therefore，probably，itwasanestuarydeposit。
　　TheremainsatPuntaAltawereembeddedinstratifiedgravelandreddishmud，justsuchastheseamightnowwashuponashallowbank。Theywereassociatedwithtwenty-threespeciesofshells，ofwhichthirteenarerecentandfourothersverycloselyrelatedtorecentforms。[1]FromthebonesoftheScelidotherium，includingeventheknee-cap，beingintombedintheirproperrelativepositions，andfromtheosseousarmourofthegreatarmadillo-likeanimalbeingsowellpreserved，togetherwiththebonesofoneofitslegs，wemayfeelassuredthattheseremainswerefreshandunitedbytheirligaments，whendepositedinthegraveltogetherwiththeshells。[2]Hencewehavegoodevidencethattheaboveenumeratedgiganticquadrupeds，moredifferentfromthoseofthepresentdaythantheoldestofthetertiaryquadrupedsofEurope，livedwhilsttheseawaspeopledwithmostofitspresentinhabitants；andwehaveconfirmedthatremarkablelawsoofteninsistedonbyMr。Lyell，namely，thatthe“longevityofthespeciesinthemammaliaisuponthewholeinferiortothatofthetestacea。”[3]
　　ThegreatsizeofthebonesoftheMegatheroidanimals，includingtheMegatherium，Megalonyx，Scelidotherium，andMylodon，istrulywonderful。
　　Thehabitsoflifeoftheseanimalswereacompletepuzzletonaturalists，untilProfessorOwen[4]solvedtheproblemwithremarkableingenuity。Theteethindicate，bytheirsimplestructure，thattheseMegatheroidanimalslivedonvegetablefood，andprobablyontheleavesandsmalltwigsoftrees；theirponderousformsandgreatstrongcurvedclawsseemsolittleadaptedforlocomotion，thatsomeeminentnaturalistshaveactuallybelieved，that，likethesloths，towhichtheyareintimatelyrelated，theysubsistedbyclimbingbackdownwardsontrees，andfeedingontheleaves。Itwasabold，nottosaypreposterous，ideatoconceiveevenantediluviantrees，withbranchesstrongenoughtobearanimalsaslargeaselephants。ProfessorOwen，withfarmoreprobability，believesthat，insteadofclimbingonthetrees，theypulledthebranchesdowntothem，andtoreupthesmalleronesbytheroots，andsofedontheleaves。Thecolossalbreadthandweightoftheirhinderquarters，whichcanhardlybeimaginedwithouthavingbeenseen，becomeonthisview，ofobviousservice，insteadofbeinganincumbrance：
　　theirapparentclumsinessdisappears。Withtheirgreattailsandtheirhugeheelsfirmlyfixedlikeatripodontheground，theycouldfreelyexertthefullforceoftheirmostpowerfularmsandgreatclaws。Stronglyrooted，indeed，mustthattreehavebeen，whichcouldhaveresistedsuchforce！TheMylodon，moreover，wasfurnishedwithalongextensiletonguelikethatofthegiraffe，which，byoneofthosebeautifulprovisionsofnature，thusreacheswiththeaidofitslongneckitsleafyfood。Imayremark，thatinAbyssiniatheelephant，accordingtoBruce，whenitcannotreachwithitsproboscisthebranches，deeplyscoreswithitstusksthetrunkofthetree，upanddownandallround，tillitissufficientlyweakenedtobebrokendown。
　　Thebedsincludingtheabovefossilremains，standonlyfromfifteentotwentyfeetabovethelevelofhigh-water；andhencetheelevationofthelandhasbeensmallwithouttherehasbeenanintercalatedperiodofsubsidence，ofwhichwehavenoevidencesincethegreatquadrupedswanderedoverthesurroundingplains；andtheexternalfeaturesofthecountrymustthenhavebeenverynearlythesameasnow。What，itmaynaturallybeasked，wasthecharacterofthevegetationatthatperiod；wasthecountryaswretchedlysterileasitnowis？Assomanyoftheco-embeddedshellsarethesamewiththosenowlivinginthebay，Iwasatfirstinclinedtothinkthattheformervegetationwasprobablysimilartotheexistingone；butthiswouldhavebeenanerroneousinferenceforsomeofthesesameshellsliveontheluxuriantcoastofBrazil；andgenerally，thecharacteroftheinhabitantsoftheseaareuselessasguidestojudgeofthoseontheland。Nevertheless，fromthefollowingconsiderations，IdonotbelievethatthesimplefactofmanygiganticquadrupedshavinglivedontheplainsroundBahiaBlanca，isanysureguidethattheyformerlywereclothedwithaluxuriantvegetation：Ihavenodoubtthatthesterilecountryalittlesouthward，neartheRioNegro，withitsscatteredthornytrees，wouldsupportmanyandlargequadrupeds。
