TheseplainsarethenewestpartofAmerica，formanyofthemhaveemergedfromtheseaonlyinrecentgeologicaltimes。Takenasawholetheresemblancebetweenthetwocontinentsisstriking。
IfthesefourphysiographicprovincesofNorthandSouthAmericalayinsimilarlatitudesintherespectivecontinentswemightexpecteachpairtohaveacloselysimilareffectonlife。Infauna，flora，andeveninhumanhistorytheywouldpresentbroadandimportantresemblances。Asamatteroffact，however，theyareasdifferentascanwellbeimagined。WhereNorthAmerica，isbathedbyicywatersfullofsealsandfloatingiceSouthAmericaisbathedbywarmseasfullofflying-fishandcoralreefs。Thenortherncontinentisbroadestinthecoollatitudesthataremostfavorableforhumanactivity。Thesouthernexpandsmostwidelyinlatitudeswhosedebilitatingmonotonyofheatandmoistureistheworstofhandicapstohumanprogress。Thegreatriversofthenortherncontinentcorrespondverycloselytothoseofthesouthern。TheMackenzie，however，isboundintherigidbandsofwinterforeightmonthseachyear，whiletheOrinoco，thecorrespondingSouthAmericanriver，liesswelteringunderatropicalsunwhichburnsitsgrassyplainstobitterdustevenasthesharpcoldreducedtheMackenzieregiontobarrentundra。TheSt。Lawrenceflowsthroughfertilegrainfieldsandthehomesofanactivepeopleofthetemperatezone，buttheAmazonwindsitsslowwayamidthemalariouslanguorofvasttropicalforestsinwhichthetreesshutouttheskyandthefewnativesareapatheticwiththeeternalinertiaofthehot，damptropics。
OnlywhenwecometotheMississippiinthenortherncontinentandtheRiodelaPlatainthesoutherndowefindapairofriverswhichcorrespondtoanydegreeinthecharacterofthelifesurroundingthem，aswellasintheirphysiographiccharacter。Yetevenherethereisavastdifference，especiallyintheuppercoursesoftheriver。Eachatitsmouthflowsthrougharich，fertileplainoccupiedbyaprogressive，prosperouspeople。ButtheRiodelaPlatatakesitsriseinoneoftheworld’smostbackwardplains，thehomeofuncivilizedIndians，heartlessrubberadventurers，andthemostrapaciousofofficials。Notinfrequently，thedegeneratewhitemenoftheseregions，yieldingtothesubtleandinsidiousinfluenceofthetropics，inflictthemostoutrageousabusesuponthenatives，andevenkillthemonslightprovocation。Thenativesinturnhatetheiroppressors，andwhenthechancecomesbetraythemorleavethemtoperishinsicknessandmisery。TheupperMississippi，ontheotherhand，comesfromaplainwhereagricultureiscarriedonwithmorelabor-savingdevicesthanarefoundanywhereelseintheworld。ThereStateslikeWisconsinandMinnesotastandintheforefrontofeducationalandsocialprogress。ThecontrastsbetweenthecorrespondingriversofthetwoAmericasaretypicalofthecontrastsinthehistoryofthetwocontinents。
CHAPTERIII。THEGEOGRAPHICPROVINCESOFNORTHAMERICA
ThefourgreatphysicaldivisionsofNorthAmerica——theLaurentianhighland，theAppalachianhighland，theplains，andthewesterncordillera——arestrikinglydifferentinformandstructure。TheLaurentianhighlandpresentsamonotonouswasteofroughhills，irregularvalleys，picturesquelakes，andcrookedrivers。Mostofitisthinlyclothedwithpinetreesandbushessuchastheblueberryandhuckleberry。Yeteverywheretheancientrockcropsout。Noonecantraveltherewithoutbecomingtiresomelyfamiliarwithfine-grained，shatteredschists，coarsegranites，andtheircuriouslybandedrelatives，thegneisses。
ThisrockyhighlandstretchesfromalittlenorthoftheSt。
LawrenceRivertoHudsonBay，aroundwhichitlapsintheformofaV，andsoisknownastheArchaeanVorshield。
EverywherethisoldestpartoftheWesternHemispherepresentsunmistakablesignsofgreatage。Theschistsbytheirfinecrumplingandscalyflakesofmineralshowthattheywereformeddeepinthebowelsoftheearth，foronlytherecouldtheybesubjectedtotheenormouspressureneededtotransformtheirmineralsintosheetsasthinaspaper。Thecoarsegranitesandgneissesproclaimstillmoreclearlythattheymusthaveoriginatedfardowninthedepthsoftheearth;theirhugecrystalsofmica，quartz，hornblende，feldspar，andothermineralscouldneverhavebeenformedexceptunderablanketofrockwhichalmostpreventedtheoriginalmagmasfromcooling。Thethousandsortensofthousandsoffeetofrockwhichonceoverlaytheschistsandstillmorethegranitesandgneissesmusthavebeenslowlyremovedbyerosion，fortherewasnootherwaytogetridofthem。Thisprocessmusthavetakentensofmillionsofyears，andyetthewholeworkmusthavebeenpracticallycompletedahundredorperhapsseveralhundredmillionyearsago。
WeknowthisbecausetheselfsameancienterodedsurfacewhichisexposedintheLaurentianhighlandisfounddippingdownundertheoldestknownfossiliferousrocks。TracesofthatprimitivelandsurfacearefoundoveralargepartoftheAmericancontinent。Elsewheretheyareusuallyburiedunderlaterstratalaiddownwhenthecontinentsankinpartbelowsea-level。OnlyinLaurentiahasthelandremainedsteadilyabovethereachoftheoceanthroughoutthemillionsofyears。
Todaythisold，oldlandmightbeasrichasmanyothersifclimatehadbeenkindtoit。Itssoil，tobesure，wouldinmanypartsbesandybecauseofthelargeamountofquartzintherocks。Thatwouldbeasmallhandicap，however，providedthesoilwerescoresoffeetdeepliketheredsoilofthecorrespondinghighlandintheGuianaregionofSouthAmerica。ButtodaytheNorthAmericanLaurentiahasnosoilworthmentioning。ForsomereasonnotyetunderstoodthiswasthepartofAmericawheresnowaccumulatedmostdeeplyandwherethelargestglacierswereformedduringthelastgreatglacialperiod。Notoncebutmanytimesitsgranitesurfacewasshroudedfortensofthousandsofyearsiniceamileormorethick。Astheicespreadoutwardinalmosteverydirection，itscrapedawaythesoilandgougedinnumerablehollowsinthesofterpartsoftheunderlyingrock。
ItlefttheLaurentianhighlandalandofrockyribsrisingbetweenclearlakesthatfillthehollows。Thelakesaredrainedbyrapidriverswhichwindthiswayandthatinhopelessconfusionastheystrivetomoveseawardoverthestrangelyunevensurfaceleftbytheice。Suchalandisgoodforthehunterandtrapper。Itisalsogoodforthesummerpleasure-seekerwhowouldfaingrowstrongbypaddlingacanoe。
Forthemanwhowouldmakeapermanenthomeitisarough，inscrutableregionwhereonehasneedofmorethanmostmen’sshareofcourageandpersistence。Notonlydidtheclimateofthepastcausetheicetoscrapeawaythesoil，buttheclimateofthepresentissocoldthatevenwherenewsoilhasaccumulatedthefarmercanscarcelymakealiving。
AroundthebordersoftheLaurentianhighlandtheiceaccomplishedaworkquitedifferentfromthedevastationoftheinterior。Oneofitschiefactivitieswasthescouringofaseriesofvasthollowswhichnowholdtheworld’slargestseriesoflakes。EventhelakesofCentralAfricacannotcomparewithourownGreatLakesandtheothersmallerlakeswhichbelongtothesameseries。TheseadditionallakesbegininthefarnorthwithGreatBearLakeandcontinuethroughGreatSlaveLake，LakeAthabasca，andLakeWinnipegtotheLakeoftheWoods，whichdrainsintoLakeSuperior。AlltheselakeslieontheedgeofthegreatLaurentianshield，wheretheice，crowdingdownfromthehighlandtothenorthandeast，wascompressedintocertainalreadyexistenthollowswhichitwidened，deepened，andleftasvastbowlsreadytobefilledwithlakes。
