemoved：forlookingatthediagram，andimaginingafreshamountofsubsidence，wecanseethatthewaveswouldthenactonthecoast-cliffswithfreshandunimpairedvigour，whilsttherockyledgenearthebeachwouldbecarrieddowntothatdepth，atwhichsandandmudwouldbedepositedonitsbareandunevensurface：aftertheformationneartheshoreofanewrockyshoal，freshsubsidencewouldcarryitdownandallowittobesmoothlycoveredup。Butinthecaseofthemanycliff-boundedislands，forinstanceinsomeoftheCanaryIslandsandofMadeira，roundwhichtheinclinationofthestratashowsthatthelandonceextendedfarintothedepthsofthesea，wherethereisnoapparentmeansofhardrockbeingwornaway——arewetosupposethatalltheseislandshaveslowlysubsided？Madeira，Imayremark，has，accordingtoMr。SmithofJordanHill，subsided。Arewetoextendthisconclusiontothehigh，cliff-
bound，horizontallystratifiedshoresofPatagonia，offwhich，thoughthewaterisnotdeepevenatthedistanceofseveralmiles，yetthesmoothbottomofpebblesgraduallydecreasinginsizewiththeincreasingdepth，andderivedfromaforeignsource，seemtodeclarethattheseaisnowadepositingandnotacorrodingagent？Iammuchinclinedtosuspect，thatweshallhereafterfindinallsuchcases，thatthelandwiththeadjoiningbedoftheseahasintruthsubsided：thetimewill，Ibelieve，come，whengeologistswillconsideritasimprobable，thatthelandshouldhaveretainedthesamelevelduringawholegeologicalperiod，asthattheatmosphereshouldhaveremainedabsolutelycalmduringanentireseason。
CHAPTERII。ONTHEELEVATIONOFTHEWESTERNCOASTOFSOUTHAMERICA。
ChonosArchipelago。
Chiloe，recentandgradualelevationof，traditionsoftheinhabitantsonthissubject。
Concepcion，earthquakeandelevationof。
VALPARAISO，greatelevationof，upraisedshells，earthofmarineorigin，gradualriseofthelandwithinthehistoricalperiod。
COQUIMBO，elevationof，inrecenttimes;terracesofmarineorigin，theirinclination，theirescarpmentsnothorizontal。
Guasco，gravelterracesof。
Copiapo。
PERU。
UpraisedshellsofCobija，Iquique，andArica。
Lima，shell-bedsandsea-beachonSanLorenzo，humanremains，fossilearthenware，earthquakedebacle，recentsubsidence。
Onthedecayofupraisedshells。
Generalsummary。
Commencingatthesouthandproceedingnorthward，thefirstplaceatwhichIlanded，wasatCapeTresMontes，inlatitude46degrees35’。Here，ontheshoresofChristmasCove，Iobservedinseveralplacesabeachofpebbleswithrecentshells，abouttwentyfeetabovehigh-watermark。SouthwardofTresMontes(betweenlatitude47and48degrees)，Byronremarks，“Wethoughtitverystrange，thatuponthesummitsofthehighesthillswerefoundbedsofshells，afootortwothick。”(“NarrativeoftheLossofthe’Wager’。”)IntheChonosArchipelago，theislandofLemus(latitude44
degrees30’)was，accordingtoM。Coste，suddenlyelevatedeightfeet，duringtheearthquakeof1829：headds，“Desrochesjadistoujourscouvertesparlamer，restantaujourd’huiconstammentdecouvertes。”
(“ComptesRendus“October1838page706。)Inotherpartsofthisarchipelago，Iobservedtwoterracesofgravel，abuttingtothefootofeachother：atLowe’sHarbour(43degrees48’)，underagreatmassoftheboulderformation，aboutthreehundredfeetinthickness，Ifoundalayerofsand，withnumerouscomminutedfragmentsofsea-shells，havingafreshaspect，buttoosmalltobeidentified。
THEISLANDOFCHILOE。
Theevidenceofrecentelevationisheremoresatisfactory。ThebayofSanCarlosisinmostpartsboundedbyprecipitouscliffsfromabouttentofortyfeetinheight，theirbasesbeingseparatedfromthepresentlineoftidalactionbyatalus，afewfeetinheight，coveredwithvegetation。Inoneshelteredcreek(westofP。Arena)，insteadofaloosetalus，therewasabareslopingbankoftertiarymudstone，perforated，abovethelineofthehighesttides，bynumerousshellsofaPholasnowcommonintheharbour。
