WithrespecttotheageatwhichtheseveralparallelridgescomposingtheCordillerawereupthrown，Ihavelittleevidence。Manyofthemmayhavebeencontemporaneouslyelevatedandinjectedinthesamemannerasinvolcanicarchipelagoeslavasarecontemporaneouslyejectedontheparallellinesoffissure。“VolcanicIslands“etc。Butthepebblesapparentlyderivedfromthewearandtearoftheporphyriticconglomerateformation，whichareoccasionallypresentintheupperpartsofthissameformation，andareoftenpresentinthegypseousformation，togetherwiththepebblesfromthebasalpartsofthelatterformationinitsupperstrata，renderitalmostcertainthatportions，wemayinferridges，ofthesetwoformationsweresuccessivelyupheaved。InthecaseofthegiganticPortillorange，wemayfeelalmostcertainthatapreexistinggraniticlinewasupraisednotbyasingleblow，asshownbythehighlyinclinedbasalticstreamsinthevalleyonitseasternflankataperiodlongsubsequenttotheupheavementoftheparallelPeuquenesrange。Ihaveendeavouredtoshowinmy“Journal“2ndeditionpage321，thatthesingularfactoftheriver，whichdrainsthevalleybetweenthesetworanges，passingthroughthePortilloandhigherline，isexplainedbyitsslowandsubsequentelevation。Therearemanyanalogouscasesinthedrainageofrivers：see“EdinburghNewPhilosophicalJournal“volume28pages33and44。Again，subsequentlytotheupheavementoftheCumbrechain，thatofUspallatawasformedandelevated;andafterwards，Imayadd，intheplainofUspallata，bedsofsandandgravelwereviolentlyupthrown。Themannerinwhichthevariouskindsofporphyriesandandesiteshavebeeninjectedoneintotheother，andinwhichtheinfinitelynumerousdikesofvariouscompositionintersecteachother，plainlyshowthatthestratifiedcrusthasbeenstretchedandyieldedmanytimesoverthesamepoints。WithrespecttotheageoftheaxesofelevationbetweenthePacificandtheCordillera，Iknowlittle：
buttherearesomelineswhichmust——namely，thoserunningnorthandsouthinChiloe，thoseeightornineeastandwest，parallel，far-extended，mostsymmetricaluniclinallinesatP。Rumena，andtheshortN。W-S。E。andN。E-
S。W。linesatConcepcion——havebeenupheavedlongaftertheformationoftheCordillera。Evenduringtheearthquakeof1835，whenthelinearnorthandsouthisletofSt。Marywasupliftedseveralfeetabovethesurroundingarea，weperhapsseeonefeeblestepintheformationofasubordinatemountain-axis。Insomecases，moreover，forinstance，nearthebathsofCauquenes，Iwasforciblystruckwiththesmallsizeofthebreachescutthroughtheexteriormountain-ranges，comparedwiththesizeofthesamevalleyshigherupwhereenteringtheCordillera;andthiscircumstanceappearedtomescarcelyexplicable，exceptontheideaoftheexteriorlineshavingbeensubsequentlyupthrown，andthereforehavingbeenexposedtoalessamountofdenudation。FromthemannerinwhichthefringesofgravelareprolongedinunbrokenslopesupthevalleysoftheCordillera，I
inferthatmostofthegreaterdislocationstookplaceduringtheearlierpartsofthegreatelevationinmass：Ihave，however，elsewheregivenacase，andM。deTschudihasgivenanother，ofaridgethrownupinPeruacrossthebedofariver，andconsequentlyafterthefinalelevationofthecountryabovethelevelofthesea。“ReiseinPeru“Band2s。8：
Author’s“Journal“2ndeditionpage359。