SouthandsouthwestoftheLaurentianhighlandthegreaticesheetprovedbeneficialtoman。There，insteadofleavingtherocknaked，asintheLaurentianregion，itmerelysmoothedoffmanyoftheirregularitiesofthesurfaceandcoveredlargeareaswiththemostfertilesoil。
Indoingthis，tobesure，theice-capscouredsomehollowsandleftavastlylargernumberofbasinssurroundedinwholeorinpartbyglacialdebris。Thesehavegivenrisetotheinnumerablelakes，largeandsmall，whosebeautysoenhancesthecharmsofCanada，NewEngland，NewYork，Minnesota，andotherStates。Theyserveasreservoirsforthewatersupplyoftownsandpowerplantsandassourcesoficeandfish。Thoughtheytakelandfromagriculture，theyprobablyaddtothelifeofthecommunityasmuchinotherwaysastheydetractinthis。Moreoverglaciationdivertedcountlessstreamsfromtheiroldcoursesandmadethemflowoverfallsandrapidsfromwhichwater-powercaneasilybedeveloped。ThatisonereasonwhyglaciatedNewEnglandcontainsoverfortypercentofallthedevelopedwater-powerintheUnitedStates。
Farmoreimportant，however，thantheglaciallakesandriversisthefertileglacialsoil。Itcomesfreshfromtheoriginalrocksandhasnotyetbeenexhaustedbyhundredsofthousandsofyearsofweathering。Italsohastheadvantageofbeingwellmixed，forgenerallyitistheproductofscrapingsfrommanykindsofrocks，eachofwhichcontributesitsownparticularexcellencetothegeneralcomposition。TakeWisconsinasanexample。*MostpartsofthatStatehavebeenglaciated，butinthesouthwesttherelieswhatisknownasthe"driftlessarea"becauseitisnotcoveredwiththe"drift"orglacialdebriswhichisthicklystrewnovertherestoftheState。Acomparisonofotherwisesimilarcountieslyingwithinandwithoutthedriftlessareashowsanastonishingcontrast。In1910theaveragevalueofallthefarmlandintwentycountiescoveredwithdriftamountedto$56。90peracre。Insixcountiespartlycoveredwithdriftandpartlydriftlessthevaluewas$59。80peracre，whileinthirteencountiesinthedriftlessareaitwasonly$33。30peracre。Inspiteofthefactthatglaciationcausesswampsandlakes，theproportionoflandcultivatedintheglaciatedareasislargerthaninthedriftless。Intheglaciatedarea61percentofthelandisimprovedandinthedriftlessareaonly43。5percent。
Moreover，eventhoughtheunderlyingrockandtheoriginaltopographybeofthesamekindinbothcases，theaverageyieldofcropsperacreisgreaterwheretheicehasdoneitswork。
Wherethecountryrockconsistsoflimestone，whichnaturallyformsarichsoil，thedifferenceinfavoroftheglaciatedareaamountstoonly1or2percent。Wherethecountryrockissandy，thesoilissomuchimprovedbyamixtureoffertilizinglimestoneorevenofclayandothermaterialsthattheaverageyieldofcropsperacreintheglaciatedareasisathirdlargerthaninthedriftless。TakingeverythingintoconsiderationitappearsthattheancientglaciationofWisconsinincreasesthepresentagriculturaloutputbyfrom20to40percent。Upwardsof10，000，000acresofglaciatedlandhavealreadybeendevelopedinthemostpopulouspartsoftheState。Iftheaveragevalueofallproductsonthisareaisreckonedat$15peracreandiftheincreasedvalueofagriculturalproductsduetoglaciationamountsto30percent，thenthenetvalueofglaciationperyeartothefarmersofWisconsinis$45，000，000。Thismeansabout$300
foreachfarmerintheglaciatedarea。
*R。H。Whitbeck，"EconomicAspectsofGlaciationinWisconsin"，in"AnnalsoftheAssociationofAmericanGeographers，"vol。III
in（1913），pp。62-67。
Wisconsinisbynomeansunique。InOhio，forinstance，thereisalsoadriftlessarea。*ItliesinthesoutheastalongtheOhioRiver。Thedifferenceinthevalueofthefarmlandthereandintheglaciatedregionisextraordinary。Inthedriftlessareatheaveragevalueperacrein1910waslessthan$24，whileintheglaciatedareaitwasnearly$64。YearbyyeartheproportionofthepopulationoftheStateintheunglaciatedareaissteadilydecreasing。ThedifferencebetweenthetwopartsoftheStateisnotduetotheunderlyingrockstructureortotherainfallexcepttoaslightdegree。SomeofthedifferenceisduetothefactthatimportantcitiessuchasClevelandandToledolieonthefertilelevelstripoflandalongthelakeshore，butthisstripitself，aswellasthelake，owesmuchofitscharactertoglaciation。Itappears，therefore，thatinOhio，perhapsevenmorethaninWisconsin，manprospersmostinthepartswheretheicehasdoneitswork。
*WilliamH。Hess，"TheInfluenceofGlaciationinOhio，"in"BulletinoftheGeographicalSocietyofPhiladelphia，"vol。XV
（1917），pp。19-42。
WehavetakenWisconsinandOhioasexamples，buttheeffectofglaciationinthoseStatesdoesnotdiffermateriallyfromitseffectalloversouthernCanadaandthenorthernUnitedStatesfromNewEnglandtoKansasandMinnesota。EachyearthepeopleoftheseregionsarericherbyperhapsabilliondollarsbecausetheicescrapeditswaydownfromLaurentiaandspreadoutoverthebordersofthegreatplainsonthewestandoftheAppalachianregionontheeast。
WehaveconsideredtheLaurentianhighlandandtheglaciationwhichcenteredthere。Letusnowturntoanotherhighlandonlythenorthernpartofwhichwasglaciated。TheAppalachianhighland，thesecondgreatdivisionofNorthAmerica，consistsofthreeparallelbandswhichextendsouthwestwardfromNewfoundlandandtheSt。LawrenceRivertoGeorgiaandAlabama。Theeasternandmostimportantbandconsistsofhillsandmountainsofancientcrystallinerocks，somewhatresemblingthoseoftheLaurentianhighlandbutbynomeanssoold。Westofthiscomesabroadvalleyerodedforthemostpartinthesofterportionsofahighlyfoldedseriesofsedimentaryrockswhichareofgreatagebutyoungerthanthecrystallinerockstotheeast。ThethirdbandistheAlleghanyplateau，composedofalmosthorizontalrockswhichliesohighandhavebeensodeeplydissectedthattheyareoftencalledmountains。
ThethreeAppalachianbandsbynomeanspreserveauniformcharacterthroughouttheirentirelength。Theeasterncrystallinebandhasitschiefdevelopmentinthenortheast。ThereitcomprisesthewholeofNewEnglandandalargepartofthemaritimeprovincesofCanadaaswellasNewfoundland。ItsbroaddevelopmentinNewEnglandcausesthatregiontobeoneofthemostclearlydefinednaturalunitsoftheUnitedStates。Ancientigneousrockssuchasgranitelieintricatelymingledwitholdandhighlymetamorphosedsediments。Sincesomeoftherocksarehardandotherssoftandsinceallhavebeenexposedtoextremelylongerosion，thetopographyofNewEnglandconsiststypicallyofirregularmassesofroundedhillsfreefromprecipices。Hereandtherehardmassesofunusuallyresistantrockstandupasisolatedroundedheights，likeMountKatahdininMaine。Theyareknownas"monadnocks"fromthemountainofthatnameinsouthernNewHampshire。InotherplaceslargerandmoreirregularmassesofhardrockformmountaingroupsliketheWhiteMountains，theGreenMountains，andtheBerkshires，eachofwhichismerelyagreatseriesofmonadnocks。
