YouaskmetostatedefinitelysomeofthepointsonwhichImuchwishforinformation;butIreallyhardlycan，fortheyaresovague;andIratherwishtoseewhatresultswillcomeoutfromcomparisons，thanhaveasyetdefinedobjects。Ipresumethat，likeotherbotanists，youwouldgive，foryourarea，theproportion（leavingoutintroducedplants）tothewholeofthegreatleadingfamilies:thisisonepointIhadintended（and，indeed，havedoneroughly）totabulatefromyourbook，butofcourseIcouldhavedoneitonlyVERYIMPERFECTLY。Ishouldalso，ofcourse，haveascertainedtheproportion，tothewholeFlora，oftheEuropeanplants（leavingoutintroduced）ANDOFTHESEPARATEGREATFAMILIES，inordertospeculateonmeansoftransportal。Bytheway，Iventuredtosendafewdaysagoacopyofthe"Gardeners’Chronicle"withashortreportbymeofsometriflingexperimentswhichIhavebeentryingonthepowerofseedstowithstandseawater。Idonotknowwhetherithasstruckyou，butithasme，thatitwouldbeadvisableforbotaniststogiveinWHOLENUMBERS，aswellasinthelowestfraction，theproportionalnumbersofthefamilies，thusImakeoutfromyourManualthatoftheINDIGENOUSplantstheproportionoftheUmbelliferaeare36/1798=1/49;for，withoutoneknowstheWHOLEnumbers，onecannotjudgehowreallyclosethenumbersoftheplantsofthesamefamilyareintwodistantcountries;butverylikelyyoumaythinkthissuperfluous。Mentioningtheseproportionalnumbers，Imaygiveyouaninstanceofthesortofpoints，andhowvagueandfutiletheyoftenare，whichIATTEMPTtoworkout……;reflectingonR。Brown’sandHooker’sremark，thatnearidentityofproportionalnumbersofthegreatfamiliesintwocountries，showsprobablythattheywereoncecontinuouslyunited，I
thoughtIwouldcalculatetheproportionsof，forinstance，theINTRODUCED
CompositaeinGreatBritaintoalltheintroducedplants，andtheresultwas，10/92=1/9。2。InourABORIGINALorindigenousfloratheproportionis1/10;andinmanyothercasesIfoundanequallystrikingcorrespondence。IthentookyourManual，andworkedoutthesamequestion;
hereIfindintheCompositaeanalmostequallystrikingcorrespondence，viz。24/206=1/8intheintroducedplants，and223/1798=1/8intheindigenous;butwhenIcametotheotherfamiliesIfoundtheproportionentirelydifferent，showingthatthecoincidencesintheBritishFlorawereprobablyaccidental！
Youwill，Ipresume，givetheproportionofthespeciestothegenera，i。e。，showonanaveragehowmanyspecieseachgenuscontains;thoughI
havedonethisformyself。
Ifitwouldnotbetootroublesome，doyounotthinkitwouldbeveryinteresting，andgiveaverygoodideaofyourFlora，todividethespeciesintothreegroups，viz。，（a）speciescommontotheoldworld，statingnumberscommontoEuropeandAsia;（b）indigenousspecies，butbelongingtogenerafoundintheoldworld;and（c）speciesbelongingtogeneraconfinedtoAmericaortheNewWorld。Tomake（accordingtomyideas）perfectionperfect，oneoughttobetoldwhetherthereareothercases，likeErica，ofgeneracommoninEuropeorinOldWorldnotfoundinyourarea。ButhonestlyIfeelthatitisquiteridiculousmywritingtoyouatsuchlengthonthesubject;but，asyouhaveaskedme，Idoitgratefully，andwritetoyouasIshouldtoHooker，whooftenlaughsatmeunmercifully，andIamsureyouhavebetterreasontodoso。
ThereisonepointonwhichIamMOSTanxiousforinformation，andI
mentionitwiththegreatesthesitation，andonlyintheFULLBELIEFthatyouwillbelievemethatIhavenotthefollyandpresumptiontohopeforasecondthatyouwillgiveit，withoutyoucanwithverylittletrouble。
Thepointcanatpresentinterestnoonebutmyself，whichmakesthecasewhollydifferentfromgeographicaldistribution。Theonlywayinwhich，I
