SKRIFTER VIDENSKAPSSELSKAPET I KRISTIANIA 1921 nn E MATEMATISK-NATURVIDENSKABELIG KLASSE 2. BIND KRISTIANIA I KOMMISSION HOS JACOB DYBWAD A. W. BROGGERS BOKTRYKKERI A/S 1922 FÅ BEN faves ADS i à À RUNS KER SKRIFTER UTGIT AV MDENSKAPSSELSKAPET | KRISTIANIA 1921 I. MATEMATISK-NATURVIDENSKABELIG KLASSE 2B ENID ——— > KRISTIANIA I KOMMISSION HOS JACOB DYBWAD A. W. BRØGGERS BOKTRYKKERI A/S 1022 20. Indhold. Rolf Nordhagen. Kalktufstudier i Gudbrandsdalen. (Med 44 tekstfigurer og 5 plancher) J. V. Zelizko. Äquivalente der untersilurischen Euloma-Niobefauna bei Plzenec in Böhmen. (Mit 3 Tafeln, 1 Kartenskizze und r Textabbildung) Fridtjof Nansen. The Strandflat and Isostasy. (With 170 illustrations and maps in the text) : S ES Pe os cd P. A. Oyen. Hippophaes idee ja fra en norsk kalktuf Hjalmar Broch. Studier over cirripedienes fylogenetiske sienta old Ivar Jerstad. Bidrag til kjendskapet til Trondelagens rustflora Bernt Lynge. Lichens from the Gjea Expedition Carl Siegel. Ueber den Thueschen Satz er ok: Th. Skolem. Untersuchungen über die möglichen Vale Ress Lösungen gewisser Gleichungen . Th. Skolem. Bericht über die PART es "Schriften L. Syge L. Vegard. Die Struktur des Nordlichts und die Art der kosmischen Strahlen. (Mit 2 Fig. im Text) ee CU ns UOTE Halfdan Bryn. Troms fylkes antropologi. (Med 20 figurer og karter i teksten). (Med tysk resumé) Side 251355 I— 27 13703 ı— 8 I— Io I— 19 D— 0 I— I2 1— 57 MI I— 16 I—176 KÆLKTUFSTUDTER I GUDBRANDSDALEN AV ROLF NORDHAGEN (MED 44 TEKSTFIGURER OG 5 PLANCHER) (VIDENSKAPSSELSKAPETS SKRIFTER. I. MAT.-NATURV. KLASSE. 1921. No. 9) UTGIT FOR FRIDTJOF NANSENS FOND KRISTIANIA I KOMMISSION HOS JACOB DYBWAD 1921 D TEE! e i som ar 4 2 » INDHOLD: Side et mu nue + cu ste rs ne d tb V Speciel del. Le KO CORTE TE HEKLA RER de OC Ce I Delionesratitom vegetation enütiden . En I BeSiratieraliskes undersokelser 5-652 aa aan See EC EU 14 CmOversist over Lemetutiens stratioraf . tu... cies ele ee ie IOS 38 INK albi ved Gallebu og Tingvold + Mr. ....-..-. ee res 54 Éonpnratrosmveretatonti nutiden sc. Aa. 31) so oe DO OST 54 BeSitatfsrafiskes undersokelser 1 2. sc = 22 sa + = occas EET 58 Cm Oversictoven Gillebutuiiens, stratigrah ee... 55> ttt ieee COSE 64 piesGniskeeglensvedadunevoldias- oer. MONTS EDI CIUS 69 TEE ar etern "oed: Nedre Dal t Faabenrg- CRC rec eee 13 VERE R GT fjer ved^Onsel. 1: Dirt aedi rece e EU cec E 15 ASEBlytis-undersokelser..2.......: I RER RGN Bi ir ars ER So GA 75 Bee uudcrsekelsen 43 ner. SES RS c EE Er re Dee ci 82 Generel del. lee elsavsmelininaen iiGudbrandSdalent 2.2. ze E de en ee 87 Il. Nogen bemerkninger om den første flora og vegetation under avsmeltningstiden..... 96 DI Gnabratasdalensebalbtw/fer200 Blytis; teorı shad oe ie ee 105 IV. Bemerkninger om Gudbrandsdalens plantevekst 1 postarktisk tid................. 115 vee Dene subarktiske MES SNS ae RE ERE to nl Yee esee eer ee IIS BE Den ET d tc enr es ne ee ee ee NS S 120 En sammenligning mellem Gudbrandsdalens og Jemtlands kalktuffer .......... 123 Elkapophaes: problemet 45 c EN ee cui es AE ree eh oe 125 FARE Fat antske hide. 2e 0.7 oL Me weet ere ele eno Ce anne SR 138 SOMMER TUMS ILI OL CALE tds er: crue cts clé Cine ELT ee CS NE ER ee 139 Pee Me SUDALATLISKE : td. PARENT ee T40 Fortegnelse over de fundne plantearter og snegler................ ........ 142 Eutersturforternelse- cc ee Re Uis Ses E SED 148 RES ARR DIANE En SES REST v 0 Sey ERE Dr nu lm D PA Re 154 RG CIREE OD Hilfølels OR. ee a AU ce doc 155 FORORD. Høsten 1913 omtalte professor R. SERNANDER Gudbrandsdalens kalktuffer under sine forelæsninger ved Kristiania universitet og opfordret undertegnede til at undersøke dem paany. Imidlertid hadde jeg av konservator P. A. ØYEN faat oplysninger om et par kalktuffer i det trondhjemske, opdaget av hr. MARTIN Moe, Stjørdalshalsen. Og da jeg somrene 1914 og 1915 opholdt mig i denne del av landet, foretok jeg en undersøkelse av forekomstene, som dog gav et lite opmuntrende resultat. Den ene forekomst mellem Olderen og Velvang paa Skatvalhalvøen bestod av jordagtig tuf avsat hoit oppe i en stupbrat ur, den anden lokalitet ved Auran (omtalt av ØYEN 1915 l. c. p. 44) opviste kun ube- tydelige tufmasser sterkt opblandet med bergartsmateriale. Helt uten interesse var undersøkelsen dog ikke. Den ene av forekomstene viste nemlig i den øvre tilgjængelige del et avbrud, karakterisert ved ansamling av smaa skifer- biter (nedraset forvitringsmateriale). Jeg har tidligere bare omtalt resultatet i en stipendie-indberetning til det Akademiske kollegium, men haaber at komme tilbake til disse kalktuffer ved en anden anledning. Sommeren 1917 lyktes det konservator ØYEN og overlærer HoLME paa Lillehammer at paavise en ny og hoist interessant kalktuf i Gudbrandsdalen, nemlig ved Tingvold og Gillebu i Wier herred, hvor HoLME allerede for mange aar siden opdaget kalktufstykker i en grusavsætning. Konservator Ove Dani og undertegnede assisterte senere ved bestem- melsen av det store materiale som yen medbragte fra Øier, og da det lyktes mig at identificere nogen eiendommelige bladavtryk med Hippophaés rhamnoides, var min interesse for alvor vakt. Da ØYEN mente at der kunde være en efterhøst at gjøre, specielt i palæofloristisk henseende, bestemte jeg mig næste sommer for at reise til Gudbrandsdalen. Turen gik først til Otta, hvor jeg haabet at finde en ny tufforekomst, idet fiskerimspektør A. LanpMARK for en del aar siden hadde iagttat hvite tuf- skorper og løse biter i de bratte lier ved Kringen, og overfor undertegnede antydet at der maatte være kalkholdige kilder paa stedet. Imidlertid viste det sig at det her bare gjaldt helt ubetydelige forekomster av jordagtig tuf og tynde skorper paa fjeldsiden; saadanne fandt jeg paa 3—4 forskjellige steder mellem Solgjem og Otta paa dalens østside. Efter to dages ophold paa Otta drog jeg til Pillarviken, et stykke oppe i Otta-dalføret (Laim), hvorfra der i sin tid var indleveret prøve av kalktuf til Universitetets samling. Findestedet laa desværre midt ute i en rugaker, men ved eierens, hr. N. SvEines elsk- værdighet fik jeg anledning til at foreta en gravning, som dog bare bragte større og mindre mosetufbiter for dagen, av samme type som de i samlingen opbevarte stuffer. Nogen indgaaende stratigrafisk studie var der saaledes ikke adgang til paa det nævnte tidspunkt. Jeg fortsatte derfor til Sørem i Vaage, hvor hr. gaardbruker SØREM i sin tid hadde fundet lose blokker av en haard kalktuf i nærheten av en nedlagt husmandsplads (Gulbrandheimen) paa Ottas anden bred, vis å vis Sørem. Jeg fandt ogsaa ganske rigtig stedet og et par tufblokker, som laa i en gammel stenmur. Men trods ihærdige undersøkelser VI i dalsiden omkring pladsen var det ikke mulig at opdage nogen tuf. Enten maa de nævnte blokker, som i sin tid blev fundet nede i stranden, være blit transportert med elven under islosningen fra et eller andet sted højere oppe i dalen, eller de maa skrive sig fra fjeldet høit over Gulbrandheimen. Tuffen var tildels breccieagtig med smaa biter av forskjellige bergarter, men uten tydelige fossiler. Antageligvis skriver den sig fra en lokal forekomst av ube- tydelig utstrækning. Efter disse undersøkelser, som heller ikke var særlig opmuntrende, drog jeg ned i Gudbrandsdalen igjen, hvor der ialfald var tuf nok at undersøke. Først stoppet jeg i Kvam for at ta Leinetuffen i øjesyn. Av forskjellige ut- talelser fra folk som i aarenes løp hadde besøkt Leine, hadde jeg faat det indtryk, at der nu for tiden bare var ubetydelige rester igjen av denne tuf, væsentlig lose biter i de øvre jordlag og avfald fra Brvrrs store indsamlinger i 1891. Desto større var derfor min overraskelse, da jeg efter et par resultat- løse prøvegravninger fik op en grøft som aabenbarte et overordentlig vakkert og sammenhængende profil. Resultatet var dog en smule forvirrende, idet jeg istedenfor én Dryas-forende horisont, saaledes som Bryrr omtaler, fandt to saa- danne med et mellemliggende bladtuflag. Magtigheten av de enkelte horisonter var ogsaa helt anderledes end Bryrrs profiler viste. Av en gammel mand i Kvam, som i sin tid hadde hjulpet Bryrr med gravearbeidet, fik jeg nøiagtig vite hvor disse profiler var optat, og det lyktes mig dernæst at konstatere at den undre del av tuffen paa dette sted var saaledes som av BLyrr beskrevet. Imidlertid var Dryas-laget og den øvre del av tuffen fjernet, saa paa dette punkt var jeg like klok. Da jeg denne sommer fortrinsvis hadde tænkt at arbeide i Wier, kunde jeg ikke ofre mere tid paa Leine, men noiet mig med at medføre et stort materiale fra de forskjellige lag i profilet. Ved Gillebu 1 Wier foretok jeg indgaaende stratigrafiske studier paa en række punkter og med positivt utbytte. Ogsaa Hippophaés’s vertikale utbre- delse i tuffen blev noiagtig undersøkt. Herfra medbragte jeg ogsaa en stor samling med haandstykker, som blev underkastet en foreløbig granskning efter hjemkomsten til Kristiania. Vaaren 1919 bestemte jeg mig for alvor til at grave op hele Leine-tuffen paany, idet jeg haabet at der maatte kunne findes et mellemled som forbandt 3LyTTs profiler med mit eget. Jeg bestemte mig for at grave en lang „skytter- grav" gjennem tuffen og opta noiagtige profiler hele veien for at komme paa det rene med om forekomsten virkelig var saadan som Brvrr hadde beskrevet den. Jeg fandt dette absolut nødvendig, da der fra forskjellige hold overfor mig blev hævdet at man ikke maatte stole for meget paa en saa subjektivt farvet fremstilling som DBrvrrs. Til disse undersokelser fik jeg likesom fore- gaaende aar et bidrag av RATHKES legat, hvorfor jeg her fremfører min bedste tak. I slutten av juni 1919 drog jeg atter til Gudbrandsdalen. Først gjorde jeg en avstikker til Ransverk i Vaage, hvor der ifølge hr. gaardbruker SonEM skulde findes kalktuf nær Mysuholet sæter mellem Ransverk og Lemonsjøen. Sammen med hr. Jens Tronuus undersokte jeg terrænget omkring den ned- lagte sæter, men vi fandt kun litt drypstensagtig vakkert krystallinsk kalk, som var meget løs, ved foten av en bergvæg i skogen. — Derefter drog jeg til Leine i Kvam, hvor jeg i lopet av de følgende uker, assistert av hr. PAUL RoEn, fik opkastet en ca. 20 m. lang og 1,5—2 m. dyp sammenhængende grøft paa langs av bakkeskraaningen, desuten en hel del tverprofiler. Alt i alt blev ca. 25 saadanne noiagtig analysert og opmaalt og et meget rikt fossil- materiale indsamlet. VII Arbeidet gav meget tilfredsstillende resultater og bød paa flere over- raskelser. Saaledes fandt jeg meget snart rester av en helt ny tufhorisont ovenpaa furutuffen, som bragte en række nye momenter ind i diskussionen. Det viste sig ogsaa at de forskjellige tuflag hadde sit maksimum paa helt for- skjellige punkter indenfor avsætningens omraade. Litt efter litt lyktes det mi at forfølge de temmelig komplicerte stratigrafiske forhold inden Leinetuffen o at sammenstille disse til et sammenhængende profil. Efter indbydelse av professor R. SERNANDER tilbragte jeg høstterminen 1919 paa det plantebiologiske institut i Uppsala, og medbragte hele mit store kalktufmateriale til naermere granskning. Institutets vakre samlinger av svensk kalktuf blev stillet til min disposition, likesom professor SERNANDER paa alle mulige maater bistod mig med litteratur og oplysninger om svenske tuffore- komster, skaffet mig sammenligningsmateriale fra herbariene o. s. v., kort sagt lettet mit arbeide paa al tænkelig vis. I lopet av høsten hadde jeg den til- fredsstillelse at kunne avslore næsten alle de mange apokryfiske ting og kurio- siteter som Leinetuffen indeholdt. Stor nytte hadde jeg av den vistnok først av Natuorst anvendte kollodiummetode, som senere HALLE har prakti- sert med udmerkede resultater. Paa de avtryk som skal undersøkes, dryppes en liten draape kollodium, som naar den er indtørket danner en fin hinde, der avløses forsigtig. De første avtryk er altid daarlige paa grund av forurens- ninger og luftblærer, men efterhaanden blir de brukbare og kan under mikro- skopet avsløre de fineste epidermis- og andre struktureiendommeligheter (spalte- aapninger, haardannelser etc.) av stor betydning for bestemmelsenes paalidelighet. I januar og februar 1920 opholdt jeg mig i Stockholm og gjennemgik med professor TH. Harrr Riksmuseets pragtfulde kalktufmontrer i den palæobotaniske samling, likesom professor HarLE elskværdigst gav mig tilladelse til at gjen- nemgaa hele museets store samlinger bl. a. fra Benestad i Skaane og fra de jemtlandske lokaliteter. Samtidig drev jeg litteraturstudier ved Vetenskaps- akademiens bibliotek og fik hos statsgeolog.dr. L. von Post information i mi- kroskopisk bestemmelse av vore skogtrærs pollen. Derefter reiste jeg atter til Uppsala, hvor jeg forblev til slutten av mars maaned og bearbeidet resten av mine samlinger. [or > œ D ? Jeg vil her faa lov til at rette en varm tak til min ærede lærer og ven professor RUTGER SERNANDER i Uppsala, som gjorde opholdet der uforglem- melig for mig, og for den store interesse han viste overfor mit arbeide. Likesaa vil jeg faa lov til at takke Växtbiologiska Institutionens amanuensis fil. lic. G. E. Du Rierz for hans hjælpsomhet og elskværdighet! Overfor professor dr. Svante ARRHENIUS og dr. OLOF ARRHENIUS ved Nobelinstitutet for fysikalsk kemi, som paa alle mulige maater hjalp mig under mit besok i Stockholm, vil jeg fremfore en dypt felt tak, likesaa overfor pro- fessor dr. TH. HALLE og dr. L. vow Posr. Efter gjennemgaaelsen av samlingene og efterat jeg forelobig hadde op- gjort mig en mening om de undersokte kalktuffer, fandt jeg det ønskelig endda en gang at ta findestedene i oiesyn, for at stille min egen opfatning paa prove — en fremgangsmaate som efter min mening gir de bedste garan- tier for resultatenes paalidelighet. I oktober 1920 tilbragte jeg nogen herlige hostdager i Kvam og fik bl. a. gravet op et profil som hvad interessant opbygning angaar, slog alle de tid- ligere studerte av marken. Jeg avla ogsaa et kort besok ved Gillebu i Gier. I slutten av maaneden reiste jeg op til Faaberg og besaa kalktuffen ved Nedre VII Dal, og efterpaa til Biri, for at lete efter den av Brvrr i sin tid undersekte tuf ved Onset. Desværre lyktes det mig ikke med sikkerhet at gjenfinde lokaliteten; men en anden forekomst, som forresten bar spor efter gravning, viste sig at indebære mange træk av interesse, Av ovenstaaende redegjørelse vil det fremgaa at undertegnede har tat sin opgave meget alvorlig, og ikke skydd noget middel som kunde bringe klarhet over kalktufproblemene. Jeg gik til undersokelsene indpodet med adskillig skepsis, ikke mindst overfor BLyrrs studier og teorier. Og den mening som under arbeidets gang litt efter litt har presset sig frem hos mig, er ikke resultatet av nogen paavirkning i denne eller hin retning. CLEMENTS har i et av sine verker kaldt BLyrrs teori for et „storm- centrum" i nordisk kvartærforskning, og ikke uten grund. Jeg har ogsaa selv hat en levende følelse av, at det at delta i den kvartærgeologiske diskussion er ensbetydende med at utæske kritiken, hvis man da ikke vælger den frem- gangsmaate at skrive et arbeide saa upersonlig at læserne ikke paa et eneste punkt oiner forfatterens ansigt. Men da bør man helst ikke sætte sit eget navn under. Kanhænde vil denne bok ogsaa bringe vind i seilene. Da kalktuffene for BLyrrs bevissthet stod som vigtige støttepunkter for hans teori, vil man forstaa at denne avhandling bevæger sig indenfor et alt andet end noi- tralt gebet. En ting er imidlertid sikker, og det er, at herefter skal man ikke behøve at diskutere sporsmaalet om hvorledes Gudbrandsdalens !alktuffer er op- bygget. Den deskriptive side av saken, som jo er den primære, er ved disse undersøkelser bragt lykkelig i havn. Man kan ikke skyte sig ind under saa- danne paaskud som at stratigrafien er mangelfuldt undersøkt, at forholdene er uklare o. s. v. Allerede dette er et fremskridt. Saa faar man stille de for- skjellige tolkningsmuligheter op mot hinanden og vælge den, som paa den mest naturlige maate besvarer alle de spørsmaal som reiser sig i det fore- liggende tilfælde, og som samtidig ikke kommer i konflikt med andre forsk- ningsomraader. Dette har jeg da efter bedste evne forsøkt at gjøre. Til slut vil jeg faa lov til at takke konservator P. A. Öven for den inter- esse han har vist overfor mine undersøkelser, og for alt det interessante han paa de mange ekskursioner i aarenes løp har vist mig og mine studiekame- rater. Jeg har i nærværende avhandling forsøkt at ta et personlig standpunkt til kalktufproblemene, og min opfatning avviker paa enkelte punkter ganske meget fra Øyvens. Det kan imidlertid aldrig være til skade for en sak at den blir kritisk belyst fra flere sider. Professor J. SCHETELIG har været saa elskværdig at hjælpe mig med berg- artsbestemmelser og litteraturoplysninger. Konservator dr. Hjarmar MÖLLER, Riksmuseet, Stockholm, har bestemt en del kalksamlende moser fra Biri, og docent F. OkrAwDp, Aas, har bestemt mit materiale av landsnegler. Avdode fil. lic. HELMER OLIVECRONA, assistent ved Norges Landbrukshoiskole, Aas, har undersøkt en del Cyanophycé-prever fra Biri. Ogsaa dr. Nırs ODHNER, Riks- museet, Stockholm, har hjulpet mig med det systematiske bestemmelsesarbeide. Til alle disse videnskapsmænd vil jeg faa lov til at rette en ærbødig og hjertelig tak for udmerket assistance, likeledes til Videnskapsselskapet i Kristiania, som har bekostet trykningen av dette arbeide. Kristiania i mai 1921. Rolf Nordhagen. SPECIEL DEL. I. Kalktuffen ved Leine i Kvam. A. Topografi og vegetation i nutiden. I Kvam (anneks til N. Fron) i Gudbrandsdalen gjør Laagen en skarp boining, idet den først løper ret mot øst, derefter mot syd-sydvest. Dalen har her karakter av en gryte eller et avlangt traug med saagodtsom al bebyggelse samlet paa nordsiden, og hvor elven boier om, paa østsiden, hvilket dels beror paa ekspositionen mot solen, dels paa det bedre jords- mon paa nordsiden. Fra nord kommer elven Veikla eller Vindeaaen fossende ned mot hoveddalføret. Denne elv og sidebækken Børju avgrænser tilsammen en mægtig landtunge, som fra Tunsbergfjeldet (944 m. o. h.) falder jevnt, men meget brat av mot dalbunden i syd. Oppe i skraaningen ligger her de gamle Leine-gaarder med sine brunsorte, solsvidde tømmerhus og de store, men tungbrukte jorder. Jordsmonnet er meget frugtbart, hvilket skyldes de kolossale moræneavleiringer som i form av et kalkholdig ler med større og mindre blokker, ofte i tætpakkede lag, dækker hele skraaningen fra Veikla og helt op til mellem 6 og 700 m. o. h., ovenfor Leinegaardene. Til trods for den voldsomt sterke insolation i sommermaanedene lider bøn- derne her ikke saa meget paa grund av tørke som man skulde vente, netop takket være lermassene, som holder paa vandet. Disse lerbakker under Leine har været ganske skjæbnesvangre for bygdens befolkning. I tidenes løp har der gang paa gang gaat kjæmpe- mæssige skred langs Veikla, og store masser av den oprindelige moræne- fylding har skyllet ut over dalbunden i syd, som av denne grund er ganske komplicert opbygget. Den største katastrofe skedde i aaret 1789, det store ulykkesaar i Gudbrandsdalens nyere historie, da ,ofsen" eller den store vandflom herjet overalt i dalen!. Den dag idag fortælles det om hvor- ledes folk reddet sig opover Leinebakkene i hui og hast for at undgaa skredene. De vedfoiede fotografier gir et litet indtryk av hvorledes topo- grafien arter sig paa stedet i nutiden. Morænemassene dækker dalsiden temmelig langt opover Veiklas dalføre og har over store strækninger form I Cfr. HecLand: Norges land og folk. Kristians amt. Bind I. Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. 9. 1 2 ROLF NORDHAGEN. M.-N. KL Fig. r. Kart over de undersokte kalktuffer i Gudbrandsdalen. I: 2 ooo ooo. av længderygger orientert lodret paa elven. Disse rygger er adskilt ved rendeformige smaadaler, som markerer de steder hvor skredene har gaat som værst. Ogsaa paa Veiklas estlige bred gjenfindes lignende lerbakker og længderygger, men i mindre maalestok. Alting tyder paa at Veiklas dalfore i tidligere tider har været sterkt opfyldt av morænemassene, 08 at elven efterhaanden har gravet sig ned og forskjøvet sig i vestlig retning. Saaledes fortæller traditionen at man i ,gamle dager" paa gaarden Veikle fik vand fra kalktufkilden høit oppe i Leinebakkene, ved hjælp av træ- render. Husene paa Veikle laa dengang lavere end i nutiden, men selv under denne forutsætning vilde det i vore dager være umulig at lede van- det paa den nævnte maate. Det hele forutsætter at lerbakkene hadde et meget slakkere forløp og skraanet jevnt ned mot Veikla, som antageligvis ogsaa gik mere øst og nærmere gaarden end nu for tiden. Et andet fænomen som peker i samme retning, er navnet »Fagervold" paa en liten plads ved foten av Leinebakkene (sees paa fig. 3). Ingen vilde nu for tiden falde paa at kalde denne eiendom med et saadant smukt navn; jordveien er alt andet end fager. — Ogsaa sidebækken Borju har foranstaltet lignende kata- strofer. Ifølge gaardbruker OLE O. Kniren, Roen, skal der mel- lem Leine og gaarden Krok ha ligget en eiendom som er helt forsvundet ved jordskred. Og- saa 1 vore dager gaar der Fig. 2. Lerbakkene østenfor Leine, mellem Røen og hver vaar i sneløsningen smaa Knipen. Utsigt mot nord fra jordet paa Veikle. Elven skred i bakkene, hvilket for- . Veikla loper i dalens bund (fra heire). øvrig ikke forhindrer folk i at Juli 1919. Nordhagen fot. dyrke dem op. I lerbakkene kommer grundvandet frem paa en række steder som is- kolde kilder, specielt nord for gaarden Røen og op for pladsen Knipen. At moræneleret er sterkt kalkholdig kan man straks se paa den rike vegetation i dalsiden; specielt er Gymmadenia conopea, som i juli er sterkt fysiognomisk fremtrædende paa fugtig bund, en god kalkbundsindikator. I denne del av Gudbrandsdalen har vi adskillige kalkførende bergarter!, og det er da disse som i første række har leveret materialet til moræneleret i Leinebakkene. Man finder ogsaa kalksten blandt blokkene i leret. Det er for saavidt ikke merkelig, at vi her ogsaa finder flere kilder som i tidens løp har avsat store mængder med kalktuf. Paa det vigtigste tuffindested dannes der i nutiden ringe mængder med mosetuf. Dette er ogsaa tilfældet paa en lokalitet nede i Børjus canon; her dækker tykke kaker av mosetuf (Mollia æruginosa) bergvæggen over en kortere strækning. Ifølge BjørLYKKE (1905 l. c. p. 213) skal der i denne dalside anstaa „kalk- | Cfr. BJoRLYKKES store arbeide (1905). Aarstallene henviser til litteraturlisten bakerst i boken. 4 ROLF NORDHAGEN. M.-N. Kl. holdig sparagmit”, altsaa en slags kalksandsten, og jeg skulde tro at det netop er denne som danner underlaget for den nævnte mosetuf. Ved pladsen Knipen, hvor der findes store kalktufblokker i jorden langs en baek ovenfor kjoreveien, har jeg ikke set nogen recent tufdannelse. Om den bekjendte Leinetufs opdagelse har baade Bıyrr og Oven (1920 l. c) i sine respektive avhandlinger skrevet saa pas indgaaende at jeg her ikke skal gaa nærmere ind paa det kapitel. Forinden jeg gaar over til at skildre tuf- fens stratigrafi, skal jeg imid- lertid omtale vegetationen paa og omkring findestedet, da dette er av stor betydning for de følgende avsnit og de plan- tegeografiske ræsonnementer som der er fremført. Man skal i vort land med dets magre jordsmon lete længe efter en dalside som hvad vege- tationens yppighet angaar, kan maale sig med disse bakker i Kvam. Det næringsrike og jevnt fugtige substrat sammen med den gunstige eksposition (den sterke heldning mot syd og sydøst) har fremkaldt en Fig. 3. Styrtningene nedenfor gaarden Røen (som i; as makeles frodighet, specielt i ligger nederst 1 Leinejordene). Orekrat, klynger av ee li des f : z z de ngiereliggende Her o or bjerk og xeromorfe græssamfund. Nederst sees plad- SE B sen ,Fagervold". Nede i dypet loper Veikla. Utsigt Knipen. Man finder her ude- mot nordvest fra Veikle, juli 1919. Kalktuffen ligger lukkende eutrafente og meso- ovenfor billedets hoire hjorne. Nordhagen fot. file, langs baekkene mere hydro- file plantesamfund, bestaaende av lovtrær, gres og urter. Lyngsamfund og andre oligotrafente typer med økonomisk husholdning ser man ikke antydning til. Imidlertid har vege- tationen paa de før omtalte længderygger og bratte lerbakker ned mot Veikla til en viss grad et xeromorft anstrok, paa grund av den sterke av- rending og den voldsomme insolation i sommermaanedene. Det vigtigste skogdannende tra indenfor det angjældende omraade i nutiden er graaören (Alnus incana)\, dernæst bjerk (baade Betula odorata og D. verrucosa). Nordenfor Knipen er det mest lav oreskog i dalsiden TQ og litet bjerk. Her er terrænget mere jevnt og ikke saa opdelt i rygger JQ som længer syd, vistnok ogsaa mere fugtig. Nedenfor Leine og Roen der- I Nomenklaturen er den samme som i Bryrr-Danr: Haandbog i Norges Flora. Kristiania 1906. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 5 imot spiller bjerken en ganske stor rolle. Oreskog og krat er her meget almindelig 1 alle forsænkningene mellem lerryggene, mens bjerken i form av en meget aapen skog eller bare isolerte trægrupper ynder de mere tørre rygger, dog kun hvor disse er stabile. De bratteste lerbakker -er fuldstæn- dig blottet for al vegetation, og de mindre bratte bærer en hoist eiendom- melig og svakt xeromorf græsvegetation, som ikke er helt sluttet og uten bundskikt av moser, hvilket altsammen beror paa substratets sterke skraaning og derav følgende instabilitet. Særlig om vaaren synes der altid at ske glidninger langs ryggenes overflate. Dette er vel ogsaa aarsaken til at bjerk og or har saa vanskelig for at vokse op og danne veritabel skog paa stedet. (Ctr. fig. 2 og fig. 3). Et moment som ogsaa maa tages i betragtning her, er den forholdsvis korte tid som er hengaat siden den store katastrofe under hvilken disse bakker blev utformet (1789). Forovrig gjør kulturpaavirkning sig sterkt gjældende. Liene anvendes som havne- hager for kjørne, tildels ogsaa som utslaatter, og folk har av denne grund næsten overalt hugget ut og lysnet op 1 lovskogene. Foruten or og bjerk er selje (Salix capræa) meget almindelig; desuten findes Salix nigricans, Rhamnus Frangula, Ribes rubrum og Lonicera Xylosteum, men temmelig sparsomt. ÂMyricaria germanica, som har stor utbredelse i Kvam langs Laagen, og som ogsaa gaar et stykke opover Veiklas dalfore, optrær i nogen faa individer langs skraaningene ved veien op for Knipen. Naar undtages Lonicera Xylosteum og Betula verrucosa, finder man mer- kelig nok ingen av vore mere kuldskjære løvtrær og busker paa stedet; de har alle sin nordgrænse længer syd i dalen. Dette er i og for sig ganske paafaldende, idet vi nemlig blandt græssene og urtene finder flere utpræ- get sydlige typer repræsentert (cfr. det følgende). Imidlertid maa jo de urteagtige planter som holder sig nærmere jorden og nyder godt av vin- terens beskyttende snedække, ha lettere for at klare sig end trær og busker. Desuten opvarmes de nedre luftlag sterkest, saa de lave planter er ogsaa gunstigere stillet hvad sommervarmen angaar. Forevrig kan jeg vanskelig tænke mig en lokalitet som bedre skulde egne sig for xerotherme relikter end denne dalside, hvor varmen f. eks. i juli maaned ofte er ganske uut- holdelig. Der er en svak mulighet for at lerskredene kan ha ødelagt even- tuelle saadanne trær og busker, men om dette vet vi ikke noget med sikkerhet. : Gran og furu mangler ogsaa fuldstændig i skraaningene ved Leine og Knipen. Forst i større hoider op mot Tunsbergfjeldet og længer nord i Veiklas dalfore ser man naaletrær, men ingen skog. Dette fænomen er utvilsomt ikke oprindelig, men beror paa uthugst. Ifølge oplysninger fra folk paa stedet har man ogsaa hist og her fundet stubber og rotter, som peker i samme retning. Dog vil jeg præcisere, at vi har ingensomhelst grund til at anta at der i historisk tid har været sammenhængende naaleskog i disse lerbakker. Den nuværende lovtrevegeta- tion (or og bjerk) paa stedet er ikke av saa recent natur som 6 ROLF NORDHAGEN. M.-N. Kl. man kanske til en begyndelse skulde tro. Derom bærer kalk- tuffen tydelige vidnesbyrd. Ved gaarden Krok, like syd for Leine, paa sydsiden av Børjubækken, træffer vi virkelig granskog. Dog er jordsmonnet her mere grundt og sten- blandet, tildels med opragende berg. Vis å vis Leine, i skraaningen ovenfor gaarden Veikle opunder Hil- lingen, er der i nutiden meget vakker furuskog. Men her er undergrunden av en helt anden natur, tør og stenet, antageligvis utvaskede moræneav- leiringer og nedraset forvitringsmateriale. Det ligger utenfor denne avhandlings ramme at skildre alle de asso- ciationstyper som udmerker dalskraaningene ved Leine. Jeg skal dog for fuldstændighetens skyld nævne en del karakteristiske eksempler. Om vi begynder med de mindst stabile, men vegetationsklædte lerbakker, saa møter vi her en eiendommelig type, som i første række kjendetegnes ved en masseoptræden av Ca/amagrostis Epigeios, et Calam- agrostidetum Epigææ. Herav findes flere varianter, baade artsrikere og arts- fattigere. I synøkologisk henseende udmerker typen sig ved en meget svak eller oftest ingen mulddannelse. Plantedækket er ikke helt sluttet; et bund- skikt av moser er flekvis antydet, men mangler gjerne helt. Dette beror sikkerlig altsammen paa substratets lite stabile karakter: overflatelagene er antageligvis baade vaar og høst, og vistnok ogsaa efter heftige regnskyl, i bevægelse (cfr. fig. 3). Okologien ligner i visse henseender forholdene hos den av BLomouisr beskrevne „Högbuskformation“ (Svensk Bot. Tidskrift Bd. 5. Ig11) fra det sydlige Sverige, hvor lignende edafiske faktorer er virksomme og bl. a. forhindrer virkelig skog i at vokse op. paa lokalitetene. Den sterke insolation og uttørring av overflatelagene i sommertiden præger ogsaa vegetationen i nogen grad, og skaper en viss likhet med klippesamfund, f. eks. de skrindmuldete skiferbakkers i Kristianiafeltet og ved Mjøsen. I Tyskland har man fænomenet endda mere utpræget i de saakaldte ,pontische" eller „sonnige Hügel” (GRAEBNER 1909). I den folgende tabel er sammenstillet to analyser, den forste fra ler- bakken ved Berju (ro >< Io m.2), den anden fra en av de bratte skraa- ninger nordøst for Roen (10 * 30 m.?) (sees paa fig. 3). Tallene angir artenes daekningsgrad indenfor ruten (HULT-SERNANDERS 5-gradige skala), den 6te oktober 1920. I II Calamagrostis Epigeios..... MV IV Dactylis glomerata....... ge II Il F SHCA OUAIS CEE I II A gerostiS Dulsams RR = I e e 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. PER GID Le RERO NS EC I ERE PRON SES ES Sal Sd ue. Brachypodium pinnatum .... Carex "ricele umi sch ius Androsace sebtentrionale .... Anthyllis vulnereria ....... Arenaria serpyllifolia ...... Artemisıa vulgaris: .......: Astragalus alpinus ........ Calamintha Acinos ........ Centaurea Scabiosa........ D ADE THERM AA Oh. ee TEFL RON ORA AGERE en aan Galium verum . 0... 1.121: Hieracıum umbellatum...... BTOC SD Le a ee ns Knautia arvensis.......... — ee ee ee pd Lotus corniculatus ......... Pıimpinella Saxifraga ...... Potentilla argentea......... Ranunculus polyanthemos TRUOUSTSANGHUS ta ooh SUCHE! VEROSaRL S E Lid ro Stenophragma Thalianum . . . Thalictrum simplex ........ Trifolium medium......... Trifolium pratense PGA GRAGCEW are Eia ME color teen AT. Rosa cinnamomea ......... Betula verrucosa (2 m.)..... Alnus incana (busk) ....... Hypnum rugosum ......... ChrysanthemumLeucanthemum Thuidium abietinum ....... me —À o—À 9 I 8 ROLF NORDHAGEN. M.-N. KL Tabellen viser en eiendommelig blanding av plantegeografiske typer, sydlige og nordlige om hinanden. Andre associationer møter os paa skraaninger som er mere stabile, og som derfor tillater en tættere, sluttet plantevekst. Det følgende eks. (5 ro m.?) viser en association fremdeles bestaaende av græs og urter, men uten Ca/amagrostis Epigeios; isteden kommer andre arter til, først og fremst Festuca ovina. Calamagrostis Epigeios ynder aabenbart det mere urolige substrat. Med sine svære krypende rhizomer passer den jo ogsaa ud- merket der. Festuca ovina IN Knautia arvensis I Calamagrostis arundinacea Il Lathyrus pratensis I Dactylis glomerata I Lotus corniculatus I Briza media I Pimpinella Saxifraga I Poa alpina I Plantago media II Poa pratensis I Potentilla verna I Agrostis vulgaris I Rubus saxatılıs I Achillea Millefohum I Rumex Acetosella I Androsace septentrionale I Sedum annuum I Antennaria dioica I Silene venosa I Campanula rotundifolia I Solidago Virgaurea I Carex ericetorum Il Trifolium medium I Centaurea Scabiosa I Trifollum repens I Cerastium vulgatum I Trifolium. pratense I Erigeron acer I Veronica saxatilis I Fragaria vesca I Vicia cracca I Gahum verum I Viola arenaria I Hieracium umbellatum I Viola canina I Hieracium Pilosella I Viola collina I Thuidium abietinum HI—IN Desuten stod der en enslig Betula verrucosa (ca. 5 m. hoi) og en Alnus incana (2—3 m. hoi), samt en busk av Rosa cinnamomea indenfor proveflaten. Ogsaa Brachypodium pinnatum kunde være associationsdannende paa mere stabil bund. Som et eks. paa orekrat fra forsenkningene mellem ryggene kan folgende proveflate (5 >< 5 m.?) anføres: Alnus incana (4—5 m.) IV Betula odorata (5 m.) I Salix caprea (3 m.) I Alera cespitosa Dactylis glomerata Eee Phalaris arundinacea Triticum caninum Carex capillaris Aconiium septentrionale Cirsium heterophyllum Equisetum arvense Geranium silvaticum en bd nm fem cee pd 1921. No. 9. KALKTUFSTUDIER 1 GUDBRANDSDALEN. 9 Rubus idœus I Tussilago Farfara IH Thalictrum simplex I Trifolium pratense I Ulmaria pentapetala I Urtica dioica I I kalktuffens hoide, ca. 520 m. o. h., er der ingen antydning til ras eller spor efter at der har gaat ut lerskred. Disse ophorer paa et lavere nivaa — heldigvis, kan man si; for ellers var der nok ikke levnet spor av denne merkelige forekomst. I den nævnte hoide indtar dyrket mark en meget bred plads og avveksler med lyse, forholdsvis lave bjerkehager, hvis bundvegetation fleresteds avslaaes til for. Disse aapne bjerkeskoger paa sterkt heldende bund er utvilsomt i sin nuværende skikkelse i hoi grad betinget av kulturen. De alternerer paa fugtigere bund med orekrat, som fleresteds opviser en bundvegetation av hoie græs og urter saa makelost frodig at man kan skjule sig i den. I disse bjerkehager og langs veikantene finder man en del inter- essante arter. Følgende eks. (5 >< 5 mJ) vil vise dette. Betula odorata Wi Knautia arvensis I Brachypodium pinnatum IV Lotus corniculatus I Calamagrostis arundinacea — MI Origanum vulgare I Anthoxanthum odoratum I Plantago media I Festuca ovina I Pimpinella Saxifraga I Poa nemoralis I Rubus saxatilis I Carex sp. (steril) I Solidago Virgaurea I Achillea Millefoltum I Trifolium medium I Brunella vulgaris I Veronica serpyllifolia I Chrysanthemum Leucanthemum I Vicia cracca I Dracocephalum Ruyschiana I Viola canına I Euphrasia sp. I Viola collina I Fragaria vesca I Hylocomium triquetrum Il Galium verum I Hypnum sp. I Geranium silvaticum I Peltigera canina I Hypochoeris maculata I Cladonia sp., basalskjæl I Kombinationen: Drachypodium pinnatum, Calamagrostis arundinacea, Origanum vulgare, Dracocephalum Ruyschiana, Trifolium medium, Viola collina er overmaade interessant ved sin sydlige, xerotherme karakter. Brachypodium pinnatum har her sin nordgrænse i Skandinavien (61 ” 40"), og Dracocephalum Ruyschiana er her nær sin nordgrænse (Dovre)!. I denne forbindelse fortjener ogsaa følgende arter at nævnes: Androsace septen- trionale, Calamintha Acinos, Carex ericetorum, Centaurea Scabiosa, Dianthus IO ROLF NORDHAGEN. M.-N. KI. deltoides, Verbascum nigrum, (Veronica verna), Viscaria viscosa o. fl.!. En del av disse er allerede nævnt tidligere i tabellene, de øvrige optraer ogsaa | Leinebakkene, med undtagelse av Veronica verna, som jeg har fundet ved Veikle. Disse arter danner ikke nogen absolut ensartet floristisk gruppe, men er allesammen av sydlig type og varmekjære. | skarp kontrast til disse staar de fjeldplanter som vi traeffer paa de samme lokaliteter: Astragalus alpinus, Veronica saxatilis, Draba incana. Disse er allerede omtalt ovenfor. Men hertil kommer: Oxytropis lapponica, Saxifraga aizoides, Poa cæsia og Gentiana nivalis, som jeg har fundet paa et par steder, og Primula scotica, som BLyrr iagttok i 18912. Sommeren 1919 opdaget jeg nogen skiferklipper i ca. 700 meters hoide, ovenfor Leinegaardene, som viste sig at være et rent asyl for fjeld- planter. Fra dette sted, men sikkerlig ogsaa fra de høiere- liggende fjeldpartier i nord og nordvest (som dog var meget fattigere paa arktisk-alpine arter paa grund av haardere sparagmiter), skriver antage- ligvis de nævnte fjeldplanter sig. Og deres forekomst i lerbakkene lavere nede (4— 500 m. o. h.) beror efter min Fig. 4. En del av skiferklippene ovenfor Leine med : j : mening først og fremst paa de græs-urtesamfund, hvori indgaar de i teksten omtalte T i k k E : DRE ; 5 SE elendommellg e :ONKUTEEN- fjeldplanter. Midt i billedet Aconitum. Utsigt mot € nordøst, Veiklas dal tilhoire med gran- og furuskog. ceforhold som her gjer sig Juli roro. Nordhagen fot. gjældende; vegetationen er jo fleresteds meget aapen og spredt, og av og til blotlegges mindre arealer ved nye ras, hvilket gir fjeld- plantene en chance til at hævde sig overfor alle de andre, som paa de van- lige lokaliteter i lavlandet formaar at utkonkurrere dem. Den manglende eller ytterst spredte trævekst sammen med den heldige eksposition gjør vel ogsaa sit til at fjeldplantene, som hyppig er fotofile, trives 1 disse sollyse bakker. Hertil kommer da som et meget vigtig moment den korte avstand op til de navnte skiferklipper, hvorfra fre og frugter meget let maa kunne fores 1 Ifølge Brvrr (l.c. p. 29) findes ogsaa Avena pubescens og Erysimum hieracrifolium ved Leine. 2 ].c.p. 28. Her nævnes ogsaa Oxytropis lapponica og Saxifraga aizoides. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. per nedover bakkene baade med vand og vind (f. eks. om vinteren)!. Ogsaa substratets kalkgehalt influerer sikkert. Flere av de anførte planter er kalk- yndende og gaar ogsaa andre steder i Gudbrandsdalen ned i dalbunden paa kalkholdige bergarter (f. eks. ved Otta og i Sel). Denne merkelige blanding av sydlige xerotherme planter og arktisk- alpine arter er altsaa et fremtrædende træk i det plantegeografiske helhets- billede som møter os i disse fantastiske lerbakker. Dog maa det skarpt fremhæves at fjeldplantene kvantitativt set spiller en helt underordnet rolle. Kun Astragalus alpinus formaar at gjore sig fysiognomisk gjældende paa enkelte mindre flekker. — Som vi senere skal se, fortæller kalktuffen os at det motsatte har været tilfældet i længst forsvundne tider. Da de ovenfor nævnte skiferklipper i 700 m.s hoide og deres vegeta- tion vil bli trukket ind 1 flere av de vigtigste ræsonnementer i nærværende avhandling, blir det her nødvendig at fæste opmerksomheten ved enkelte hovedtræk i deres plantevekst. Klippene ligger ovenfor gaarden Hagen, omtrent 200 m. hoiere end kalktuffen, og bestaar av lose, smuldrende skifre. BJoRLYKKE omtaler herfra en graa, skruklet fyllit med kvartskirtler med bøl- gende skifrighetsfald og hoiere oppe en skruklet, graagrøn skifer med fald mot N.NO.; den fører undertiden kalkholdige sandstenslag (1905 l. c. p. 215). Følgende floraliste vil gi et indtryk av hvilken besynderlig konstellation av arter disse klipper huser (6te juli 1919): Aconitum septentrionale Alectorolophus minor Antennaria dioica Anthyllis vulneraria Arabis hirsuta Arctostaphylos uva ursi Botrychium Lunaria Brunella vulgaris Calamagrostis arundinacea Calluna vulgaris Carex capillaris Carex ericetorum Carex ornithopoda Carex sparsiflora Cotoneaster integerrima Cystopteris fragilis Dianthus deltoides Euphrasia sp. Fragaria vesca Festuca ovina Galium boreale Galium uliginosum Gentiana Amarella Geranium silvaticum Hieracium Pilosella Knautia arvensis Melica nutans Origanum. vulgare Parnassia palustris Pinguicula vulgaris Plantago media Polygonum viviparum Phegopteris Robertiana Potentilla Tormentilla ! Om denne nedvandring er av forholdsvis recent natur, eller har paagaat gjennem geo- logisk set langvarige tidsrum, kan vi foreløbig ikke avgjore. Dog er det neppe tvil om at lerskredene og de derigjennem skapte edafiske tilstande har begunstiget ned- vandringen. Cfr. forovrig den generelle del. 12 ROLF NORDHAGEN. M.-N. Kl. Potentilla verna. Gentiana nivalis. Rubus ideus. Gentiana tenella. Saxifraga adscendens. Juncus trifidus. Sedum annuum. Phyllodoce coerulea. Silene rupestris. Poa alpina. Vaccinium vitis idea. Poa cesta. Verbascum nigrum. Sagina Linnea. Veronica officinalis. Selaginella spinulosa. Vicia cracca. Veronica saxatilis. Viola collina. Woodsia rufidula Ved en bæk i naerheten av klip- É pene notertes bl. a.: Juncus triglumis. Antennaria alpina. Salix cfr. arbuscula (bastard ?). Astragalus alpinus. Salix lapponum. Cerastium alpinum. Salix reticulata (meget sparsom). Cetraria nivalis. Saxıfraga aizoides. Draba hirta. Saussurea alpina. Draba incana. Thalictrum alpinum. En saa fantastisk kombination som paa den ene side Verbascum ni- grum, Origanum vulgare, Calamagrostis arundinacea og Juncus trifidus, Anten- naria alpina, Gentiana tenella og de andre fjeldplanter paa den anden, har jeg ikke set noget andet sted i vort land, ialfald ikke søndenfjelds. Kun i det indre av Nordland fylke, paa kalk og dolomit, har jeg iagttat lignende, tilsyneladende paradoksale artskonstellationer. Klippene er i vore dager fuldstændig træbare, med tyndt jorddække sterkt opblandet med fyllitmateriale. De synes ogsaa at være sterkt utsat for vinden, og bærer sandsynligvis om vinteren et ubetydelig snedække. Ovenfor klippene følger et mere plataaagtig omraade, bestaaende av haar- dere bergarter (tildels overdækket) med lyngvegetation (associationer av Empetrum nigrum, Calluna, Phyllodoce, Vaccinium-arter, Arctostaphylos al- pina, tildels med lav /umiperus). Her notertes Pulsatilla vernalis og Lyco- podium alpinum. I 850 m.s hoide saaes følgende fjeldplanter ved en bæk: Bartschia alpina, Betula nana, Cerastium trigynum, Juncus biglumis, Ranunculus hy- perboreus, Salix glauca, S. herbacea, S. lanata, S. lapponum, S. myrsinites, S. reticulata (sparsom). Opunder Tunsbergfjeldet findes lave, spredte gran- og furu-individer, granen oftest som lave, vindtorre avlæggergrupper. Begge to gaar saa godt som helt op til fjeldets top (944 m. efter rekt- angelkartet). I goo m.s hoide vokste TZurritis glabra og Saxifraga Cotyledon sammen. Ellers er Tunsbergfjeldet meget plantefattig og trivielt paa grund av de haarde sparagmiter hvorav det er opbygget. Ingensteds finder man en saa rik flora som paa fyllitklippene længer nede, ja en hel del arter 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 13 syntes udelukkende at være knyttet til disse. Antageligvis vil Torgerkampen, et fjeld som ligger 5—6 km. længer vest, vise sig rikere end Tunsberg- fjeldet; BJORLYKKES oplysninger om bergartene tyder paa det. Mine floristiske optegnelser, som blev revidert under et nyt besøk 17 juli 1919, er i flere henseender bemerkelsesværdige. Saaledes mangler Dryas octopetala fuldstændig paa fyllitklippene og ogsaa hoiere oppe. Hovedhensigten med min ekskursion til fjeldene ovenfor Leine var netop at opspore Dryas; men til trods for en ihærdig leting var den ikke til at opdage. Da kalktuffen som bekjendt indeholder Dryas i kolossale masser i en bestemt horisont, er det nævnte faktum meget overraskende og gir os et tydelig vink om hvilke store forandringer vegetationen her i Kvam har undergaat i aartusenernes lop. Skiferklippene og deres vegetation gir os vigtige holdepunkter og angrepspunkter i den følgende diskussion. Som jeg senere skal forsøke at klargjøre, er det ingen tvil om at Dryas den- gang kalktuffen var tæt bevokset med denne art, ogsaa dominerte paa de angjældende klipper, som efter de erfaringer jeg har gjort med hensyn til denne dvergbusks livskrav rundt omkring 1 Norges fjeldtrakter, skulde synes at være ideelle som voksested netop for Dryas octopetala. En noiere gjen- nemgaaelse av den anførte floraliste gir ogsaa fingerpek i denne retning. Hvor langt indover fjeldet vi maa gaa i vore dager for at finde den nær- meste Dryas, vet vi foreløbig ikke. Vegetationen paa selve tuffindestedet er i nutiden ikke naturlig, men sterkt kulturpaavirket. Tuffen ligger nederst i et brat jorde under den østligste av Leinegaardene. Kilden kommer ret frem av jorden under en stor stenrois, som antageligvis er meget gammel (fra den tid da jorden 1 nærheten blev ryddet), og herfra fører et litet bækkeleie med spredte klynger av vidjebusker og bjerk nedover bakken, som en stripe mellem to dyrkede enger, og fortsætter gjennem en ny stenrøis over i orekrat længer nede. I stenrøisens omgivelser hvor bunden er mest tør, vokser et krat av Detula verrucosa og B. odorata, samt litt Salix capræa, S. nigricans og Rosa cinnamomea. Markvegetationen langs bækken er nu ødelagt av kreatur- traakk og gravninger, likesom ogsaa den primitive kjorevei som passerer paa skraa over tuffindestedet, har influert paa omgivelsene (cfr. fig. 5 og 6). Græs og urter danner et slags dække nedover bakken, men uten syn- derlig orden. Følgende arter optrær indenfor kalktufomraadet: Aconitum septentrionale, Aera caspitosa, Agrostis stolonifera, A. vulgaris, Alectorolophus minor, Alchimilla officinalis, Anthyllis vulneraria, Artemisia vulgaris, Brachypodium pinnatum, Briza media, Brunella vulga- ris, Calamagrostis arundinacea, Campanula rotundifolia, Carex capillaris, C. flava, C. panicea, Carum Carvi, Centaurea Scabiosa, Cerastium vulga- tum, Chrysanthemum Leucanthemum, Cirsium heterophyllum, Crepis paludosa, 14 ROLF NORDHAGEN. M.-N. Kl. Dactylis glomerata, Equisetum arvense, E. pratense, Euphorbia Helioscopia, Euphrasia officinalis, Festuca ovina, F. rubra, Fragarıa vesca, Galium palustre, G. uliginosum, Geum rivale, Gymnadenia conopea, Hieracium umbellatum, Juncus bufonius, Knautia arvensis, Lathyrus pratensis, Leontodon autumna- lis, Linum catharticum, Lotus corniculatus, Molinia coerulea, Phalaris arun- dinacea, Pimpinella Saxifraga, Plantago media, Poa alpina, Polygonum vivi- parum, Potentilla anserina, Potentilla Tormentilla, Ranunculus acer, R. repens, Rubus saxatılis, Silene venosa, Solidago Virgaurea, Thalictrum | simplex, Trifolium medium, T. pratense, Triglochin palustre, Tussilago Farfara, Ul- maria pentapetala, Urtica dioica, Vicia cracca, V. sepium, Viola tricolor. Forskjellige ting tyder dog paa at oprindelig en Carex panicea-asso- ciation av eutrafent og hydrofilt præg har behersket bækkens nærmeste omgivelser. Laenger nede 1 bakken, i tuffens periferi, optrær nemlig saa- danne plantesamfund over en kortere strækning. For at belyse dette har jeg i nedenstaaende tabel opført analyser av to prøveflater, hver paa ca. 4 m°, fra .dette sted: il 2 1 2 Carex panicea . . . . . . |I] -— HIIIV—VI Alectcrolophus minor . . I 2 Juncus lamprocarpus . .| IV L | Drunellazonlganıs. 2.2.0 == Hera CeSPuosa? > m . | II | Cirsium heterophyllum .| — I Agrostis vulgaris . . . .| — II | Mentha sp. (steril) . . .| I = Phalaris arundinacea . .| — It Parnassia palustmis.. | me I Ehleum pratense. 2 ...| — I | Polygonum viviparum .| I T CORE TUA. este I — 1 RARUNCUINS (CORE ERE ONE I Juncus compressus …… .| — I. | Zhabhetrum"simples.. | — I Triglochin palustre . . .| 1 I | Zussilago Farfara . . .| I I Equisetum arvense . . .| I IL | Ulmaria pentapetala . .