InthelatitudeofsouthernNewYorkthecrystallinerocksarecompressedintonarrowcompassandlosetheirmountainouscharacter。TheyformtheirregularhillsonwhichNewYorkCityitselfisbuiltandwhichmakethesuburbsofWestchesterCountyalongtheeasternHudsonsodiverseandbeautiful。Tothesoutheastthetopographyoftheoldcrystallinebandbecomesstilllesspronounced，asmaybeseenintherolling，fertilehillsaroundPhiladelphia。Farthersouththebanddividesintotwoparts，themountainsproperandthePiedmontplateau。ThemountainsbeginattheBlueRidge，whichinVirginiaraisesitseven-toppedheightsmileaftermileacrossthelengthofthatState。InNorthCarolina，however，theylosetheircharacterasasingleridgeandexpandintothebroadmassofthesouthernAppalachians。ThereMountMitchelldominatestheeasternpartoftheAmericancontinentandissurroundedbyoverthirtyothermountainsrisingtoaheightofatleastsixthousandfeet。ThePiedmontplateau，whichliesattheeasternfootoftheBlueRidge，isnotreallyaplateaubutapeneplainorancientlowlandwornalmosttoaplain。ItexpandstoawidthofonehundredmilesinVirginiaandtheCarolinasandformsthepartofthoseStateswheremostofthelargertownsaresituated。AmongitslowgentleheightsthererisesanoccasionallittlemonadnocklikeChapelHill，wheretheUniversityofNorthCarolinaliesonaruggedeminencewhichstrikinglyrecallsNewEngland。Forthemostpart，however，thehillsofthePiedmontregionarelowerandmoreroundedthanthoseintheneighborhoodofPhiladelphia。
Thecountrythusformedhasmanyadvantages，foritisflatenoughtobeusedforagricultureandyetvariedenoughtobefreefromthemonotonyofthelevelplains。
TheprolongedandbrokeninnervalleyformingthesecondbandoftheAppalachianswasofsomeimportanceasahighwayinthedaysoftheIndians。Todaythemainhighwaysoftraffictouchitonlytocrossitasquicklyaspossible。FromLakeChamplainittrendsstraightsouthwardintheHudsonValleyuntiltheCatskillshavebeenpassed。Then，whiletherailroadsandallthetrafficgoondownthegorgeoftheHudsontoNewYork，thevalleyswingsoffintoPennsylvaniapastScranton，Wilkesbarre，andHarrisburg。
Theretheunderlyingrockconsistsofaseriesofalternatelyhardandsoftlayerswhichhavebeencrumpledupmuchasonemightwrinklearugwithone’sfoot。Thepressureinvolvedintheprocesschangedandhardenedtherockssomuchthatthecoalwhichtheycontainwasconvertedintoanthracite，thefinestcoalinalltheworldandtheonlyexampleofitskind。EventhefamousWelshcoalhasnotbeensothoroughlyhardened。Duringalongperiodoferosionthetopsofthefoldedlayerswerewornofftoadepthofthousandsoffeetandthewholecountrywasconvertedintoanalmostlevelplain。TheninthelategeologicalperiodknownastheearlyTertiarythelandwasliftedupagain，andoncemoreerosionwenton。Thesoftrockswerethusetchedawayuntilbroadvalleyswereformed。Thehardlayerswereleftasabewilderingsuccessionofridgeswithflattops。AsingleridgemaydoublebackandforthsooftenthattheregionwelldeservestheoldIndiannameofthe"EndlessMountains。"
Southwestwardthevalleygrowsnarrower，andtheridgeswhichbreakitssurfacebecomestraighter。Everywheretheyareflat-topped，steep-sided，andnarrow，whilebetweenthemliepartsofthemainvalleyfloor，flatandfertile。Hereinthesouth，evenmoreclearlythaninthenorth，thevalleyisborderedontheeastbythesharplyupstandingrangeofthecrystallineAppalachians，whileonthewestwithequalregularityitcomestoanendinanescarpmentwhichrisestotheAlleghanyplateau。
Thisplateau，thethirdgreatbandoftheAppalachians，beginsonthesouthsideoftheMohawkValley。TothenorthitsplaceistakenbytheAdirondacks，whichareanoutlierofthegreatLaurentianareaofCanada。ThefactthattheoutlierandtheplateauareseparatedbythelowstripoftheMohawkValleymakesthistheoneplacewherethehighlycomplexAppalachiansystemcaneasilybecrossed。IftheAlleghanyplateaujoinedtheAdirondacks，PhiladelphiainsteadofNewYorkwouldbethegreatestcityofAmerica。WheretheplateaufirstrisesonthesouthsideoftheMohawk，itattainsheightsoffourthousandfeetintheCatskillMountains。WethinkoftheCatskillsasmountains，buttheirsteepcliffsandtable-toppedheightsshowthattheyarereallytheremnantsofaplateau，thenearlyhorizontalstrataofwhichhavenotyetbeenwornaway。WestwardfromtheCatskillstheplateaucontinuesthroughcentralNewYorktowesternPennsylvania。ThosewhohavetraveledonthePennsylvaniaRailroadmayrememberhowtherailroadclimbstheescarpmentatAltoona。Farthereastthetrainhaspassedalternatelythroughgorgescutintheparallelridgesandthroughfertileopenvalleysformingthemainflooroftheinnervalley。
ThenitwindsupthelongascentoftheAlleghanyfrontinasplendidhorseshoecurve。Atthetop，afterashorttunnel，thetrainemergesinawhollydifferentcountry。Thevalleysarewithoutorderorsystem。Theywindthiswayandthat。Thehillsarenotlongridgesbutisolatedbitsleftbetweenthewindingvalleys。Hereandtherebedsofcoalblackenthesurface，forhereweareamongtherocksfromwhichtheworld’slargestcoalsupplyisderived。Sincethelayersliehorizontallyandhaveneverbeencompressed，thesamematerialwhichintheinnervalleyhasbeenchangedtohard，clean-burninganthracitehereremainssoftandsmoky。
InitssouthwesterncontinuationthroughWestVirginiaandKentuckytoTennesseetheplateaumaintainsmanyofitsPennsylvaniancharacteristics，butitnowriseshigherandbecomesmoreinaccessible。Theonlyhabitableportionsarethebottomsofthevalleys，buttheyareonlywideenoughtosupportamostscantypopulation。Betweenthemmostofthelandistooroughforanythingexceptforests。Hencethepeoplewholiveatthebottomsofthevalleysarestrangelyisolated。Theyseelittleornothingoftheworldatlargeorevenoftheirneighbors。Theroadsaresofewandthetrailssodifficultthatthefarmerscannoteasilytaketheirproducetomarket。Theironlyrecoursehasbeentoconverttheirbulkycornintowhisky，whichoccupiedlittlespaceinproportiontoitsvalue。Sincethemountaineerhasnoothermeansofgettingreadymoney，itisnotstrangethathehasbecomeamoonshinerandhasfoughtbitterlyforwhathegenuinelybelievedtobehisrightsinthatoccupation。Educationhasnotprosperedontheplateaubecausethenarrownessofthevalleyscausesthepopulationtobetoopoorandtooscatteredtosupportschools。Forthesamereasonfeudsgrowup。Whenpeoplelivebythemselvestheybecomesuspicious。Notbeingusedtodealingwiththeirneighbors，theysuspectthemotivesofallbuttheirintimatefriends。Moreover，inthosedeepvalleys，withtheirsteepsidesandtheirgeneralinaccessibility，lawscannoteasilybeenforced，andthereforeeachfamilytakesthelawintoitsownhands。
TodaythemoreruggedpartsoftheAppalachiansystemarechieflyimportantasahindrancetocommunication。OntheAtlanticslopeoftheoldcrystallinebandtherearegreatareasofgentlereliefwhereanabundantpopulationcandwell。Westwardontheedgesoftheplateauandtheplainsbeyondastillgreaterpopulationcanfindaliving，butintheinterveningspacethereisopportunityforonlyafew。Thegreatproblemistocrossthemountainsaseasilyaspossible。Eachaccessiblecrossing-placeisassociatedwithacity。Boston，aswellasNewYork，owesmuchtothelowMohawk-Hudsonroute，butisbadlyhandicappedbecauseithasnoeasymeansofcrossingtheeasterncrystallineband。