　　Thatlargeanimalsrequirealuxuriantvegetation，hasbeenageneralassumptionwhichhaspassedfromoneworktoanother；butIdonothesitatetosaythatitiscompletelyfalse，andthatithasvitiatedthereasoningofgeologistsonsomepointsofgreatinterestintheancienthistoryoftheworld。TheprejudicehasprobablybeenderivedfromIndia，andtheIndianislands，wheretroopsofelephants，nobleforests，andimpenetrablejungles，areassociatedtogetherineveryone’smind。If，however，werefertoanyworkoftravelsthroughthesouthernpartsofAfrica，weshallfindallusionsinalmosteverypageeithertothedesertcharacterofthecountry，ortothenumbersoflargeanimalsinhabitingit。Thesamethingisrenderedevidentbythemanyengravingswhichhavebeenpublishedofvariouspartsoftheinterior。WhentheBeaglewasatCapeTown，Imadeanexcursionofsomedays’lengthintothecountry，whichatleastwassufficienttorenderthatwhichIhadreadmorefullyintelligible。
　　Dr。AndrewSmith，who，attheheadofhisadventurousparty，haslatelysucceededinpassingtheTropicofCapricorn，informsmethat，takingintoconsiderationthewholeofthesouthernpartofAfrica，therecanbenodoubtofitsbeingasterilecountry。Onthesouthernandsouth-easterncoaststherearesomefineforests，butwiththeseexceptions，thetravellermaypassfordaystogetherthroughopenplains，coveredbyapoorandscantyvegetation。Itisdifficulttoconveyanyaccurateideaofdegreesofcomparativefertility；butitmaybesafelysaidthattheamountofvegetationsupportedatanyonetime[5]byGreatBritain，exceeds，perhapseventenfold，thequantityonanequalarea，intheinteriorpartsofSouthernAfrica。Thefactthatbullock-waggonscantravelinanydirection，exceptingnearthecoast，withoutmorethanoccasionallyhalfanhour’sdelayincuttingdownbushes，gives，perhaps，amoredefinitenotionofthescantinessofthevegetation。Now，ifwelooktotheanimalsinhabitingthesewideplains，weshallfindtheirnumbersextraordinarilygreat，andtheirbulkimmense。Wemustenumeratetheelephant，threespeciesofrhinoceros，andprobably，accordingtoDr。Smith，twoothers，thehippopotamus，thegiraffe，theboscafferaslargeasafull-grownbull，andtheelan——butlittleless，twozebras，andthequaccha，twognus，andseveralantelopesevenlargerthantheselatteranimals。Itmaybesupposedthatalthoughthespeciesarenumerous，theindividualsofeachkindarefew。BythekindnessofDr。Smith，Iamenabledtoshowthatthecaseisverydifferent。Heinformsme，thatinlat。24degs。，inoneday’smarchwiththebullock-waggons，hesaw，withoutwanderingtoanygreatdistanceoneitherside，betweenonehundredandonehundredandfiftyrhinoceroses，whichbelongedtothreespecies：thesamedayhesawseveralherdsofgiraffes，amountingtogethertonearlyahundred；andthatalthoughnoelephantwasobserved，yettheyarefoundinthisdistrict。Atthedistanceofalittlemorethanonehour’smarchfromtheirplaceofencampmentonthepreviousnight，hispartyactuallykilledatonespoteighthippopotamuses，andsawmanymore。Inthissamerivertherewerelikewisecrocodiles。Ofcourseitwasacasequiteextraordinary，toseesomanygreatanimalscrowdedtogether，butitevidentlyprovesthattheymustexistingreatnumbers。Dr。Smithdescribesthecountrypassedthroughthatday，as“beingthinlycoveredwithgrass，andbushesaboutfourfeethigh，andstillmorethinlywithmimosa-trees。”Thewaggonswerenotpreventedtravellinginanearlystraightline。