Theupperextremitiesoftheseshells，standinguprightintheirholeswithgrassgrowingoutofthem，wereabradedaboutaquarterofaninch，tothesamelevelwiththesurroundingwornstrata。Inotherparts，Iobserved(asatPudeto)agreatbeach，formedofcomminutedshells，twentyfeetabovethepresentshore。Inotherpartsagain，thereweresmallcaveswornintothefootofthelowcliffs，andprotectedfromthewavesbythetaluswithitsvegetation：onesuchcave，whichIexamined，haditsmouthabouttwentyfeet，anditsbottom，whichwasfilledwithsandcontainingfragmentsofshellsandlegsofcrabs，fromeighttotenfeetabovehigh-watermark。
>Fromtheseseveralfacts，andfromtheappearanceoftheupraisedshells，I
inferredthattheelevationhadbeenquiterecent;andoninquiringfromMr。Williams，thePortmaster，hetoldmehewasconvincedthatthelandhadrisen，ortheseafallen，fourfeetwithinthelastfouryears。Duringthisperiod，therehadbeenonesevereearthquake，butnoparticularchangeoflevelwasthenobserved;fromthehabitsofthepeoplewhoallkeepboatsintheprotectedcreeks，itisabsolutelyimpossiblethatariseoffourfeetcouldhavetakenplacesuddenlyandbeenunperceived。Mr。Williamsbelievesthatthechangehasbeenquitegradual。Withouttheelevatorymovementcontinuesataquickrate，therecanbenodoubtthattheseawillsoondestroythetalusofearthatthefootofthecliffsroundthebay，andwillthenreachitsformerlateralextension，butnotofcourseitsformerlevel：someoftheinhabitantsassuredmethatonesuchtalus，withafootpathonit，wasevenalreadysensiblydecreasinginwidth。
Ireceivedseveralaccountsofbedsofshells，existingatconsiderableheightsintheinlandpartsofChiloe;andtooneofthese，nearCatiman，I
wasguidedbyacountryman。Here，onthesouthsideofthepeninsulaofLacuy，therewasanimmensebedoftheVenuscostellataandofanoyster，lyingonthesummit-edgeofapieceoftableland，350feet(bythebarometer)abovethelevelofthesea。Theshellswerecloselypackedtogether，embeddedinandcoveredbyaveryblack，damp，peatymould，twoorthreefeetinthickness，outofwhichaforestofgreattreeswasgrowing。Consideringthenatureanddampnessofthispeatysoil，itissurprisingthatthefineridgesontheoutsideoftheVenusareperfectlypreserved，thoughalltheshellshaveablackenedappearance。Ididnotdoubtthattheblacksoil，whichwhendry，cakeshard，wasentirelyofterrestrialorigin，butonexaminingitunderthemicroscope，Ifoundmanyveryminuteroundedfragmentsofshells，amongstwhichIcoulddistinguishbitsofSerpulaeandmussels。TheVenuscostellata，andtheOstrea(O。
edulis，accordingtoCaptainKing)arenowthecommonestshellsintheadjoiningbays。Inabedofshells，afewfeetbelowthe350feetbed，I
foundahornofthelittleCervushumilis，whichnowinhabitsChiloe。
TheeasternorinlandsideofChiloe，withitsmanyadjacentislets，consistsoftertiaryandboulderdeposits，wornintoirregularplainscappedbygravel。NearCastro，andfortenmilessouthward，andontheisletofLemuy，Ifoundthesurfaceofthegroundtoaheightofbetweentwentyandthirtyfeetabovehigh-watermark，andinseveralplacesapparentlyuptofiftyfeet，thicklycoatedbymuchcomminutedshells，chieflyoftheVenuscostellataandMytilusChiloensis;thespeciesnowmostabundantonthislineofcoast。Astheinhabitantscarryimmensenumbersoftheseshellsinland，thecontinuityofthebedatthesameheightwasoftentheonlymeansofrecognisingitsnaturalorigin。NearCastro，oneachsideofthecreekandrivuletoftheGamboa，threedistinctterracesareseen：thelowestwasestimatedataboutonehundredandfiftyfeetinheight，andthehighestataboutfivehundredfeet，withthecountryirregularlyrisingbehindit;obscuretraces，also，ofthesesameterracescouldbeseenalongotherpartsofthecoast。