Philadelphia，ontheotherhand，benefitsfromthefactthatinitsvicinitythecrystallizesarelowandcanreadilybecrossedevenwithouttheaidofthevalleysoftheDelawareandSchuylkillrivers。Itishandicapped，however，bytheAlleghanyescarpmentatAltoona，eventhoughthisislowertherethanfarthersouth。Baltimore，inthesameway，owesmuchofitsgrowthtotheeasypathwaysoftheSusquehannaonthenorthandthePotomaconthesouth。FarthersouthboththecrystallinebandandtheAlleghanyplateaubecomemoredifficulttotraverse，sothatcommunicationbetweentheAtlanticcoastandtheMississippiValleyisreducedtosmallproportions。HappyisNewYorkinitssituationwherenooneofthethreebandsoftheAppalachiansopposesanyobstacle。TheplainsofNorthAmericaformthethirdofthefourmainphysicaldivisionsofthecontinent。ForthemostparttheyliebetweenthegreatwesterncordilleraononesideandtheLaurentianandAppalachianhighlandsontheother。
YettheylaparoundthesouthernendoftheAppalachiansandrunfaruptheAtlanticcoasttoNewYork。Theyremainedbeneaththeseatillalatedate，muchlaterthantheotherthreedivisions。
Theywerenot，however，coveredwithdeepwaterlikethatoftheabysmaloceans，butonlywithshallowseasfromwhichthelandattimesemerged。Inspiteoftheoldbelieftothecontrary，thecontinentsappeartobesopermanentthattheyhaveoccupiedpracticallytheirpresentpositionsfromtheremotestgeologicaltimes。Theyhavemovedslowlyupanddown，however，sothatsomepartshavefrequentlybeensubmerged，andtheplainsarethepartsthatremainedlongestunderwater。
TheplainsofNorthAmericamaybedividedintofourpartsaccordingtothecharacteroftheirsurface：theAtlanticcoastalplain，theprairies，thenorthwesternpeneplain，andthesouthwesternhighplains。TheAtlanticcoastalplainliesalongtheAtlanticcoastfromNewYorksouthwardtoFloridaandAlabama。ItalsoformsagreatembaymentuptheMississippiValleyasfarastheOhioRiver，anditextendsalongtheshoreoftheGulfofMexicototheRioGrande。ThechiefcharacteristicofthisAtlanticandGulfcoastalplainisitsbeltednature。Onelayerofrocksissandy，anotherconsistsoflimestone，andathirdofclay。Whenupliftedanderodedeachassumesitsownspecialtopographyandiscoveredwithitsownspecialtypeofvegetation。ThusinSouthCarolinaandGeorgiathecrystallinePiedmontbandoftheAppalachianprovinceisborderedonthesoutheastbyabeltofsandstone。Thisrockissofarfromtheseaandhasbeenraisedsohighaboveitthaterosionhasconverteditintoaregionofgentlehills，whosetopsaresixhundredorsevenhundredfeetabovesea-level。Itssandysoilissopoorthatfarmingisdifficult。Thehillsarelargelycoveredwithpine，yieldingtarandturpentine。Fartherseawardcomesabroadbandofyoungerrockwhichformsaclayeysoilorelseayellowsandyloam。Thesesoilsaresorichthatsplendidcottoncropscanberaised，andhencetheregionisthicklypopulated。
Againtherecomesabeltofsand，theso-called"pinebarrens，"
whichformapoorsectionaboutfiftymilesinlandfromthecoast。Finallythecoastalbeltitselfhasemergedfrombeneaththeseasorecentlyandliessonearlyatsea-levelthatithasnotbeengreatlyeroded，andisstillcoveredwithnumerousmarshesandswamps。Therichsoilandthemoisturearegoodforrice，buttheregionissounhealthyandsohardtodrainthatonlysmallpartsareinhabited。
Everywhereinthecoastalplainthissamebeltedcharacterismoreorlessevident。Ithasmuchtodowithallsortsofactivitiesfromfarmingtopolitics。OnconsultingthemapshowingthecottonproductionoftheUnitedStatesin1914，onenoticesthetwodarkbandsinthesoutheast。Oneofthem，extendingfromthenorthwesternpartofSouthCarolinaacrossGeorgiaandAlabama，isduetothefertilesoilofthePiedmontregion。Theother，lyingnearerthesea，beginsinNorthCarolinaandextendswellintoAlabamabeforeitswingsaroundtothenorthwesttowardtheareaofheavyproductionalongtheMississippi。Itisduetothefertilesoilofthatpartofthecoastalplainknownasthe"cottonbelt。"Portionsofitarecalledthe"blackbelt，"notbecauseofthecoloredpopulation，butbecauseofthedarknessofthesoil。Sincethislandhasalwaysbeenprosperous，ithasregularlybeenconservativeinpolitics。
TheAtlanticcoastalplainisbynomeanstheonlypartoftheUnitedStateswherethefertilityofthesoilisthedominantfactinthelifeofthepeople。BecauseoftheirrichsoiltheprairieswhichextendfromwesternOhiototheMissouriRiverandnorthwardintoCanadaarefastbecomingthemoststeadilyprosperouspartofAmerica。Theyowetheirsurpassingrichnesslargelytoglaciation。Wehavealreadyseenhowthecomingoftheice-sheetbenefitedtheregionsonthebordersoftheoldLaurentianhighland。Thissamebenefitextendedoverpracticallythewholeofwhatarenowtheprairies。BeforetheadventoftheicethewholesectionconsistedofabroadlybandedcoastalplainmucholderthanthatoftheAtlanticcoast。Whentheicewithitsburdenofmaterialscrapedfromthehillsofthenorthpassedoverthecoastalplain，itfilledthehollowswithrichnewsoil。
Theicystreamsthatflowedoutfromtheglacierswerefulloffinesediment，whichtheydepositedoverenormousfloodplains。
Duringdryseasonsthewindspickedupthisdustandspreaditoutstillmorewidely，formingthegreatbanksofyellowloesswhosefertilesoilmantlesthesidesofmanyavalleyintheMississippibasin。Thusglaciers，streams，andwindslaiddownten，twenty，fifty，orevenonehundredfeetofthefinest，mostfertilesoil。WehavealreadyseenhowmuchthesoilwasimprovedbyglaciationinWisconsinandOhio。ItwasintheprairieStatesthatthisimprovementreachedamaximum。Thesoilthereisnotonlyfinegrainedandfreefromrocks，butitconsistsofparticlesbroughtfromwidelydifferentsourcesandisthereforefullofallkindsofplantfoods。Inmostpartsoftheworldafine-grainedsoilisformedonlyafteraprolongedperiodofweatheringwhichleachesoutmanyvaluablechemicalelements。Intheprairies，however，thesoilconsistslargelyofmaterialsthatweremechanicallygroundtodustbytheicewithoutbeingexposedtotheactionofweathering。Thustheyhavereachedtheirpresentresting-placeswithoutthelossofanyoftheiroriginalplantfoods。Whensuchasoilisfoundwithaclimatewhichisgoodforcropsandwhichisalsohighlystimulatingtoman，thecombinationisalmostideal。ThereissomejustificationforthosewhosaythatthenorthcentralportionoftheUnitedStatesismorefortunatethananyotherpartoftheearth。Nowhereelse，unlessinwesternEurope，istheresuchacombinationoffertilesoil，fineclimate，easycommunication，andpossibilitiesformanufacturingandcommerce。IronfromthatoutlieroftheLaurentianhighlandwhichformsthepeninsulaofnorthernMichigancaneasilybebroughtbywateralmosttothecenteroftheprairieregion。Coalinvastquantitiesliesdirectlyunderthesurfaceofthisregion，fortherockoftheancientcoastalplainbelongstothesamePennsylvanianserieswhichyieldsmostoftheworld’scoal。Heremanis，indeed，blessedwithresourcesandopportunitiesscarcelyequaledinanyotherpartoftheworld，andfindstheonlydrawbackstobetheextremesoftemperatureinbothwinterandsummerandtheremotenessoftheregionfromthesea。Becauseoftherichnessoftheirheritageandbecausetheylivesafelyprotectedfromthreatsofforeignaggression，thepeoplewholiveinthispartoftheworldareindangerofbeingslowtofeelthecurrentsofgreatworldmovements。