think，youpossiblycoulddoitwithlittletroublewouldbetobearinmind，whilstcorrectingyourproof—sheetsoftheManual，myquestionandputacrossormarktothespecies，andwheneversendingaparceltoHookertoletmehavesucholdsheets。Butthiswouldgiveyouthetroubleofrememberingmyquestion，andIcanhardlyhopeorexpectthatyouwilldoit。ButIwilljustmentionwhatIwant;itistohavemarkedthe"closespecies"inaFlora，soastocompareinDIFFERENTFloraswhetherthesamegenerahave"closespecies，"andforotherpurposestoovaguetoenumerate。
Ihaveattempted，byHooker’shelp，toascertaininasimilarwaywhetherthedifferentspeciesofthesamegeneraindistantquartersoftheglobearevariableorpresentvarieties。ThedefinitionIshouldgiveofa"CLOSESPECIES"wasonethatYOUthoughtspecificallydistinct，butwhichyoucouldconceivesomeotherGOODbotanistmightthinkonlyaraceorvariety;or，again，aspeciesthatyouhadtrouble，thoughhavingopportunitiesofknowingitwell，indiscriminatingfromsomeotherspecies。Supposingthatyouwereinclinedtobesoverykindastodothis，andcould（whichIdonotexpect）sparethetime，asIhavesaid，amerecrosstoeachsuchspeciesinanyuselessproof—sheetswouldgivemetheinformationdesired，which，Imayadd，Iknowmustbevague。
HowcanIapologiseenoughforallmypresumptionandtheextremelengthofthisletter？Thegreatgoodnatureofyourlettertomehasbeenpartlythecause，sothat，asistoooftenthecaseinthisworld，youarepunishedforyourgooddeeds。Withheartythanks，believeme，Yoursverytrulyandgratefully，CH。DARWIN。
CHARLESDARWINTOJ。D。HOOKER。
Down，18th[July，1855]……IthinkIamgettingaMILDcaseaboutCharlockseed（Inthe"Gardeners’
Chronicle"，1855，page758，appearedanotice（halfacolumninlength）bymyfatheronthe"VitalityofSeeds。"Thefactsrelatedrefertothe"Sand—walk";thewoodwasplantedin1846onapieceofpasturelandlaiddownasgrassin1840。In1855，onthesoilbeingduginseveralplaces，Charlock（Brassicasinapistrum）sprangupfreely。Thesubjectcontinuedtointeresthim，andIfindanotedatedJuly2nd，1874，inwhichmyfatherrecordedthatforty—sixplantsofCharlocksprangupinthatyearoveraspace（14x7feet）whichhadbeendugtoaconsiderabledepth。）;butjustasaboutsalting，ill—lucktoit，IcannotrememberhowmanyyearsyouwouldallowthatCharlockseedmightliveintheground。Nexttimeyouwrite，showaboldface，andsayinhowmanyyears，youthink，Charlockseedwouldprobablyallbedead。Amantoldmetheotherdayof，asI
thought，asplendidinstance，——andSPLENDIDitwas，foraccordingtohisevidencetheseedcameupaliveoutoftheLOWERPARToftheLONDONCLAY！！
IdisgustedhimbytellinghimthatPalmsoughttohavecomeup。
YouaskhowfarIgoinattributingorganismstoacommondescent;IanswerIknownot;thewayinwhichIintendtreatingthesubject，istoshow（AS
FARASICAN）thefactsandargumentsforandagainstthecommondescentofthespeciesofthesamegenus;andthenshowhowfarthesameargumentstellfororagainstforms，moreandmorewidelydifferent:andwhenwecometoformsofdifferentordersandclasses，thereremainonlysomesuchargumentsasthosewhichcanperhapsbededucedfromsimilarrudimentarystructures，andverysoonnotanargumentisleft。
[ThefollowingextractfromalettertoMr。Fox[October，1855（Inthisyearhepublished（’Phil。Mag。’x。）apaper’Onthepoweroficebergstomakerectilinearuniformly—directedgroovesacrossasubmarineundulatorysurface。’"）givesabriefmentionofthelastmeetingoftheBritishAssociationwhichheattended:]"Ireallyhavenonews:theonlythingwehavedoneforalongtime，wastogotoGlasgow;butthefatiguewastomemorethanitwasworth，andE。caughtabadcold。OnourreturnwestayedasingledayatShrewsbury，andenjoyedseeingtheoldplace。IsawalittleofSirPhilip（SirP。EgertonwasaneighbourofMr。Fox。）（whomI
likedmuch），andheaskedme"whyonearthIinstigatedyoutorobhispoultry—yard？’Themeetingwasagoodone，andtheDukeofArgyllspokeexcellently。"]
CHAPTER1。XII。
THEUNFINISHEDBOOK。
MAY1856TOJUNE1858。