| — I I det første eksempel fandtes ogsaa Hypnum filicinum WI med nedtil halvveis forkalkede skud. Denne moseart optrær ogsaa hoiere oppe hvor vandet silrer utover den blottede tufoverflate. — Hvis vegetationen fik anledning til at falde tilbake til naturtilstanden, vilde utvilsomt Alnus incana indfinde sig saaledes som længer nede i bakken, og et orekrat omgi tuf- kilden, med litt bjerk paa de tørrere flekker. B. Stratigrafiske undersokelser. Som resultat av en række barometermaalinger i juli 1919 fremgaar det at kalktuffen ligger 232 m. heiere end Slettens landhandleri nede i dalbunden. Da dette maa antages at ligge et par meter hoiere end Kvam station (287,7 m. o. h.), skulde kalktuffens hoide over havet bli ca. 520 m. Bıytt angir ca. 500 m. (496 m. efter barometermaaling) men dette er 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. Es utvilsomt for lavt. 1 oktober 1920 medførte jeg et andet barometer sam- tidig med at lufttemperaturen bestemtes ved hjælp av slyngetermometer. Resultatet blev 232 m. over dalbunden, altsaa nøiagtig middeltallet av fjor- aarets maalinger. Lerbakkene paa tuffindestedet skraaner fra vest mot øst, dog ikke ganske jevnt. Heldningsvinkelen er i gjennemsnit 15>—20 ; dog kan den lokalt være betydelig større!. Hvor stor utstrækning tuffen har, kan ikke siges med sikkerhet. Avstanden mellem mit nordligste og sydligste profil er ca. 15 m.; paa begge disse steder skraaner tuffen indunder dyrket mark, som forbød Fig. 5. Fra tuffindestedet ved Leine. Utsigt mot nordøst. Tilhoire kjøreveien. Foto 5te oktober 1920 (efter groftens gjenkastning). videre gravning. Imidlertid skulde jeg anta at tuffen ganske sikkert har hat en utstrækning i denne retning (9: tvers paa skraaningen) som er dobbelt saa stor som det opgitte tal. Avstanden mellem mit heiestliggende profil (indunder den før omtalte stenrøis) og mit laveste, maalt langs efter skraaningen (2: vest— øst), er ca. 20 m. Opad synes tuffen at kile ut ganske snart, men nedad synes dens grænser slet ikke at være naadd. Under opdyrkningen av den omgivende mark synes store tufmasser at være brutt op av jorden; saaledes ligger der svære tufblokker (hvorav en som er 1,5 m. X I m. X 0,30 m.), hoved- sakelig bestaaende av mosetuf, paa en stenrois længer nede i bakken. Disse blokker skriver sig uten tvil fra tuffens undre lag. Ogsaa de løse tufstykker 1 Paa lengdeprofilet (fig. 11) er heldningen i tuffens ovre del noget overdrevet for at undgaa altfor store knæk og bølger i lagrækken (paa grund av den forskjellige hoid=- og lengdemadlestok). 16 ROLF NORDHAGEN. M-.N. Kl. som har ramlet længer nedover lien og ligger spredt hist og her i ore- krattet, skriver sig vel fra en eller anden nydyrkningsperiode eller oprensk- ning av beekkeleiet. Der er ialfald i den del av tuffen som jeg har under- sokt, intet tegn til ras eller utglidninger. Dog er det mulig at saadanne kan ha foregaat laenger nede. De forskjellige tuflag viser sig i det store og hele tat at være omtrent paralelle med bakkens skraaning; men der er en maengde smaa avvikelser i forskjellige retninger, saa stratigrafien er ganske komplicert. Den kalk- tufavsættende kilde kommer ret ut av bakken like i tuffens overkant, og nogen store variationer i dens lop har netop av denne grund ikke indtraadt i tidenes lop. Imidlertid har de enkelte karakteristiske tuflag sin største tykkelse paa helt forskjellige punkter indenfor omraadet, hvilket kunde tyde paa at bækken saa at si har pendlet frem og tilbake indenfor en cirkel- sektor med tufkildens ,dagaapning" som centrum, ialfald til en viss grad. Dette er bare naturlig, da jo en saadan kalkdannende kilde stadig fylder op sit eget leie og derved tvinger sig selv over i et nyt lop. Imidlertid kommer her ogsaa et andet og meget vigtig moment til, som Brvrr først opdaget, nemlig at kalktufavsætningen ved Leine ikke har været kontinuerlig, men intermitterende; dette vil fremgaa av den folgende utredning. Og det er ganske klart at en stans i avseetningen ledsaget av forvitring og mulddannelse i hoi grad maa virke bestemmende paa kildens fremtidige lop, naar den atter begynder sin kalkdannende virksomhet. — Overfor enkelte tufavsætninger med tydelige avbrud i avsætningen og derav følgende muldstriper eller forvitringshorisonter, har man gjort gjældende at dette kunde skyldes det forhold, at kilden periodevis har tat et helt nyt lop. For Leinetuffens vedkommende kan imidlertid dette ræsonnement ikke gjøres gjældende, da kilden som nævnt kommer ret ut av jorden i tuffens overkant. Det vilde ialfald være hoist ubegripelig hvorledes denne kilde, hvis den under de to avbrud i avsætningen som tuffen viser, hadde et andet løp, atter kunde indfinde sig præcis i det gamle underjordiske løp og komme frem i dagen nøiagtig paa det gamle sted, ikke bare én gang, men gjentagne ganger. I Gudbrandsdalens tuffer kan man i likhet med hvad SERNANDER har vist for svenske kalktuffers vedkommende (1916 |. c.), adskille sedimentære cg sedentere lag. Hvis et lag viser sig at bestaa av lose blader, kvister og andre avkastede plantedeler som vandet har bundfældt, og som senere litt efter litt er forkalket, eller av rent fysikalsk utfældt fossilfri tuf, faar man en sedimentær avsætning. I andre tilfælder derimot kan tuffens over- flate være dækket av en sammenhængende, rotfæstet, levende vegetation, som ogsaa gradvis kan forkalkes. Man faar da en veritabel autokton dannelse, en fossilificert vegetation in situ, en sedenter avsætning. I praksis kan det undertiden være vanskelig at holde disse to typer ut fra hinanden; saaledes kan visse mosetuffer og cyanofycé-tuffer være saa kom- pakte og strukturlose at de sterkt minder om fysikalsk utfældt, sedimentær 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. p tufl. Men i almindelighet er de sedentære lag meget karakteristiske, med ortotropt orienterte skud og andre sikre kjendetegn. For utredningen av vegetationens historie er den slags horisonter meget vigtige, idet man her kan finde rester av urteagtige planter, som jo visner sukcessivt ned uten bladfældning og under vanlige omstændigheter raatner væk meget raskt, og som derfor helt naturlig mangler i sedimentære lag. Et par av Leinetuffens lag er i denne henseende meget interessante. Meget ofte begynder en kalk- tufavsætning med sedentære lag (mosetuf) og fortsætter som sedimentær avleiring. Men dette er slet ikke altid tilfældet, hvilket vil fremgaa av profilene i nærværende avhandling. Imidlertid gir og- saa de sedimentære lag i Leinetuffen utvilsomt et ad- ækvat billede av vegetationen paa stedet, netop fordi kilden kommer ut av jorden og saa- ledes ikke kan ha transportert plantedeler langveisfra. Dog vil selvfølgelig den slags ting kunne ske under sneløsningen eller i flomtider. Som i forordet nævnt lykkedes det mig med bistand av en gammel mand som i 1891 assisterte BLYTT, at ut- ve 2 ‘ig. 6. Den øvre del av Lei ffen. Kilden k ar finde noiagtig det sted hvor Fig 6 : n ovre del av Leinetuffen ilden omme; B Es t tler? frem av jorden overst mellem buskene, som skjuler LYTT OptokK sine to proller”. ; : : : : : p P stenroisen. Billedet er tat efter groftens gjenkastning. Disse laa like i naerheten av Nordhagen foto, 6te oktober 1920. hinanden i overkanten av den gamle bygdevei som skraar over tuffen. BLyrrs profiler kan meget smukt indpasses i min serie og utfylder et hul i denne. For fuldstændighetens skyld, og for at man skal faa det rigtige ind- tryk av hvor lovmæssig tuffen er opbygget, skal jeg i det folgende beskrive alle de opmaalte og undersokte profiler. Fremstillingen vil ogsaa vise hvilke fuldstændig misvisende resultater en mere overfladisk undersokelse kunde ha ført til, idet en hel del av tuffens mere perifere profiler tilsynelatende 1 Jeg agter ved en anden anledning at komme tilbake til sporsmaalet om kalktuffenes genesis. I de senere aar har tyske forskere tildels git vigtige bidrag til tufutskillelsens mekanik. 2 Manden fortalte ogsaa.at da „han kom ned til det tredje laget i tuffen, fandt Bryrr en plante som han kaldte Dryen (9: Dryas)". Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. 9. 2 18 ROLF NORDHAGEN. M.-N. Kl. er himmelvidt forskjellige fra de mere centrale i tuffens hovedparti, mens de i virkeligheten meget harmonisk indordner sig under disse. I nedenstaaende utredning av profilene er disse inddelt i flere serier efter sin beliggenhet i forhold til den store grøft som blev gravet paa langs av bækken. Først kommer en venstre serie, optat nedenfra og opad bakke paa grøftens venstre (9: søndre) side. Den tar sit ut- gangspunkt i Brvrrs profil, som er det nederste i serien, og ender opun- der stenrøisen, hvor tuffen antageligvis kiler ut ganske snart. Tilsvarende hertil faar vi en heire serie paa grøftens motsatte side, ogsaa nedenfra og opad. Endelig har jeg en serie paa tvers av bækken, tverserien, fra syd mot nord, som ender i profilet av 1920. Alle disse er optat ovenfor den nævnte kjerevei, som gaar paa skraa henover tuf- findestedet. Som profiler nedenfor veien beskrives et par vigtige grøfter optat længer nede i bakken; de ligger i ca. 20—25 meters avstand fra det øverste profil i venstre serie. Længdeprofilet! (fig. 11) er konstruert paa grundlag av venstre serie og profilene nedenfor veien, tverprofilet (fig. 12) ved hjælp av tverserien og venstre serien. Som ,Alnus-tuf" betegnes den allerøverste, tidligere ukjendte tufhori- sont eller rester av denne. „Furutuf“, ,Dryastuf' og ,bladtuf” er tildels de samme betegnelser som Brvrr anvendte. Dog omfatter BLyrrs bladtut eller „birketuffen“ ogsaa den underliggende mosetuf, som hænger sammen med birketuffen. Jeg foretrækker dog at betegne denne som „mosetuf“. Ved „undre Dryashorisont" forstaaes en sedentær horisont i bladtuffens underkant (mosetuffens øvre del), som tidligere ikke er beskrevet fra Leine- tuffen; den mangler ogsaa i enkelte profiler og er av meget mindre dimen- sioner end den hoiere oppe i lagrækken forekommende ,Dryastuf". Ved „rod lere" forstaaes den heist eiendommelige, i visse profiler skrikende røde lere som optrær umiddelbart under den laveste mosetuf, og som over hele tufomraadet bedækker den underliggende morænelere, som benævnes „blaa lere“. i For alle profilers vedkommende gjælder at lagfølgen beskrives nedenfra og opad (kronologisk orden). Venstre serie. Profil bBrværkrson) I. Jokeller med vandreblokker. II. Jernholdig ler uten forsteninger indtil 0,03 m. III. }Gulgraa skifrig birketuf (uten furu) 0,45 m. IV. (Heri er som nævnt indbefattet mosetuffen paa bunden (BryTrtl.c.p.7). 1 Profilet benævnes her længdeprofil fordi det er optat langs med bækken (tverprofilet tvers paa bækken). Geologisk set er længdeprofilet i grunden et tverprofil; men da stratigrafien ved Leine er ytterst komplicert, kan man her ikke tale om „strok“ og „fald“ i vanlig stratigrafisk betydning. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 19 Gulgraa, tildels jordagtig Dryastuf (med furu) indtil 0,03 m. * |Grenliggraat ler uten forsteninger 0,04 m. VI. Graahvit furutuf 0,58— 0,68 m. VII. Muldjord o,10—0,15 m. Forevrig henvises til Brvrrs egen beskrivelse av de forskjellige lag (1892 1. c.). Profil LH. I. Blaa lere, ukjendt mægtighet. IE Red lere ca..3 cm. IIl. Mosetufkompleks. A. 10 cm. graagren, slagg- eller koralagtig mosetuf, brunfarvet paa undersiden, med avtryk og hulheter efter Eguisetum variegatum. B. ro cm. redlig mosetuf. C. 5—8 cm. hvitagtig kalkgrus (mosetufbiter). IV. Bladtuf, 25 cm., planskifrig, med blader av Detula odorata, Populus tremula, Salices. V. Dryastuf, 3 cm., les og smuldrende med massevis av Dryas-blader og stammer !. VI. Furutuf, 18—20 cm., sterkt forvitret, med masser av furunaaler, bla- der av Vaccinium vitis idea. | Øverst muldblandet. VII. Muldjord, 20—25 cm. med stener og smaa fragmenter av Alnus-tuf, med blader av Alnus incana. Sammenlignes dette profil med Brvrrs, som laa ca. 2 m. længer nede i bakken, ser man at lagene er præcis de samme, men meegtigheten er helt anderledes. Den slags variationer moter os imidlertid overalt indenfor tuffens omraade. Profil Hl I. Blaa lere. II. Red lere, noget grusblandet med smaa skiferfragmenter, samt en stor, raatten skiferblok midt i grøften. III. Mosetuf, ca. ro cm., nederst med Æquisetum variegatum og utydelige bladavtryk (SaZx sp.) pores og slaggagtig. Hanger sammen med overliggende. IV. Bladtuf, 15 cm., grenbroget, vakkert laget, med byerk, asp, Salices. V. Dryastufkompleks, ca. 15 cm., danner nederst en skorpe ovenpaa blad- tuffen. Tuffen var eiendommelig sinteragtig, i vaat tilstand rodfiolet, i tør tilstand kridthvit og lite egnet til at opbevare fossilavtryk. Dog fandtes en række blader (13) av Dryas octopetala, furunaaler og et par blader av Betula odorata. Øverst fandtes en hvitagtig, lerlig- nende sone, bestaaende av opsmuldret tuf med mindre, fastere biter, utvilsomt et forvitringslag, op til Io cm. tykt. 1 Dryas octopetala er en dvergbusk med træagtig stamme. 20 VI. VIL III. AVE V. VE VII. ROLF NORDHAGEN. M.-N. Kl. Furutufkompleks, 30 cm.; nederst en veritabel forkalket furustok (grov gren eller fragment av en stamme), som var løs og smuldrende (raatten)! Ellers temmelig los furutuf, tildels jordagtig; de faste stykker med umaadelige masser av furunaaler. Muldjord med rotter, 15—20 cm. 1 eco 0 NI AE Blaa lere. Rod lere, typisk. Mosetufkompleks. A. to cm. hullet, slaggagtig, graagron mosetuf, med Æquisetum varie- gatum og huller efter smaa kvister og pinder (Salices?). Lokalt fandtes en liten linseformig, hvit lermasse ovenpaa denne mosetuf. B. 7—10 cm. mosetuf, øverst med den undre Dryashorisont utviklet, med blader og stammer av Dryas (middels mængde), Equisetum variegatum, bladfragment av Betula odorata, en lever- mos som antageligvis er en Pellia sp., et eiendommelig avtryk som muligens er Zofeldia palustris, samt snegler. Bladtuf, 10—15 cm., meget vakker og planskifrig med de vanlige lovblader i stor mængde. Dryastufkompleks, temmelig komplicert bygget. A. Underst antydning til mosetuf ovenpaa bladtuffen, 2—3 cm. B. Graagrøn Dryastuf, med uhyre masser av Dryasblader og stam- mer, desuten et blad av .Sa/ix reticulata og et bladfragment av bjerk, ca. 5 cm. mægtig. C. En tynd, 1,5—2 cm. mægtig sedimentær horisont, grønlig av farve med: Dryas (temm. sparsom), furu (flere store og brede naaler), dz7erk (bladfragmenter), Salix arbuscula (mange blader), Salix caprea (1 bladfragment), asp (bladfragmenter), Pyrola minor (et par blader), samt en stor fuglefjer. D. 1—1,5 cm. hvit kalkgrus (forvitringshorisont). Furutufkompleks, ca. 45 cm. Nedtil tildels litt fin mosetuf, dels furu- tuf med mange naaler og blader av Salix arbuscula (det eneste sted i furutuffen hvor denne art er fundet!). Derover vanlig furutuf, som opad viser antydning til en sedentær sone. Øverst løs og jordagtig (forvitret) furutuf. Muldjord, 20 cm., med rester av Alnus-tuf og en eiendommelig krøllet tuf (mosetuf?). Dette profil er interessant derved, at vi her for første gang møter en ganske indviklet bygget Dryastuf, et fænomen som de følgende profiler ogsaa viser. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. . 2I III. IV. VI. VII. Profe. Blaa lere. Red lere, typisk. Mosetufkompleks. A. 5—7 cm. hullet slagg-tuf, normal. D. 5—10 cm. mosetuf, lysere av farve, øverst mot bladtuffen med en antydet undre Dryashorisont (Dryas-blader, Equisetum varie- gatum, utydelige /ovolader). Bladtuf, 20 cm., normal. Dryastufkompleks. A. 5—7 cm. grønlig Dryastuf med masser av Dryas-rester, aldeles kaotisk. B. 2—3 cm. lagdelt horisont, med avvekslende grønlige og gulhvite lag, indeholdende: Dryas (flere blader), Salıx arbuscula (et litet blad), Pyrola minor (3 blader), furu (flere store naaler) byerk (mange blader, hunrakler), asp (bladfragmenter), Carex sp. (en liten plante med 3 blader). Alt dette tyder paa at tuffen har baaret en meget sparsom vegetation paa dette sted, og laget er halvt sedentært, halvt sedimentært. — Alleroverst viser denne horisont sig at være belagt med en ytterst tynd, hvit skorpe av kalkgrus, som gjerne lesner sig av idet stykkene hakkes los. C. Meget eiendommelig los sone, kun paatruffet tydelig i dette profil, 3 cm. mægtig. De smaa klidbred-lignende tufstykker ligger (især nedtil) i et fint, hvitt kalksmuldr og indeholder massevis av ytterst fine furunaaler samt mange Dryas-blader, desuten et blad av .Sa/ix arbuscula og et fragment av byerk. Som nær- mere utredet i det folgende, er dette lag en forkalket, destruert forne »: sterkt opraatnet barnaalavfald, som danner raa- humus i skogbunden. Antageligvis er det dette lag som 1 visse profiler danner forvitringshorisonten øverst i Dryaskomplekset (cfr. foregaaende profil). Furutufkompleks, 40 cm.; nedtil med massevis av store furunaaler og mange blader av Vaccinium vitis idea; underflaten er altid fri og hanger aldrig sammen med foregaaende horisont. Der- over et mere lest furutuflag, optil mere kompakt tuf. Muldjord, 25 cm., med Alnus-tuf og krøllet, forvitret, grov tuf. ProtbbevL Dette er i virkeligheten optat midt i groften, men medtages av forskjel- lige grunde her. 1 II. III. Blaa lere. Red lere. Mosetufkompleks. 22 ROLF NORDHAGEN. M.-N. Kl. A. 5 cm. slaggagtig tuf, normal. B. 4 cm. hvitlig, grovt mosetufgrus. C. 5 cm. mosetuf, øverst med nogen blader av Dryas, altsaa antydet undre Dryashorisont. IV. Bladtuf, ca. ro cm., normal. V. Dryastufkompleks. A. 7 cm. grenliggraa kaotisk Dryastuf, med uhyre masser av Dryas- rester, bl.a. pragtfuldé stammer med paasittende bladrester, en blomst i frugtstadium; videre et par furunaaler samt fragment av bjerkeblad. B. 3 cm. lagdelt sone med Dryas temmelig sparsom (som i foregaa- ende profil). C. 3 cm. løs, smuldrende, klidagtig tuf, med fine furunaaler og litt Dryas (som i foregaaende profil, men mere opsmuldret og les). VI. Furutufkompleks, 40 cm., som i foregaaende profil. VII. Muldjord, 25 cm., med biter av Alnus-tuf. Dette profil er interessant idet bladtuffen her er paa vei til at kile ut over mot groftens hoire side. Dette fænomen blir nærmere omtalt under „heire serie“. Protil Vill, I. Blaa lere. II. Red lere. III. Mosetufkompleks. A. 7 cm. hullet slaggagtig, graagron mosetuf (normal). B. 5 cm. kalkgrus, bestaaende av mosetufstykker. C. 5 cm. undre Dryashorisont, med Dryas-blader og lovblader. IV. Bladtuf, ro cm., normal (Ajer&, asp, Salices). V. Dryastufkompleks, ca. r5 cm. A. 8 cm. ren Dryastuf, tildels et eneste smuldr av Dryas. B. 2 cm. lagdelt ovre sone, med furunaaler og sparsom Dryas (cfr. foregaaende profiler). Øverst et tyndt, hvitt grusagtig belæg med nogen furunaaler. C. 5 cm. løst lag, tildels bare fint kalkgrus, men med biter av den samme klidagtige tuf som 1 de foregaaende profiler. VI. Furutufkompleks, 20—25 cm., meget lost, øverst jordagtig og sterkt forvitret; ellers normal furutuf. VIL Muldjord med Alnus-tuf, 20 cm. Prot) Val: I plaa ere: II. Red lere. III. Mosetufkompleks, ca. 20 cm., præcis som i profil VII. IV. Bladtuf, ca. ro cm., normal. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 23 M. VI. VII. II. II. IV. VI. VIL Dryastufkompleks. A. 8 cm. ren Dryastuf som i profil VIL. B. 2 cm. lagdelt øvre sone som i p. VII. C. 5 cm. grønbrun, gruset lere, som gik over i foregaaende profils kalkgruslag (C), og som utvilsomt er et forvitringsprodukt herav. Furutufkompleks. A. 20 cm. meget løs og smuldrende mosetufagtig furutuf. B. 20—25 cm. furutuf, bestaaende av en række mindre lag: 1. 4 cm. sprød, men tæt gul tuf, meget fin i bruddet, med faa furunaaler. Muligens av sedentær natur. 2. 1,5 cm. kulførende sort stripe. 3. 2 cm. graagul jordagtig tuf. 4. 2 cm. sort kuljord. 5. graa- gul jordagtig tuf, ca. 1o cm. C. 15 cm. løs, sterkt forvitret furutuf. Muldjord, 20 cm., med Alnus-tuf. Profil IX. Blaa lere. Red lere. Mosetufkompleks. A. 7 cm. hullet slaggagtig tuf, normal. B. 8 cm. redlig mosetuf, haardere. C. 4—5 cm. mosetuf med bladrester (bjerk, asp, Salices). D. 3—4 cm. undre Dryashorisont, med mængdevis av Dryasblader og flere stammer samt en frugtstand, bladfragment av dyerk og Salix sp. og folios levermos (cfr. Pellia sp.). Bladtuf, ca. 8 cm., meget vakkert planskifrig, typisk. Dryastufkompleks. A. 3 cm. typisk Dryastuf, kaotisk. B. 2—3 cm. laget sone med furu, bjerk, Dryasblader. C. 3 cm. lost lag, med smaa tufstykker indeholdende Dryas og furunaaler. C. 1,5 cm. hvitagtig lere. Furutufkompleks. A. ca. 3 cm. mosetuf med furunaaler. B. 5—7 cm. graagul, tæt, men fin og sprød furutuf, muligens seden- tær, med forholdsvis faa furunaaler, blader av Vaccinium vitis idea, ledstykker av Æquisetum hiemale og en kurv av Cirsium hetero- phyllum, samt blader av en mindre urt (utydelige). C. 30—35 cm. temmelig les, men tydelig skiktet furutuf, delvis tuf- jord, med mængdevis av furunaaler, bark, flere kongler samt tytteberblader. Muldjord, ca. 20 cm., med Alnus-tuf. 24 ROLF NORDHAGEN. M.-N. KL Profile Dette profil er det første som blev undersøkt (1918), og det avslutter venstre serie op mot stenroisen. I. Il. III. IV. Blaa lere, ukjendt meegtighet. Red lere, 4 cm. Mosetufkompleks, ganske komplicert sammensat: A. B. (8 5—6 cm. hullet graagron mosetuf, normal, med Zguisetum varie- gatum som vanlig. 2—3 cm. redlig, haardere mosetuf. I cm. smal, rod lere med smaa sandkorn, ligner fuldstændig den røde lere paa bunden, og er antageligvis bare en saadan som bækken har gravet ut litt heiere oppe og ganske lokalt skyllet ut over mosetuffen nedenfor. 5—6 cm. mosetuf, optil mere sedimentær. 4 cm. skifrig, fossilfattig tuf, halvt sedentær, ialfald nedtil mose- tufagtig, med grønbrogete lag avvekslende med gulagtige; bjerk (blader, rakleskjæl, Salices (bladfragmenter), Equisetun variegatum. 3 cm. opsmuldret mosetuf, øverst hvitagtig kalklere. Undre Dryashorisont, 4—5 cm., med mængdevis av Dryasblader, stammer, en blomst i frugtstadiet, Sax arbuscula (1 blad), bjerk (flere store blader). Bladtuf, 8— 10 cm., skifrig, normal, med djerk, asp. Salices (bl. a. en mindre form, muligens .S. phylicifolia), desuten et par store Dryasblader. V. Dryastufkompleks: ME VII. A. B. 2 cm. los, smuldrende Dryastuf, normal. 2 cm. graabrun jordagtig stripe, tildels sortfarvet av kul, over mot foregaaende profil mere hvitagtig lere, som var temmelig seig. Et par smaa tufbiter viste furunaaler (tversnit). Furutufkompleks: A. 4—5 cm. graagron furutuf med mængder av barnaaler, desuten B: et par blader av Vaccinium uliginosum. Paa ett sted litt mosetuf. 4—5 cm. graagul, skjer og fin furutuf, tildels med avvekslende graagronne og mere gulgraa lag, indeholdende huller efter Aster, furunaaler, Cirsium heterophyllum (4 kurver, blomsterstilker, store bladfragmenter), Tofieldia palustris (flere vifteformige bladrosetter), Fragaria vesca (1 blad), Pyrola minor (mange blader, samt en hel plante med paasittende blader), Equisetum sp., moser, samt avtryk av en lavart, vistnok Parmelia physodes. Utpræget sedentær horisont. 1—2 cm. kulstripe. 30—40 cm. furutuf, noget varierende, med /urunaaler, kvister, bark, kongler i stor mængde, /yffeberblader, samt Vaccinium uli- ginosum (flere blader). Muldjord, 20—25 cm., med store biter av Alnus-tuf og mindre stener. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 25 Profilet udmerker sig ved bladtuffens ringe mægtighet; den holder her paa at kile ut og viser flere avvikende træk (f. eks. sparsomme Dryasblader). Den undre Dryashorisont under bladtuffen opnaar her sin største mægtig- het, mens Dryastuffen gir indtryk av at være sterkt forvitret og reducert. Endelig byr furutuffen paa flere interessante træk, specielt den sedentære horisont med urteagtige planter, hvorav flere aldrig før er fundet fossile i kvartære avleiringer. Høire serie. Denne serie, som løper paralelt med den venstre, men paa grøftens anden (9: nordre) side, viser først fire profiler som stemmer helt overens med venstre-serien, men avsluttes opad med 4 utkilingsprofiler. Bla d- tuffen og Dryastuffen kiler nemlig ut mot nord og nordvest i forhold til groftens midtlinje; men utkilingssonen ligger nærmere midtlinjen i tuffens øvre del end længer nede i bakken, hvor først tver- profilet overskjærer utkilingssonen (cfr. dette). Man kan ogsaa uttrykke det samme paa den maate, at bladtuffen og Dryastuffen nu for tiden optrær i en skaalformig, men uregelmæssig omgrænset fordypning, men forsvinder til sidene, hvor imidlertid baade den underliggende mosetuf og de over- liggende tuflag (furutuf og Alnus-tuf) fortsætter, tildels med stor mægtighet. Bladtuffens „centrum“ ligger der hvor Brvrr optok sit profil, altsaa like ovenfor kjøreveien; her opnaar den sin største tykkelse. Imidlertid er der flere sikre beviser paa at bladtuffen engang i tiden (09: da dens dannelsestid var avsluttet) har overdækket et meget storre areal end den nu gjor, men at den senere igjen er vitret ned i stor utstrækning, forinden furutuffen begyndte at dannes. Jeg kommer tilbake til dette betydningsfulde punkt under beskrivelsen av tverprofilet, som er meget oplysende i saa henseende. Poti lh XE I. Blaa lere, ukjendt meegtighet. IL Rod, lere, ca. 3 cm. III. Mosetufkompleks: A. Io cm. graagron, hullet, slagg eller koralagtig mosetuf, brun- farvet paa undersiden, med avtryk og hulheter efter Æquisetnm variegatum. B. ro cm. los mosetuf, brytes let istykker. C. 5 cm. mosetuf med blader av Dryas; undre Dryashorisont. Haenger sammen med underliggende saavelsom med overliggende lag. IV. Bladtuf, ca. 20 cm., planskifrig og med mængder av lovblader (Betula odorata, Populus tremula, Salices). V. Dryastuf Av denne fandtes her bare spor aller øverst i bladtuffens overkant (Dryas, Salix arbuscula (mange blader og 2 Q-rakler), Pinus 26 ROLF NORDHAGEN. M.