Therecanbenodoubtthattheirthreeescarpmentsrecordpausesintheelevationoftheisland。ImayremarkthatseveralpromontorieshavethewordHuapi，whichsignifiesintheIndiantongue，island，appendedtothem，suchasHuapilinao，Huapilacuy，Caucahuapi，etc。;andthese，accordingtoIndiantraditions，onceexistedasislands。InthesamemannerthetermPuloinSumatraisappendedtothenamesofpromontories，traditionallysaidtohavebeenislands(Marsden’s“Sumatra“page31。);inSumatra，asinChiloe，thereareupraisedrecentshells。TheBayofCarelmapu，onthemainlandnorthofChiloe，accordingtoAguerros，wasin1643agoodharbour(“DescripcionHist。delaProvinciadeChiloe“page78。FromtheaccountgivenbytheoldSpanishwriters，itwouldappearthatseveralotherharbours，betweenthispointandConcepcion，wereformerlymuchdeeperthantheynoware。);itisnowquiteuseless，exceptforboats。
VALDIVIA。
Ididnotobservehereanydistinctproofsofrecentelevation;butinabedofverysoftsandstone，formingafringe-likeplain，aboutsixtyfeetinheight，roundthehillsofmica-slate，thereareshellsofMytilus，Crepidula，Solen，Novaculina，andCytheraea，tooimperfecttobespecificallyrecognised。AtImperial，seventymilesnorthofValdivia，Aguerrosstatesthattherearelargebedsofshells，ataconsiderabledistancefromthecoast，whichareburntforlime。(Ibidpage25。)TheislandofMocha，lyingalittlenorthofImperial，wasupliftedtwofeet，duringtheearthquakeof1835。(“Voyagesof’Adventure’and’Beagle’“
volume2page415。)
CONCEPCION。
IcannotaddanythingtotheexcellentaccountbyCaptainFitzroyoftheelevationofthelandatthisplace，whichaccompaniedtheearthquakeof1835。(Ibidvolume2page412etseq。Involume5page601ofthe“GeologicalTransactions“Ihavegivenanaccountoftheremarkablevolcanicphenomena，whichaccompaniedthisearthquake。Thesephenomenaappeartometoprovethattheaction，bywhichlargetractsoflandareuplifted，andbywhichvolcaniceruptionsareproduced，isineveryrespectidentical。)Iwillonlyrecalltotherecollectionofgeologists，thatthesouthernendoftheislandofSt。Marywasupliftedeightfeet，thecentralpartnine，andthenorthernendtenfeet;andthewholeislandmorethanthesurroundingdistricts。Greatbedsofmussels，patellae，andchitonsstilladheringtotherockswereupraisedabovehigh-watermark;andsomeacresofarockyflat，whichwasformerlyalwayscoveredbythesea，wasleftstandingdry，andexhaledanoffensivesmell，fromthemanyattachedandputrefyingshells。ItappearsfromtheresearchesofCaptainFitzroythatboththeislandofSt。MaryandConcepcion(whichwasupliftedonlyfourorfivefeet)inthecourseofsomeweekssubsided，andlostpartoftheirfirstelevation。Iwillonlyaddasalessonofcaution，thatroundthesandyshoresofthegreatBayofConcepcion，itwasmostdifficult，owingtotheobliteratingeffectsofthegreataccompanyingwave，torecogniseanydistinctevidenceofthisconsiderableupheaval;onespotmustbeexcepted，wheretherewasadetachedrockwhichbeforetheearthquakehadalwaysbeencoveredbythesea，butafterwardswasleftuncovered。
OntheislandofQuiriquina(intheBayofConcepcion)，Ifound，atanestimatedheightoffourhundredfeet，extensivelayersofshells，mostlycomminuted，butsomeperfectlypreservedandcloselypackedinblackvegetablemould;theyconsistedofConcholepas，Fissurella，Mytilus，Trochus，andBalanus。Someoftheselayersofshellsrestedonathickbedofbright-red，dry，friableearth，cappingthesurfaceofthetertiarysandstone，andextending，asIobservedwhilstsailingalongthecoast，for150milessouthward：atValparaiso，weshallpresentlyseethatasimilarredearthymass，thoughquiteliketerrestrialmould，isreallyinchiefpartofrecentmarineorigin。OntheflanksofthisislandofQuiriquina，atalessheightthanthe400feet，therewerespacesseveralfeetsquare，thicklystrewedwithfragmentsofsimilarshells。