[IntheAutobiographicalchapter（page69，）myfatherwrote:——"Earlyin1856Lyelladvisedmetowriteoutmyviewsprettyfully，andIbeganatoncetodosoonascalethreeorfourtimesasextensiveasthatwhichwasafterwardsfollowedinmy’OriginofSpecies;’yetitwasonlyanabstractofthematerialswhichIhadcollected。"Thelettersinthepresentchapterarechieflyconcernedwiththepreparationofthisunfinishedbook。
TheworkwasbegunonMay14th，andsteadilycontinueduptoJune1858，whenitwasinterruptedbythearrivalofMr。Wallace’sMS。Duringthetwoyearswhichwearenowconsideringhewrotetenchapters（thatisaboutone—half）oftheprojectedbook。Heremainedforthemostpartathome，butpaidseveralvisitstoDr。Lane’sWater—CureEstablishmentatMoorPark，duringoneofwhichhemadeapilgrimagetotheshrineofGilbertWhiteatSelborne。]
LETTERS。
CHARLESDARWINTOC。LYELL
May3[1856]……Withrespecttoyoursuggestionofasketchofmyviews，Ihardlyknowwhattothink，butwillreflectonit，butitgoesagainstmyprejudices。
Togiveafairsketchwouldbeabsolutelyimpossible，foreverypropositionrequiressuchanarrayoffacts。IfIweretodoanything，itcouldonlyrefertothemainagencyofchange——selection——andperhapspointoutaveryfewoftheleadingfeatures，whichcountenancesuchaview，andsomefewofthemaindifficulties。ButIdonotknowwhattothink;Iratherhatetheideaofwritingforpriority，yetIcertainlyshouldbevexedifanyoneweretopublishmydoctrinesbeforeme。Anyhow，Ithankyouheartilyforyoursympathy。IshallbeinLondonnextweek，andIwillcallonyouonThursdaymorningforonehourprecisely，soasnottolosemuchofyourtimeandmyown;butwillyouletmethistimecomeasearlyas9o’clock，forIhavemuchwhichImustdointhemorninginmystrongesttime？
Farewell，mydearoldpatron。
Yours，C。DARWIN。
Bytheway，THREEplantshavecomeupoutoftheearth，perfectlyenclosedintherootsofthetrees。Andtwenty—nineplantsinthetable—spoonfulofmud，outofthelittlepond;Hookerwassurprisedatthis，andstruckwithit，whenIshowedhimhowmuchmudIhadscrapedoffoneduck’sfeet。
IfIdidpublishashortsketch，whereonearthshouldIpublishit？
IfIdoNOThear，IshallunderstandthatImaycomefrom9to10onThursday。
CHARLESDARWINTOJ。D。HOOKER。
May9th，[1856]……IverymuchwantadviceandTRUTHFULconsolationifyoucangiveit。I
hadagoodtalkwithLyellaboutmyspecieswork，andheurgesmestronglytopublishsomething。IamfixedagainstanyperiodicalorJournal，asI
positivelywillNOTexposemyselftoanEditororaCouncil，allowingapublicationforwhichtheymightbeabused。IfIpublishanythingitmustbeaVERYTHINandlittlevolume，givingasketchofmyviewsanddifficulties;butitisreallydreadfullyunphilosophicaltogivearesume，withoutexactreferences，ofanunpublishedwork。ButLyellseemedtothinkImightdothis，atthesuggestionoffriends，andontheground，whichImightstate，thatIhadbeenatworkforeighteen（Theintervalofeighteenyears，from1837whenhebegantocollectfacts，wouldbringthedateofthisletterto1855，not1856，neverthelessthelatterseemsthemoreprobabledate。）years，andyetcouldnotpublishforseveralyears，andespeciallyasIcouldpointoutdifficultieswhichseemedtometorequireespecialinvestigation。Nowwhatthinkyou？Ishouldbereallygratefulforadvice。Ithoughtofgivingupacoupleofmonthsandwritingsuchasketch，andtryingtokeepmyjudgmentopenwhetherornotopublishitwhencompleted。Itwillbesimplyimpossibleformetogiveexactreferences;anythingimportantIshouldstateontheauthorityoftheauthorgenerally;andinsteadofgivingallthefactsonwhichIgroundmyopinion，Icouldgivebymemoryonlyoneortwo。InthePrefaceIwouldstatethattheworkcouldnotbeconsideredstrictlyscientific，butameresketchoroutlineofafutureworkinwhichfullreferences，etc。shouldbegiven。Eheu，eheu，IbelieveIshouldsneeratanyoneelsedoingthis，andmyonlycomfortis，thatITRULYneverdreamedofit，tillLyellsuggestedit，andseemsdeliberatelytothinkitadvisable。