ThewesternhalfoftheplainsofNorthAmericaconsistsoftwopartsunlikeeithertheAtlanticcoastalplainortheprairies。
FromSouthDakotaandNebraskanorthwardfarintoCanadaandwestwardtotheRockyMountainsthereextendsanancientpeneplainworndowntogentlereliefbytheerosionofmillionsofyears。Itisnotsolevelastheplainsfarthereastnorsolow。Itswesternmarginreachesheightsoffourorfivethousandfeet。Hereandthere，especiallyonthewesternside，itrisestothecrestofaruggedescarpmentwheresomeresistantlayerofrocksstillholdsitselfupagainsttheforcesoferosion。
Elsewhereitssmoothsurfacesarebrokenbylava-cappedmesasorbyridgeswheresomeancientvolcanicdikeissohardthatithasnotyetbeenwornaway。Thesoil，thoughexcellent，isthinnerandlessfertilethanintheprairies。Neverthelessthepopulationmightintimebecomeasdenseandprosperousasalmostanyintheworldifonlytherainfallweremoreabundantandgoodsuppliesofcoalwerenotquitesofaraway。Yetinspiteofthesehandicapsthenorthwesternpeneplainwithitsvastopenstretches，itscattle，itswheat，anditsopportunitiesisamostattractiveland。
SouthofNebraskaandWyomingthe"highplains，"thelastofthefourgreatdivisionsoftheplains，extendasfaraswesternTexas。These，liketheprairies，havebeenbuiltupbydepositsbroughtfromotherregions。Inthiscase，however，thedepositsconsistofgravel，sand，andsiltwhichtherivershavegraduallywashedoutfromtheRockyMountains。Astherivershavechangedtheircoursesfromonebedtoanother，layerafterlayerhasbeenlaiddowntoformavastplainlikeagentlyslopingbeachhundredsofmileswide。Inmostplacesthestreamsarenolongerbuildingthisup。Frequentlytheyhavecarvednarrowvalleyshundredsoffeetdeepinthematerialswhichtheyformerlydeposited。Elsewhere，however，asinwesternKansas，mostofthecountryissoflatthatthehorizonislikethatoftheocean。Itseemsalmostincrediblethatatheightsoffourorfivethousandfeettheplainscanstillbesowonderfullylevel。Whenthegrassisgreen，whenthespringflowersareattheirbest，itwouldbehardtofindapictureofgreaterbeauty。Herethebuffalowanderedinthedaysbeforethewhitemandestroyedthem。HeretodayisthegreatcattleregionofAmerica。Hereistheregionwherethesoulofmanisfilledwiththefeelingofinfinitespace。
Tothestudentoflandformsthereisaneverpresentcontrastbetweenthoseduedirectlytotheprocesseswhichbuilduptheearth’ssurfaceandthoseduetotheerosiveforceswhichdestroywhattheothershavebuilt。InthegreatplainsofNorthAmericatwoofthedivisions，thatis，theAtlanticcoastalplainofthesoutheastandthepeneplainofthenorthwest，owetheirpresentformtotheforcesoferosion。Theothertwo，thatis，theprairiesandthehighplains，stillbeartheimpressoftheoriginalprocessesofdepositionandhavebeenmodifiedtoonlyaslightextentbyerosion。
AsimilarbutgreatercontrastseparatesthemountainsofeasternNorthAmericaandthoseofthewesterncordillera——thefourthandlastofthemainphysicaldivisionsofthecontinent。InboththeLaurentianandtheAppalachianhighlandstheeasternmountainsshownotraceoftheoriginalformsproducedbythefaultingofthecrustorbyvolcanicmovements。Alltheoriginaldistinctivetopographyhasbeenremoved。Whatweseetodayistheproductoferosionworkinguponrocksthatwerethousandsoffeetbeneaththesurfacewhentheywerebroughttotheirpresentpositions。Inthewesterncordillera，onthecontrary，althoughmuchofthepresentformofthelandisduetoerosion，avastamountisduedirectlytoso-called"tectonic"activitiessuchasthebreakingofthecrust，thepouringoutofmoltenlavas，andtheburstingforthofexplosiveeruptions。
Thecharacterofthesetectonicactivitieshasdifferedwidelyindifferentpartsofthecordillera。Abroadupheavalofgreatblocksoftheearth’scrustwithouttiltingordisturbancehasproducedtheplateausofArizonaandUtah。Thegorgesthathavebeenrapidlycutintosuchgreatupheavedblocksformpartoftheworld’smoststrikingscenery。TheGrandCanyonoftheColoradowithitstremendousplatforms，mesas，andawe-inspiringcliffscouldhavebeenformedinnootherway。EquallywonderfularesomeofthenarrowcanyonsinthebroadlyupheavedplateausofsouthernUtahwherethetributariesoftheVirginandotherrivershavecutredorwhitechasmsthousandsoffeetdeepandsonarrowthatattheirbottomsperpetualtwilightreigns。Itisacuriousproofofthefallibilityofhumanjudgmentthatthesegreatgorgesareoftencitedasthemoststrikingexamplesofthepoweroferosion。Wonderfulasthesegorgescertainlyare，thePiedmontplainorthenorthwesternpeneplainisfarmorewonderful。Thoseregionshadtheirgrandcanyonsonceuponatime，butnowerosionhasgonesofarthatithasreducedthewholeareatothelevelofthebottomsofthegorges。Thoughsuchafateisinstoreforallthemarveloussceneryofthewesterncordillera，wehaveit，forthepresentatleast，asoneofthemoststimulatingpanoramasofourAmericanenvironment。Nomanworthyofthenamecansitonthebrinkofagreatcanyonorgazeupfromthedarkdepthsofagorgewithoutasenseofaweandwonder。There，asinfewotherplaces，Natureshowswithunmistakablegrandeurthemarvelouspowerandcertaintywithwhichherlawsworkoutthedestinyoftheuniverse。
InotherpartsofthegreatAmericancordillerasomeofthesimplestandyoungestmountainridgesintheworldarefound。InsouthernOregon，forexample，lavablockshavebeenbrokenandupliftedandnowstandwithsteepfreshfacesononesideandwiththeoldsurfaceincliningmoregentlyontheother。TiltedblocksonalargerscaleandmuchmoredeeplycarvedbyerosionarefoundintheloftySt。EliasMountainofAlaska，wheremuchoftheerosionhasbeendonebysomeoftheworld’sgreatestglaciers。ThewesternslopeoftheWasatchMountainsfacingthedesertofUtahisthewallofahugefracture，asistheeasternfaceoftheSierraNevadasfacingthedesertsofNevada。Eachofthesegreatfaceshasbeendeeplyeroded。Atthebase，however，recentbreakingandupheavalofthecrusthavegivenrisetofreshunerodedslopes。Sometaketheformoftriangularfacets，whereaseriesofridgeshasbeenslicedacrossandliftedupbyagreatfault。Othersassumetheshapeofterraceswhichsometimescontinuealongthebaseofthemountainsforscoresofmiles。Inplacestheyseemlikebluffscutbyanancientlake，butsuddenlytheychangetheiraltitudeorpassfromonedrainageareatoanotherasnolake-formedstrandcouldpossiblydo。
Inotherpartsofthecordillera，mountainshavebeenformedbyasinglearchingofthecrustwithoutanybreaking。SuchisthecaseintheUintaMountainsofnorthwesternUtahandinsomeoftherangesoftheRockyMountainsinColorado。TheBlackHillsofSouthDakota，althoughlyingoutintheplains，areanexampleofthesamekindofstructureandreallybelongtothecordillera。