Duringasubsequentvisitofthe“Beagle“toConcepcion，Mr。Kent，theassistant-surgeon，wassokindastomakeformesomemeasurementswiththebarometer：hefoundmanymarineremainsalongtheshoresofthewholebay，ataheightofabouttwentyfeet;andfromthehillofSentinellabehindTalcahuano，attheheightof160feet，hecollectednumerousshells，packedtogetherclosebeneaththesurfaceinblackearth，consistingoftwospeciesofMytilus，twoofCrepidula，oneofConcholepas，ofFissurella，Venus，Mactra，Turbo，Monoceros，andtheBalanuspsittacus。Theseshellswerebleached，andwithinsomeoftheBalaniotherBalaniweregrowing，showingthattheymusthavelonglaindeadinthesea。TheabovespeciesIcomparedwithlivingonesfromthebay，andfoundthemidentical;buthavingsincelostthespecimens，Icannotgivetheirnames：thisisoflittleimportance，asMr。
Broderiphasexaminedasimilarcollection，madeduringCaptainBeechey’sexpedition，andascertainedthattheyconsistedoftenrecentspecies，associatedwithfragmentsofEchini，crabs，andFlustrae;someoftheseremainswereestimatedbyLieutenantBelchertolieattheheightofnearlyathousandfeetabovethelevelofthesea。(“ZoologyofCaptainBeechey’sVoyage“page162。)Insomeplacesroundthebay，Mr。KentobservedthattherewerebedsformedexclusivelyoftheMytilusChiloensis：thisspeciesnowlivesinpartsneveruncoveredbythetides。Atconsiderableheights，Mr。Kentfoundonlyafewshells;butfromthesummitofonehill，625feethigh，hebroughtmespecimensoftheConcholepas，MytilusChiloensis，andaTurbo。Theseshellsweresofterandmorebrittlethanthosefromtheheightof164feet;andtheselatterhadobviouslyamuchmoreancientappearancethanthesamespeciesfromtheheightofonlytwentyfeet。
COASTNORTHOFCONCEPCION。
ThefirstpointexaminedwasatthemouthoftheRapel(160milesnorthofConcepcionandsixtymilessouthofValparaiso)，whereIobservedafewshellsattheheightof100feet，andsomebarnaclesadheringtotherocksthreeorfourfeetabovethehighesttides：M。Gayfoundhererecentshellsatthedistanceoftwoleaguesfromtheshore。(“AnnalesdesScienc。Nat。”
Avril1833。)Inlandtherearesomewide，gravel-cappedplains，intersectedbymanybroad，flat-bottomedvalleys(nowcarryinginsignificantstreamlets)，withtheirsidescutintosuccessivewall-likeescarpments，risingoneaboveanother，andinmanyplaces，accordingtoM。Gay，wornintocaves。Theonecave(C。delObispo)whichIexamined，resembledthoseformedonmanysea-coasts，withitsbottomfilledwithshingle。Theseinlandplains，insteadofslopingtowardsthecoast，areinclinedinanoppositedirectiontowardstheCordillera，likethesuccessivelyrisingterracesontheinlandoreasternsideofChiloe：somepointsofgranite，whichprojectthroughtheplainsnearthecoast，nodoubtonceformedachainofoutlyingislands，ontheinlandshoresofwhichtheplainswereaccumulated。AtBucalemu，afewmilesnorthwardoftheRapel，Iobservedatthefoot，andonthesummit-edgeofaplain，tenmilesfromthecoast，manyrecentshells，mostlycomminuted，butsomeperfect。Therewere，also，manyatthebottomofthegreatvalleyoftheMaypu。AtSanAntonio，shellsaresaidtobecollectedandburntforlime。Atthebottomofagreatravine(QuebradaOnda，ontheroadtoCasaBlanca)，atthedistanceofseveralmilesfromthecoast，Inoticedaconsiderablebed，composedexclusivelyofMesodesmadonaciforme，Desh。lyingonabedofmuddysand：thisshellnowlivesassociatedtogetheringreatnumbers，ontidal-flatsonthecoastofChile。
VALPARAISO。