-N. Kl. silvestris (naaler), Betula ordorata (bladfragmenter), Populus tremula (do.) samt flere tvilsomme avtryk). Vl. Furutuf, ca. 25 cm., temmelig les og opstykket. Kolossale masser av Pinus silvestris-naaler og andre rester. I midten antydning til en mosetufagtig horisont med lovbladfragmenter. Øverst muldblandet forvitret tuf. VII. Muldjord med rotter av den nuværende vegetation, 20 cm., og med med smaa biter av forvitret Alnus-tuf med blader av Alnus incana. Profil XI I. »Blaalere: Il. Rod lere, normal. III. Mosetufkompleks: A. ro cm. slaggagtig, hullet mosetuf, normal. B. 20 cm. lysere mosetuf. IV. Bladtuf, ca. 25 cm., meget lost skifrig, tildels bladet eller skjællet; typisk. V. Dryastufkompleks: A. 6 cm. kaotisk Dryastuf med masser av blader og stammer, des- uten flere furunaaler og fragmenter av byerkeblader. Lokalt var den fin og med klidagtig struktur (kanske fin mosetuf). D. 2 cm. smal lersone op mot furutuffen. VI. Furutuf, her utviklet som en stor kompakt tufblok, 20—25 cm. tyk, som syntes at ha glidd litt fremover paa grund av gravningen neden- for, som ophævet mottrykket fra denne kant. Øverst meget forvitret. VII. Muldjord med Alnus-tuf rikelig, 30—40 cm. I dette profil mangler den undre Dryashorisont, 1 likhet med hvad til- fældet var i Brvrrs profiler. En del av profilet sees paa fig. 7. Po pL I. Blaa lere. II edere. Ill. Mosetufkompleks: A. 5 cm. graagron slagg-tuf med Æquisetum variegatum; typisk. B. r5 cm. mosetuf, i den øvre del med grenbrogete lag indeholdende bjerkeblader, Salix-blader og Dryas meget sparsomt (kun 2 blader). IV. Bladtuf, 25 cm., overordentlig vakker og fossilrik, nedtil smuldrende, finskifrig. V. Dryastufkompleks: A. 5—8 cm. ren Dryastuf med masser av Dryas-rester, Salix reticu- lata (2 blader), Sa/ix herbacea (1 blad), .S. arbuscula (blader), furu- naaler (sparsomt, kun et par naaler set), desuten insektrester (bakkropsringer) og flere utydelige avtryk. KALKTUFSTUDIER I GUDBRANDSDALEN. D -1 B. 2 cm. lagdelt, mere sedimentær sone med bjerkeblader, asp, Salices, hvoriblandt .S. arbuscula og kanske .S. phylicifoha, furunaaler (sparsomt), Dryasblader (sparsomt). C. 1,5—2 cm. gruset kalklere. VI. Furutufkompleks. A. 4 cm. les furutuf med masser av naaler og smaa tyttebaerblader. B. ro cm. sinteragtig, los, fossiltom tuf (kun med træbiter). C. 30 cm. furutuf, temmelig los og øverst sterkt forvitret. litt mosetuf. VII. Muldjord, 15 cm. Profilet er ganske inter- essant derved, at det viser den samme antydning til tredeling av Dryastufkomplekset som vi saa i venstre-seriens centrale profiler. Dryastuffen var her særlig artsrik og pragtfuldt utviklet. Profhd-XIV. I. Blaa lere. II. Red lere. IIl. Mosetufkompleks. A. Io cm. slaggagtig mosetuf, normal. Be 4 cm. hvit- lere: C. ro cm. vakker mo- setuf. IV. Bladtuf, 25 cm., meget vakker; typisk. V. Dryastufkompleks. Dein Nedtil Meiselen staar nederst fast ı Fig. 7. Profil XII. den røde lere og markerer mosetufkompleksets tyk- kelse. B—B = bladtuffen, hvis skifrighet sees ret over meiselen. Papirkorsene avmerker Dryastuf- komplekset. Øverst den kompakte furutuf. Juli 1919. Nordhagen fot. LI 7 cm. kaotisk Dryastuf med mængder av Dryasrester (blader, stammer, en knop eller blomst i begyndende frugtstadium, ,ana- tomiske“ tversnit), Sa/rx reticulata (3—4 blader), S. arbuscula, bjerk, asp, Equisetum variegatum, furunaaler (meget sparsomt). litt los, fin mosetuf. Nedtil B. 2—3 cm. lagdelt sone med byerk, asp, Salix caprea, S. reticulata (6 blader), S. arbuscula, S. cfr. phylicifolia, Dryas, Pinus silvestris (flere store naaler). C. 1,5 cm. hvitagtig til chokoladefarvet tuflere (gruset kalklere). VI. Furutufkompleks. A. 2 cm. utpræget sone med smuldrende tuf, tætpakket av furu- naaler og med smaa fine blader av Vaccinium vıtıs idea samt fragmenter av Salıx-blader. 28 ROLF NORDHAGEN. M.-N. KL B. 2 cm. lerlignende stripe. C. 7—8 cm. hvitagtig sinter-tuf, fossilfattig, men med furunaaler, til- dels meget løs og opsprukket. D. 15 cm. mosetufagtig furutuf. E. 30 cm. kompakt furutuf, tre plater over hinanden, øverst sterkt forvitret... Rik paa fururester. VII. Muldjord, 20 cm. med mange smaa biter av Alnus-tuf allerøverst. Profilet er meget fuldstændig og viser en mægtig furutuf med ganske komplicert bygning. Profil XV. ie Blaa lene: I. Red Tere Ill. Mosetuf, ro cm. hullet slaggagtig mosetuf, typisk. IV. Mangler cfr. næste lag. V. Mangler 3 VI. Furutufkompleks. A. to—15 cm. los sone, tildels brunlig lere med smaa tufstykker fuldproppet med furunaaler og med smaa tyttebaerblader, desuten mosetufrester. Svarer utvilsomt til den underste del av furu- tuffen 1 foregaaende profil, som her synes at være opknust under vegten av den overliggende meegtige furutuf og trykket ned i en leragtig masse (forvitringsprodukt av bladtuffen). D. 3o—40 cm. haard, sammenhængende furutuf, fossilrik, meget kompakt og tung. C. 25 cm. forvitret løs furutuf, tildels tufjord. VII. Muldjord, 3o cm., med Alnus-tuf og andre utydelige tufrester. Vi meter her det første utkilingsprofil hvor baade bladtuffen og Dryastuffen er forsvundet; antageligvis er den leragtige substans et for- vitringsprodukt herav. Profilet kan meget let forfølges over til groftens venstre side, og her kommer baade bladtuf og Dryastuf til som en kile fra venstre, men forsvinder indunder furutuffen tilheire i grøften, saaledes som nærværende profil viser. Profil xvi: I. Blaa lere. IL Rod lere. III. Mosetuf, 5 cm. hullet slaggtuf, typisk. IV. 1,5 cm. hvitt kalkgrus. V. Kaotisk kompleks, 20 cm.; brungrøn .tuflere med tufstykker, inde- holdende Dryasblader, furunaaler; et stykke indeholdt d/adtufrester overst og mosetuf nederst. Overst furutufstykker. VI. Furutufkompleks, 30—35 cm., øverst løsere og forvitret, nedtil mere kompakt og haard tuf. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 29 VII. Muldjord med tufbiter, 20 cm. Dette profil er meget instruktivt, idet det viser os de sidste smuldrende rester av den utkilende bladtuf og Dryastuffen. Profil XVII. I. Blaa lere. I. Red lere. III. Mosetufkompleks. A. 3 cm. grenlig, gruset stripe. B. 5 cm. hullet mosetuf, typisk. C. 5—7 cm. forvitret redlighvit mosetuf; tildels gruset, hvit kalklere. 4 Bem gruset tuflere, 8— 10 cm., med Dryastufstykker (ogsaa furu- naaler i disse) med mængder av Dryasrester, fragmenter av bjerk og asp ' |(sparsomt), szeg/er. Furunaalene var temmelig tynde og fine. 7 = 5 c VI. cm kom først ES rai EROSION stripe, som nedtil var AVSÆTNING sterkt red og optil blaalig, 3—5 cm. Der- = efter fulgte 30 cm. furutuf, B. som 1 foregaaende profil, med /ururester (naaler, kongler, en Salıx-rakle O. a. VII. Muldjord. 20 cm. med Alnus-tuf. Dette profil supplerer foregaaende paa en udmerket maate. Imidlertid Fig. 8. Skematisk tegning av en stratigrafisk in- version. B=blaa lere. R = rod lere. er lerstripen VI (under furutuffens nederste del) ganske gaadefuld. Vi har her nemlig akkurat det omvendte av hvad vi finder paa bunden av tuf- fen, nemlig rod lere og derefter blaa. Dette fænomen kan ikke forklares paa anden maate end at bækken dengang furutuffen skulde begynde at dannes, maa ha gravet sig ned til de underste lerlag paa et sted hoiere oppe i bakken (hvor kanske ogsaa mosetuffen var vitret ned). Den har da selvfølgelig først erodert i den røde tere som ligger øverst, og atter avsat denne længer nede, derefter i den underliggende blaa og placert denne oppaa den røde længer nede i bakken. Dog synes baade dette erosionsfænomen og avsætningsfænomen at ha været ganske lokalt (vi møter det atter i næste profil). — Denne stratigrafiske inver- sion tyder paa ganske sterk vandføring i bækken i begyndelsen av furu- tuffens tid (cfr. fig. 8). Dette profil er forøvrig et ukilingsprofil av det under venstre serie omtalte profil VI, som var optat midt i grøften. Fotografiet (fig. 9) med forklaring viser dette. 30 ROLF NORDHAGEN. M.-N. KL Profil XVIIE I. Blaa lere. II. Kun antydet rod horisont, som rode flammer i overkanten av den blaa lere. III. Mosetufkompleks. A. 5 cm. gronlig hullet mosetuf, normal. D. 5—8 cm. mosetuf- kalkgrus, tildels ler- agtig. IV. 15 cm. brun, gruset tuflere we | med Dryastufstykker. VI. A. 5—6cm. lere; nederst I—2 cm. skrikende rød lere, øverst 4 cm. blaalig, sandet lere (samme fænomen som i foregaaende profil). D. 10—12 cm. kalkgrus, hvitagtig. C. 30 cm. furutuf, tem- melig les og forvitret. VII. Muldjord, 20 cm., med tufbiter. Profilet stemmer helt med Fig. 9. Billedet viser en del av profil VI tilvenstre og dets utkiling over mot profil XVII tilhoire. I= blaa lere, II=rod lere (hvis mørke farve sees paa foregaaende; det danner dets billedet), III — mosetuffen, IV — bladtuffen, som kiler forlængelse opad og greenser ut paa det sted som er betegnet med > . Papir- op mot stenreisen, avslutter korset markerer ogsaa bladtuffen. V = Dryastuffen; altsaa hoire serie. Bladtuffen kiler altsaa ut opad bakken og over til heire; tilhoire er denne ogsaa avmerket med et kors. VI = furutuffen. Lagene skraaner sterkt mot iagttageren. Juli 1919. Nordhagen fot. i det overste profil i venstre serie fandtes den fremdeles, men var her, som vi har set, av ringe mæg- tighet (8—10 cm.) og kiler vel ogsaa ut opunder stenroisen paa dette sted. Tverserien. Denne begynder med profil IV i venstre serie og passerer profil XV i hoire serie, hvortil henvises. Derefter følger endda længer tilvenstre (: nordligere) følgende profil. Dopo XX I; Blaa lere: II. Red lere. III. Mosetuf, 5 cm. hullet slaggagtig tuf, normal. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 31 IV. )mangler. Isteden optrær ro cm. brunlig olivenfarvet fuflere med smaa V. [mosetufbiter. VI. Furutufkompleks; mægtig og avvekslende. A. 8— 10 cm. mosetuf med furunaaler og kongler. B. 30 cm. haard, tildels flinthaard furutuf med mængdevis av furu- rester, desuten Vaccinium vitis idea, Salices o. a. Især nedtil tydelig lagdelt og meget haard. C. 20 cm. løs jordagtig tuf med et mere sammenhængende, sprødt lag, som mindet om den sedentære sone i profil IX og X. VII. Muldjord, 20 cm. med Alnus-tuf i store stykker, desuten et stykke av en bladrik furutuf, som indeholdt talrike furubar, blader av asp, bjerk (vistnok B. verrucosa), Salix sp., Sorbus Aucuparia (x blad- finne), £y/feber, samt nogen valkformige, glatte forhoininger, som muli- gens skriver sig fra blaagronne alger (cyanofycé-tuf). Dette profil viser de samme forhold som profil XV, med en utkilende bladtuf. Furutuffen derimot opnaar her omtrent sin største meegtighet (cfr. næste profil). Bol RN. Danner en fortsaettelse av foregaaende over mot venstre. i Biaa lere. Il. Rød lere, typisk. III. Mosetuf, 20 cm., slaggagtig, med Æquisetum variegatum og thallose levermoser (Marchantia polymorpha); normal. Brun, jordagtig rand, 3 cm. med smaa flate bladtuffragmenter (Betula odorata, diverse blader og rakleskjæl), som var sterkt brunfarvet paa oversiden. Derover 5 cm. grønlig sandblandet tuflere. VI. Furutufkompleks, tilsammen ca. 70 cm. A. to cm. løs furutuf, vistnok mosetuf, med sparsomme furunaaler. DB. ro cm. grenbroget, valket furutuf med masser av fururester. C. 15 cm. meget haard mosetufagtig furutuf med sparsom furu, Salix- blader samt /ovó/lad-fragmenter. Tildels meget kompakt og plate- formig. D. ro cm. furutuf, normal type, med et eneste kaos av naaler og andre rester av furu. E. 20 cm. les, forvitret og jordblandet furutuf. VI. Muldjord, 20 cm., med smaa tufbiter. Profilet er i flere henseender et av de interessanteste i hele tuffen. Bladtufrestene i den brunlige jordstripe laa meget smukt paa rad bortover, i naturlig stilling (skifrigheten orientert paralel med bakkens overflate, som her næsten var horisontal over en kortere strækning). De er utvilsomt de sidste rester av en tidligere bladtuf, som er vitret ned forinden furutuffens dannelse blev paabegyndt. Den grønlige lere er ogsaa tydelig et forvitringsprodukt. 32 ROLF NORDHAGEN. M.-N. KI. Furutuffen derimot har paa dette sted sit maksimum hvad mægtigheten angaar og udmerker sig ved en række med stratigrafisk forskjelligartede horisonter. Fig. 10 viser et fotografi av profilet. Profil XXI. Dette blev optat høsten 1920 og ligger hele 9 m. nordenfor profil XX. Mellem dem ligger der, saaledes som antydet paa tverprofilet (fig. 12) en Fig. ro. Profil XX. Nederst ved vandpytten sees mosetuffen (III). Derpaa følger den brune rand (IV) med bladtufrestene, og den grønlige tuflere (V). Øverst sees furutuffen (VD, som fortsætter ovenfor billedets rand. Juli roro. ^ Nordhagen fot. stenreis og bjerkekrat. Overensstemmelsen mellem dette profil og de grav- ninger som jeg foretok nedenfor kjøreveien, er ganske slaaende (cfr. nedenfor), og de er alle sammen meget forskjellige fra tuffens øvrige profiler derved, at Alnus-tuffen her er paafaldende mægtig utvik- let, mens den jo ellers kun er tilstede i form av mindre stykker øverst i jordlaget. Rækkefølgen i profil XXI var saaledes: I. Store stener i bunden. II. Mosetuf, ca. to cm., nedtil rustfarvet paa undersiden og slaggagtig, graagron med Æquisetum variegatum. Den stemmer helt overens med bundlaget ellers i tuffen. Øverst mere redlighvit og tæt mosetuf. III. Kaotisk kompleks, bestaaende av graaagtig tufjord med talrike løse tufstykker, 8—10 cm. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 33 A. Nederst mot mosetuffen fandtes smaa 6/adtufstykker, sterkt forvit- ret; typiske. B. Hoiere oppe fandtes større og mindre stykker (op til 20 <20 <7 cm.) av furutuf, typisk, med masser av bar, mange store kongler, tytteberblader, dverggrener av asp; de var sterkt forvitret og brune i overflaten (planche IV, fig. 1). C. Jordagtig stripe, ca. 3 cm., med biter av trækul. IV. Alnustufkompleks, 90—95 cm. A. 25 cm. blekt redlig tufjord (bleke) med en del mindre fastere stykker, som let knuses mellem fingrene. De bestod vistnok av mosetuf med en del utydelige planteavtryk (græsstraa). Øverst fandtes en svakt antydet kulstripe. B. 8—10 cm. mosetuflag, meget sprødt og porøst, med blader av Alnus incana, Salix sp., dverggrener, vedbiter, ledstykker av Equisetum hiemale. I sin øvre del var dette lag sterkt rustfarvet, særlig i pronlets hoire del, mere utydelig i den venstre del, hvor de overliggende lag var haardere. Rustsonen bør muligens tolkes som et podsolfænomen (cfr. det følgende). 20—25 cm. haardere mosetuf fulgte ovenpaa rusthorisonten, uten avbrytelse i lagræk- ken. Denne tuf var grovere og mere kaotisk end foregaaende og stemmer helt overens med Alnus-tuf fra muldlaget i andre profiler; den var temmelig fossilfattig (Alnus incana, Salix sp., græsblader, moser); enkelte partier sinteragtige. C. 20—25 cm. løs, blekeagtig tufjord med haardere biter, graalig- hvit av farve, øverst meget hvit og fin. D. 12 cm. muldblandet tufjord med haardere biter. V. Muldjord med røtter, 5 cm. Alnustuffens lag viste et fald paa ca. 30° mot øst-nordøst og ligger, som fig. 12 viser, i en slags mulde ovenpaa den forvitrede furutuf. Profilets allerunderste del stemmer helt overens med tuffens øvrige profiler, og likesom i foregaaende profil træffer vi her restene av en forvitret bladtuf oppaa mosetuffen. Men, man kunde fristes til at si, det sens a- tionelle moment ligger i den forvitrede furutuf som her møter os, og som aabenbarer en diskordans mellem furutuffen og Alnustuf- fen. Dette fænomen kunde man forøvrig slutte sig til paa forhaand, da restene av Alnustuffen i de øvrige profiler altid ligger ovenpaa furutuffen, og fordi der aldrig er iagttat nogen overgang mellem furutuf og Alnustuf, som har helt forskjellig struktur, farve og fossilindhold. Men nærværende profil viser til evidens at paa dette sted var furu- tuffen vitret ned til et løst kaos av muldblandet tuf forinden Alnustuffen begyndte at dannes. Antageligvis har furutuffen paa dette sted været mindre mægtig end i de foregaaende profiler i tverserien. Flere ting tyder paa at foregaaende profil markerer furutuffens maksimum, og at den derfra har skraanet noget til begge kanter (baade nordover og sydover). Dog Vid.-Selsk. Skr. I. M.-N. Kl. 1921. No. 9. 3 34 ROLF NORDHAGEN. M.-N. Kl. er det ikke mulig at rekonstruere furutuffens oprindelige utseende. Vi har før set at den i saagodtsom alle profiler er meget løs og forvitret optil, og antageligvis har den overalt været mægtigere end nu, selv om dette ikke kan siges med bestemthet. Tverprofilet viser os saaledes hvad jeg allerede indledningsmæssig fremhævet, at i Leine-tuffen har de forskjellige horisonter nu for tiden sit maksimum paa helt forskjellige steder. Bladtuffens ligger i en mulde længst syd ved bækken, furutuffens ligger litt nordligere og Alnus-tuffens maksimum endda længer mot nord. Imidlertid vil de følgende profiler nedenfor veien vise at Alnustuffen ogsaa har et maksimum længer nede i bakken i en lignende mulde, hvor ogsaa furutuffen er hoist reducert. Profilet er videre meget oplysende om selve Alnus-tuffen. Vi ser at den gjennemgaaende har en ytterst løs, tildels blekeagtig karakter, og at den i vertikal retning opviser en række forskjellige lag, videre at den er meget mægtig sammenlignet med tuffens øvrige hovedlag. Det er sikker- lig oretuffens løse, smuldrende natur som er hovedaarsaken til at den gjen- nemgaaende er meget sterkt reducert over store arealer paa tuffindestedet. En speciel omtale fortjener den rustfarvete stripe indenfor mosetuflaget. Jeg har ovenfor antydet at dette fænomen muligens er av sekundær natur, en utfældning som har foregaat efter Alnustuffens dannelsesperiode. Som nævnt var den meget utpræget 1 profilets venstre del, men over til heire blev den mere utvisket; her var den overliggende tuf temmelig haard. Hadde vi her hat en autokton jernholdig tufhorisont, burde man ha ventet at den var lik overalt. Det er derfor mulig at rusthorisonten er et saa- kaldt podsolfænomen, og motsvarer den anrikningshorisont av jernforbin- delser som optrær i en mængde jordbundsformer under en overliggende saakaldt blekjord. Podsolprofil utvikles bedst i granskoger med tykt lag av raahumus øverst (TAMM 1920 l.c.. Imidlertid pleier et kalkholdig under- lag, særlig hvor det er skraanende, at fremkalde en helt anden jordbunds- type uten tydelig podsolering (HESSELMANN 1917 l.c.p. 397—411) Som substrat for vegetationen betragtet, er jo en kalktufforekomst, specielt under perioder hvor avsætningen paagaar, meget fugtig, og man skulde ogsaa av denne grund ikke vente at finde podsolering; en saadan proces synes nemlig, efter hvad man vet, ikke at foregaa paa meget fugtig bund (cfr. Tamm I. c. p. 55). Den omtalte rusthorisont i Alnustuffen ligger imidlertid netop inden- for en del av Leinetuffen som nu for tiden er meget tør (ca. ro m. fjernet fra det nuværende bækkeleie), saa av denne grund var podsolering nok mulig. Dog vover jeg ikke at uttale noget herom med sikkerhet, men noier mig med at gjøre opmerksom paa forholdet. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 35 Profiler nedenfor veien. Under selve kjøreveien og i dens nærmeste omgivelser var det selv- sagt umulig at foreta nogen gravninger (bl. a. paa grund av bækkens mulige ødelæggelser hvis den kom i et nyt leie). Mit første profil nedenfor veien ligger ca. 2 m. fra veikanten. Proti XXI. = Blaa lere. II. Red lere. III. Mosetufkompleks, tilsammen 20 cm., utviklet som en sammenhængende bænk, som nedtil var hullet og slagget (typisk). Øverst fandtes en sone med talrike blader av Salix arbuscula, bladfragmenter av Betula odorata samt en Q-rakle av samme, Æquisetum variegatum. Svarer uten tvil til den undre Dryashorisont i de øvrige profiler, men mangler altsaa Dryas. IV. Bladtuf, 25—30 cm., normal, men med talrike .Sa/ix-blader foruten bjerk (blader, rakleskjæl) og asp. Vakkert skifrig, optil les. VL | Derefter fulgte en 10—15 cm. mægtig les, kaotisk sone med A. Bladtufbiter nederst (1 bladtuffens overkant). B. Et vakkert stykke Dryastuf, meget forvitret, men med r5 bladav- tryk paa overflaten, desuten en stammedel og et bjerkeblad. C. Forvitrede furutufstykker med masser av naaler samt tyttebær- blader; typisk. VI. Alnustufkompleks, 15—20 cm., meget lest, tildels jordagtig, med større og mindre fastere stykker indeholdender Alnus-blader rikelig; typisk. VIII. Muldjord, 30 cm. nedtil med Alnus-tuf, hvorav flere store stykker. Dette eiendommelige profil ligner 1 flere henseender meget det nord- ligste i tverserien. Bl. a. er furutuffen her ogsaa tydelig vitret ned, ja vitringen har eiensynlig grepet endda dypere om sig, helt ned 1 bladtuffens ovre del. Dryastufstykket er specielt værdifuldt; det viser nemlig at for- vitringsproduktene ligger ganske i sin naturlige orden paa hinanden, og vidner om at her ogsaa har vaeret en veritabel Dryastuf paa stedet, saa- ledes som hoiere oppe i tuffen. Endelig er Alnus-tuffen ganske godt opbevaret. Profil XXIII. Optat ca. 3 m. nedenfor foregaaende. L II. III. Mosetufkompleks. A. r5 cm. normal mosetuf med Æquisetum variegatum. Runde stener i greftens bund. 36 ROLF NORDHAGEN. M.-N. KL D. 5 cm. grenbroget horisont med Salıx arbuscula, gresstraa ete., nøjagtig som i foregaaende profil. IV. Bladtuf, ca. 15 cm. med massevis av .Sa/ix-blader, vistnok mest .S. ca- prea, ellers typisk. Optil los og forvitret. V. | Løs sone, 15 cm., bestaaende av kul og muldblandet tufjord med tal- IV. J rike furutufstykker (7 —8 cm. tykke), desuten biter av en merkelig kornet, sammenkittet grustuf uten fossiler. Nederst plateformige bladtufbiter. " e| Moræne-lere m Dryashorizont, - HT Oyenpaa mosetuffen WIN Rod lere, Bladtufbænk, lo ©] under mosetuffen tilhdire forvitret Furutufbenk, tilhöire forvitret 0 retuf Mosetufbank Druastu i Oretufrester 2 3 f i muddlaget a sn s el ee CUN vy —————__ 0 Fig. 11. Længdeprofil, Leine. B angir tverprofilets beliggenhet. VI. Alnustufkompleks, 25— 30 cm., graagul blekeagtig tuf med haardere stykker, især nedad. VIII. Muldjord, 30 cm., med store biter av Alnus-tuf nederst. Sammenholdes disse to profiler, som er temmelig like, med tverseriens nordligste profil, gir det hele et ganske interessant billede av av Alnus- tuffens forekomstmaate. Den har sin største mægtighet der hvor furutuffen er mest forvitret, og hvor der av denne grund er mulde- agtige fordypninger i tuffens øvre del. Det er da ganske naturlig at den 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 37 her er bedst bevaret; men kanske har den ogsaa paa disse steder oprindelig været mægtigere end paa alle andre punkter inden omraadet. Hvor meget der atter er vitret bort over største- parten av tuffens areal, er det umulig at avgjøre; de i muldlaget fore- kommende tufrester er av flere typer (Alnus-rikere og -fattigere, mosetuf- agtige, krøllet-cyanofycé-lignende o. s. v.) og er tydelige vidnesbyrd om, at selv paa de punkter hvor denne øverste tufhorisont nu er ytterst reducert, har der engang været flere vertikale facies. Moræne-lere UEM Bladtufbænk == Furutufbænk RSS NE Redlereunder EE Dryastuf, S28) Oretuf g Ge mosetuifen >= Mosetufbænk — | Bladtutrester Oretufrester , | 1 Lu. wnderfurutuf imuldlaget 0 1 2 3m. Höidemaalestok ——$—<——$—<_ —— EN 5 em. Længde » 5 N Fig. 12. Tverprofil, Leine. A angir lengdeprofilets beliggenhet. Alle disse tre perifere profiler, som ved forste oiekast ser hoist para- doksale ut, og som for en iagttager der ellers var ubekjendt med tuffens stratigrafi, vilde være ganske problematiske, indordner sig i virkeligheten meget smukt i helhetsbilledet. Saalænge det ytterste profil i tverserien var ukjendt, kunde man nok staa tvilende overfor litt av hvert. Men da over- ensstemmelsen er saa slaaende i disse ytterpunkter av tufomraadet, baade nordover og østover, hvilket fig. 11 og fig. 12 tydelig viser, blir det ende- lige resultat av denne stratigrafiske detaljstudie, at kalktuffen ved Leine har en strengt lovmæssig, klar og oversigtlig opbyg- ning, som ikke kan misforstaaes. 