Iaminapeckoftroublesanddoprayforgivemefortroublingyou。
Yoursaffectionately，C。DARWIN。
CHARLESDARWINTOJ。D。HOOKER。
May11th[1856]……NowforaMOREIMPORTANT！subject，viz。，myownself:Iamextremelygladyouthinkwellofaseparate"PreliminaryEssay"（i。e。，ifanythingwhateverispublished;forLyellseemedrathertodoubtonthishead）（Themeaningofthesentenceinparenthesesisobscure。）;butIcannotbeartheideaofBEGGINGsomeEditorandCounciltopublish，andthenperhapstohavetoAPOLOGISEhumblyforhavingledthemintoascrape。InthisonerespectIaminthestatewhich，accordingtoaverywisesayingofmyfather’s，istheonlyfitstateforaskingadvice，viz。，withmymindfirmlymadeup，andthen，asmyfatherusedtosay，GOODadvicewasverycomfortable，anditwaseasytorejectBADadvice。ButHeavenknowsIamnotinthisstatewithrespecttopublishingatallanypreliminaryessay。
Ityetstrikesmeasquiteunphilosophicaltopublishresultswithoutthefulldetailswhichhaveleadtosuchresults。
Itisamelancholy，andIhopenotquitetrueviewofyoursthatfactswillproveanything，andarethereforesuperfluous！ButIhaveratherexaggerated，Isee，yourdoctrine。Idonotfearbeingtieddowntoerror，i。e。，IfeelprettysureIshouldgiveupanythingfalsepublishedinthepreliminaryessay，inmylargerwork;butImaythus，itisverytrue，domischiefbyspreadingerror，whichasIhaveoftenheardyousayismucheasierspreadthancorrected。IconfessIleanmoreandmoretoatleastmakingtheattemptanddrawingupasketchandtryingtokeepmyjudgment，whethertopublish，open。ButIalwaysreturntomyfixedideathatitisdreadfullyunphilosophicaltopublishwithoutfulldetails。Icertainlythinkmyfutureworkinfullwouldprofitbyhearingwhatmyfriendsorcritics（ifreviewed）thoughtoftheoutline。
ToanyonebutyouIshouldapologiseforsuchlongdiscussiononsopersonalanaffair;butIbelieve，andindeedyouhaveproveditbythetroubleyouhavetaken，thatthiswouldbesuperfluous。
Yourstrulyobliged，CH。DARWIN。
P。S。Whatyousay（forIhavejustre—readyourletter）thattheEssaymightsupersedeandtakeawayallnoveltyandvaluefromanyfuturelargerBook，isverytrue;andthatwouldgrievemebeyondeverything。Ontheotherhand（againfromLyell’surgentadvice），IpublishedapreliminarysketchoftheCoralTheory，andthisdidneithergoodnorharm。IbeginMOSTHEARTILYtowishthatLyellhadneverputthisideaofanEssayintomyhead。
FROMALETTERTOSIRC。LYELL[July，1856]。
"IamdelightedthatImaysay（withabsolutetruth）thatmyessayispublishedatyoursuggestion，butIhopeitwillnotneedsomuchapologyasIatfirstthought;forIhaveresolvedtomakeitnearlyascompleteasmypresentmaterialsallow。Icannotputinallwhichyousuggest，foritwouldappeartooconceited。"
FROMALETTERTOW。D。FOX。
Down，June14th[1856]。
"……WhatyousayaboutmyEssay，Idaresayisverytrue;anditgavemeanotherfitofthewibber—gibbers:IhopethatIshallsucceedinmakingitmodest。OnegreatmotiveistogetinformationonthemanypointsonwhichIwantit。ButItrembleaboutit，whichIshouldnotdo，ifI
allowedsomethreeorfourmoreyearstoelapsebeforepublishinganything……"
[ThefollowingextractsfromletterstoMr。Foxareworthgiving，asshowinghowgreatwastheaccumulationofmaterialwhichnowhadtobedealtwith。
June14th[1856]。
"Verymanythanksforthecapitalinformationoncats;IseeIhadblunderedgreatly，butIknowIhadsomewhereyouroriginalnotes;butmynotesaresonumerousduringnineteenyears’collection，thatitwouldtakemeatleastayeartogooverandclassifythem。"
November1856。
"SometimesIfearIshallbreakdown，formysubjectgetsbiggerandbiggerwitheachmonth’swork。"]
CHARLESDARWINTOC。LYELL
Down，16th[June，1856]。