DuringtwosuccessiveyearsIcarefullyexamined，partofthetimeincompanywithMr。Alison，intoallthefactsconnectedwiththerecentelevationofthisneighbourhood。Inverymanypartsabeachofbrokenshells，aboutfourteenorfifteenfeetabovehigh-watermark，maybeobserved;andatthislevelthecoast-rocks，whereprecipitous，arecorrodedinaband。Atonespot，Mr。Alison，byremovingsomebirds’dung，foundatthissamelevelbarnaclesadheringtotherocks。Forseveralmilessouthwardofthebay，almosteveryflatlittleheadland，betweentheheightsof60and230feet(measuredbythebarometer)，issmoothlycoatedbyathickmassofcomminutedshells，ofthesamespecies，andapparentlyinthesameproportionalnumberswiththoseexistingintheadjoiningsea。
TheConcholepasismuchthemostabundant，andthebestpreservedshell;
butIextractedperfectlypreservedspecimensoftheFissurellabiradiata，aTrochusandBalanus(bothwell-known，butaccordingtoMr。Sowerbyyetunnamed)andpartsoftheMytilusChiloensis。Mostoftheseshells，aswellasanencrustingNullipora，partiallyretaintheircolour;buttheyarebrittle，andoftenstainedredfromtheunderlyingbrecciatedmassofprimaryrocks;somearepackedtogether，eitherinblackorreddishmoulds;
somelielooseonthebarerockysurfaces。Thetotalnumberoftheseshellsisimmense;theyarelessnumerous，thoughstillfarfromrare，upaheightof1，000feetabovethesea。Onthesummitofahill，measured557feet，therewasasmallhorizontalbandofcomminutedshells，ofwhichMANY
consisted(andlikewisefromlesserheights)ofveryyoungandsmallspecimensofthestilllivingConcholepas，Trochus，Patellae，Crepidulae，andofMytilusMagellanicus(？)(Mr。Cuminginformsmethathedoesnotthinkthisspeciesidenticalwith，thoughcloselyresembling，thetrueM。
MagellanicusofthesouthernandeasterncoastofSouthAmerica;itlivesabundantlyonthecoastofChile。)：severaloftheseshellswereunderaquarterofaninchintheirgreatestdiameter。Myattentionwascalledtothiscircumstancebyanativefisherman，whomItooktolookattheseshell-beds;andheridiculedthenotionofsuchsmallshellshavingbeenbroughtupforfood;norcouldsomeofthespecieshaveadheredwhenalivetootherlargershells。Onanotherhill，somemilesdistant，and648feethigh，IfoundshellsoftheConcholepasandTrochus，perfect，thoughveryold，withfragmentsofMytilusChiloensis，allembeddedinreddish-brownmould：Ialsofoundthesesamespecies，withfragmentsofanEchinusandofBalanuspsittacus，onahill1，000feethigh。Abovethisheight，shellsbecameveryrare，thoughonahill1，300feethigh(Measuredbythebarometer：thehighestpointintherangebehindValparaisoIfoundtobe1，626feetabovethelevelofthesea。)，IcollectedtheConcholepas，Trochus，Fissurella，andaPatella。Atthesegreaterheightstheshellsarealmostinvariablyembeddedinmould，andsometimesareexposedonlybytearingupbushes。Theseshellsobviouslyhadaverymuchmoreancientappearancethanthosefromthelesserheights;theapicesoftheTrochiwereoftenworndown;thelittleholesmadebyburrowinganimalsweregreatlyenlarged;andtheConcholepaswasoftenperforatedquitethrough，owingtotheinnerplatesofshellhavingscaledoff。
Manyoftheseshells，asIhavesaid，werepackedin，andwerequitefilledwith，blackishorreddish-brownearth，restingonthegraniticdetritus。I
didnotdoubtuntillatelythatthismouldwasofpurelyterrestrialorigin，whenwithamicroscopeexaminingsomeofitfromtheinsideofaConcholepasfromtheheightofaboutonehundredfeet，Ifoundthatitwasinconsiderablepartcomposedofminutefragmentsofthespines，mouth-
bones，andshellsofEchini，andofminutefragments，ofchieflyveryyoungPatellae，Mytili，andotherspecies。IfoundsimilarmicroscopicalfragmentsinearthfillingupthecentralorificesofsomelargeFissurellae。Thisearthwhencrushedemitsasicklysmell，preciselylikethatfromgarden-mouldmixedwithguano。Theearthaccidentallypreservedwithintheshells，fromthegreaterheights，hasthesamegeneralappearance，butitisalittleredder;itemitsthesamesmellwhenrubbed，butIwasunabletodetectwithcertaintyanymarineremainsinit。Thisearthresemblesingeneralappearance，asbeforeremarked，thatcappingtherocksofQuiriquinaintheBayofConcepcion，onwhichbedsofsea-shellslay。Ihave，also，shownthattheblack，peatysoil，inwhichtheshellsattheheightof350feetatChiloewerepacked，containedmanyminutefragmentsofmarineanimals。Thesefactsappeartomeinteresting，astheyshowthatsoils，whichwouldnaturallybeconsideredofpurelyterrestrialnature，mayowetheirorigininchiefparttothesea。