38 ROLF NORDHAGEN. M.-N. KL C. Oversigt over Leinetuffens stratigrafi. Efter at ha skildret alle de mange enkeltprofiler, skal jeg nedenfor gi en samlet oversigt over tuffen! og diskutere de enkelte horisonter nærmere. Den blaa lere. Under kapitlet ,isavsmeltningen i Gudbrandsdalen" vil spørsmaalet om morænemassenes oprindelse og alder bli nærmere berørt. En række av kjendsgjerninger taler for at de er avsat av en bræ fra nordvest, antage- ligvis under en periode med lokalglaciation i det centrale Norge (Port- landia-nivaaet). De snegleformer som det lykkedes mig at fremfinde i den blaa leres øvre del, Vitrina pellucida (Müıı.), Conulus fulvus (MbLL.) samt Limnæa truncatula (Müziz.)? er ikke særlig oplysende i klimatologisk henseende. Det er altsammen temmelig ubikvisite former, som baade kan tyde paa et alpint og et subalpint klima. Den rode lere. Denne horisont er saa eiendommelig at den fortjener den største op- merksomhet fra geologenes side. Den er i gjennemsnit 3 cm. tyk, under- tiden tykkere, men ofte ogsaa tyndere. I sin mest typiske form er den meget sterkt rød, næsten skrikende, og forbauser altid ved sin tilsynekomst under den laveste mosetuf. I fugtig tilstand er den noksaa plastisk, under- tiden sees litt tilblandet sand (blaalige kvartskorn bl. a.). I motsætning til den underliggende blaa leres overflatelag indeholder den nu ingen opbe- varte snegler. At den røde lerhorisont er et forvitringsprodukt av den blaa morænelere, er hævet over enhver tvil. Og det skyldes kalktuffen, som har lagt sig som et beskyttende skjold over den, at den her er bevaret, mens den ellers overalt er forsvundet. I jordbundslæren adskiller man som bekjendt flere typer av forvitring efter de klimatiske forhold. I et relativt humid klima faar man jordbunds- typer karakterisert ved en utpræget oplesning og bort- førelse av opleselige forvitringsprodukter fra de everste markskikt, altsaa en utvaskning og absolut ingen ophobning i overflate- lagene. I motsætning hertil staar den aride type, hvor der netop paa grund av klimatiske 'forhold sker en ansamling av forvitringspro- dukter i overflaten. Hovedforskjellen mellem disse to klimatiske typer, 1 QvrN har i sit arbeide om kalktuffene kommentert Brvrrs oprindelige beskrivelse paa en række punkter. Imidlertid er disse supplerende oplysninger tildels noget misvisende, hvilket nærværende stratigrafiske oversigt godtgjør. De grunder sig paa studiet av Brvrrs efterlatte samlinger alene, ikke paa nye iagttagelser paa findestedet. 2 Den sidstnævnte art er bestemt av dr. Nizs ODHNER, Stockholm. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 39 som selvfølgelig ikke er skarpt adskilt, ligger i forholdet mellem nedbør og fordampning; i et humid klima mottar marken mere vand end den av- gir ved fordampning, og overskuddet synker ned og bortfører ustanselig visse forvitringsprodukter. I et arid klima derimot er der likevegt, eller oftest en stor deficit paa grund av den intense fordampning, hvilket be- virker den nævnte akkumulerende virksomhet i overflatelagene (cfr. RAMANN 1911, HESSELMANN 1917 p. 397). Alting tyder paa at lerbakkene ved Leine i tidsrummet efter den sidste isbræs tilbakerykning har været gjenstand for en intens oksydation og Tegnforklaring. EF Saltbitterjordens vig- tigste forekomststrek. Bomaas — linjer, der angir den aarlige nedbørsmængde i mm. fondre d Bergen hus, Kartskisse over nordre Gudbrandsdalen, visende de vigtigste forekomststrok av saltbitterjord. 1 : 750 000. Fig. r3. Tallene angir nedborheiden i mm. L = Leine i Kvam. (Five rorr). anden kemisk omdannelse i overflaten under ganske saregne forhold. At klimatet har været ytterst kontinentalt, kanske likefrem arid, er meget sandsynlig: Det er i denne forbindelse meget interessant at den ovre del av Gud- brandsdalen i nutiden hører med til de nedborfattigste egne i hele det syd- lige Norge, med under 400 mm. aarlig nedborheide. De stationer som ligger nærmest Kvam, er Botn i Sel med 332 mm. og Steinfinsbe i He- dalen med 325 mm. I Skjaak gaar nedberheiden ned til 254 mm. (Metorol. Institut 1. c.). Som vistnok BjorLYKKE først har gjort opmerksom paa, har vi i disse strøk ogsaa i nutiden en virkelig arid jordbundstype, nemlig ,salt- bitterjorden" i Vaage, Skjaak, Dovre og Lesje (1911 1. c.). Denne er spe- cielt studert av I. Five, som har skrevet en meget interessant opsats om saltbitterjorden, dens utbredelse og økonomiske betydning (1g11 |. c.) 40 ROLF NORDHAGEN. M.-N. KL »Saltbitteret", skriver Five, „som viser sig paa jordoverflaten i den varme og tørre aarstid, enten som skorpe, klumper eller kruster, bestaar hoved- sagelig av gips (svovlsur kalk); men indeholder ogsaa adskillig bittersalt (svovlsur magnesia), som gjør, at det smaker bittert. Desuten kan det være smaa mængder av a/kaliesulfater, samt en del klorider." „Saltbitteret holdes opløst i jordvandet, som bevæger sig i jordens porer. Denne bevægelse vil i den varme og regnfattige forsommer (tildels ogsaa utover høstparten) væsentlig være 1 opadgaaende retning. De foran nævnte salte følger med i opløst tilstand helt til jordoverflaten. Naar saa vandet dunster væk ut- fældes saltene (saltbitteret) i en av de før nævnte former" (I. c. p. 23). Ved- foiede kartskisse er hentet fra Fives arbeide og viser saltbitterjordens ut- bredelse samt nedborkurver. Kalktuffens beliggenhet,er avmerket med L. i kartets sydøstre hjørne. — Aarsakene til denne merkelige jordarts dannelse maa ifølge Five sokes i de klimatiske forhold: „et utpræget indlandsklima med varm sommer og kold vinter — og /ifen nedbør, specielt i vaarmaanederne" (l. c. p. 9, hvor en række tabeller belyser forholdene). BjørLYKKE omtaler ogsaa aride ,,hardpan"-dannelser og saltjorder fra de øvre deler av vore østlandske dalfører i ,Norges jordbundsprovinser og klimatiske hovedstrøk" !. Den ,fossile jordbund" under kalktuffen er efter min mening et tydelig og værdifuldt vidnesbyrd om at de kontinentale forhold var i endda heiere -grad- potensert i disse "længst forsvundnestidies Kanske sterke fohnvinder kan ha bidradd til at paaskynde oksydations- processene. Desuten har utvilsomt den heldige eksposition og derav fel- gende sterke insolation og opvarmning stimulert de kemiske omsætninger. Imidlertid sier det sig selv at en saadan forvitringshorisont ikke opstaar i en haandvending, men kræver tid til sin dannelse. — Nogen anden for- klaring paa fænomenet kan for tiden ikke gives. Saavidt jeg vet, foreligger der i litteraturen ingen oplysninger om tilsvarende fænomener fra andre strøk i Skandinavien, som kan gi angrepspunkter for en mere indgaaende diskussion?. Om lerbakkene ved Leine under denne periode var vegetationsklædt eller ikke, kan ikke siges med bestemthet, da alle tydelige organiske rester mangler. Undertiden synes den rede lere at indeholde mere brunlige par- tier, som muligens er destruerte levninger av plantevekst; dette kunde jo tyde paa en meget spredt vegetation. Et andet moment som fortjener op- merksomhet, er det faktum, at den underste, slaggagtige mosetufhorisont er brunfarvet paa undersiden og her fleresteds bærer tydelige avtryk efter kvister og mindre grener (Salices?). Men disse kan ogsaa først ha ind- 1 Naturforskermotets forhandlinger 1916. Kristiania 1918, p. 522— 523. 2 Den rode lere minder baade om ,terra rossa" og lateritdannelser; men da disse op- staar i varme klimatomraader, er det vanskelig at trække nogen mere indgaaende sammenligning. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. AT fundet sig paa stedet da kalktufkilden begyndte at sprudle frem av bakken !. Flere ting tyder med bestemthet paa at den røde lere ved Leine ikke er et rent lokalklimatisk fænomen, men av mere generel natur. Kalk- tuffen ved Gillebu i Oier længer syd i Gudbrandsdalen viser nemlig det samme fænomen. Her er, som vi senere skal se, tuffens underlag meget sterkt oksydert og rikt paa jernforbindelser, hvilket bl. a. ogsaa har hat tilfolge at selve tuffens bundlag tildels er mørkt brunt eller chokoladefarvet, mens lagene hoiere oppe har den vanlige graagule tuffarve (cfr. OYEN 1920, p. 285). Mosetufkomplekset. Den første kalktufhorisont som meter os ved Leine, er en mosetuf. Og den underste del av denne, som er meget karakteristisk, gjenfindes i samtlige profiler, har altsaa en sammenhzengende utbredelse over hele omraadet. Denne mosetuf er hullet, porøs og uren, og kan betegnes baade som slaggagtig og koralagtig. Mosetufstrukturen er meget utvisket paa grund av forkalkningen, men aabenbarer sig ikke sjelden paa .brudflater, hvor mosens blader ofte sees. Farven er i fugtig tilstand eiendommelig graa- grøn, og temmelig mørk. Hovedmassen utgjøres muligens av en Amblvyste- gium-art, men det er ikke mulig at konstatere dette med nogen sikkerhet. Dog kan det ikke være A. falcatum, da denne art, som heiere oppe i tuffen er almindelig, er meget grovere. Tuffen viser en paafaldende likhet med stuffer fra subarktiske lag i tuffen ved Hemrike i Lerdala, Västergötland (SERNANDER 1916, l. c. p. 141, Våxtbiologiska Institutionens kalktufsamling). Som før nævnt er mosetuffens underside rødfarvet av den underlig- gende lere. Men ogsaa selve den først dannede kalktuf er fleresteds meget sterkt jernholdig og rødfarvet, desuten forurenset med kvartskorn. Paa undersiden, men ogsaa heiere oppe, er der avtryk og hulrum efter flere middels grove træpinder (muligens trærøtter), hvorav en del var 1 cm. i diameter; et grovt, men mere tvilsomt, halvcylindrisk avtryk var 3,5 cm. i diameter. Muligens skriver de sig fra Salix-busker, da jeg andre steder i tuffen har fundet utydelige smaa Sa/ix-blader (som minder litt om .S. phy- licifolia eller S. arbuscula). Ellers egner denne porøse mosetuf sig meget daarlig for opbevaring av blader og andre urteagtige plantedeler. — Gjennem næsten hele mosetuffens masse findes nogen smaa hvite, tynde rørlignende fragmenter, som skriver sig fra Characéer (planche I, fig. 10). De viser den største likhet med saavel svenske characé-holdige tuffer som recent characé-kalk fra bunden av gotlandske sjøer (Våxtbiologiska Institutionens i Uppsala samling av organogene kalkdannelser). Nogen artsbestemmelse er 1 Kilden har tydeligvis virket eroderende i begyndelsen og skyllet væk en del av den røde lere (cfr. mosetuffens underste, jernholdige parti) og fjernet opløselige salter i denne. 42 ROLF NORDHAGEN. M.-N. Kl. ikke mulig, neppe engang nogen sikker slegtsbestemmelse; dertil er frag- mentene altfor lite utpræget. I Skandinavien findes der baade Chara og Nitella-arter som gaar ganske høit over havet (RABENBORST |. c.). Ellers er Æquisetum variegatum ytterst karakteristisk for denne underste mosetuf. Overalt træffer man avtryk og hulheter efter dens stængler, ofte i tætte masser. Av landsnegler fandtes Conulus fulvus MOLL. Alt i alt maa man anta at lerbakken ved Leine ved tufavsætningens begyndelse har været klædt med en svulmende, meget fugtig mosmatte indenfor det av bækken overrislede omraade. I denne mosmatte har der vokset Marchantia polymorpha (cfr. profil XX), Characéer! og Equisetum variegatum; muligens var der et krat av Salices (ialfald har traer eller busker været tilstede), eller kanske spredte vidjebusker. Desuten kan man være sikker paa at en række med gras og urter ogsaa har holdt til paa stedet (f. eks. subalpine Carices, Epilobium-arter o. s. v.), saaledes som til- fældet er med den subalpine kildevegetation i nutiden. Ovenpaa dette aller underste sedentære tuflag kommer der i flere pro- filer mere kompakte, grovere mosetuffer, som hovedsakelig synes at være dannet av Amblystegium falcatum (Bıytt 1892 ].c.). Andre steder findes mere sprøde smuldrende mosetufpartier. Farven er gjennemgaaende rødlig eller gulhvit i motsætning til den underste graagrønne bænk (renere kalk). I de øverste profiler IX og X i venstre serie møter vi et ganske kompli- cert bygget mosetutkompleks. Her kommer nemlig øverst en halvsedimen- tær, av avvekslende grønlige og gule lag bestaaende sone med tydelige bladrester av Betula odorata, Populus tremula og Salices, hvilket viser at disse trær og busker har været tilstede næsten helt fra tufavsætningens begyndelse. At de mangler i det allerunderste lag (cfr. dog kvistavtrykkene), kan som ovenfor antydet bero paa at denne sedentære, porøse horisont ikke egner sig for opbevaring av myke eller flate, avfaldne plantedeler. En ganske stor overraskelse møter os i dette sedentære mosetufkom- pleks's aller øverste parti, nemlig den undre Dryashorisont. Denne mangler i flere profiler, specielt i den del av tuffen hvor Bryrr foretok sine undersøkelser, hvilket jeg selv ved mine gravninger har erfaret. Og nedenfor kjoreveien finder vi heller ikke Dryas paa dette sted i lagræk- ken, men en smal horisont med anrikning av Salix arbuscula, som dog utvilsomt korresponderer med den undre Dryashorisont hoiere oppe i bak- ken. Dette nivaa er for saavidt av en anden valer end den højereliggende „Dryastuf“, som for det første er meget mægtigere og markert, og som desuten er av helt generel natur. 1 Eventuelt i mindre kulper med aapent vand. I naturparken ved Sylene findes Nitella opaca paa denslags lokaliteter i 700 m. hoide. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 43 Den undre Dryashorisont er dog i flere henseender meget interessant. Den lærer os for det første at arter som Dryas octopetala, Salix arbuscula og andre Salices, Betula odorata, Equisetum variegatum og Pellia sp. vokste ved Leine paa dette tidspunkt, altsaa en blanding av alpine og subalpine arter. Bryrr fremhæver i sit arbeide ganske sterkt at de arktiske planter mangler i den undre halvpart av tuffen, netop fordi, som vi har set, den undre Dryashorisont ikke findes i hans profiler. Og for ham maatte da de arktiske planters pludselige masseoptræden i Dryastuffen synes end mere paafaldende. Dog har han tydeligvis studset over forholdet; han skriver nemlig om Dryas og de øvrige arktiske arter: „de mangler ikke blot i den overliggende furutuf, men merkelig nok ogsaa i den underlig- a EEUU —- — — (1692 l c. p. 6). Nu vet vi imidlertid at saa ikke var tilfældet; vi maa derimot anta at lerbakkene under mosetuffens tid har hat en blandingav alpine og subalpine arter. Imidlertid er Dryas, som jeg i det folgende kommer til at diskutere naermere, en dvergbusk med xerofil bygning, som ynder tor bund, specielt lose, smuldrende skifre og kalkbund. Den undre Dryashorisont er derfor, saavidt jeg kan forstaa, et tegn paa en mindre oscillation 1 tufkil- dens vandføring. Enkelte partier av omraadet er blit mindre fugtige end før, og her har bl. a. Dryas kommet ind. Dette synes specielt at ha været tilfældet allerøverst i venstre serien, nær kildens utspring (profil IX og X). Andre partier har ikke gjennemgaat nogen forandring paa dette tidspunkt, men opviser den samme svulmende, vanddrukne mosmatte som før. Nedenfor veien synes Salix arbuscula at ha dominert lokalt. Mosetufkompleksets sedentære natur potenseres saaledes opad, hvor det kulminerer i den undre Dryashorisont. Men derefter synes tufkilden at ha svulmet ganske voldsomt op, og den følgende tid viser os utpræget sedimentære tuflag. Bladtuffen. Dette utpræget sedimentære kompleks er saa karakteristisk at man kan kjende det igjen selv i ganske smaa biter. Skiktningen er meget markert, ofte er tuffen likefrem skjællet-skifrig. Planterestene ligger tydelig klappet paa hinanden; det ser ut som om de alle sammen er blit tvunget over i horisontal stilling (eller rettere paralel bakkens overflate) og har lagt sig paa hinanden etagevis!. Betula odorata, Populus tremula, Salices (S. capræa, S. glauca, S. hastata, S. cfr. nigricans, S. cfr. phylicifolia) forekommer her i umaadelige kvantiteter; enkelte partier av tuffen bestaar ikke av andet ! Om dette simpelthen skyldes en rolig bundfældning i vandet eller dets raske strømning, kan neppe avgjøres med sikkerhet. Bladene synes ialfald at ha hat tid til at ,ordne sig" inden de blev forkalket (cfr. Gillebu-tuffen, hvor forholdet er et andet). 44. ROLF NORDHAGEN. M.-N. Kl. end forkalkete bladrester. Desuten fandt Biyrr i sin tid et blad av Aes rubrum, samt tvilsomme bladfragmenter av Alnus incana. Efter opdagelsen av Alnus-tuffen ved Leine har jeg et rikholdig materiale av Alnus incana- blader i alle mulige størrelser, og sammenlignes de av Bryrr omtalte frag- menter med de sikre oreblader, ser man at overensstemmelsen er meget svak. Jeg tror at det kun er fragmenter av nogen store bjerkeblader; der- om vidner baade hovednervene og det fra orebladene avvikende anasto- möse-net mellem disse. Makroskopiske fururester mangler totalt; hundrede- vis av haandstykker er undersøkt, men med negativt resultat. Derimot indeholder bladtuffen furu-pollen, som først av Dr. G. HoLMSEN paavist i haandstykker fra Bryrrs samling!. Da jeg i en anden forbindelse kom- mer til at diskutere spørsmaalet om furuens første optræden i Gudbrands- dalen?, skal jeg her noie mig med at præcisere, at vi vel maa anta at Pinus silvestris under denne periode levet.i dalen, men at den av klimatiske aar- saker har været løvtrærne helt underlegen”, Naar tre forskjellige tufdan- nelser paa rad nedover dalen fra Kvam til Lillehammer (cfr. Gillebu og Nedre Dal) viser noiagtig samme fænomen, saa kan man ikke længer tale om tilfældigheter. Man staar da overfor en lovmæssighet som kræver en tilfredsstillende forklaring. Sporsmaalet om pollenets langflugt kommer jeg senere tilbake til; hvor stor vegt man vil tillægge denne feilkilde, er fore- løbig i høj grad en trossak. — Forekomsten av furupollen i bladtufbænken er imidlertid et interessant fænomen, som fortjener vor største opmerksom- het. Det forandrer imidlertid ikke opfatningen av bladtuffen som et distinkt palæofloristisk ledenivaa i Gudbrandsdalens kalktuffer. De forvitrede bladtufrester som det lykkedes mig at fremfinde i utkilings- profilene baade i heire serie og 1 tverserien, viser med al ønskelig tyde- lighet at bladtuffen engang har overdækket” saagodtsom hele omraadet. Dog er det mulig, at dens magtighet altid har været størst der hvor den nu har sit maksimum, og at tykkelsen har avtat fra 1 Jeg har senere gjort pollenanalyser av kalktuf og iagttat forskjellige ting som er av interesse. For at undgaa feilkilder har jeg vasket tufstykkene meget omhyggelig og finknust dem og vasket tufpulveret paany. Dette er absolut nødvendig, idet saa- godtsom al tuf er porøs og indeholder forurensninger i alle hulrummene (avsat av ned- sivende vand). Man har ingen garanti for at disse forurensninger skriver sig fra det samme tidsrum som selve kalktufsubstansen; de kan være yngre. Ved Leine er hele tufavsætningen gjennemfiltrert av vand, og under gravearbeidet har man stadige ubehageligheter av kilden. — Jeg har fundet at efter en meget omhyggelig knusning og utvaskning indeholder selve kalktuffen bare smaa mængder av pollen, tildels minimale (opløsning i fortyndet saltsyre, efterpaa kokes bundfaldet med kalilut). I enkelte prøver finder jeg ikke spor av pollen. — Kalktuffen ved Gillebu er ogsaa uhyre let tilgjængelig for nedsivende regnvand og for strømninger i grundvandet. 2 Cfr. den generelle del. Forekomsten av Hippophaös ved Gillebu og de biologiske fænomener som knytter sig til denne, peker ogsaa i samme retning. Cfr. den generelle del. IQ2I. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 45 dette punkt og til sidene. — I det øverste profil i venstre-serien indeholdt bladtuffen et og andet Dryasblad, men uhyre sparsomt. Dette beviser at planten ogsaa under bladtuffens tid har eksistert langs tuffens overkant. Ellers er bladtuffen paafaldende ensformig og artsfattig uten variationer, hverken i vertikal eller horisontal retning. Kun nedenfor veien er der antydning til en ophobning av .Sa/ix-blader (S. cfr. nigricans). Som helhet betragtet tyder bladtuffen paa stor vandføring i bækken. Dette gjælder sedimentære lag i sin almindelighet. Noget brud mel- lem det underliggende mosetufkompleks og bladtuffen eksi- sterer ikke. De danner tilsammen en serie med den sterkeste tufdan- nelse til slut; dog er der som tidligere omtalt antydning til mindre oscilla- tioner i fugtighetsforholdene i periodens begyndelse. Dryastuffen. At denne merkelige og utpræget sedentære horisont maatte vække Brvrrs store interesse da han første gang fik oie paa den, er let forstaae- lig. Og dog synes Dryastuffen i Bryrts profiler ikke at ha været saa pragtfuld som fleresteds i de ovenfor beskrevne serier, hvor man faktisk kan ta ut det ene store stykke efter det andet som ikke bestaar av andet end Dryasrester. Dryastuffen har en meget karakteristisk graagrøn farve!, specielt i fug- tig tilstand. En undtagelse fra denne regel møter vi i profil I, hvor tuffen var rødlighvit eller svakt fiolet og eiendommelig sinteragtig (ujevn, vortet og knutet og med paralelle tynde, bølgende lag). Muligens har her cyano- fycéer lokalt været virksomme ved kalkutskillelsen. Paa enkelte punkter har Dryastuffen karakter av en mosetuf (cfr. BLvrr 1892 p. rr; her omtales en recent mosetuf av Hypnum filicinum fra Bardodalen i Tromsø amt, som ifølge BLyTT viser stor likhet med visse partier av Dryastuffen). Tuffindestedet ved Leine maa under denne periode ha frembudt et ganske enestaaende syn. Bakken maa paa forsommeren ha været et eneste hav av blomstrende Dryas. Det vedfoiede fotografi av Dryas i fuldt flor fra Hesjehompan i Saltdalen gir et indtryk av hvorledes markvegetationen saa ut. Nu er Dryas en utpræget xerofil plante, og da kalkkildens nær- meste omgivelser utvilsomt har været fugtigere end den øvrige del av bak- ken, ialfald til visse aarstider, maa man nødvendigvis anta at Dryas har været likesaa frodig, ja sandsynligvis endda frodigere rundt omkring tuf- findestedet, hvor man jo overalt har den kalkholdige jordbund. De forholdsvis sparsomme rester av bjerk, asp og andre løvfældende lignoser samt de spredte furunaaler tyder paa en meget spredt og aapen trævekst. Dryas er en utpræget lyselskende plante, som ikke taaler over- 1 Dette skyldes tuffens urene karakter. Furutuffen er derimot paafaldende ren kalk og gir tildels intet residuum ved opløsning i saltsyre. 4.6 ROLF NORDHAGEN. M.