Inthemthelayersoftheearth’scrusthavebeenbentupintheformofagreatdome。Thedomestructure，tobesure，hasnowbeenlargelydestroyed，forerosionhaslongbeenactive。Theresultisthattheharderstrataformaseriesofconcentricridges，whilebetweenthemarering-shapedvalleys，oneofwhichissolevelandunbrokenthatitisknowntotheIndiansasthe"race-course。"Inotherpartsofthecordilleragreatmassesofrockhavebeenpushedhorizontallyuponthetopsofothers。InMontana，forexample，thestrataoftheplainshavebeenbentdownandoverriddenbythoseofthemountains。Theseareonlyafewofthecountlessformsofbreaking，faulting，andcrumplingwhichhavegiventothecordilleraanalmostinfinitevarietyofscenery。
Theworkofmountainbuildingisstillactiveinthewesterncordillera，asisevidentfromsuchaneventastheSanFranciscoearthquake。IntheOwensValleyregioninsouthernCaliforniathegravellybeachesofoldlakesarerentbyfissuresmadewithinafewyearsbyearthquakes。Inotherplacesfreshterracesonthesidesofthevalleymarkthelinesofrecentearthmovements，whilenewlyformedlakeslieintroughsattheirbase。TheseOwensValleymovementsofthecrustarepartsofthestupendousupliftwhichhasraisedtheSierraNevadatoheightsofover14，000feetafewmilestothewest。Alongthefaultlineatthebaseofthemountainsthererunsforover9。50milestheworld’slongestaqueduct，whichwasbuilttorelieveLosAngelesfromthedangerofdrought。Itisastrangeironyoffatethatsodelicateandsovitalanarteryofcivilizationshouldbeforcedtoliewherearenewalofearthquakemovementsmaybreakitatanytime。Yettherewasnootherplacetoputit，forinspiteofman’sgrowingcontrolofnaturehewasforcedtofollowthetopographyoftheregioninwhichhelivedandlabored。
OnthesouthernsideoftheMohaveDesertalittletotheeastofwheretheLosAngelesaqueductcrossesthemountainsinitssouthwardcourse，therecordofanearthquakeispreservedinuniquefashion。Thesteepfaceofaterraceiscoveredwithtreesfortyorfiftyyearsold。Nearthebasethetreesarebentinpeculiarfashion。Theirlowerportionsstandatrightanglestothesteeplyslopingfaceoftheterrace，butafterafewfeetthetrunksbendupwardandstandvertically。Clearlywhenthesetreeswereyoungtheterracewasnotthere。Thenanearthquakecame。
Oneblockoftheearth’scrustwasdroppeddownwhileanotherwasraisedup。Alongthedividinglineaterracewasformed。Thetreesthathappenedtostandalongthelineweretiltedandleftinaslantingpositionontheslopingsurfacebetweenthetwopartsoftheearth’scrust。Theysawnoreasontostopgrowing，but，turningtheirtipstowardthesky，theybravelypushedupward。Thustheypreserveinastrikingwaytherecordofthisrecentmovementoftheearth’scrust。
Volcanoesaswellasearthmovementshaveoccurredonagrandscalewithinafewhundredyearsinthecordillera。Evenwherethereistodaynovisiblevolcanicactivity，recenteruptionshavelefttracesasfreshasiftheyhadoccurredbutyesterday。
OnthebordersoftheGrandCanyonoftheColoradoonecanseenotonlyfreshconesofvolcanicashbutlavawhichhaspouredovertheedgesofthecliffsandhardenedwhileintheactofflowing。FromOrizabaandPopocatepetlinMexicothroughMountSanFranciscoinArizona，LassenPeakandMountShastainCalifornia，MountRainierwithitsglaciersintheCascadeRangeofWashington，andMountWrangellinAlaska，thecordilleracontainsanalmostunbrokenchainofgreatvolcanoes。Allareeitheractiveatpresentorhavebeenactivewithinveryrecenttimes。In1912MountKatmai，nearthenorthwesternendofthevolcanicchain，eruptedsoviolentlythatitsentdustaroundthewholeworld。ThepresenceofthedustcausedbrilliantsunsetssecondonlytothoseduetoKrakatoain1883。ItalsocutoffsomuchsunlightthattheeffectwasfeltinmeasurementsmadebytheSmithsonianInstitutionintheFrenchprovincesofNorthAfrica。Inearliertimes，throughoutthelengthofthecordilleragreatmassesofvolcanicmaterialwerepouredouttoformhighplateauslikethoseofsouthernMexicooroftheColumbiaRiverinOregon。InUtahsomeofthesehavebeenliftedupsothatheavycapsoflavanowformisolatedsheetstoppingloftyplateaus。Therethelowlandshepherdsdrivetheirsheepinsummerandliveinabsoluteisolationformonthsatatime。There，aseverywhere，thecordillerabearsthemarksofmountainsinthemaking，whilethemountainsofeasternAmericabearthemarksofthosethatweremadewhentheworldwasyoung。
ThegeysersandhotspringsoftheYellowstoneareanotherproofofrecentvolcanicactivity。Theyowetheirexistencetohotrockswhichlieonlyalittlewaybelowthesurfaceandwhichnotlongagoweremoltenlava。Theterracesandplatformsbuiltbythegeysersareanotherevidencethatthecordilleraisaregionwherethesurfaceoftheearthisstillbeingshapedintonewformsbyforcesactingfromwithin。Thephysicalfeaturesofthecountryarestillinprocessofconstruction。
Inspiteoftheimportanceoftheconstructiveforceswhicharestillbuildingupthemountains，muchofthefinestsceneryofthecordilleraisduetothedestructiveforcesoferosion。ThemajesticColumbiaCanyon，likeothersofitskind，istheworkofrunningwater。Glaciersalsohavedonetheirpart。DuringtheglacialperiodtheforceswhichcontrolthepathsofstormsdidnotgivetothecordilleraregionsuchanabundanceofsnowaswassifteddownuponLaurentia。Thereforenosuchhugecontinentalglaciershaveflowedoutovermillionsofsquaremilesoflowercountry。Neverthelessamongthemountainsthemselvestheicegougedandscrapedandsmoothedandatitsloweredgesdepositedgreatmoraines。ItsworktodaymakesthecliffsandfallsoftheYosemiteoneoftheworld’smostfamousbitsofscenery。Thissceneryisyounganditsbeautywillpassinashorttimeasgeologycountstheyears，forinnaturalsceneryasinhumanlifeitisyouththatmakesbeauty。Thecanyons，waterfalls，andgeysersofthecordillerasharetheiryouthwiththelakes，waterfalls，andrapidsduetorecentglaciationintheeast。Nevertheless，thoughyouthistheconditionofmoststrikingbeauty，maturityandoldagearetheconditionofgreatestusefulness。Theyoungcordillerawithitsmountainsstillinthemakingcansupportonlyascantypopulation，whereastheoldeasternmountains，withthelinesoflonglifeengraveduponeveryfeature，opentheirarmstomanandlethimliveandprosper。
Itisnotenoughthatweshouldpicturemerelythefourdivisionsofthelandofourcontinent。Wemustseehowthelandmeetsthesea。InlowlatitudesinboththeOldWorldandtheNew，thecontinentshavetendedtoemergefartherandfartherfromtheseaduringrecentgeologicaltimes。HenceontheeasternsideofbothNorthandSouthAmericafromNewJerseytoBraziltheoceanisborderedforthemostpartbycoastalplains，upliftedfromtheseaonlyashorttimeago。Onthemountainouswesternsideofbothcontinents，however，theseabottomshelvesdownwardsosteeplythatitsemergencedoesnotgiverisetoaplainbutmerelytoasteepslopeonwhichlieaseriesofoldbeachesseveralhundredandevenonethousandfeetabovethepresentshoreline。Suchconditionsarenotfavorabletohumanprogress。