BeingwellawarefromwhatIhaveseenatChiloeandinTierradelFuego，thatvastquantitiesofshellsarecarried，duringsuccessiveages，farinland，wheretheinhabitantschieflysubsistontheseproductions，Iamboundtostatethatatgreaterheightsthan557feet，wherethenumberofveryyoungandsmallshellsprovedthattheyhadnotbeencarriedupforfood，theonlyevidenceoftheshellshavingbeennaturallyleftbythesea，consistsintheirinvariableanduniformappearanceofextremeantiquity——inthedistanceofsomeoftheplacesfromthecoast，inothersbeinginaccessiblefromthenearestpartofthebeach，andintheabsenceoffreshwaterformentodrink——intheshellsNOTLYINGINHEAPS，——and，lastly，intheclosesimilarityofthesoilinwhichtheyareembedded，tothatwhichlowerdowncanbeunequivocallyshowntobeingreatpartformedfromthedebrisoftheseaanimals。(Inthe“ProceedingsoftheGeologicalSociety“volume2page446，IhavegivenabriefaccountoftheupraisedshellsonthecoastofChile，andhavetherestatedthattheproofsofelevationarenotsatisfactoryabovetheheightof230feet。IhadatthattimeunfortunatelyoverlookedaseparatepagewrittenduringmysecondvisittoValparaiso，describingtheshellsnowinmypossessionfromthe557feethill;Ihadnotthenunpackedmycollections，andhadnotreconsideredtheobviousappearanceofgreaterantiquityoftheshellsfromthegreaterheights，norhadIatthattimediscoveredthemarineoriginoftheearthinwhichmanyoftheshellsarepacked。Consideringthesefacts，Idonotnowfeelashadowofdoubtthattheshells，attheheightof1，300
feet，havebeenupraisedbynaturalcausesintotheirpresentposition。)
Withrespecttothepositioninwhichtheshellslie，Iwasrepeatedlystruckhere，atConcepcion，andatotherplaces，withthefrequencyoftheiroccurrenceonthesummitsandedgeseitherofseparatehills，oroflittleflatheadlandsoftenterminatingprecipitouslyoverthesea。Theseveralabove-enumeratedspeciesofmollusca，whicharefoundstrewedonthesurfaceofthelandfromafewfeetabovetheleveloftheseauptotheheightof1，300feet，allnowliveeitheronthebeach，oratonlyafewfathoms’depth：Mr。Edmondston，inalettertoProfessorE。Forbes，statesthatindredgingintheBayofValparaiso，hefoundthecommonspeciesofConcholepas，Fissurella，Trochus，Monoceros，Chitons，etc。livinginabundancefromthebeachtoadepthofsevenfathoms;anddeadshellsoccurredonlyafewfathomsdeeper。ThecommonTurritellacingulatawasdredgeduplivingatevenfromtentofifteenfathoms;butthisisaspecieswhichIdidnotfindhereamongsttheupraisedshells。Consideringthisfactofthespeciesbeingalllittoralorsub-littoral，consideringtheiroccurrenceatvariousheights，theirvastnumbers，andtheirgenerallycomminutedstate，therecanbelittledoubtthattheywereleftonsuccessivebeach-linesduringagradualelevationoftheland。Thepresence，however，ofsomanywholeandperfectlypreservedshellsappearsatfirstadifficultyonthisview，consideringthatthecoastisexposedtothefullforceofanopenocean：butwemaysuppose，eitherthattheseshellswerethrownduringgalesonflatledgesofrockjustabovethelevelofhigh-watermark，andthatduringtheelevationofthelandtheyareneveragaintouchedbythewaves，or，thatduringearthquakes，suchasthoseof1822，1835，and1837，rockyreefscoveredwithmarine-animalswereitoneblowupliftedabovethefuturereachofthesea。