-N. Kl. skygning, og dens masseoptræden forutsætter med bestemthet at der ikke har eksistert nogen tæt sammenhængende skog paa stedet, saaledes som under bladtuffens tid. Som vi senere skal se, utder Dryas ganske tydelig ved Leine som en følge av furuskogens tiltagende tæthet i den efterføl- gende tid. Efter alt hvad vi vet om artens utbredelse i skandinaviske fjeldtrakter i nutiden, maa Dryas octopetala karakteriseres som utpræget xerofil og kalkyndende (cfr. A. CLEvE 1901 l. c., SCHROETER: Das Pflanzenleben Fig. 14. Dryadetum octopetalae paa kalkberg. Hesjehompan, Saltdalen i Nordland. Juli 1920. Nordhagen fot. der Alpen 1908 p. 182). Som Bryrr altid fremhævet i sine plantegeogra- fiske arbeider, er den knyttet til lose, smuldrende skifre (særlig kalkholdige) og kalkbergarter. Den elsker en varm og i vegetationsperioden ter jord- bund og optrær her associationsdannende. Svenske forskere adskiller ofte en lavrik og en mosrik ,,Dryas-hede"; men dette skille er temmelig tvil- somt og lar sig ikke altid gjennemføre i praksis, ialfald i visse strøk av den skandinaviske fjeldkjæde (cfr. SAMUELSSON 1916, hvor forholdene ved Finse omtales; i naturparken ved Sylene har jeg konstatert det samme). I det nordlige Norges kalk og dolomitstrøk, f. eks. mellem Ranen og Suli- tjelma, er Dryadeta octopetalae meget utbredt og synes her at være mere ekstremt xerofile end sydpaa (cfr. ogsaa FRIES 1913, TENGWALL 1920 |. c.). Ved Leine har man hat det særsyn, at et Dryadetum optrer som’ undervegetation i en meget lysaapen .skes 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 47 (om samfundet som helhet fortjente navnet skog, er et sporsmaal hvorom der kan disputeres). Sidste sommer iagttok jeg en motsvarighet hertil ute i naturen, nemlig i Junkersdalsuren i Salten, Nordland. Som en følge av eiendommelige edafiske forhold (stadige jordras og ophobning av talusma- teriale fra de stupbratte styrtninger i uren) er skogen her fleresteds meget aapen og indskrænker sig til smaa trægrupper (furu og løvtrær, særlig bjerk). Store matter av Dryas dækker her flekvis den kalkrike, ujevne bund}. Av de øvrige i Dryastuffen fundne arter indgaar Salix reticulata, S. herbacea, Pyrola minor og Equisetum variegatum allesammen i de av mig statistisk undersokte Dryadeta i naturparken ved Sylene (i Sor-Trondelag fylke). Salix reticulata er, som Brvrr fremholdt (l.c. p. 5), en plante „som paa vore fjelde trofast pleier at ledsage Dryas“; man burde ogsaa ha ventet at Thalictrum alpinum og Carex rupestris hadde været tilstede. Disse er imidlertid ikke fundet fossile. Sammenlignes nu denne sedentære horisont med den underliggende bladtuf, er kontrasten sterkt ioinefaldendeZ. Under Dryastuffens tid maa bekkens vandføring være svundet betydelig ind, og antageligvis har bækken været helt uttørret i sommertiden. Den tætte, xerofile Dryasmattes tilstedeværelse kan ikke forklares paa anden maate. Periodevis har vel bækken silret utover marken og avsat kalktuf, men ikke til stadighet. Undersøker vi de profiler nærmere hvor Dryastufkomplekset har sin største maegtighet, finder vi flere komplikationer. Saaledes tyder den i en række profiler forekommende ganske tynde, lagdelte og halvsedimentære horisont som er avsat ovenpaa Dryasmatten, paa en mindre opsvulmning i bækkens vandføring, dog ikke stor nok til at fordrive den sedentære vegetation (Dryas, Salix reticulata, Pyrola minor, Carex sp.). Den allerøverste del av komplekset er atter meget karakteristisk. I saagodtsom alle profiler meter vi her en opsmuldret, for- vitret, tildels leragtig sone med enten utydelige tufrester eller smaa biter indeholdende furu og Dryas. I Brvrrs profiler fandtes et virkelig grusblandet kalkler (4 cm. mægtig), utvilsomt et forvitringsprodukt; de i palæontologisk museums kalktufmonter utstillede prover fra BLyrrs samling viser dette. Av undertegnedes profiler er f. eks. nr. HI og X alleroverst ved stenroisen meget oplysende. Paa sidstnævnte sted fandtes en 2 cm. tyk graabrun jordagtig stripe, som over mot profil IX antok natur av seig lere, ovenpaa den opsmuldrede Dryastuf. Under oprenskning av dette pro- fils nordligste del viste Dryastuffen sig at være aldeles brun og forvitret 1 Merkelig nok syntes Carex rupestris, en av Dryas’s trofaste ledsagere, at taale beskyg- ning meget bedre end Dryas. Den optraadte i Junkersdalsuren fleresteds i skogbun- den (paa meget torre steder) i store masser. 2 Dog maa det specielt fremhzeves at der mellem bladtuffen og Dryastuffen ikke er spor av brud eller diskontinuitet i lagfolgen i de fuldsteendige profiler. 48 ROLF NORDHAGEN. M.-N. Kl. paa overflaten. Alle utkilingsprofilene i højre serie og i tverserien er 1 denne forbindelse ogsaa meget værdifulde. Her viser Dryastuffen sig at vere ytterst forvitret eller mangler helt, samt rdg med at ogsaa den underliggende bladtuf er vitret med tm ubetydelige rester. Isteden finder man brunlige eller olivenfarvete lerstriper paa disse tufhorisonters plads i lagfolgen. Dette faktum kan ikke forklares paa anden maate end ved den anta- gelse, at under en periode forut for furutuffens dannelse og efter bladtuf- fens tilblivelse, har kilden svundet saa sterkt ind at der over visse arealer av tuffens overflate ingen avsætning har foregaat, men tvertimot en for- vitring av den tidligere dannede kalktuf. Utkilingsprofilene og de øvrige ,fuldstendige serier taler her et samstemmig sprog, som. ikke kan fortolkes paa mere end en maaté Cm til en begyndelse blev avsat Dryastuf over hele tuffens omraade, vet vi ikke med sikkerhet. Det er meget mulig at der f. eks. i profil XX og XXI i tverserien, hvor ingen Dryasrester er opbevaret, aldrig har været nogen tufavseetning under denne periode, men kun forvitring. — Det karakteri- stiske Dryastufstykke som blev fundet nedenfor kjoreveien (profil XXII), viser at der ogsaa foregik kalkdannelse længer nede i bakken. Men alt i alt lar grænsene for Dryastuffens oprindelige horisontale utbredelse sig ikke fast- sætte med sikkerhet. Der er, som vi har set, antydning til en tredeling i Dryastufkomplekset. Men det allerøverste lag er gjerne vitret ned, undertiden ogsaa det mid- terste, halvsedimentære; dog er det ikke sikkert at dette har været avsat overalt!. Profil V i venstre serie og dets naboprofiler opviser enkelte træk av speciel interesse. Her er nemlig det alleroverste lag i Dryaskomplekset bedst opbevaret og ytterst eiendommelig. Man finder her en ca. 3 cm. mægtig overordentlig fin og sprød horisont, som jeg ovenfor har betegnet som „klidagtig“, fordi den har en viss likhet med det saakaldte klidbrød (som indeholder hveteklid). Den er meget porøs og aabenbarer ved nøiere eftersyn en utallighet av fine kanaler. Disse skriver sig fra meget tynde furunaaler, saa tynde og korte at hvis man ikke saa det karakteristiske halvmaaneformete tversnit og den typiske gruppering i naalepar, kunde man staa tvilraadig overfor deres natur. Da furunaalene baade i furutuffen og i det underliggende lag var store, brede og kraftige, fik jeg den tanke, at de ovennævnte fine avtryk maatte skrive sig fra sterkt opraatnede furu- naaler, hvor grønvævet var forsvundet og kun den centrale karstrengagtige del med omgivende skeder var tilbake. ^ Ved undersokelser i furuskogen ovenfor gaarden Veikle i Kvam, kunde jeg konstatere at denne tydning var 1 Oyen skriver (1920 l.c. p. 253) at Dryastuffen er tredelt med et egte Dryaslag i midten og et overgangslag nedad mot birketuffen og et opad mot furutuffen. Dette er, soma mine profiler viser, ikke ganske rigtig. I9Q2I. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 49 rigtig. Skogbunden var her tet dækket av nedfaldne recente naaler (saa- kaldt ,fald-forna" efter SERNANDERS terminologi 19181. c). Disse var ufor- andret, store og brede. Men dypere nede blev de sukcessivt forandret, mere og mere myke og tynde, og til slut fandtes en raahumus bestaaende av tæt sammenfiltrede eller sammenklæbede fine naaler, hvor bare de for- vedede elementer endnu holdt stand mot forraatnelsen. Naalene var ofte Brulkket over paa tvers i kortere stykker, og hele massen hadde den mest slaaende likhet med den i kalktuffen fore- kommende horisont. Dryas octopetala’s blader er ogsaa som bekjendt leragtige og ,eviggronne" og motstaar meget længe forraatnelsen, hvilket man kan iagtta paa gamle eksemplarer ute i naturen, som altid har en mængde indtørrede, gamle blader sittende paa stammene. Denne merkelige lille tufhorisont utdyper saaledes paa en udmerket maate billedet av naturforholdene paa stedet under den tid da kilden var meget reducert. Den viser os at furuskogen maa ha tyknet til; fjeldplan- tene gaar sin undergang imøte under den tiltagende beskygning; de sidste Dryasblader møter os her. Og kalkavsætningen synes at ha fore- gaat ytterst trægt; barnaalene har hat tid til at raatne op og danne raa- humus og er efterhaanden langsomt forvandlet til en sprød, smuldrende og pores tuf. Antageligvis markerer profil V og de tilstøtende profiler, som dog er mindre utpræget, det eneste sted indenfor tufomraadet hvor en fort- løpende, men mere og mere utpint avsætning har fundet sted. Dryastuffen indeholder de første makroskopiske fururester og tilkjende- gir dette træslags indvandring paa stedet. Dette beror utvilsomt paa en tiltagen 1 sommertemperaturen sammenlignet med bladtuffens tid. Under Dryastuffens tid synes lerbakkene ved Leine at ha været tørre og varme i sommermaanedene. Antageligvis har vintrene været strenge. Om Leine dengang laa ved furuens høidegrænse over havet, saaledes som BLYTT antok, eller om træet gik endda hoiere tilfjelds, kan ikke avgjores med sik- kerhet. Bryrr fremhæver at furunaalene i Dryastuffen er korte og smalere end i furutuffen, og tyder dette som et tegn paa relativt ugunstige kaar. Imidlertid viser den halvsedimentære horisont (midt i Dryaskomplekset) store, kraftige og brede furunaaler (flere 3,6—4 cm. lange), saa jeg tror ikke at man kan komme til nogen sikre resultater ad denne vei. At furunaalene i den sedentære Dryasmatte er smaa, kan muligens bero paa forraatnelse (cfr. det øverste, klidagtige lag). Forøvrig viser furunaalene i en recent skog meget. store variationer, alt efter deres stilling paa grenene og efter be- skygningen. Efter at ha diskutert spørsmaalet om tuflagenes geologiske alder kommer jeg i et følgende kapitel tilbake til de arktiske planterester ved Leine og deres betydning for spørsmaalet om fjeldplantenes utbredelse i Skandinavien i tiden før den postglaciale varmetid. BLiyrr anfører i sit arbeide ogsaa Cotoneaster vulgaris fra Dryaslaget ved Leine, dog under tvil; desuten opføres Betula nana og B. intermedia Vid.-Selsk. Skr. I. M.-N. Kl. 1921. No. o. ! 4 50 ROLF NORDHAGEN. M.-N. KI. samt Arctostaphylos officinalis som meget usikre. Jeg har selv hat an- ledning til at se disse avtryk og finder dem ogsaa meget problematiske og utydelige. Og vi gjør derfor rettest i ikke at ta dem med i det plante- geografiske ræsonnement, hvorpaa de forøvrig ikke influerer i nogen av- gjørende grad. Forresten er det slet ikke usandsynlig at de kan ha vokset paa stedet !. Av landsnegler er følgende arter iagttat i Dryastuffen: Cochlicopa lu- brica Mürr., Conulus fulvus Müıı., Ayalinia radiatula ALDErR og Pyrami- dula ruderata STUDER. Furutuffen. Da tufkilden i den efterfølgende tid atter begyndte at vælde frem med stor kraft, var stedet dækket av en dyster furuskog, for at anvende Brvrrs ord. Selv de allerunderste lag viser en enorm mængde med store furu- naaler, som danner et eneste løst, forkalket kaos. I et par profiler er der fundet antydning til litt mosetuf underst, men gjennemgaaende har furu- tuffen et sedimentært præg helt fra bunden av. Den i profil XVII og XVIII forekommende lerstripe (rød og blaa lere), som er skyllet ovenpaa Dryas- tuffen, tyder vistnok paa sterk vandføring helt fra begyndelsen av (i likhet med det sedimentære præg). Furutuffen er ellers meget ren og rødlig av farve. Ellers viser profilene adskillige variationer i vertikal retning, uten at egentlig bestemte gjennemgaaende horisonter kan paapekes. Og furutuffen er paafaldende ensformig; store masser av naaler, barkstykker, grener og en mængde furukongler gjenfindes overalt, desuten blader av Vaccinium vitis idæa. Den anden art V. uliginosum er betydelig sparsommere i sin optræden Mian faar et levende indtryk av at en tæt dues urskog av furu har behersket. Leinebakkene under Zdenwe Periode I furutuffens øvre del gjenfindes, ialfald i en del av de øverste profiler ved stenroisen, en sedentær horisont, som frembyr flere træk av inter- esse. De opbevarte rester av urteagtige planter (Cirsium heterophyllum, Fragaria vesca, Pyrola minor, Tofieldia palustris) samt Parmelia physodes tyder paa meget rask tufavsætning. De blote blader av Cirszum har ikke engang faat tid til at raatne op, ja de opbevarte kurver bærer tildels forkalkede rester av blomstene i sit indre (planche II, fig. 1). Horisonten er som nævnt meget fin og sprød, tildels mosetufagtig, og fossilfattig, men er antageligvis til en viss grad fysikalsk utfældt tuf. Fossilene tyder paa en mere englignende vegetation i bækkens nærhet under lagets avsætnings- I Naar Oyen i sit sidste arbeide opfører Betula nana, Cotoneaster og Arctostaphylos officinalis for Dryastuffen uten spor av reservationer, er dette efter min mening meget misvisende. Naar Brvrr, som kjendte sine arter ut og ind, satte sporsmaalstegn efter bestemmelsene, har vi ingensomhelst grund til at sloife dem! 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 51 tid. Højere oppe i lagfolgen moter vi imidlertid den samme kaotiske furu- tuf som længer nede. Fragaria vesca fortjener særlig opmerksomhet, da den er av en plante- geografisk set, sydlig type. Dog gaar den selv i nutiden paa lokalklimatisk særlig gunstige steder over 1000 m. o. h. i fjeldtraktene (RESvoLL-HoLMSEN 7920 |. c. p. 255). Tofieldia palustris, som er en typisk fjeldplante, viser at selv under denne periode har der vokset arktisk-alpine arter i Leinebakkene!. Dryas synes dog at være helt forsvundet. Brvrrs fund av Mnium punctatum og Peltigera canina „midt i bænken" (l. c. p. 4) tyder paa forekomsten av en lignende sedenter horisont længer nede i bakken. Av løvfældende trær optraadte folgende under furutuffens tid: Betula odorata og B. verrucosa, Populus tremula, Salix capræa (og muligens flere arter) og Sorbus Aucuparia. Ingen av disse arter er i klimatologisk hen- seende særlig oplysende, uten kanske Befula verrucosa. Bjerkeblader er vanskelige at bestemme paa grund av artenes store variationsvidde. Dog tror jeg at det av Bryrr fremfundne dobbelttandete blad (l. c. p. 12) og et lignende, som undertegnede fandt i et furutufstykke i profil XIX, maa hen- føres til Betula verrucosa, Denne art staar pea grænsen til vore kuldskjære lovtrær og gaar 1 almindelighet ikke hoiere end 4— 500 m. o. h. (Brvrr- Danur: Haandbog i Norges Flora 1906). Nordpaa gjør den et stort sprang fra Indereen til Salten, hvor konservator Ove Daur og undertegnede fandt den i Junkersdalsuren sommmeren 1920. Desuten kommer den igjen i Ost- Finmarken”, hvor den er indvandret fra Finland. Betula verrucosa og Fragaria vesca tyder begge paa at klimatet maa ha bedret sig betydelig siden bladtuffens og Dryastuffens tid. Da Betula verrucosa, som BrvrT fremholder, i nutiden er nær sin hoidegraense ved Leine (ca. 600 m. o. h.), maa man anta at klimatet under furutuffens avsætningstid ialfald ikke kan ha vaeret strengere end i nutiden?. Vi har her en minimumsgraense som er ganske værdifuld. Furutuffen har i likhet med bladtuffen oprindelig dannet et sammen- hængende lag over hele omraadet. At dens nuværende maksimum (pro- fil XX i tverserien) "betegner det sted hvor den ogsaa "oprindelig var mægtigst, er meget sandsynlig, men kan ikke bevises. Furutuffen hviler, som vi har set, diskordant paa Dryastufkomplekset (muligens med undtagelse av profil V, hvor der som ovenfor nævnt er svak antydning til kontinuitet), og viser ingensomhelst tegn til nogen overgangs- I Et eiendommelig avtryk i den undre Dryashorisont tilhører muligens ogsaa denne art (profil IV). Her er den nylig opdaget av forstmænd. 3 Hvor høit Leine dengang laa over havet, kan neppe siges med bestemthet, dog vistnok bo ikke lavere end 4 a 450 m. 52 ROLF NORDHAGEN. M.-N. Kl. sone mot Alnus-tuffen. Jeg skulde ogsaa være tilboielig til at tro at furu- tuffen ingensteds indenfor det undersøkte omraade opviser sin oprinde- lige mægtighet; den er overalt meget forvitret øverst, og man savner paa en maate en logisk avslutning av komplekset opad (f. eks. i form av en sedentær sone). Som helhet betragtet maa furutuffens tid ha været en livlig kalkdannende periode; derom vidner den betydelige mægtighet. Trækulrestene og de lokale kulstriper indenfor furutuffen paa forskjel- lige punkter viser, som Brvrr ogsaa nævner, at lynnedslag ikke var nogen sjeldenhet under denne periode. Ogsaa i Alnus-tuffen fandtes kulrester (profil XXI). Disse katastrofer synes ikke at ha influert paa kalkavsætningen i nogen paaviselig grad. Av landsnegler er følgende arter fundet i furutuffen: Conulus fulvus Müzz., Hyalinia radiatula ALDER og Vitrina pellucida MOLL. Alnus-tuffen. I likhet med bladtuffen og furutuffen er denne horisont saa karak- teristisk i petrografisk henseende at den kan gjenkjendes selv i smaa frag- menter: Farven er gjennemgaaende brunlig, og tuffen meget grov med store hulrum, bølget og valket og uten tydelig skiktning. Fleresteds har den karakter av grov mosetuf. Følgende arter er med sikkerhet konstatert i oretuffen: Betula odorata, Alnus incana (blader, talrike Q-rakler), Populus tremula, Salix caprea, Pinus silvestris (nogen faa, men tydelige naaler), Equisetum hiemale (talrike ledstykker), samt grove blader og straa av græs og Carices og flere sorter mos. Enkelte av de lose stykker fra muldlaget viser stor likhet med recente Cyanofyce-tuffer!. Tuffen gir gjennemgaaende indtryk av at vaere dannet temmelig raskt (cfr. mangelen paa utpræget skiktning). Profili XXI og de to profiler nedenfor veien, hvor Alnus-tuffen var bedst bevaret, viser at kalken tildels har været utfældt som jordagtig tuf, der alternerer med fastere sedentære horisonter: Paa dette punkt stemmer Leinetuffen med en flerhet av de svenske tufforekomster, hvor de alleryngste tuflag meget ofte er ytterst sprøde og sterkt forvitret (SERNANDER 1916 p. 129 og 160). Da rester av oretuffen er fundet over hele det undersøkte areal, viser dette at kilden ogsaa under denne tufavsættende periode har været ganske betydelig og har overrislet hele arealet. Jeg har for paapekt at A/nus-tuffen antageligvis har hat sit maksimum i de muldeagtige forsænkninger (op til 95 cm. i pro- fil XXI), selv om dette ikke kan siges med sikkerhet. Pollenundersekelser fra en række med haandstykker har bragt for dagen furu, or, bjerk og Salix-pollen, derimot ikke antydninger til 1 Folgende snegler er iagttat i Alnus-tuffen: Cochlicopa lubrica Mürr., Hyalinia radiatula ALDER, Pyramidula ruderata STUDER, Vertigo alpestris ALDER, samt Hydrobia Steini v. MART. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 53 gran. Da Leinetuffen under denne periode har været dækket av et fugtig orekrat med en englignende, hydrofil eller mesofil bundvegeta- tion (cfr. den recente preveflate som er beskrevet p. 8) og saaledes maa ha frembudt stor likhet med de nutidige forhold i Leinebakkenes fugtigere partier, kunde man ogsaa vente at finde rester efter gran, som likeledes optrær i den samme dalside (ialfald ikke mere end 1—2 km. vestenfor tuffindestedet) i nutiden. Men undersøkelsen har altsaa git et negativt re- sultat, hvilket kunde tyde paa at kalktufavsætningen var op- hart allerede forinden granen var indvandret til Kvam. Imidlertid utelukker ikke dette negative resultat en mere sporadisk fore- komst av gran i bygden. Det er ogsaa mulig, at de partier av Alnus-tuffen som nu tydeligvis er forsvundet, kan ha inde- Boldt spor efter granen. Alnus-tuffen er meget interessant derved, at den bygger en bro over til nutiden. Som i indledningen omtalt, er Alnus incana fremdeles et meget vigtig skog- og kratdannende træslag i dalskraaningene under Leine og langs Veikla. Man kunde ved første oiekast tro at dette forhold hoved- sakelig var fremstaat som et resultat av kulturpaavirkning (uthugst og op- rydning). Men kalktuffen viser os ganske tydelig at nutidsvegetationen har sine rotter langt tilbake i tiden. Alnus-tuffen utfylder et hul mellem furutuffens tid og nutiden; og det helhetsbillede som vi nu faar av Leinetuffen, er ganske anderledes har- monisk end tilfældet var tidligere da oretuffen ikke var kjendt, og da furu- tuffen saa at si braastanset, uten spor av overgangsled til stedets recente vegetation. Hvad der ligger mellem furutuffen og Alnus-tuffen, og hvorledes vege- tationen har artet sig paa voksestedet i dette tidsrum, er foreløbig hyllet i merke. Diskordansen og den sterke nedbrytning av furu- tuffen i tuffens nordre og sydøstlige del (nedenfor veien) mew at tufkilden har stoppet op; der, er ingen antyd- ning til overgang mellem furutuf og oretuf. Forvitringen har til og med grepet om sig endda dypere; saaledes er i profilene nedenfor veien baade Dryastuffen og bladtuffens øverste del forvitret. Dog foreligger her en anden mulighet, som ikke bør oversees, nemlig at baade Dryastuffen og de øverste lag i bladtuffen paa dette sted kunde være vitret ned alle- rede i slutten av Dryastuffens tid (saaledes som i profil XIX og XX); de to forvitringshorisonter skulde altsaa motes. Forovrig er den første even- tualitet slet ikke udelukket; ti furutuffen kan paa dette sted ha været meget mindre mægtig end hoiere oppe i bakken (det samme ræsonnement gjælder ytterprofilet i tverserien (nr. XXI)). Jeg skal foreløbig ikke opholde mig nærmere ved denne interessante diskordans, men isteden fæste opmerksomheten ved et andet forhold, som 54 ROLF NORDHAGEN. M.-N. KI. ogsaa er av betydning, nemlig Alnus-tuffens forvitring. Det er ganske klart at denne maa ha. foregaat mellem tuffens avsætnings- periode og nutiden. I vore dager er tufkilden forholdsvis beskeden og danner som før nævnt ubetydelige mængder av mosetuf hist og her. Vi har altsaa atter en oscillation i denne merkelige kildes kalkdannende virksomhet fra Alnus-tuffens tid og til nutiden, ledsaget av tydelig for- vitring. Og denne forvitring har ikke alene forvandlet oretuffen til ube- tydelige rester øverst i det stadig voksende muldlag over store deler av tufomraadet, men har ogsaa begyndt at angripe furutuffen, altsaa atter to forvitringsperioder som griper over i hinanden! Jeg haaber ved denne utredning, som ikke indeholder et eneste postulat, men som er en fuldstændig nøktern diskussion av Leinetuffen ut fra stratigrafiske, genetiske og plantegeografiske synspunkter, at ha vist at denne tuf hører med til vore mest interessante kvartærgeologiske av- leiringer. Opbygningen er helt lovmæssig og klar, og de problemer som knytter sig til den, fortjener den allerstørste opmerksomhet og alvorlig drøftelse. II. Kalktuf ved Gillebu og Tingvold i Qier. A. Topografi og vegetation i nutiden. I Oier, som ligger ca. 60 km. sydøst for Leine, gjør Laagen en bei- ning, som viser en paafaldende likhet med forholdene i Kvam. Den danner nemlig et utpræget S. Paa det sted hvor elven løper ret vest—øst, ligger Tingvold og Tolstad, og her kommer en liten bæk nedover skraaningen fra nord—nordvest og løper ut i Laagen. Bækken render langs en for- sænkning mellem den temmelig bratte Skarskampen (fig 15 tilvenstre) og Skjensbergkampen (tilhoire). Terrænget er her tæt bevokset med naaleskog og tilhører gaarden Gillebu, som ligger straks ostenfor. Gillebutuffen ligger omtrent halvveis oppe i lien i ca. 50 meters heide over landeveien ved Tingvold og i alt ca. 240 m. o. h., ifølge OYENS maalinger (1920 |. c.). Som i indledningen berørt blev tuffen opdaget av OYEN og HoLME sommeren 1917, efterat HoLmE allerede for mange aar siden hadde frem- fundet løse kalktufstykker i et grustak ved Tingvold, like i kanten av lande- veien. Disse to forekomsters beliggenhet og relation til hinanden vil frem- gaa av fig. 16, som gir et meget skematisk billede av forholdene. Da mine undersøkelser paa stedet i flere henseender gav betydnings- fulde resultater, som utvider kjendskapet til tuffens stratigrafi, skal jeg her gi en utførlig fremstilling av denne. Redegjørelsen blir i det hele tat en logisk fortsættelse av den beskrivelse som Oyen tidligere har publicert over denne interessante tufforekomst (1920 |. c.). 5 on 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. Den omtalte bæk, som nu er ganske ubetydelig i sommertiden, har, som fig. 16 viser, ved tilbakeskridende erosion gravet sig et markert leie i dalsidens løse dække, som bestaar av bundmorzene og bræelvgrus. Kalk- tuffen optrær nu kun som rester paa begge sider av bækken, og er like- som den øvrige del av skraaningen bevokset med naaleskog. Tra- bestanden i denne utgjores av gran og furu i blanding, dog mest av den forste. Bundvegetationen er fysiognomisk præget av Aylocomium parietinum og H. proliferum. Særlig den første danner pragtfulde grønne matter Fig. 15. Grustaket ved Tingvold og Gillebuskogen hoiere oppe. Bækken kommer ut av skogen mellem huset og telegrafstolpen og render over til venstre, bakenfor skigarden. August 1918. Nordhagen fot. mellem stammene. Associationens konstitution vil fremgaa av neden- staaende analyse, der omfatter 10 prøver à 0,25 m.?: de 5.ferste er fra bækkens østside, de 5 sidste fra vestsiden. Tallene angir daekningsgraden (HuzT-SERNANDERS 5-gradige skala). H to w EN on O\ -1 eo "TEN o Vaccinium xus Ta eee es eum SRE EN RE Bas ee a ES Seles nied borenlis: LE hein im wise Xs Soul oie EE Sal ules Sh) Calamagrostis arundinacea ........ Pe pc Me og Ua | et ae cl) Or RA a ED ED WT OLSC LE Git dan TER i reno 5 | Dee Hylocomium parietinum........... SAS ol Sul SR SAR AE | Be: 56 ROLF NORDHAGEN. M.-N. Kl. Hylocomium proliferum........... dues: 4| 1| 4| I] 4/0 Dicranum undulatum............. I 2 r| 1| r| zx] UM AOTOSUS S UMLEGK USE TN TUN ME — I Campanula Persictfona zn en: = I Carex. dii Qi. ARTE cy etat 2| a a | FOSU RO DIR MR OR NE oe I [| 2 — | — — | — _ — FLVCKACHUIN SD Fete OR EC =e a: 2 Juniperus communis (liten) ........ Fx els pe TI | Ei DOS I COKTACUIRTHS. ne: I - : = JANE DONNE t ee IT |— |—|— | — — | be Melampyrum silvaticum........... ES EEN — |) E (Oma asd cetosella: =. ee — I|—| 1! I -| r|—| a1] 1 Phegopteris Dryopteris — | —|— | 2|—}]—]|] — | — | — | — Phegopteris Robertiana —|— | — | — | — |— UN eae Pimpinella Saxifraga — |— | | — | Eic se erne eine) Lofer plejer tele Pirola chlorantha — | 11 — 1] 3} el ue | | 4 9 99 Rubus ideus NE ae 6, Uubinlie ele je je: © Jef le) celle me oy (øllet eje Rubus saxatilis zie — acu xs end Silene venosa Sorbus Aucuparia (liten) ll IP — aps eo 0/0 le" A ION TND Stellaria graminea — I OQ UO TOOL HD ket vælte Lolo stereo Vaccinium Myrtillus — | r{—|—]|--|— CELO ue) ise) ie) lehefoelele ere [A 270Y 28022 CMS PEL EE reg (AO ULE eel ne (Pees Dl dst VAGOSCVOCCO RIESCO TERR AU — I TI —= Viola collina zx de ee es ie ei | — Viola Riviniana — | — | — I —|—| — BY le) (e) ele lsh/a te lois Le enkelte. je. 6 Viola arenaria - I|—- Cladonia spp. 2-2. ple |e ee red ot o M 0 201 0 ON De GO er ine) ie] For Je) (eile, el" ere Cladina silvatica —}|—}—|—]—| 7 Dicranum majus — ass ee) : Sod OG OO ket seler te "ere, ele Dicranum scoparium WLU ECHOUMAPNIOSE: hs 8 eee ox | |) oe ae | ee OD FICRAMESD In TN dese 1 licen Tabellen viser os en tæt mosmatte med meget spredt bevoksning av tyttebær, Linnea, jordbær og Calamagrostis arundinacea. Av de øvrige arter kan merkes Oxalis Acetosella, Carex digitata og Pirola chlorantha. Bekkedalens skraaninger var meget lose og lite stabile. Naale- skogen gaar tildels nedover bratten, men gjennemgaaende ser man her en aapen vegetation, som er temmelig vekslende og ganske artsrik: 1921. No. 9. Antennaria dioica Arabis. hirsuta Arenaria serpyllifolia Calamintha Acinos Echinospermum deflexum Epilobium montanum Erigeron acer Festuca ovina Galeopsis tetrahit Galium verum Hieractum Pilosella Hieracıum spp. Knautia arvensis Lathyrus pratensis Linaria vulgaris Lotus corniculatus KALKTUFSTUDIER I GUDBRANDSDALEN. 57. Melica nutans Moehringia trinervia Myosotis arvensis Origanum vulgare Phegopteris Robertiana Phegopteris Dryopteris Pimpinella Saxifraga Sedum album Sedum maximum Stellaria graminea Trifolium medium Trifolium pratense Verbascum nigrum. Verbascum Thapsus Vicia cracca Viola collina Artslisten minder delvis om den for Leinebakkene anførte og viser en række sydlige typer. Bækkedalens bund var tildels ganske fugtig. Her vokste spredte trær og busker: Alnus incana, Picea excelsa, Prunus Padus, Rhamnus Frangula. Bundvegetationen bestod av mesofile, tildels hydrofile græs og urter. De kvantitativt fremherskende arter var følgende: Aconitum septentrionale Aera cespitosa Agrostis vulgaris Brunella vulgaris Circea alpina Impatiens noli tangere Knautia arvensis Leontodon autumnalis Oxalis Acetosella Pteridium Aquilinum Ranunculus repens Rumex Acetosa Stachys palustris Stellaria nemorum Taraxacum officinale Trifolium repens Tussilago Farfara Ulmaria pentapetala Valeriana sambucifolta Desuten fandtes nedenstaaende arter i mindre mængde: Achillea Mille- folium, Alchimilla vulgaris, Anthriscus silvestris, Artemisia vulgaris, Athyrium Fılix femina, Caltha palustris, Campanula rotundifolia, Carduus crispus, Carum Carvi, Cerastium vulgatum, Chrysanthemum Leucanthemum, Cystopteris fragilis, Dactylis glomerata, Epilobium montanum, Festuca rubra, Fragaria vesca, Galeopsis tetrahit, Galium palustre, G. uliginosum, Geum rivale, Glechoma hederacea, Hieracium Auricula, Mentha sp. (steril), Phego- 58 ROLF NORDHAGEN. M-.N. Kl. pteris polypodioides, Plantago major, P. media, Poa nemoralis, Poa pratensis, Polygonum viviparum, Ranunculus acer, Rumex Acetosella, Rubus idæus, Silene venosa, Solanum Dulcamara, Stellaria media, Struthiopteris ger- manica, Trollius europeus, Urtica dioica, Verbascum nigrum, Veronica officinalis, Vicia sepium, Viola canına, V. Riviniana, V. umbrosa. Av mo- sene i bunden var C/imacium dendroides en av de mest fremtrædende. — Flere av de opregnede arter er utvilsomt indkommet paa stedet med beitende kreaturer; skogen anvendes nemlig tildels som havnehage. Forøvrig er planteveksten i Oier lite kjendt. De bratte styrtninger under Skarskampen like vest for kalktuffen opviste ganske mange interessante arter, tildels de samme som ovenfor er omtalt fra baekkedalens sider. Carex muricata, Geum urbanum, Turritis glabra, Viscaria vi- scosa, Triticum caninum og Po- lygonum dumetorum anfores her som et supplement til oven- nævnte liste. Forekomsten av Polygonum dumetorum var gan- Fig. 16. Kalktuffen ved Gillebu (K) og dens forhold til gruskeglen ved Tingvold (G). Kı—Kı = kalktuf ske overraskende, da denne art transportert ovenfra av bækken. Meget skematisk. die ere ikke var kjendt længer nord end paa Ringerike i det ostenfjeldske Norge. Langs kysten optrær den meget sparsomt inde i fjordene til nordsiden av Trond- hjemsfjorden (Fosen 63? 50‘). Efter disse orienterende bemerkninger om vegetationen paa kalktuffen og i dens nærmeste omgivelser, skal jeg gaa over til at beskrive de strati- grafiske forhold. B. Stratigrafiske undersøkelser. Kalktuffen i Gillebuskogen er som antydet paa fig. 16 opbevaret paa "begge sider av bækken i ca. 50 meters hoide over landeveien. Hoved- massen ligger i nutiden paa vestsiden av bækkedalen. Imidlertid maa fore- komsten i tidligere tider ha været meget større; man finder nemlig tufrester højere oppe i lien (antydet paa fig. 16) og længere nede. Paa det nederste med K betegnede sted paa figuren ligger der dog bare løse blokker, saavidt jeg har kunnet se; disse kan tænkes at være ført ovenfra og nedover under en eller anden flomkatastrofe. Avstanden mellem den allerøverste fore- komst og den sidstnævnte noget tvilsomme blev ved maaling med staal- traadline fundet at være ca. go m., og avstanden mellem de mest perifere I92I. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 59 tufrester paa baekkens vestside og dens østside (maalt tvers paa bækkens længdeakse) 30 m. Efter tuffens opdagelse har adskillige personer besokt findestedet, og efter ytringer som de har latt falde, synes enkelte at ha dannet sig den opfatning av forholdene, at ,der er avsat litt tuf paa begge sider av bækken", Imidlertid vil den følgende fremstilling vise at det her ikke er tale om to eller flere selvstændige tufavsætninger, men om restene av én, stor sammenhængende kalktuf, saaledes som OYEN allerede fra første stund av var klar over. Dog maa man selvsagt finde sig i at der blir avkrævet én absolute, haandgripelige beviser naar man fremsætter en saadan antagelse. I denne henseende er nedenstaaende profil av av- gjorende betydning. Profil I paa bækkens ostside. ØYEN anfører herfra et profil, som over morænegruset i bunden viser tre tufforende horisonter. I det overste lag fandtes et stykke med furu- naaler, men ,paa grund av et antal meterstore blokker stikkende op av moraenegruset, blir stillingen av serie 2 og enkelte lag av serie 4 tildels noget dubios, idet de begge antar paa sine steder karakteren av koncentriske kalktufkruster omkring blokkeoverflaten" (OYEx I. c. p. 287). For ØYEN og HorwE var dette profil meget avgjorende, idet de nemlig paa grundlag av de i gruskeglen ved Tingvold (cfr. fig. 16) fundne lose tufstykker nødven- digvis maatte treekke den slutning, at baade et bladtufkompleks og et furu- tufkompleks maatte eksistere in situ hoiere oppe i dalsiden. Bladtuffen fandt de med engang, men av furutuffen saaes bare det ene stykke som er om- talt ovenfor. Den opgave som undertegnede stillet sig, var da for det forste at grave op et stort og helt tydelig profil paa denne side av bækken, og dernæst at lete efter mulige furutufrester. Heldigvis var der like for min ankomst til Oier opkastet en grøft paa stedet for at faa konstatert om tuffen var saa betydelig at den hadde nogen økonomisk betydning. Med utgangspunkt i denne grøft fik jeg oparbeidet et meget vakkert profil, som hadde følgende utseende: I. Grovt morænegrus med større og mindre blokker av kvartsit, skifre etc. Midt i profilet laa 2 store avrundede blokker. Gruset var brunt og gjennemgaaende sterkt oksydert. Il. Bladtufkompleks, tilsammen 45—50 cm. A. Underst kom en I0— 20 cm. sterkt jernholdig, rustbrun til choko- ladefarvet tuf, som var tydelig lagdelt og temmelig los og sprod. Paa tuffens underflate masser av Hippophaés-blader, ellers byerk- og Salix-blader i mængde. B. Kaotisk, foldet og valket graagul bladtuf, 20—23 cm., med mængder av bjerkeblader, porøs og lakunes og meget los. 60 ILE. IV. ROLF NORDHAGEN. M.-N. Kl. C. Utpræget lagdelt, fossilfattig, gul tuf, 5—8 cm.; temmelig kompakt med smukt foldede lag, men sprød og let at trænge igjennem. Lagene kan let løsnes fra hinanden og viser sparsomme bjerke- blader (5. odorata) paa flaten. Jordstripe, 5—8 cm., bestaaende av brunlig, fin tufblandet jord uten haardere klumper. Optil var den undertiden mere graahvit av farve. Furutufkompleks, ca. 30 cm. A. 1,5—3 cm. smukt laget, gul, fossilfri tuf; knækkes let over med ET wt w 5 Fig. 17. Profil fra baekkens østside, Gillebu. Nederst moræne, derover bladtuf. Korsene angir jordstripen. Øverst furutuf og muldlag. (Cfr. beskrivelsen i teksten). August 1918. ve Nordhagen fot. fingrene. Over denne fandtes en uhyre tynd (0,5 cm.) brunlig stripe. B. 25—27 cm. furutuf, nedtil eiendommelig konglomeratagtig med bittesmaa gronblaa, avrundede kvartsitbiter, sammenkittet med smaa tufbiter, samt furunaaler, der var fossilificert som tynde ror eller dobbeltrer (naalepar). Derover kom meget los furutuf med masser av naaler, en kongle, blader av tyttebaer (sparsomt) samt bjerkeblader. Tuffen var tildels bolget-knudret og drypstensagtig, altid meget let, pores og sprød. Paa. de fleste punkter var kompleksetrz sammenwitret til et lost smuldsende kaos av tufstykker. 15 cm. muldjord; øverst 3 cm. humus av Hylocomier. 2927. NO. 9. KALKTUFSTUDIER 1 GUDBRANDSDALEN. 61 Fig. 17 viser en del av profile. Den underste papirremse avmerker „jerntuffens“ grænse mot det underliggende morænegrus; den utfylder ogsaa mellemrummet mellem de to store blokker og kitter disse fast sammen. Papirkorsene er fæstet i jordstripen mellem bladtuffen og furutuffen. Mellem kors nr. 2 og 3 fra venstre markerer en tynd horisontal papirstripe den ,knækkelige” tuf underst i furutufkomplekset. Av billedet og den skematiske figur 18 ser man at alle tuflagene helder estover, hvor de desuten blir smalere. Desuten skraaner alle lag ganske sterkt ret imot iagttageren. Disse stratigrafiske eiendommeligheter beviser at tuffen umulig kan være avsat av en kilde fra ost eller nordest. Den eneste mulige tydning er den, at Im. Fig. 18. Profil fra bækkens østside, Gillebu. I = Morænegrus med blokker. II = bladtuf- kompleks. III = jordstripe. IV = furutufkompleks. Øverst raahumus og muld. lagene engang har fortsat sammenhængende over tilvenstre, urglasformig, men senere er blit borterodert av baekken. Dermed er sammenhængen med tufmassene paa bækkens vestside git, og vi kan med sikkerhet paastaa at Gillebutuffen oprindelig har ligget som en skjoldformig masse over det sted hvor nu bækken har sit lop. Profilet viser ogsaa at furutuffen er ytterst forvitret og daarlig opbe- varet. Dette fænomen er endda mere fremtrædende paa baekkens vestside. Protl IL. Vestsiden. Profilet er optat vis à vis I, men noget mere mot nord, og like i randen av bækkedalen. I. Grovt oksydert grus. II. Morkebrun, jernholdig tufjord, 4 cm. Denne sone manglet hvor der laa større stener i bunden. II. A. Jerntuf, ca. 36 cm. Nedtil var den sterkt brunfarvet og hadde en slaaende likhet med utbrændt koks. Mange blader av Hippo- phaés, Betula odorata, Populus tremula, Salix Sp. 62 ROLF. NORDHAGEN. M.-N. Kl. B. Haard bladtuf, 15 cm., i midten noksaa uregelmæssig, men optil og nedtil smukt laget. Den var jevnt forbundet med foregaaende. IV. Les tufjord, ca. 8 cm., med lose biter av en skjor, laget tuf. V. Muld og raahumus, 15 cm. I dette profil er bladtuffen vakkert utviklet og stemmer udmerket med foregaaende profil. Furutuffen derimot er helt forsvundet paa dette sted. Prom ME Veen Profilet ligger ca. 8 m. fjernet fra foregaaende og ret i vest for dette. I. Grovt grus, med knytnævestore avrundede stener, sammenkittet av kalktuf til en sammenhængende meget haard masse. Det kunde for- følges til 40 cm. dyp. II. Derpaa fulgte et kuriost brunt lag, bestaaende av taet sammenfiltrede "levende og døde rotfibre. Det kunde flækkes av som en filt, 0,5 cm. tyk. Aarsaken til lagets forekomst maa sokes i det underliggende ugjennemtrængelige lag, som tvinger den recente vegetations retter til at forgrene sig horisontalt langs lagets overflate. III. Bladtufkompleks, tilsammen 20— 25 cm. A. Les jordagtig tuf, 5 cm. B. Bladtuf, les og sprød med bjerkeblader i stor mængde, 10— HS cm. C. Overst 35 cm. lagdelt sone, som ligner II. € i profilsl IV. Tufholdig jord, 15—20 cm., med talrike tufbiter fra nettestore til (15 X 10 < 7) cm, med sparsomme /urunaaler, især nedtil, dog i et par stykker i mængde. Desuten rester av en laget, knækkelig og sprød tuf. Laget hadde fleresteds karakteren av les jord fra øverst til nederst. V. Muldjord, 10—ı5 cm., med skiferbiter. "Øverst 3—4 cm. raahumus av Hylocomier. Profilet var helt igjennem temmelig lost og gjennemsat av træretter. Interessant var det at finde furutufstykker paa dette sted; de var dog meget forvitret og smaa. Ogsaa bladtuffen synes at kile ut vestover. Profil IV. Vestsiden. Omtrent 1,5 m. nordvest for foregaaende profil kiler tuffen helt ut. Her saaes folgende serie: I. Grovt, stenblandet grus med avrundede stener, brunlig av farve (oksydert). I. Brun tufjord, 5 cm. Fin og jevn. III. Furutuf, 3—4 cm.; dannet en fast plate med tydelig lagning. IV. Les tufjord, 15 cm., med spredte furutufbiter. Rikelig med furunaaler samt et aspeblad. V. Muldjord med skiferbiter, 25 cm. Overst som vanlig raahumus. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 63 Dette utkilingsprofil er meget interessant. Bladtuffen er her forsvundet, og underst findes bare brun tufjord. Derimot er furutuffen meget tydelig opbevaret i sammenligning med andre steder i nærheten, og viser at av de to hovedlag i tuffen, har furutuffen transgrediert længst utover til siden. Profilet viser (i likhet med de øvrige) at furutuffen hviler diskordant oven- paa det underliggende; ti der er ingen overgang mellem bladtuf og furu- tuf. Den brune jord paa bunden er muligens fervitret bladtuf, men svarer vel snarere til jordstripen i profil I. Profil V. Vestsiden. Dette er optat omtrent 3 m. sondenfor profil HI og like i kanten av bækkedalen. I. Grovt grus med storre og mindre stener, oksy- dert. Il. Bladtufkompleks. A. Jerntufhorisont, 3— 4 cm., mork av farve, tildels sandet. Laen- ger vest i grøften var den Io cm. og jevnt laget. B. Eiendommelig laget, haard tuf, roo cm., avsat skalformig om- kring større og min- Fig. ro. Profil V paa bækkens vestside. Den eien- dre stener. Cfr. fig.19. : ates : dommelige konglomeratagtige tuf, avsat skaliormig III. Muldjord med stener og : A URN 3 omkring stenene, sees midt i billedet. August 1918. smaa forvitrede tufbiter, Na de non 20 cm. En speciel interesse knytter sig til lag II. B. Det synes at bestaa av fysikalsk utfældt, næsten krystallinsk tuf, avsat kuleskalformig.omkring runde stener, og viste en meget fin lamellert veksling av rødbrune og gulagtige lag, som uten tvil er uttryk for en viss periodicitet i avsætningen. Det er mulig at vi her befinder os i nærheten av det oprindelige leie for den kalk- avsættende bæk, eller rettere sagt: der hvor strømmen i denne har været sterkest. Profil VE "Vestsrden. Længer vest i samme grøft, men samtidig noget lavere i terrænget, saaes folgende lagrække : I. Stenblandet grus som i foregaaende profil, med flere svære blokker. 64 ROLF NORDHAGEN. M.-N. KL II. Bladtufkompleks, tilsammen ca. 50 cm. A. Jerntuf, ro cm., typisk, med Æippophaës og bjerkeblader. B. Laget tuf, 20 cm., jevnt forbundet med foregaaende. C. Los bladtuf, 15—20 cm., tildels rent kaotisk med masser av bjerke- blader, desuten sparsomt /ippophaës og Salix caprea. Mellem D. og C. fandtes ganske lokalt en 2 cm. tyk stripe av tuflere; den forsvandt til begge sider. D. Øverst fandtes en ganske tynd (0,5 cm.) lagdelt sone belagt med chokoladefarvet overdrag. III. Tufjord med løse tufbiter, hvori en og anden furunaal, desuten stykker av en noget lagdelt, sandet tuf. IV. Muldjord, 20 cm. Profilet er alt i alt helt normalt, >: det stemmer med de foregaaende. Det gik kontinuerlig over i det sidst beskrevne (V), saa horisonten Il. B i dette er bare at opfatte som en speciel horisontal facies av bladtuf- komplekset. C. Oversigt over Gillebutuffens stratigrafi. Fig. 20 viser et svakt skematisert tverprofil omtrent lodret paa bækkens længdeakse, altsaa V—Ø. Det er basert paa profilene I, II, III og IV. Morænegruset. Tuffens underlag bestaar av et stenblandet grovt grus, som undertiden fører større blokker. Det gir indtryk av at være vandslitt og noget ut- vasket. Ellers frembyr det ingen specielle træk av interesse. Det maa oprindelig ha dannet en sammenhængende masse der hvor bækkedalen senere er skaaret ned (I paa fig. 20). I sin øverste del er gruset meget sterkt oksydert, rustbrunt til chokoladefarvet; det maa altsaa ha ligget aapent for forvitring i tidsrummet mellem sin avsætning og dannelsen av de første tuflag. I flere profiler var gruset øverst sammenkittet av utfældt kalk til en konglomeratagtig masse. ; Dladtuf komplekset. Som ovenfor antydet, er de først avsatte tuflag ytterst karakteristiske. De er morkfarvede, rustbrune til chokoladefarvede, undertiden svakt blaalige, hvilket beror paa kalkens sterke forurensning med jernforbindelser. » Jern- tuffen“ viser altsaa at da kildene paa stedet begyndte sit lop, indeholdt jordbunden store mængder av oksydations- og forvitrings- produkter, som utfældtes sammen med den kulsure kalk. Jern- tuffen ser i sin mest ekstreme form ut som gammelt rustent jernskrap eller koksslagger, og blir op til 30 cm. mægtig. Den er tydelig skiktet og danner 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 65 hyppig kruster omkring morænegrusets blokker, og viser derfor en meget valket overflate. Naar man bryter tuffen løs og faar væltet stykkene om, saaledes at underflaten blir fri, blir man overrasket ved at finde avtryk av Hippophaés- blader hobet paa hinanden i store mængder. Jerntuffen viser os et avtryk av bakkens overflate ved tufavsætningens begyn- delse. Desuten sees blader av Betula odorata og Salices, hvorav en del vakre avtryk vistnok tilhører Salix phylicifolia, men ogsaa andre arter synes at vere repræsentert, f. eks. S. capræa. Imidlertid er .Sa/ix-blader overordentlig vanskelige at bestemme i fossil tilstand. Talrike mellemformer av hybrid natur kjendetegner jo specielt denne slegt, som til og med spe- dos nek Me, € an orm Fig. 20. Tverprofil av Gillebutuffen. I = morænegrus. II = bladtufkompleks med jerntuffen nederst. III = furutuf. Hoiden er overdrevet to ganger i forhold til horisontalutbredelsen. cialistene har vanskelig for at mestre. Det er indlysende at artsbestemmelsen for de fossile Salices’ vedkommende maa bli endda mere dubies, da alle de saakaldte ,habituelle" kjendetegn (farve, behaaring, voksemaate, bla- denes konsistens etc.) er meget utvisket eller mangler. Jerntuffens underside har undertiden en heist eiendommelig traadet struktur, som minder svakt om mosetuf, men som muligens ogsaa kan skyldes blaagronne alger. Nogen tydelig mosetufbænk saaledes som ved Leine foreligger ikke; avsætningen har helt fra begyndelsen av sedimen- tært præg paa de fleste steder, og turde være fysikalsk utfældt i stor ut- strækning. Over jerntuffen følger oftest vekslende tuflag av vanlig graagul farve, hyppig sterkt kaotiske, med løvblader fossilificert 1 alle mulige planer. Mange blader viser sig at være forkalket i helt fri stilling, 2: det oprinde- lige blad er helt erstattet av kalk, som fuldstændig har antat bladets form, nervatur og tanding. Visse partier av bladtuffen maa derfor sandsynligvis være dannet meget raskt, idet man vanskelig kan tænke sig en saadan for- Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. o. 5 66 ROLF NORDHAGEN. M.-N. Kl. kalket uordentlig bladmasse, der viser den største likhet med netop ned- faldent, rotet løv om høsten, som en sekulær avsatning!. I denne blad- masse finder man hist og her mindre, lose mosetufpartier, over- ordentlig vakre, med frie, ortotrope skud (op til 5 cm. lange). Ogsaa disse lag synes at være dannet temmelig raskt. Opad avsluttes komplekset som oftest, og specielt i de mindst for- vitrede deler av tuffen, med en utpræget lagdelt søne, som viser tydelig og vakker lamellering, et sikkert vidnesbyrd om periodicitet i av- sætningen. Lagene er tildels meget tynde, og denne øvre sone synes i motsætning til den underliggende løse tuf at være avsat gjennem længere tidsrum med noget svakere vandføring i bækken end tidligere. — Hippophaés rhamnoides findes spredt gjennem hele bladtufkomplekset og er temmelig almindelig, men bladavtrykkene er ingensteds saa talrike som paa jern- tuffens underside. Som helhet betragtet er bladtufkomplekset uhyre trivielt og artsfattig i palæofloristisk henseende, mens kvantiteten derimot er desto mere fremtrædende. I denne henseende ‘er overensstemmelsen med Leine- tuffen slaaende. Betula odorata, Hippophaës rhamnoides, Populus tremula, Salix caprea, S. phylicifolia, Salix cfr. nigricans samt en eller et par mos- arter — dermed er materialet uttomt. Chancene for ved nye gravninger at finde flere arter er uhyre smaa; ti baade OYEN og HoLmE og under- tegnede har undersokt hundredevis av haandstykker uten at bringe nye former for dagen. Heller ikke de paa sekundeert leiested (i Tingvoldgruskeglen) fremfundne typiske bladtufrester gir nye oplysninger om floraen paa den tid. Oyen anforer herfra (l.c. p. 273) bl. a. Vaccinium vitis idea og Alnus incana efter Danis og undertegnedes bestemmelser. Jeg har senere gransket disse stykker nærmere og tror at vi gjør rettest i at sætte den sidstnævnte art ut av betragtning, da bestemmelsen nu, efter at jeg har hat anledning til at gjennemgaa mit eget store materiale og svenske samlinger, forekom- mer mig ganske tvilsom. Ovenstaaende skildring viser det typiske bladtufkompleks’ utformning. Imidlertid moter der os adskillige horisontale facies. Av disse er den kon- glomeratagtige tuf i profil V tidligere omtalt. De eiendommelige sfæriske kalktufskaller med den fine lamellering og den likefrem krystallinske struktur tyder paa fysikalsk utfældning i strømmende vand?. Midt inde i saadanne agat-lignende kuler har jeg paa lagflatene fundet bladavtryk av Hippophaés og bjerk. Hvordan den gjentatte veksling av rødbrune og gulagtige lag skal fortolkes, tor være tvilsomt. Man kunde tænke paa vaarflom i bækken led- saget av sterkere avsætning (gulagtige lag) og en trægere utfældnimg ut- over sommeren (brunlige lag). Men lagene varierer saa sterkt i tykkelse at jeg ikke vover at paastaa noget med bestemthet. — Ogsaa i andre profiler 1 Cfr. Leinetuffen, hvor bladtuffens karakter overalt var en helt anden. 