MydearLyell，Iamgoingtodothemostimpudentthingintheworld。Butmybloodgetshotwithpassionandturnscoldalternatelyatthegeologicalstrides，whichmanyofyourdisciplesaretaking。
Here，poorForbesmadeacontinentto[i。e。，extendingto]NorthAmericaandanother（orthesame）totheGulfweed;HookermakesonefromNewZealandtoSouthAmericaandroundtheWorldtoKerguelenLand。HereisWollastonspeakingofMadeiraandP。Santo"asthesureandcertainwitnessesofaformercontinent。"HereisWoodwardwritestome，ifyougrantacontinentover200or300milesofoceandepths（asifthatwasnothing），whynotextendacontinenttoeveryislandinthePacificandAtlanticOceans？Andallthiswithintheexistenceofrecentspecies！Ifyoudonotstopthis，iftherebealowerregionforthepunishmentofgeologists，Ibelieve，mygreatmaster，youwillgothere。Why，yourdisciplesinaslowandcreepingmannerbeatalltheoldCatastrophistswhoeverlived。YouwilllivetobethegreatchiefoftheCatastrophists。
There，Ihavedonemyselfagreatdealofgood，andhaveexplodedmypassion。
Somymaster，forgiveme，andbelieveme，everyours，C。DARWIN。
P。S。Don’tanswerthis，Ididittoeasemyself。
CHARLESDARWINTOJ。D。HOOKER。
Down[June]17th，1856……IhavebeenverydeeplyinterestedbyWollaston’sbook（’TheVariationofSpecies，’1856。），thoughIdifferGREATLYfrommanyofhisdoctrines。
Didyoueverreadanythingsorich，consideringhowveryfarhegoes，ashisdenunciationsagainstthosewhogofurther:"Mostmischievous，"
"absurd，""unsound。"Theologyisatthebottomofsomeofthis。ItoldhimhewaslikeCalvinburningaheretic。Itisaveryvaluableandcleverbookinmyopinion。Hehasevidentlyreadverylittleoutofhisownline。
IurgedhimtoreadtheNewZealandessay。HisGeologyalsoisrathereocene，asItoldhim。InfactIwrotemostfrankly;hesaysheissurethatultra—honestyismycharacteristic:Idonotknowwhetherhemeantitasasneer;Ihopenot。Talkingofeocenegeology，IgotsowrathabouttheAtlanticcontinent，moreespeciallyfromanotefromWoodward（whohaspublishedacapitalbookonshells），whodoesnotseemtodoubtthateveryislandinthePacificandAtlanticaretheremainsofcontinents，submergedwithinperiodofexistingspecies，thatIfairlyexploded，andwrotetoLyelltoprotest，andsummedupallthecontinentscreatedoflateyearsbyForbes（theheadsinner！）YOURSELF，Wollaston，andWoodward，andaprettynicelittleextensionoflandtheymakealtogether！Iamfairlyrabidonthequestionandtherefore，ifnotwrongalready，amprettysuretobecomeso……
Ihaveenjoyedyournotemuch。Adios，C。DARWIN。
P。S。[June]18th。LyellhaswrittenmeaCAPITALletteronyourside，whichoughttoupsetmeentirely，butIcannotsayitdoesquite。
ThoughImusttryandceasebeingrabidandtrytofeelhumble，andallowyoualltomakecontinents，aseasilyasacookdoespancakes。
CHARLESDARWINTOC。LYELL。
Down，June25th[1856]。
MydearLyell，Iwillhavethefollowingtremendouslettercopiedtomakethereadingeasier，andasIwanttokeepacopy。
Asyousayyouwouldliketohearmyreasonsforbeingmostunwillingtobelieveinthecontinentalextensionsoflateauthors，Igladlywritethem，as，withoutIamconvincedofmyerror，Ishallhavetogivethemcondensedinmyessay，whenIdiscusssingleandmultiplecreation;Ishallthereforebeparticularlygladtohaveyourgeneralopiniononthem。ImayQUITE
LIKELYhavepersuadedmyselfinmywraththatthereismoreinthemthanthereis。Iftherewasmuchmorereasontoadmitacontinentalextensioninanyoneortwoinstances（asinMadeira）thaninothercases，Ishouldfeelnodifficultywhatever。ButifonaccountofEuropeanplants，andlittoralseashells，itisthoughtnecessarytojoinMadeiratothemainland，HookerisquiterighttojoinNewHollandtoNewZealand，andAucklandIsland（andRaoulIslandtoN。E。），andthesetoS。AmericaandtheFalklands，andthesetoTristand’Acunha，andthesetoKerguelenLand;thusmaking，eitherstrictlyatthesametime，oratdifferentperiods，butallwithinthelifeofrecentbeings，analmostcircumpolarbeltofland。SoagainGalapagosandJuanFernandezmustbejoinedtoAmerica;andifwetrusttolittoralseeshells，theGalapagosmusthavebeenjoinedtothePacificIslands（2400milesdistant）aswellastoAmerica，andasWoodwardseemstothinkalltheislandsinthePacificintoamagnificentcontinent;