Thislatterexplanationis，perhaps，themostprobableonewithrespecttothebedsatConcepcionentirelycomposedoftheMytilusChiloensis，aspecieswhichlivesbelowthelowesttides;andlikewisewithrespecttothegreatbedsoccurringbothnorthandsouthofValparaiso，oftheMesodesmadonaciforme，——ashellwhich，asIaminformedbyMr。Cuming，inhabitssandbanksatthelevelofthelowesttides。ButeveninthecaseofshellshavingthehabitsofthisMytilusandMesodesma，bedsofthem，wherevertheseagentlythrowsupsandormud，andthusprotectsitsownaccumulations，mightbeupraisedbytheslowestmovement，andyetremainundisturbedbythewavesofeachnewbeach-line。
Itisworthyofremark，thatnowherenearValparaisoabovetheheightoftwentyfeet，orrarelyoffiftyfeet，Isawanylinesoferosiononthesolidrocks，oranybedsofpebbles;this，Ibelieve，maybeaccountedforbythedisintegratingtendencyofmostoftherocksinthisneighbourhood。
Noristhelandheremodelledintoterraces：Mr。Alison，however，informsme，thatonbothsidesofonenarrowravine，attheheightof300feetabovethesea，hefoundasuccessionofratherindistinctstep-formedbeaches，composedofbrokenshells，whichtogethercoveredaspaceofabouteightyfeetvertical。
IcanaddnothingtotheaccountsalreadypublishedoftheelevationofthelandatValparaiso，whichaccompaniedtheearthquakeof1822(Dr。Meyen“ReiseumErde“Th。1s。221，foundin1831seaweedandotherbodiesstilladheringtosomerockswhichduringtheshockof1822wereliftedabovethesea。)：butIhearditconfidentlyasserted，thatasentinelonduty，immediatelyaftertheshock，sawapartofafort，whichpreviouslywasnotwithinthelineofhisvision，andthiswouldindicatethattheupliftingwasnothorizontal：itwouldevenappearfromsomefactscollectedbyMr。
Alison，thatonlytheeasternhalfofthebaywasthenelevated。Throughthekindnessofthissamegentleman，Iamabletogiveaninterestingaccountofthechangesoflevel，whichhavesupervenedherewithinhistoricalperiods：abouttheyear1680alongsea-wall(orPrefil)wasbuilt，ofwhichonlyafewfragmentsnowremain;uptotheyear1817，theseaoftenbrokeoverit，andwashedthehousesontheoppositesideoftheroad(wheretheprisonnowstands);andevenin1819，Mr。J。Martinrememberswalkingatthefootofthiswall，andbeingoftenobligedtoclimboverittoescapethewaves。Therenowstands(1834)ontheseawardsideofthiswall，andbetweenitandthebeach，inonepartasinglerowofhouses，andinanotherparttworowswithastreetbetweenthem。Thisgreatextensionofthebeachinsoshortatimecannotbeattributedsimplytotheaccumulationofdetritus;foraresidentengineermeasuredformetheheightbetweenthelowestpartofthewallvisible，andthepresentbeach-lineatspring-tides，andthedifferencewaselevenfeetsixinches。
ThechurchofS。Augustinisbelievedtohavebeenbuiltin1614，andthereisatraditionthattheseaformerlyflowedverynearit;bylevelling，itsfoundationswerefoundtostandnineteenfeetsixinchesabovethehighestbeach-line;sothatweseeinaperiodof220years，theelevationcannothavebeenasmuchasnineteenfeetsixinches。Fromthefactsgivenwithrespecttothesea-wall，andfromthetestimonyoftheelderinhabitants，itappearscertainthatthechangeinlevelbegantobemanifestabouttheyear1817。Theonlysuddenelevationofwhichthereisanyrecordoccurredin1822，andthisseemstohavebeenlessthanthreefeet。Sincethatyear，Iwasassuredbyseveralcompetentobservers，thatpartofanoldwreck，whichisfirmlyembeddednearthebeach，hassensiblyemerged;hencehere，asatChiloe，aslowriseofthelandappearstobenowinprogress。Itseemshighlyprobablethattherockswhicharecorrodedinabandattheheightoffourteenfeetabovetheseawereactedonduringtheperiod，whenbytraditionthebaseofS。Augustinchurch，nownineteenfeetsixinchesabovethehighestwater-mark，wasoccasionallywashedbythewaves。
VALPARAISOTOCOQUIMBO。