Thecoastalplainsproducedbyupliftofthelandmaybefertileandmayfurnishhappyhomesforman，buttheydonotpermitreadyaccesstotheseabecausetheyhavenoharbors。ThechiefharborofMexicoatVeraCruzismerelyalittlenickinthecoast-lineandcouldneverprotectagreatfleet，evenwiththehelpofitsbreakwater。WhereanenterprisingcitylikeLosAngelesliesontheupliftedPacificcoast，itmustspendmillionsinwrestingaharborfromtheveryjawsofthesea。
Inhighlatitudesinallpartsoftheworldthelandhasrecentlybeensubmergedbeneaththesea。Insomeplaces，especiallythoselikethecoastsofVirginiaandcentralCaliforniawhichlieinmiddlelatitudes，arecentslightsubmergencehassucceededapreviouslargeemergence。Whereversuchsinkingofthelandhastakenplace，ithasgivenrisetocountlessbays，gulfs，capes，islands，andfiords。Theoceanwaterhasenteredthevalleysandhasdrownedtheirlowerparts。Ithassurroundedthebasesofhillsandleftthemasislands;ithascoveredlowvalleysandhascreatedlongsoundswheretrafficmaypasswithsafetyeveningreatstorms。Thoughmuchlandhasthusbeenlostwhichwouldbegoodforagriculture，commercehasbeenwonderfullystimulated。ThroughLongIslandSoundtherepasseachdayhundredsofboatswhichagainandagainwouldsufferdistressandlossiftheywerenotprotectedfromtheopensea。ItisnoaccidentthatoftheeightlargestmetropolitandistrictsintheUnitedStatesfivehavegrownupontheshoresofdeepinletswhichareduetothedrowningofvalleys。
Normustthevalueofscenerybeforgotteninasurveysuchasthis。Yearbyyearwearelearningthatinthisrestless，strenuousAmericanlifeofoursvacationsareessential。Wearelearning，too，thattheloveofbeautyisoneofNature’sgreatesthealers。RegionslikethecoastofMaineandPugetSound，whereruggedlandandlife-givingoceaninterlock，areworthuntoldmillionsbecauseoftheirinspiringbeauty。ItisindeedmarvelousthatinthelatitudeofthenorthernUnitedStatesandsouthernCanadasomanycircumstancesfavorabletohumanhappinessarecombined。Fertilesoil，levelplains，easypassageacrossthemountains，coal，iron，andothermetalsimbeddedintherocks，andastimulatingclimate，allshowertheirblessingsuponman。Andwithalltheseblessingsgoestheadvantageofacoastwhichwelcomesthemarinerandbringsthestimulusofforeignlands，whileatthesametimeitaffordsrestandinspirationtothetoilershereathome。
CHAPTERIV。THEGARMENTOFVEGETATION
Nopartoftheworldcanbetrulyunderstoodwithoutaknowledgeofitsgarmentofvegetation，forthisdeterminesnotonlythenatureoftheanimalinhabitantsbutalsotheoccupationsofthemajorityofhumanbeings。Althoughthesoilhasmuchtodowiththecharacterofvegetation，climatehasinfinitelymore。Itistemperaturewhichcausesthemossandlichensofthebarrentundrasinthefarnorthtobereplacedbyorchids，twiningvines，andmahoganytreesneartheequator。ItisrainfallwhichdeterminesthatvigorousforestsshallgrowintheAppalachiansinlatitudeswheregrasslandsprevailintheplainsanddesertsinthewesterncordillera。
Forests，grass-lands，deserts，representthethreechieftypesofvegetationonthesurfaceoftheearth。Eachisaresponsetocertainwell-definedconditionsofclimate。Forestsdemandanabundanceofmoisturethroughouttheentireseasonofgrowth。
Wherethisseasonlastsonlythreemonthstheforestisverydifferentfromwhereitlaststwelve。Butnoforestcanbevigorousifthegroundhabituallybecomesdryforaconsiderableperiodduringwhichtheweatheriswarmenoughforgrowth。Desertvegetation，ontheotherhand，whichconsistsprimarilyofbusheswithsmall，drought-resistantleaves，needsonlyafewirregularandinfrequentshowersinordertoendurelongperiodsofheatanddrought。Discontinuityofmoistureisthecauseofdeserts，justascontinuityisthenecessaryconditionofforestgrowth。
Grassesprevailwheretheclimaticconditionsareintermediatebetweenthoseoftheforestandthedesert。Theirprimaryrequisiteisashortperiodoffairlyabundantmoisturewithwarmthenoughtoripentheirseeds。Unlikethetreesoftheforests，theythriveeventhoughthewetperiodbeonlyafractionoftheentiretimethatiswarmenoughforgrowth。
Unlikethebushesofthedesert，theyrarelythriveunlessthegroundiswellsoakedforatleastafewweeks。Mostpeoplethinkofforestsasofferingfarmorevarietythaneitherdesertsorgrass-lands。Tothemgrassisjustgrass，whiletreesseemtopossessindividuality。Inreality，however，theshortturfygrassofthefarnorthdiffersfromthefour-footfrondsofthebunchysaccatongrassofArizona，andfromthefartallertuftsoftheplumedpampasgrass，muchmorethanthepinetreediffersfromthepalm。Desertsvaryevenmorethaneitherforestsorgrass-lands。ThetravelerintheArizonadesert，forexample，hasbeenjoggingacrossagravellyplainstuddedatintervalsofafewyardswithlittlebushesafoothigh。Thesceneryissomonotonousandthenoonsunshinesowarmthathealmostfallsasleep。Whenhewakesfromhisdaydream，soweirdarehissurroundingsthathethinkshemustbeinoneoftheplacestowhichSindbadwascarriedbytheroc。Thetrailhasenteredanopenforestofjoshuas，asthebigtreeyuccasarecalledinArizona。Theirshaggytrunksanduncouthbranchesarerendereddoublyunkemptbyswordlike，ashy-yellowdeadleavesthatdoublebackonthetrunkbutrefusetofalltotheground。Ataheightoffromtwelvetotwentyfeeteacharmofthemany-branchedcandelabrumendsinastiffrosetteofgray-greenspikyleavesastoughashemp。Equallybizarreandmuchmoreimposingisadesert"stand"ofgiantsuhuaros，greatflutedtree-cactithirtyfeetormorehigh。Inspiteoftheirsizethesuhuarosaredeserttypesastrulyasissagebrush。
InAmericathemostwidespreadtypeofforestistheevergreenconiferouswoodlandofthenorth。Itspines，firs，spruces，hemlocks，andcedarswhicharereallyjunipers，covermostofCanadatogetherwithnorthernNewEnglandandtheregionsouthofLakesHuronandSuperior。Atitsnorthernlimittheforestlooksthoroughlyforlorn。Thegnarledandstuntedtreesarethicklystuddedwithhalf-deadbranchesbentdownbytheweightofsnow，sothattheloweronessweeptheground，whiletheupperlooktiredanddiscouragedfromtheirstrugglewithaninclementclimate。Farthersouth，however，theforestlosesthisaspectofterrificstruggle。InMaine，forexample，itgivesapleasantimpressionofcomfortableprosperity。Whereverthetreeshaveroomtogrow，theyarefullandstocky，andevenwheretheyarecrowdedtogethertheirslenderupspringingtrunkslookalertandenergetic。Thesignsofdeathanddecay，indeed，appeareverywhereinfallentrunks，deadbranches，anddecayedmassesofwood，butmossandlichens，twinflowersandbunchberriessoquicklymantletheprostratetreesthattheydonotseemliketokensofweakness。Then，too，ineveryopenspacethousandsofyoungtreesbanktheirsoftgreenmassessogracefullythatonehasanever-presentsenseofpleasedsurpriseashecomesuponthisyoungerfoliageoutofthedimaislesamongthebiggertrees。
Exceptontheirsouthernbordersthegreatnorthernforestsarenotgoodasapermanenthomeforman。Thesnowliessolateinthespringandthesummersaresoshortandcoolthatagriculturedoesnotprosper。Asahomeforthefox，marten，weasel，beaver，andmanyotherfur-bearinganimals，however，theconiferousforestsarealmostideal。ThatiswhytheHudson’sBayCompanyisoneofthefewgreatorganizationswhichhavepersistedandprosperedfromcolonialtimestothepresent。Aslongagoas1670
