Thesefactsareofhighgeologicalinterestwithrespecttotheclimateofthenorthernhemisphereattheperiodwhenbouldersweretransported。
Iwillnotheredetailhowsimplythetheoryoficebergsbeingchargedwithfragmentsofrock，explaintheoriginandpositionofthegiganticbouldersofeasternTierradelFuego，onthehighplainofSantaCruz，andontheislandofChiloe。InTierradelFuego，thegreaternumberofboulderslieonthelinesofoldsea-channels，nowconvertedintodryvalleysbytheelevationoftheland。Theyareassociatedwithagreatunstratifiedformationofmudandsand，containingroundedandangularfragmentsofallsizes，whichhasoriginated[15]intherepeatedploughingupofthesea-bottombythestrandingoficebergs，andbythemattertransportedonthem。Fewgeologistsnowdoubtthatthoseerraticboulderswhichlienearloftymountainshavebeenpushedforwardbytheglaciersthemselves，andthatthosedistantfrommountains，andembeddedinsubaqueousdeposits，havebeenconveyedthithereitheronicebergsorfrozenincoast-ice。Theconnectionbetweenthetransportalofbouldersandthepresenceoficeinsomeform，isstrikinglyshownbytheirgeographicaldistributionovertheearth。InSouthAmericatheyarenotfoundfurtherthan48degs。oflatitude，measuredfromthesouthernpole；inNorthAmericaitappearsthatthelimitoftheirtransportalextendsto53。5degs。fromthenorthernpole；butinEuropetonotmorethan40degs。oflatitude，measuredfromthesamepoint。Ontheotherhand，intheintertropicalpartsofAmerica，Asia，andAfrica，theyhaveneverbeenobserved；norattheCapeofGoodHope，norinAustralia。[16]
OntheClimateandProductionsoftheAntarcticIslands——ConsideringtheranknessofthevegetationinTierradelFuego，andonthecoastnorthwardofit，theconditionoftheislandssouthandsouth-westofAmericaistrulysurprising。SandwichLand，inthelatitudeofthenorthpartofScotland，wasfoundbyCook，duringthehottestmonthoftheyear，“coveredmanyfathomsthickwitheverlastingsnow；“andthereseemstobescarcelyanyvegetation。Georgia，anisland96mileslongand10broad，inthelatitudeofYorkshire，“intheveryheightofsummer，isinamannerwhollycoveredwithfrozensnow。”Itcanboastonlyofmoss，sometuftsofgrass，andwildburnet；ithasonlyoneland-bird(Anthuscorrendera)，yetIceland，whichis10degs。nearerthepole，has，accordingtoMackenzie，fifteenland-birds。TheSouthShetlandIslands，inthesamelatitudeasthesouthernhalfofNorway，possessonlysomelichens，moss，andalittlegrass；andLieut。Kendall[17]foundthebay，inwhichhewasatanchor，beginningtofreezeataperiodcorrespondingwithour8thofSeptember。Thesoilhereconsistsoficeandvolcanicashesinterstratified；
andatalittledepthbeneaththesurfaceitmustremainperpetuallycongealed，forLieut。Kendallfoundthebodyofaforeignsailorwhichhadlongbeenburied，withthefleshandallthefeaturesperfectlypreserved。Itisasingularfact，thatonthetwogreatcontinentsinthenorthernhemisphere(butnotinthebrokenlandofEuropebetweenthem)，wehavethezoneofperpetuallyfrozenundersoilinalowlatitude——namely，in56degs。
inNorthAmericaatthedepthofthreefeet，[18]andin62degs。inSiberiaatthedepthoftwelvetofifteenfeet——astheresultofadirectlyoppositeconditionofthingstothoseofthesouthernhemisphere。Onthenortherncontinents，thewinterisrenderedexcessivelycoldbytheradiationfromalargeareaoflandintoaclearsky，norisitmoderatedbythewarmth-bringingcurrentsofthesea；theshortsummer，ontheotherhand，ishot。IntheSouthernOceanthewinterisnotsoexcessivelycold，butthesummerisfarlesshot，forthecloudedskyseldomallowsthesuntowarmtheocean，itselfabadabsorbentofheat：andhencethemeantemperatureoftheyear，whichregulatesthezoneofperpetuallycongealedunder-soil，islow。Itisevidentthatarankvegetation，whichdoesnotsomuchrequireheatasitdoesprotectionfromintensecold，wouldapproachmuchnearertothiszoneofperpetualcongelationundertheequableclimateofthesouthernhemisphere，thanundertheextremeclimateofthenortherncontinents。