　　Besidestheselargeanimals，everyonetheleastacquaintedwiththenaturalhistoryoftheCape，hasreadoftheherdsofantelopes，whichcanbecomparedonlywiththeflocksofmigratorybirds。Thenumbersindeedofthelion，panther，andhyaena，andthemultitudeofbirdsofprey，plainlyspeakoftheabundanceofthesmallerquadrupeds：oneeveningsevenlionswerecountedatthesametimeprowlingroundDr。Smith’sencampment。Asthisablenaturalistremarkedtome，thecarnageeachdayinSouthernAfricamustindeedbeterrific！Iconfessitistrulysurprisinghowsuchanumberofanimalscanfindsupportinacountryproducingsolittlefood。Thelargerquadrupedsnodoubtroamoverwidetractsinsearchofit；andtheirfoodchieflyconsistsofunderwood，whichprobablycontainsmuchnutrimentinasmallbulk。Dr。Smithalsoinformsmethatthevegetationhasarapidgrowth；nosoonerisapartconsumed，thanitsplaceissuppliedbyafreshstock。Therecanbenodoubt，however，thatourideasrespectingtheapparentamountoffoodnecessaryforthesupportoflargequadrupedsaremuchexaggerated：
　　itshouldhavebeenrememberedthatthecamel，ananimalofnomeanbulk，hasalwaysbeenconsideredastheemblemofthedesert。
　　Thebeliefthatwherelargequadrupedsexist，thevegetationmustnecessarilybeluxuriant，isthemoreremarkable，becausetheconverseisfarfromtrue。Mr。BurchellobservedtomethatwhenenteringBrazil，nothingstruckhimmoreforciblythanthesplendouroftheSouthAmericanvegetationcontrastedwiththatofSouthAfrica，togetherwiththeabsenceofalllargequadrupeds。
　　InhisTravels，[6]hehassuggestedthatthecomparisonoftherespectiveweightsifthereweresufficientdataofanequalnumberofthelargestherbivorousquadrupedsofeachcountrywouldbeextremelycurious。Ifwetakeontheoneside，theelephant，[7]hippopotamus，giraffe，boscaffer，elan，certainlythree，andprobablyfivespeciesofrhinoceros；andontheAmericanside，twotapirs，theguanaco，threedeer，thevicuna，peccari，capybaraafterwhichwemustchoosefromthemonkeystocompletethenumber，andthenplacethesetwogroupsalongsideeachother，itisnoteasytoconceiveranksmoredisproportionateinsize。
　　Aftertheabovefacts，wearecompelledtoconclude，againstanteriorprobability，[8]thatamongthemammaliathereexistsnocloserelationbetweenthebulkofthespecies，andthe_quantity_ofthevegetation，inthecountrieswhichtheyinhabit。
　　Withregardtothenumberoflargequadrupeds，therecertainlyexistsnoquarteroftheglobewhichwillbearcomparisonwithSouthernAfrica。
　　Afterthedifferentstatementswhichhavebeengiven，theextremelydesertcharacterofthatregionwillnotbedisputed。IntheEuropeandivisionoftheworld，wemustlookbacktothetertiaryepochs，tofindaconditionofthingsamongthemammalia，resemblingthatnowexistingattheCapeofGoodHope。Thosetertiaryepochs，whichweareapttoconsiderasaboundingtoanastonishingdegreewithlargeanimals，becausewefindtheremainsofmanyagesaccumulatedatcertainspots，couldhardlyboastofmorelargequadrupedsthanSouthernAfricadoesatpresent。Ifwespeculateontheconditionofthevegetationduringtheseepochsweareatleastboundsofartoconsiderexistinganalogies，asnottourgeasabsolutelynecessaryaluxuriantvegetation，whenweseeastateofthingssototallydifferentattheCapeofGoodHope。
　　Weknow[9]thattheextremeregionsofNorthAmerica，manydegreesbeyondthelimitwherethegroundatthedepthofafewfeetremainsperpetuallycongealed，arecoveredbyforestsoflargeandtalltrees。Inalikemanner，inSiberia，wehavewoodsofbirch，fir，aspen，andlarch，growinginalatitude[10]64degs。
　　wherethemeantemperatureoftheairfallsbelowthefreezingpoint，andwheretheearthissocompletelyfrozen，thatthecarcassofananimalembeddedinitisperfectlypreserved。Withthesefactswemustgrant，asfaras_quantityalone_ofvegetationisconcerned，thatthegreatquadrupedsofthelatertertiaryepochsmight，inmostpartsofNorthernEuropeandAsia，havelivedonthespotswheretheirremainsarenowfound。Idonotherespeakofthekindofvegetationnecessaryfortheirsupport；because，asthereisevidenceofphysicalchanges，andastheanimalshavebecomeextinct，somaywesupposethatthespeciesofplantshavelikewisebeenchanged。