alsotheislandsintheSouthernIndianOceanintoanothercontinent，withMadagascarandAfrica，andperhapsIndia。IntheNorthAtlantic，Europewillstretchhalf—wayacrosstheoceantotheAzores，andfurthernorthrightacross。Inshort，wemustsupposeprobably，halfthepresentoceanwaslandwithintheperiodoflivingorganisms。TheGlobewithinthisperiodmusthavehadaquitedifferentaspect。Nowtheonlywaytotestthis，thatIcansee，istoconsiderwhetherthecontinentshaveundergonewithinthissameperiodsuchwonderfulpermutations。InallNorthandSouthandCentralAmerica，wehavebothrecentandmiocene（oreocene）
shells，quitedistinctontheoppositesides，andhenceIcannotdoubtthatFUNDAMENTALLYAmericahashelditsplacesinceatleast，themioceneperiod。InAfricaalmostallthelivingshellsaredistinctontheoppositesidesoftheinter—tropicalregions，shortasthedistanceiscomparedtotherangeofmarinemollusca，inuninterruptedseas;henceI
inferthatAfricahasexistedsinceourpresentspecieswerecreated。EventheisthmusofSuezandtheAralo—Caspianbasinhavehadagreatantiquity。
SoIimagine，fromthetertiarydeposits，hasIndia。InAustraliathegreatfaunaofextinctmarsupialsshowsthatbeforethepresentmammalsappeared，Australiawasaseparatecontinent。IdonotforoneseconddoubtthatverylargeportionsofallthesecontinentshaveundergoneGREAT
changesoflevelwithinthisperiod，butyetIconcludethatfundamentallytheystoodasbarriersinthesea，wheretheynowstand;andthereforeI
shouldrequiretheweightiestevidencetomakemebelieveinsuchimmensechangeswithintheperiodoflivingorganismsinouroceans，where，moreover，fromthegreatdepths，thechangesmusthavebeenvasterinaverticalsense。
SECONDLY。
Submergeourpresentcontinents，leavingafewmountainpeaksasislands，andwhatwillthecharacteroftheislandsbe，——ConsiderthatthePyrenees，SierraNevada，Apennines，Alps，Carpathians，arenon—volcanic，EtnaandCaucasus，volcanic。InAsia，AltaiandHimalaya，Ibelievenon—volcanic。
InNorthAfricathenon—volcanic，asIimagine，AlpsofAbyssiniaandoftheAtlas。InSouthAfrica，theSnowMountains。InAustralia，thenon—
volcanicAlps。InNorthAmerica，theWhiteMountains，AlleghaniesandRockyMountains——someofthelatteralone，Ibelieve，volcanic。InSouthAmericatotheeast，thenon—volcanic[Silla？]ofCaracas，andItacolumiofBrazil，furthersouththeSierraVentanas，andintheCordilleras，manyvolcanicbutnotall。Nowcomparethesepeakswiththeoceanicislands;asfarasknownallarevolcanic，exceptSt。Paul’s（astrangebedevilledrock），andtheSeychelles，ifthislattercanbecalledoceanic，inthelineofMadagascar;theFalklands，only500milesoff，areonlyashallowbank;NewCaledonia，hardlyoceanic，isanotherexception。Thisargumenthastomegreatweight。CompareonaGeographicalmap，islandswhich，wehaveSEVERALreasonstosuppose，wereconnectedwithmainland，asSardinia，andhowdifferentitappears。Believing，asIaminclined，thatcontinentsascontinents，andoceansasoceans，areofimmenseantiquity——Ishouldsaythatifanyoftheexistingoceanicislandshaveanyrelationofanykindtocontinents，theyareformingcontinents;andthatbythetimetheycouldformacontinent，thevolcanoeswouldbedenudedtotheircores，leavingpeaksofsyenite，diorite，orporphyry。Buthavewenowhereanylastwreckofacontinent，inthemidstoftheocean？St。Paul’sRock，andsucholdbatteredvolcanicislands，asSt。Helena，maybe;butIthinkwecanseesomereasonwhyweshouldhavelessevidenceofsinkingthanofrisingcontinents（ifmyviewinmyCoralvolumehasanytruthinit，viz。:thatvolcanicoutburstsaccompanyrisingareas），forduringsubsidencetherewillbenocompensatingagentatwork，inrisingareastherewillbetheADDITIONALelementofoutpouredvolcanicmatter。