Thecaseofthesailor’sbodyperfectlypreservedintheicysoiloftheSouthShetlandIslands(lat。62to63degs。S。)，inaratherlowerlatitudethanthat(lat。64degs。N。)underwhichPallasfoundthefrozenrhinocerosinSiberia，isveryinteresting。Althoughitisafallacy，asIhaveendeavouredtoshowinaformerchapter，tosupposethatthelargerquadrupedsrequirealuxuriantvegetationfortheirsupport，neverthelessitisimportanttofindintheSouthShetlandIslandsafrozenunder-soilwithin360milesoftheforest-cladislandsnearCapeHorn，where，asfarasthe_bulk_ofvegetationisconcerned，anynumberofgreatquadrupedsmightbesupported。TheperfectpreservationofthecarcassesoftheSiberianelephantsandrhinocerosesiscertainlyoneofthemostwonderfulfactsingeology；butindependentlyoftheimagineddifficultyofsupplyingthemwithfoodfromtheadjoiningcountries，thewholecaseisnot，Ithink，soperplexingasithasgenerallybeenconsidered。TheplainsofSiberia，likethoseofthePampas，appeartohavebeenformedunderthesea，intowhichriversbroughtdownthebodiesofmanyanimals；ofthegreaternumberofthese，onlytheskeletonshavebeenpreserved，butofotherstheperfectcarcass。Now，itisknownthatintheshallowseaontheArcticcoastofAmericathebottomfreezes，[19]anddoesnotthawinspringsosoonasthesurfaceoftheland，moreoveratgreaterdepths，wherethebottomoftheseadoesnotfreezethemudafewfeetbeneaththetoplayermightremaineveninsummerbelow32degs。，asinthecaseonthelandwiththesoilatthedepthofafewfeet。Atstillgreaterdepths，thetemperatureofthemudandwaterwouldprobablynotbelowenoughtopreservetheflesh；andhence，carcassesdriftedbeyondtheshallowpartsnearanArcticcoast，wouldhaveonlytheirskeletonspreserved：
nowintheextremenorthernpartsofSiberiabonesareinfinitelynumerous，sothatevenisletsaresaidtobealmostcomposedofthem；[20]andthoseisletslienolessthantendegreesoflatitudenorthoftheplacewherePallasfoundthefrozenrhinoceros。Ontheotherhand，acarcasswashedbyafloodintoashallowpartoftheArcticSea，wouldbepreservedforanindefiniteperiod，ifitweresoonafterwardscoveredwithmudsufficientlythicktopreventtheheatofthesummer-waterpenetratingtoit；andif，whenthesea-bottomwasupraisedintoland，thecoveringwassufficientlythicktopreventtheheatofthesummerairandsunthawingandcorruptingit。
Recapitulation——Iwillrecapitulatetheprincipalfactswithregardtotheclimate，ice-action，andorganicproductionsofthesouthernhemisphere，transposingtheplacesinimaginationtoEurope，withwhichwearesomuchbetteracquainted。Then，nearLisbon，thecommonestsea-shells，namely，threespeciesofOliva，aVoluta，andaTerebra，wouldhaveatropicalcharacter。InthesouthernprovincesofFrance，magnificentforests，intwinedbyarborescentgrassesandwiththetreesloadedwithparasiticalplants，wouldhidethefaceoftheland。ThepumaandthejaguarwouldhauntthePyrenees。InthelatitudeofMontBlanc，butonanislandasfarwestwardasCentralNorthAmerica，tree-fernsandparasiticalOrchideaewouldthriveamidstthethickwoods。EvenasfarnorthascentralDenmark，humming-birdswouldbeseenflutteringaboutdelicateflowers，andparrotsfeedingamidsttheevergreenwoods；andintheseathere，weshouldhaveaVoluta，andalltheshellsoflargesizeandvigorousgrowth。Nevertheless，onsomeislandsonly360milesnorthwardofournewCapeHorninDenmark，acarcassburiedinthesoil(orifwashedintoashallowsea，andcoveredupwithmud)wouldbepreservedperpetuallyfrozen。Ifsomeboldnavigatorattemptedtopenetratenorthwardoftheseislands，hewouldrunathousanddangersamidstgiganticicebergs，onsomeofwhichhewouldseegreatblocksofrockbornefarawayfromtheiroriginalsite。AnotherislandoflargesizeinthelatitudeofsouthernScotland，buttwiceasfartothewest，wouldbe“almostwhollycoveredwitheverlastingsnow。”andwouldhaveeachbayterminatedbyice-cliffs，whencegreatmasseswouldbeyearlydetached：