CharlesIIgrantedtoPrinceRupertandseventeennoblemenandgentlemenachartersosweepingthat，asidefromtheirownpowersofassimilation，therewasalmostnolimittowhatthe"GovernorandCompanyofAdventurersofEnglandtradingintoHudson’sBay"
mightacquire。By1749，nearlyeightyyearsafterthegrantingofthecharter，however，theCompanyhadonlyfourorfivefortsonthecoastofHudsonBay，withabout120regularemployees。
NeverthelessthepoorIndiansweresoignorantofthevalueoftheirfursandtheconsequentprofitsweresolargethat，afterCanadahadbeencededtoGreatBritainin1763，arivalorganization，theNorthwestFurCompanyofMontreal，wasestablished。ThentherebegananerathatwastrulyterriblefortheIndiansofthenorthernforest。IntheireagernesstogetthevaluablefursthecompaniesofferedtheIndiansstrongliquorsinanabundancethatruinedthepoorredman，bodyandsoul。
Moreoverthefur-bearinganimalswerekillednotonlyinwinterbutduringthebreedingseason。Manymotheranimalswereshotandtheirlittleoneswerelefttodie。HenceinashorttimethewildcreaturesofthegreatnorthernforestweresoscarcethattheIndianswell-nighstarved。
Inspiteofthisslaughteroffur-bearinganimals，thesameCompanystilldrawsfatdividendsfromthenorthernforestanditsfurryinhabitants。Iftheforesthadbeenmorehabitable，itwouldlongagohavebeenoccupiedbysettlers，ashaveitswarmer，southernportions，andtheCompanywouldhaveceasedtoexist。Asidefromtheregionstoocoldortoodrytosupportanyvegetationwhatever，fewpartsoftheworldaremoredeadeningtocivilizationthantheforestsofthefarnorth。NearthenorthernlimitofthegreatevergreenforestofNorthAmericawildanimalsaresorarethatafamilyofhuntingIndianscanscarcelyfindalivinginathousandsquaremiles。Todaythevoraciousmawofthedailynewspaperiseatingthespruceandhemlockbymeansofrelentlesssawsandrattlingpulp-mills。InthewakeofthelumbermensettlersaretardilyspreadingnorthwardfromthemorefavoredtractsinnorthernNewEnglandandsouthernCanada。Neverthelessmostoftheevergreenforestsofthenorthmustalwaysremainthehomeofwildanimalsandtrappers，abackwardregioninwhichitiseasyforagreatfurcompanytomaintainapracticalmonopoly。
OutliersofthepineforestextendfardownintotheUnitedStates。TheeasternmostliesinpartalongtheAppalachiansandinpartalongthecoastalplainfromsouthernNewJerseytoTexas。Thecoastalforestisunliketheotherconiferousforestsintworespects，foritsdistributionandgrowtharenotlimitedbylongwintersbutbysandysoilwhichquicklybecomesdry。Thisdriersouthernpineforestlacksthebeautyofitsnortherncompanion。Itstreesareoftentallandstately，buttheyareusuallymuchscatteredandaresurroundedbystretchesofscantygrass。Thereisnotraceofthemossycarpetanddensecopsesofundergrowththataddsomuchtothepicturesquenessoftheforestsfarthernorth。Theunkempthalf-breedorIndianhunterisreplacedbytheprosaicgathererofturpentine。Asthemanofthesouthernforestsshufflesalonginblueorkhakioverallsandcarrieshisbucketsfromtreetotree，heseemsadullfigurecontrastedwiththeactivenorthernhunterwhoglidesswiftlyandsilentlyfromtraptotraponhisrawhidesnowshoes。Yetthoughthesouthernpineforestmaybelesspicturesquethanthenorthern，itismoreusefultoman。Inspiteofitssandysoil，muchofthisforestlandisbeingreclaimed，andallwillsomedayprobablybecoveredbyfarms。
TwootheroutliersofthenorthernevergreenforestextendsouthwardalongthecoolheightsoftheRockyMountainsandofthePacificcoastrangesoftheUnitedStates。IntheOlympicandSierraNevadarangesthemostwesternoutlierofthisnorthernbandofvegetationprobablycontainsthemostinspiringforestsoftheworld。TheregrowthevigorousOregonpines，firs，andspruces，andthestillmorefamousBigTreesorsequoias。HighonthesidesoftheSierraabovetheyuccas，theliveoaks，andthedeciduousforestofthelowerslopes，onemeetstheseBigTrees。
Tocomeuponthemsuddenlyafteralong，roughtrampoverthesunnylowerslopesistheexperienceofalifetime。Upwardthegreattreesrisesheeronehundredfeetwithoutabranch。Thehugeflutedtrunksencasedinsoft，redbarksixinchesorafootthickaremoreimpressivethanthecolumnsofthegrandestcathedral。Itseemsirreverenttospeakaboveawhisper。Eachtreeisanewwonder。Onehastowalkarounditandstudyittoappreciateitsenormoussize。Whereatreechancestostandisolatedsothatonecanseeitsfullmajesty，thesenseofaweistemperedbythefeelingthatinspiteoftheirsizethetreeshaveabeautyalltheirown。Liftedtosuchheights，thebranchesappeartobecoveredwithmassesofpeculiarlysoftandroundedfoliagelikethepiled-upbanksofawhitecumuluscloudbeforeathunderstorm。Atthebaseofsuchatreetheeyeiscaughtbythesharp，triangularoutlineofoneofitsyoungprogeny。Thelowerbranchessweeptheground。Thefoliageisharshandrough。Inalmostnootherspeciesoftreesistheresuchachangefromcomparativelyungracefulyouthtoasuperblybeautifuloldage。
ThesecondgreattypeofAmericanforestisdeciduous。Thetreeshavebroadleavesquiteunliketheslenderneedlesoroverlappingscalesofthenorthernevergreens。Eachwintersuchforestsshedtheirleaves。Amongthemountainswherethefrostscomesuddenly，theblazeofgloryandbrillianceofcolorwhichheraldthesheddingoftheleavesaresurpassedinnootherpartoftheworld。EventhecolorsofthePaintedDesertinnorthernArizonaandthewonderfulflowersoftheCaliforniaplainsarelesspleasing。InthePaintedDesertthepatchesofred，yellow，gray-blue，white，palegreen，andblackhaveagarish，almostrepellentappearance。InCaliforniatheflame-coloredacresofpoppiesinsomeplaces，ofwhiteoryellowdaisylikeflowersinothers，orofpurpleblossomselsewherehaveasofterexpressionthanthebaresoilofthedesert。Yettheylackthedelicateblendingandharmonyofcolorswhichisthegreatestcharmoftheautumnfoliageinthedeciduousforests。Evenwheretheforestsconsistofsuchtreesasbirches，beeches，aspens，orsycamores，whoseleavesmerelyturnyellowinthefall，thecontrastbetweenthiscolorandthegreentintofsummerorthebarebranchesofwinteraddsaspiceofvarietywhichislackinginotherandmoremonotonousforests。
Fromstillotherpointsofviewthedeciduousforesthasanalmostunequaleddegreeofvariety。Inoneplaceitconsistsofgracefullittlebircheswhosewhitetrunksshimmeringinthetwilightformjustthebackgroundforghosts。Contrastthemwiththeoakforesthalfamileaway。Therethesenseofgracefulnessgivesplacetoafeelingofstrength。Thelinesarenolongerverticalbuthorizontal。Theknottedelbowsofthebranchesrecallthekeelsofsturdymerchantmenofbygonedays。Theacornsunderfootsuggestfoodfortheherdsofhalf-wildpigswhichroamamongthetreesinmanyasoutherncounty。OfquiteanothertypearethestatelyforestsoftheAppalachianswheresplendidmagnoliaandtuliptreesspreadtheirbroadlimbsaloftatheightsofonehundredfeetormore。