THIRDLY。
Consideringthedepthoftheocean，Iwas，beforeIgotyourletter，inclinedvehementlytodisputethevastamountofsubsidence，butImuststrikemycolours。Withrespecttocoralreefs，Icarefullyguardedagainstitsbeingsupposedthatacontinentwasindicatedbythegroupsofatolls。Itisdifficulttoguess，asitseemstome，theamountofsubsidenceindicatedbycoralreefs;butinsuchlargeareasastheLoweArchipelago，theMarshallArchipelago，andLaccadivegroup，itwould，judging，fromtheheightsofexistingoceanicarchipelagoes，beodd，ifsomepeaksoffrom8000to10，000feethadnotbeenburied。Evenafteryourletterasuspicioncrossedmewhetheritwouldbefairtoarguefromsubsidencesinthemiddleofthegreatestoceanstocontinents;butrefreshingmymemorybytalkingwithRamsayinregardtotheprobablethicknessinoneverticallineoftheSilurianandcarboniferousformation，itseemstheremusthavebeenATLEAST10，000feetofsubsidenceduringtheseformationsinEuropeandNorthAmerica，andthereforeduringthecontinuanceofnearlythesamesetoforganicbeings。Buteven12，000feetwouldnotbeenoughfortheAzores，orforHooker’scontinent;IbelieveHookerdoesnotinferacontinuouscontinent，butapproximategroupsofislands，with，ifwemayjudgefromexistingcontinents，notPROFOUNDLY
deepseabetweenthem;buttheargumentfromthevolcanicnatureofnearlyeveryexistingoceanicislandtellagainstsuchsupposedgroupsofislands，——forIpresumehedoesnotsupposeamerechainofvolcanicislandsbeltingthesouthernhemisphere。
FOURTHLY。
Thesupposedcontinentalextensionsdonotseemtome，perfectlytoaccountforallthephenomenaofdistributiononislands;astheabsenceofmammalsandBatrachians;theabsenceofcertaingreatgroupsofinsectsonMadeira，andofAcaciaeandBanksias，etc。，inNewZealand;thepaucityofplantsinsomecases，etc。Notthatthosewhobelieveinvariousaccidentalmeansofdispersal，canexplainmostofthesecases;buttheymayatleastsaythatthesefactsseemhardlycompatiblewithformercontinuousland。
FINALLY。
Fortheseseveralreasons，andespeciallyconsideringitcertain（inwhichyouwillagree）thatweareextremelyignorantofmeansofdispersal，I
cannotavoidthinkingthatForbes’’Atlantis，’wasanill—servicetoscience，ascheckingaclosestudyofmeansofdissemination。Ishallbereallygratefultohear，asbrieflyasyoulike，whethertheseargumentshaveanyweightwithyou，puttingyourselfinthepositionofanhonestjudge。ItoldHookerthatIwasgoingtowritetoyouonthissubject;andIshouldlikehimtoreadthis;butwhetherheoryouwillthinkitworthtimeandpostageremainstobeproved。
Yoursmosttruly，CHARLESDARWIN。
[OnJuly8thhewrotetoSirCharlesLyell。
"IamsorryyoucannotgiveanyverdictonContinentalextensions;andI
inferthatyouthinkmyargumentofnotmuchweightagainstsuchextensions。IknowIwishIcouldbelieveso。"]
CHARLESDARWINTOASAGRAY。
Down，July20th[1856]……Itisnotalittleegotistical，butIshouldliketotellyou（andIdonotTHINKIhave）howIviewmywork。Nineteenyears（！）agoitoccurredtomethatwhilstotherwiseemployedonNaturalHistory，ImightperhapsdogoodifInotedanysortoffactsbearingonthequestionoftheoriginofspecies，andthisIhavesincebeendoing。Eitherspecieshavebeenindependentlycreated，ortheyhavedescendedfromotherspecies，likevarietiesfromonespecies。Ithinkitcanbeshowntobeprobablethatmangetshismostdistinctvarietiesbypreservingsuchasarisebestworthkeepinganddestroyingtheothers，butIshouldfillaquireifIweretogoon。