thisislandwouldboastonlyofalittlemoss，grass，andburnet，andatitlarkwouldbeitsonlylandinhabitant。FromournewCapeHorninDenmark，achainofmountains，scarcelyhalftheheightoftheAlps，wouldruninastraightlineduesouthward；andonitswesternflankeverydeepcreekofthesea，orfiord，wouldendin“boldandastonishingglaciers。”Theselonelychannelswouldfrequentlyreverberatewiththefallsofice，andsooftenwouldgreatwavesrushalongtheircoasts；numerousicebergs，someastallascathedrals，andoccasionallyloadedwith“noinconsiderableblocksofrock。”wouldbestrandedontheoutlyingislets；atintervalsviolentearthquakeswouldshootprodigiousmassesoficeintothewatersbelow。Lastly，somemissionariesattemptingtopenetratealongarmofthesea，wouldbeholdthenotloftysurroundingmountains，sendingdowntheirmanygrandicystreamstothesea-coast，andtheirprogressintheboatswouldbecheckedbytheinnumerablefloatingicebergs，somesmallandsomegreat；andthiswouldhaveoccurredonourtwenty-secondofJune，andwheretheLakeofGenevaisnowspreadout！[21][1]Thesouth-westerlybreezesaregenerallyverydry。January29th，beingatanchorunderCapeGregory：averyhardgalefromW。byS。，clearskywithfewcumuli；temperature57degs。，dew-point36degs。，——difference21degs。OnJanuary15th，atPortSt。Julian：inthemorning，lightwindswithmuchrain，followedbyaveryheavysquallwithrain，——settledintoheavygalewithlargecumuli，——clearedup，blowingverystrongfromS。S。W。Temperature60degs。，dew-point42degs。，——difference18degs。
[2]Rengger，Natur。derSaeugethierevonParaguay。
S。334。
[3]CaptainFitzRoyinformsmethatinApril(ourOctober)，theleavesofthosetreeswhichgrownearthebaseofthemountainschangecolour，butnotthoseonthemoreelevatedparts。Irememberhavingreadsomeobservations，showingthatinEnglandtheleavesfallearlierinawarmandfineautumnthaninalateandcoldone，Thechangeinthecolourbeinghereretardedinthemoreelevated，andthereforecoldersituations，mustheowingtothesamegenerallawofvegetation。ThetreesofTierradelFuegoduringnopartoftheyearentirelyshedtheirleaves。
[4]DescribedfrommyspecimensandnotesbytheRev。J。M。Berkeley，intheLinneanTransactions(vol。xix。p。37)，underthenameofCyttariaDarwinii；theChileanspeciesistheC。Berteroii。
ThisgenusisalliedtoBulgaria。
[5]IbelieveImustexceptonealpineHaltica，andasinglespecimenofaMelasoma。Mr。Waterhouseinformsme，thatoftheHarpalidaethereareeightorninespecies——theformsofthegreaternumberbeingverypeculiar；ofHeteromera，fourorfivespecies；ofRhyncophora，sixorseven；andofthefollowingfamiliesonespeciesineach：Staphylinidae，Elateridae，Cebrionidae，Melolonthidae。Thespeciesintheotherordersareevenfewer。Inalltheorders，thescarcityoftheindividualsisevenmoreremarkablethanthatofthespecies。MostoftheColeopterahavebeencarefullydescribedbyMr。WaterhouseintheAnnalsofNat。Hist。
[6]Itsgeographicalrangeisremarkablywide；itisfoundfromtheextremesouthernisletsnearCapeHorn，asfarnorthontheeasterncoast(accordingtoinformationgivenmebyMr。Stokes)
aslat。43degs。，——butonthewesterncoast，asDr。Hookertellsme，itextendstotheR。SanFranciscoinCalifornia，andperhapseventoKamtschatka。
Wethushaveanimmenserangeinlatitude；andasCook，whomusthavebeenwellacquaintedwiththespecies，founditatKerguelenLand，nolessthan140degs。inlongitude。
[7]VoyagesoftheAdventureandBeagle，vol。i。
p。363——Itappearsthatsea-weedgrowsextremelyquick——Mr。Stephensonfound(Wilson’sVoyageroundScotland，vol。ii。p。228)thatarockuncoveredonlyatspring-tides，whichhadbeenchiselledsmoothinNovember，onthefollowingMay，thatis，withinsixmonthsafterwards，wasthicklycoveredwithFucusdigitatustwofeet，andF。esculentussixfeet，inlength。
[8]WithregardtoTierradelFuego，theresultsarededucedfromtheobservationsofCapt。King(GeographicalJournal，1830)，andthosetakenonboardtheBeagle。FortheFalklandIslands，I
amindebtedtoCapt。Sulivanforthemeanofthemeantemperature(reducedfromcarefulobservationsatmidnight，8A。M。，noon，and8P。M。)ofthethreehottestmonths，viz。，December，January，andFebruary。ThetemperatureofDublinistakenfromBarton。
[9]Agueros，Descrip。Hist。delaProv。deChiloe，1791，p。94。
[10]SeetheGermanTranslationofthisJournal；
andfortheotherfacts，Mr。Brown’sAppendixtoFlinders’sVoyage。
[11]OntheCordilleraofcentralChile，Ibelievethesnow-linevariesexceedinglyinheightindifferentsummers。Iwasassuredthatduringoneverydryandlongsummer，allthesnowdisappearedfromAconcagua，althoughitattainstheprodigiousheightof23，000feet。