Tobebrief，IASSUMEthatspeciesariselikeourdomesticvarietieswithMUCHextinction;andthentestthishypothesisbycomparisonwithasmanygeneralandprettywell—establishedpropositionsasIcanfindmadeout，——ingeographicaldistribution，geologicalhistory，affinities，etc。，etc。Anditseemstomethat，SUPPOSINGthatsuchhypothesisweretoexplainsuchgeneralpropositions，weought，inaccordancewiththecommonwayoffollowingallsciences，toadmitittillsomebetterhypothesisbefoundout。Fortomymindtosaythatspecieswerecreatedsoandsoisnoscientificexplanation，onlyareverentwayofsayingitissoandso。ButitisnonsensicaltryingtoshowhowItrytoproceedinthecompassofanote。Butasanhonestman，ImusttellyouthatIhavecometotheheterodoxconclusionthattherearenosuchthingsasindependentlycreatedspecies——thatspeciesareonlystronglydefinedvarieties。Iknowthatthiswillmakeyoudespiseme。IdonotmuchunderratethemanyHUGE
difficultiesonthisview，butyetitseemstometoexplaintoomuch，otherwiseinexplicable，tobefalse。Justtoalludetoonepointinyourlastnote，viz。，aboutspeciesofthesamegenusGENERALLYhavingacommonorcontinuousarea;iftheyareactuallinealdescendantsofonespecies，thisofcoursewouldbethecase;andthesadlytoomanyexceptions（forme）havetobeexplainedbyclimatalandgeologicalchanges。Afortiorionthisview（butonexactlysamegrounds），alltheindividualsofthesamespeciesshouldhaveacontinuousdistribution。OnthislatterbranchofthesubjectIhaveputachaptertogether，andHookerkindlyreaditover。
Ithoughttheexceptionsanddifficultiesweresogreatthatonthewholethebalanceweighedagainstmynotions，butIwasmuchpleasedtofindthatitseemedtohaveconsiderableweightwithHooker，whosaidhehadneverbeensomuchstaggeredaboutthepermanenceofspecies。
Imustsayonewordmoreinjustification（forIfeelsurethatyourtendencywillbetodespisemeandmycrotchets），thatallmynotionsaboutHOWspecieschangearederivedfromlongcontinuedstudyoftheworksof（andconversewith）agriculturistsandhorticulturists;andIbelieveIseemywayprettyclearlyonthemeansusedbynaturetochangeherspeciesandADAPTthemtothewondrousandexquisitelybeautifulcontingenciestowhicheverylivingbeingisexposed……
CHARLESDARWINTOJ。D。HOOKER。
Down，July30th1856。
MydearHooker，YourletterisofMUCHvaluetome。IwasnotabletogetadefiniteanswerfromLyell（OnthecontinentalextensionsofForbesandothers。），asyouwillseeintheenclosedletters，thoughIinferredthathethoughtnothingofmyarguments。Haditnotbeenforthiscorrespondence，Ishouldhavewrittensadlytoostrongly。YoumayrelyonitIshallputmydoubtsmoderately。Thereneverwassuchapredicamentasmine:hereyoucontinentalextensionistswouldremoveenormousdifficultiesopposedtome，andyetIcannothonestlyadmitthedoctrine，andmustthereforesayso。I
cannotgetoverthefactthatnotafragmentofsecondaryorpalaeozoicrockhasbeenfoundonanyislandabove500or600milesfromamainland。
YourathermisunderstandmewhenyouthinkIdoubtthePOSSIBILITYofsubsidenceof20，000or30，000feet;itisonlyprobability，consideringsuchevidenceaswehaveindependentlyofdistribution。Ihavenotyetworkedoutinfulldetailthedistributionofmammalia，bothIDENTICALandallied，withrespecttotheONEELEMENTOFDEPTHOFTHESEA;butasfarasIhavegone，theresultsaretomesurprisinglyaccordantwithmyverymosttroublesomebeliefinnotsuchgreatgeographicalchangesasyoubelieve;
andinmammaliawecertainlyknowmoreofMEANSofdistributionthaninanyotherclass。Nothingissovexatioustome，assoconstantlyfindingmyselfdrawingdifferentconclusionsfrombetterjudgesthanmyself，fromthesamefacts。
IfancyIhavelatelyremovedmany（notgeographical）greatdifficultiesopposedtomynotions，butGodknowsitmaybeallhallucination。