2 Da de runde stener i laget ligger helt omgit av tuf, kunde man vere tilboielig til at tro at bækken har revet stener med sig ovenfra i flomtiden og avsat dem længer nede. Ogsaa dette moment peker hen paa at vi her befinder os nær bækkens centrale del- 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 67 meter man antydning til lignende forhold, f. eks. paa det aller øverste sted i bakken hvor der anstaar tuf. Her er lagene sterkt forvitret, men den samme kuleskalstruktur (omkring runde stener) er her smukt utviklet (fig. 21). I skraaningen paa baekkens vestside, like nedenfor profil II, hadde jern- tuffen en besynderlig breccieagtig struktur, idet den bestod av et utal av smaa tufbiter, som atter var sammenkittet av utfældt tuf. Hvordan dette fænomen genetisk set skal forklares, er meget usikkert. Man kunde tænke sig glidninger, opknusninger og forskyvninger i den først avsatte tufmasse, kanske ogsaa sprængninger foraarsaket av isdannelse. Enkelte partier av bladtuffen minder ogsaa sterkt om cyanofycé-tuf. Men desværre vet vi endda saa overordentlig litet om sam- menhængen mellem kalktuf- fenes dannelsesmaate og deres struktur, at en gene- tisk klassifikation foreløbig er utelukket. SERNANDERS interessante ,genetiska bi- Mao (1916 |. c.)-er i vir- keligheten det eneste sikre som hittil er fremkommet i skandinavisk litteratur ved- rorende dette overordentlig vigtige emne. Vi maa derfor foreløbig finde os i at an- Fig. 21. Fint skiktet kalktuf, avsat skalformig omkring vende mere eller mindre ufuld- = : en sten. (Det undre lamellerte stykke har sittet uten- komne, morfologisk-petrogra- T. zem tne paa en anden sten, horer altsaa ikke sammen med fiske analogibetegnelser som ace) BET irn Ut „einter-agtig , ,drypsten-ag- tig“, „breccie-agtig“ tuf o. s. v.!, som i virkeligheten ikke sier noget ab- solut sikkert om dannelsesmaaten. Paa den skematiske figur 16 er ogsaa avmerket det aller nederste sted i baekkedalen hvor kalktuf er paatruffet. Her fandtes bladtufblokker i jorden, som var optil 25 cm. tykke og sterkt forvitret i overflaten. Tuffen var optil smukt skiktet med talrike store blader av Salix capræa, desuten bjerk og Hippophaës, men var delvis mere kompakt og haard end ellers. En blok viste tydelig mosetufstruktur paa undersiden. Som tidligere antydet foreligger der den mulighet, at disse blokker her befinder sig paa sekundært leiested og egentlig hører hjemme hoiere oppe i lien. Jordstripen. Denne er bare tydelig opbevaret paa bækkens østside, hvilket hænger sammen med at furutuffen her ogsaa er bedst vedlikeholdt. I de øvrige | Cfr. Øvens ,konkretionsagglomerat" etc. (Naturen 1918). 68 ROLF NORDHAGEN. M.-N. Kl. profiler er furutuffen saa forvitret at man oppaa bladtuffen kun finder et tykkere eller tyndere jordlag med stumper og stykker av furutuffen; og det er da ganske klart at den oprindelige lagraekke: bladtuf—jords:ripe —furutuf er utvisket. Profil I er derfor saerlig vaerdifuldt, idet det viser os en tydelig dis- kordans mellem de to hovedlag. Der er ingen overgang at spore. Lik- heten med Leinetuffen er for saavidt slaaende. Imidlertid finder vi ved Gillebu ingen spor efter nogen Dryasforende horisont. Og der blir heller ikke, som profil I viser, nogen plads for en saadan, idet baade bladtuffens avslutning og furutuffens begyndelseslag er meget karakteristiske og let kjendelige. Oyen antyder i sit arbeide (I. c. p. 284) at der muligens kan ha vaeret avsat Dryastuf ved Gillebu, da han i det for omtalte furutufstykke paa baekkens ostside fandt et blad der mindet om Salix reticulata. Det er senere ødelagt under transporten, da det var meget skjort. — Imidlertid har jeg selv baade i bladtuffen og furutuffen fundet lignende smaa rundagtige Salix-blader, som ikke er Salix reticulata, da nervevinklene og strukturen er helt anderledes end hos denne art. Des- uten var de altfor tynde og sprøde; Salix reticulata er altid meget solid og grov selv i fragmentariske avtryk, paa grund av sine tykke læragtige blader. Jeg har som sagt ikke set spor av denne art eller Dryas i nogen av de profiler som jeg meget omhyggelig har studert. Og profil I viser at der ikke er plads for nogen Dryastuf, da jordstripen kommer ind i dens sted. Som vi senere skal se, er Dryastuffen som saadan et lokalfænomen ejendommelig for Leine. Det generelle moment derimot ligger i diskordansen mellem bladtuffen os furutuffen. Furutuffen. Denne tuf er paafaldende los og sprød, hvilket utvilsomt er aarsaken til at den er saa sterkt forvitret. Imidlertid har selvsagt forvitringen bi- dradd sterkt til at gjøre tuffen endda mere skjer og porøs end den var oprindelig. Komplekset begynder med en ganske specifik dannelse, nemlig den fossilfrie, knækkelige tuf, som utgjør en egen: plate underst. Rester av denne er ogsaa fundet paa bækkens vestside. — I profil I er som nævnt furutuffen tildels konglomeratagtig med tilblandede smaa runde stener, hvilket kan tyde paa sterk vandføring i bækken. Enkelte partier var sterkt knudret og valket, tildels avsat som cylindriske rør omkring kvister og pinder, der dannet tynde kanaler gjennem tufmassen. Artslisten er meget beskeden: Pinus silvestris (naaler, en kongle, grener, bark etc.), dyerk (mange fragmentariske blader, hvoriblandt sikker B. odorata), Populus tremula, Salix sp.', Vaccinium vitis idea (sparsomme blader). | Ovrw anfører Salix aurita fra furutufstykker paa sekundært leiested ved Tingvold, efter DAHLS og undertegnedes foreløbige bestemmelse. Denne er muligens rigtig, men ikke sikker. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 69 Fra gruskeglen ved Tingvold har Oyen og Horme plukket frem en mængde lose furutufstykker, som jeg ogsaa har hat anledning til at under- soke. Men de bringer ingen nye arter for dagen. Et interessant faktum er det at Hippophaës ikke er iagttat i et eneste furu- Buistykke, hverken fra Gillebutuffen eller Tingvoldgrus- taket. Den synes at være utdod paa stedet i tidsrummet mellem bladtuffens avsætning og furutuffens begyndelse. Jeg kommer senere tilbake til dette vigtige punkt. Profilene paa vestsiden synes at antyde at furütuffen har transgrediert utover til sidene noget længer end bladtuffen. Antageligvis har hele komplekset oprindelig vaeret ganske betydelig ogsaa i vertikal retning. Hvad der folger efter furutufkomplekset, om der oprindelig har vaeret avsat nok en tufbænk i Gillebuskogen, saaledes som vi saa ved Leine, derom kan vi foreløbig ikke opgjore os nogen mening. Det er imidlertid klart at bækken maa ha skaaret sig ned gjennem kalktuffen først efter at furutuffen var dannet. Nye holdepunkter for bedømmelsen faar vi først efter at ha undersøkt gruskeglen ved Tingvold. D. Gruskeglen ved Tingvold. Da grustaket ved Tingvold er indgaaende undersøkt og beskrevet av OvEx (1920 |. c), skal jeg her bare gi en kortfattet oversigt over de stratigrafiske forhold paa dette sted. Av den skematiske tegning fig. 16 og fig. 15 faar man et nogenlunde korrekt indtryk av gruskeglens beliggenhet i terrænget. Den har sit ut- gangspunkt i skogbrynet tilvenstre for det lille huset paa fig. 15 og brer sig herfra vifteformig ut over det lavereliggende terræng. Avstanden ned til skigarden er ca. 80 m. Bækken har nu gravet sig et litet leie norden- for grustakets centrale del, og selve keglens overflate er i stor utstrækning opdyrket. Fig. 22 viser et snit gjennem lagrækken like i overkanten av chausséen ved Tingvold landhandleri. Meegtigheten er her tilsammen 8 à 9 m. over veiens nivaa. I. Paa bunden ligger et tykt lag av morænegrus med større og mindre blokker. IL. Derover kommer en mægtig fluvioglacial grusavleiring med skraatstillede lag, som helder 10— 15 mot ost (OYEN l. c. p. 275 fig. 4). III. Diskordant avsat herpaa følger en gruskegle.med svævende lagstilling, ca. 3 m. megtig. Oyen adskiller her en hel suite med underavdelinger, som dels har karakteren av utvaskede blokke- lag, dels mere normal gruskarakter. Avsætningen gir forevrig et noksaa rotet indtryk. I dens ovre halvdel var det at HormE oprin- delig fandt de lose tufstykker. Man finder her en ganske distinkt horisont, som i keglens centrale del har karak- 70 ROLF NORDHAGEN. M.-N. KL teren av et dobbeltlag, med talrike større og mindre tufstykker og los tufjord med tilblandet muldjord (K—K paa figuren). De en- kelte tuflag som vi stiftet bekjendtskap med i Gillebutuffen, er rikt repræsentert. Det lykkedes Oven og HozmE at fremfinde ikke mindre end 67 mindre blokker av furutuffen, hvilket gir et tydelig vink om at ogsaa denne oprindelig maa ha været ganske mægtig in situ. — "Høsten 1920 viste sig at være ganske heldig for studiet av denne horisonts karakter i den nordvestlige del av gruskeglen, idet der var foretat større gravninger og kjort væk betydelige grusmasser. Pro- filet saa her saaledes ut ovenfra og nedad (cfr. fig. 23): SEE [^ «m re TO —_—_ ne E C I jig — 2 Leu nz à 4 im Fig. 22. Snit gjennem grustaket ved Tingvold. I = moræne. II = fluvioglacialt grus. III = gruskegle med svævende lagstilling. K—K — gruslag med kalktufstykker og muld. Skematisert. (Efter Øyens og egne undersøkelser). A. Muldjord og raahumus, 20 cm. B. Gruslag, 80 cm., noget varierende. C. Kalktufforende lag, tilsammen 20—25 cm. (fig. 23). Smal mørkebrun muldlignende stripe. 2. Et par cm. blekgraa tufjord. 3. 5—8 cm. brungraa tufjord. 4. 5—8 cm. tufgrus, med masser av smaa tufstykker og kalk- smuler. 5. 8 cm. brunlig tufjord. D. Grovt stenblandet grus, overst noget sammenkittet av utfaeldt kalk, fortsatte vistnok ca. 1,5 m. nedover. De dypere lag var over- dækket. Paa dette sted var altsaa den kalktufførende horisont ganske kom- plicert bygget, men ikke særlig mægtig. Forholdene stemmer. for- øvrig med Øyens beskrivelse; han omtaler nemlig at horisontens dobbeltkarakter utviskes til sidene (1. c. p. 281). 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. fat Over kalktuflaget følger, som profilet viser, atter gruslag. Fleresteds var der antydning til en podsolagtig rustjordstripe akkurat i overkanten av tuflaget; det saa ut som om jernforbindelsene var utfældt netop i grænse- sonen (cfr. fig. 23 tilvenstre). Længer øst i grustaket var dette mindre frem- trædende; dog var der her ogsaa tydelige podsoleringsfænomener i de øvre gruslag. Denne gruskegle er et overmaade værdifuldt supplement til Gillebutuffen, og tilsammen gir disse to geologiske dannelser et meget interessant billlede av forholdene. Vi ser hvorledes bækken ved tilbakeskridende erosion litt efter litt har arbeidet sig ned i dalsidens dække og avlastet materialet længer nede i det flatere terræng i form av svævende lag ovenpaa det fluvioglaciale grus. Sluttelig har den ogsaa begyndt at angripe kalktuffen, og har i tiden efter furutuffens dannelsesperiode ikke alene evnet at sage sig ned gjennem de forskjellige tuflag og fjerne disse over store strækninger, men har ogsaa gravet sig dypt ned i det underliggende morænegrus, som vi gjenfinder aller øverst i gruskeglens svævende lag. — Nu for tiden er bækken helt ubetydelig og synes ikke engang i flomtiden at foranstalte nogensomhelst katastrofer. I tørre somre tørker den næsten helt ind. Gruskeglens dannelse forutsætter en ganske anderledes stor vandfering 1 bækken: Naar alle momenter tages i betragtning, kommer man for bækkens ved- kommende til det konsekvente resultat, at den likesom kilden ved Leine har veret intermitterende, med tre tydelige opsvulmingsperioder av sekulær natur: 1) under bladtuffens dannelsestid, 2) under furutuffens tid, 3) under kalktuffens nedbrytning og bækkedalens utformning paa finde- stedet. Det er ialfald et ganske respektabelt arbeide som bækken har præ- stert i tiden efter furutuffens avslutning (cfr. fig. 20). Mellem bladtuffen og furutuffen ligger der, som vi for har set, et tydelig avbrud i bækkens virksomhet (jordstripen). At der mellem furutuffens tid og den sidste „erosionsperiode“ ligger et lignende avbrud, er meget sand- synlig. Oyen fremhæver forekomsten av betydelige mængder muldjord i gruskeglens kalktufførende horisont som et tegn paa at furutuffen efter sin dannelse maa ha været mulddækket og faat tid til at hærdne (l. c. p. 272). Ialfald har vi her et moment som maa tages i betragtning under diskussionen. Gillebutuffen mangler oiensynlig en tredje tufhorisont (tilvarende til Alnus-tuffen ved Leine). Ialfald er der hittil ikke fundet spor efter en saadan. Men til gjengjæld har man her en erosions- og akkumulations- periode. Dette forhold kan muligens bero derpaa, at bækken ved Gillebu har været stridere og vandrikere end kilden ved Leine. Imidlertid kan aarsaken vel ogsaa ligge i en viss forskjellighet i selve det kalkydende substrat. Bækken ved Leine faar sin kalkgehalt fra moræneleret, og dette er endda ikke uttomt. Ved Gillebu derimot kan neppe det utvaskede dal- 72 ROLF NORDHAGEN. M.-N. Kl. sidegrus under tuffen og hoiere oppe ha levert saa store kalkmængder som Gillebutuffens opstaaen forutsætter. Bækken har vel snarere erhvervet sin kalkholdighet under passage gjennem kalkrike bergarter hoiere oppe i dal- siden, og det er tænkbart at den til slut har saget sig ned gjennem disse og saaledes for fremtiden er blit berovet den oprindelige tilgang paa kulsur kalk. En noiagtig undersokelse av bækkeleiet mellem Gillebuskogen og g de højereliggende Rindalssætre vil selvfølgelig kunne gi sikre holde- Fig. 23. Den kalktufførende horisont i gruskeglen ved Tingvold (nordvestlige del av grustaket). Nordhagen fot. 6te oktober 1920. punkter i denne sak. — For tiden er der ingensomhelst antydning til tuf- dannelse langs bækkedalen. Da Gudbrandsdalen saaledes som tidligere omtalt har været herjet sterkt av flomkatastrofer helt op imot nutiden, kunde man kanske til en begyndelse være tilbøielig til at sætte gruskeglens dannelse i forbindelse med denslags begivenheter. Men den kalktufførende horisonts jevne forløp og de overliggende jevne gruslag tyder ikke paa nogen pludselig opstaaen. Desuten er der flere ting, som med sikkerhet viser at keglens dannelse ligger langt tilbake i tiden. Som av OYEN paavist, løper nemlig den æld- gamle kjorevei i Gudbrandsdalen, „kongeveien“, henover gruskeglens over- flate. Hvor gammel denne kan være, vet vi ikke med bestemthet; den litteratur om norske veier! som jeg har hat anledning til at undersøke, gir 1 YnGvar NIELSEN: Om Norges veier før 1814, Historisk tidsskrift, bd. IV. Jou. ScHou- GAARD: Det norske veivæsens historie. 1899. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 3 ingen absolut sikre oplysninger herom. Imidlertid har hovedfærdselsaaren gjennem dalen altid gaat paa nordsiden av Laagen, og da „kongeveien“ ved Tingvold synes at ha et hensigtsmæssig og naturlig forlop, tør det nok hænde at den gaar helt tilbake til middelalderen. Under veilegemet gjorde Oyen og HoLme desuten en anden interessant opdagelse; de fandt nemlig restene efter en kulmile (cfr. fig. 22). Denne maa nødvendigvis være endda ældre, men da der ingen redskaper er fundet paa stedet, kan kulmilen ikke dateres med sikkerhet. Oyen har fremsat den formodning, at den kanske skriver sig fra jernalderen. Vi ser saaledes at i lys av disse kjendsgjerninger rykker gruskeglens dannelsestid allerede langt bakover i tiden. Og én ting kan ialfald betragtes som fastslaat: kalktuffens nedbrytning og avsætningen av de svævende gruslag ved Tingvold skyldes ikke nogen recent katastrofe. Sandsynlig- heten taler for at vi her har med forhistoriske fænomener at gjøre. Mens vi ved Leine, takket være det øvre tuflag (A/nus-tuffen), kunde opspore nutidsvegetationens oprindelse og binde denne sammen med den fossile, er vi for Gillebutuffens vedkommende ikke i den samme hel- dige situation. Den sidst dannede tufbænk paa dette sted vidner om tat furuskog som fremherskende plantesamfund. I nutiden indgaar imidlertid granen som en væsentlig bestanddel i det skogsamfund som omgir bækken. Men om granens indvandring og vegetationens forandringer op imot histo- risk tid, derom fortæller disse interessante avleiringer i Oier desværre intet. III. Kalktuffen ved Nedre Dal i Faaberg. Denne kalktuf er indgaaende beskrevet av Bryrr (1892 I. c.). Den ligger i 225 m.’s hoide over havet paa Gudbrandsdalens sydside, men med østlig eksposition, og adskiller sig fra baade Leine- og Gillebutuffen ved at mangle distinkte tufbænker. Tuffen findes i en brat li nedenfor det store opdyrkede jordet paa Nedre Dal. Her kommer en liten bæk frem av bakken og rinder nedover mellem et virvar av større og mindre stener og klippestykker. I jorden mellem stenene ligger der kalktufblokker, hvorav en del er ca. 0,5 m. 1 dia- meter, andre mindre. De er forresten nu fjernet og spaltet op i stor ut- strækning. Terrænget er i det hele tat meget uryddig og brat, og jeg tror for mit personlige vedkommende at her engang i tiden maa ha gaat et ras. Det store bratte jorde like ovenfor findestedet bestod, saavidt jeg kunde se, av lerholdig moræne, og der er intet iveien for at der her, kanske i forhistorisk tid, har gaat ut et skred. Brvrr fandt to stratigrafisk og palæofloristisk helt forskjellige nivaaer repræsentert ved Nedre Dal, en bladtuf med bjerk, asp, Salices uten makroskopiske fururester, og en furutuf, fuldstændig typisk og overens- stemmende med Leinetuffen (og Gillebutuffen, som Brvrr ikke kjendte). 74 ROLF NORDHAGEN. M.-N. KI. Men blokker av disse to tufslag laa ved siden av hinanden paa stedet, aldrig tydelig ovenpaa hinanden som bænker!. Nogen overgangstuf kunde han ikke finde, heller ikke nogen Dryastuf. Blokkene tilhørte alle sammen enten den ene eller den anden sort. Bryrr antok der- for med rette at de skrev sig fra to forskjellige tider, saaledes som ved Leine. Han skriver ogsaa (l. c. p. 9) at han anser blokkene for at ligge der »hvor de blev dannede"; men han har ikke levert noget bevis for at de befinder sig in situ i strengeste forstand. Biyrr tænkte sig en hel del smaa lokale tufdannelser langs bækken, hvilket altsaa resulterte i blokkenes opstaaen. Og aarsaken til at furutuffen ikke laa ovenpaa bladtuffen, tænkte han sig maatte ligge i det forhold, at det gamle vandlop til en viss grad hadde skiftet retning da det igjen be- gyndte sit lop under furutuffens tid (l. c. p. 9). Jeg avla høsten 1920 et besok ved Nedre Dal og grov op en del tuf- blokker paa stedet. Saavidt jeg kunde se, laa pragtfulde blad- tufblokkker like op til typiske furutufstykker (,side om side” Brvrr l.c. og jeg har vanskelig for at tro at Bryrrs tolkning er rigtig. At tufblokkene skriver sig fra to forskjellige” tider, er hævet over enhver tvil; derom vidner deres helt forskjellige fossilindhold og karakter og den paafaldende overensstemmelse baade med Leine- og Gillebutuffens to horisonter. Men i motsætning til BLYTT og ØYEN, som slutter sig til Biytts opfatning eller ialfald refererer denne uten, kommentar (1920 |. c. p. 256—258), antar jeg at blokkene befinder sig paa sekundært leiested, ograt der oprindelig har eksistert en kate" Nedre Dal ‚med.ito tufbenker ovenpaachinanden mener senere er odelagt.ved utglidninger. Jalfald har jeg ikke paa nogen anden tufforekomst i vort land set og heller ikke i litteraturen fundet omtalt tufdannelser av en saadan natur og med en saadan genesis som av BLYTT antat. Bladtuffen ved Nedre Dal er vakkert planskifrig og næsten smukkere utviklet end bladtuffen ved Leine; og jeg har meget vanskelig for at fore- stille mig, hvorledes en saadan struktur skulde kunne komme istand hvis tufdannelsen var koncentrert paa en række adskilte punkter og uten hori- sontal kontinuitet, ialfald over en viss strækning. En saadan abrupt blokke- dannelse som Blytt tænkte sig, vilde neppe kunne skape en saa planskifrig og regelmæssig struktur. Det moment som imidlertid veier mest i denne forbindelse, er furutufblokkenes optræden side om side med bladtufstykkene, i samme dybde i jorden — et forhold som umulig kan være oprindelig, men som maa bero paa sekundære forstyrrelser. Den antatte utglidning behøver paa den anden side ikke at ha været av særlig store dimensioner. 1 @yen skriver i sit sidste arbeide (1920 l. c. p. 256) at man ved Dal har to ,tufbznker". Dette er altsaa ikke ganske korrekt. Bryrr bruker selv meget konsekvent uttrykket »blokke" om tuffen ved Dal. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 7| oi I bladtuffen ved Nedre Dal fandt Brvrr foruten de vanlige lovblad- rester ogsaa Prunus Padus, Salix nigricans og av snegler Vitrina pellucida, Pupa muscorun og Helix arbustorum, som supplerer artslistene fra de ovrige forekomster i Gudbrandsdalen. Forevrig stemmer de alle sammen paafaldende godt overens. Det samme gjælder furutuffen, hvor BLYTT ogsaa fandt et blad av Linnea borealis. I nutiden dominerer Urtica dioica 1 faretruende tætte bestander paa findestedet; dette har som nævnt tildels karakteren av en skraanende, svær stenreis. Lon (Acer platanoides), rogn og hassel er temmelig almindelige paa stedet; men der er ingen sammenhængende skog, bare smaakrat og træklynger. Kalktuffen ved Nedre Dal er, til trods for de noget dubiose stratigra- fiske forhold, som jeg her har forsokt at tolke paa en naturligere maate, meget interessant og værdifuld; den viser os nemlig at de to perioder som hoiere oppe i Gudbrandsdalen var karakterisert ved bladtuf- resp. furu- tufdannelse, har været av neiagtig samme karakter i floristisk og fysiografisk henseende ogsaa helt nede i Faaberg ved dalens begyndelse. Ellers er den historie som tuffen ved Dal fortæller os, adskillig mere fragmentarisk end hvad tilfældet er med Leine- og Gillebutuffene. IV. Kalktuffer ved Onset i Biri. A. Blytts undersøkelser. I 1892 undersokte Brvrr en kalktufforekomst ovenfor gaarden Onset i Biri ved Mjesen (cfr. kartet p. 2). Han har selv aldrig publicert noget om sine fund; dog omtaler han i det efterlatte manuskript som blev trykt i Bergens Museums aarbok 1909 (l. c. p. 15), Onsettuffen med følgende ord: »furutuf og birketuf i særskilte blokke fra to forskjellige tidsrum fandtes ogsaa i Biri ved Mjøsen". Brvrrs efterlatte samlinger opbevares paa Geologisk Museum i Kristi- ania, og samlingene fra Biri er vedlagt folgende veiledning, skrevet av BLYTT selv: „Al tuf i denne kasse er fra Biri, samlet af A. BLYTT i 1892. Øverst ligger stykker af furutuf, taget i uren ved veien mellem Eriksrud og Kræm- merodden!. Al furutuf er fra dette sted undtagen et stykke som har etiket, og er fra Undset?. Fra Undset er al den øvrige tuf med Betula, Salix cfr. caprea etc. Ved Undset ligger furutuffen i klumper i los jord over birketuffen, som danner større blokke." Derefter anfører han følgende profil: ! Denne lokalitet ligger nordenfor Onset. R.N. 2 Uthævet her. 76 ROLF NORDHAGEN. M.-N. Kl. Kalkjord. Smaa tufklumper med Pinus. Kalkjord. : Storre blokker med Betula, Salix. Kalkjord. Glacialler. Desuten har Bryrr foiet til: ,Mellem Eriksrud og Kraemmerodden kun furutuf i smaa klumper lose i uren." (Cfr. OYEN 1920 I. c. p. 259). I samlingen findes altsaa kun et eneste stykke furutuf fra Onset; resten er fra uren mellem Eriksrud og Kraemmerodden, altsaa en helt anden lokalitet. Den etiket som Bryrr *omtaler, bærer følgende indskrift: „Furutuf fra Undset. Smaa klumper i los kalkjord over den i større blokke forekommende birketuf. Maaske er denne klumpformede tuf ækvivalent med Dryastuffen ved Leine.” Desværre er det nu ikke mulig med sikkerhet at avgjøre hvilket stykke i samlingen. denne etiket tilhører. Dog er der ikke mere end to stuffer som det her kan være tale om. Den ene av disse er nu spaltet i fire smaa- deler med en meisel og viser en meget fin mosetufstruktur samt en del hulheter koncentrert paa et bestemt sted, intet andet. Disse hule avtryk ser ut som furunaaler ved første oiekast; men flere av dem er helt cylindriske, óg ingen av dem viser det typiske og letkjendelige halvmaaneformete tver- snit som udmerker furunaalsavtryk. Jeg tror snarere at de skriver sig fra et græs. Det andet stykke er meget litet (ca. 4 cm. paa hver kant) og delt i to. Det viser tydelige furunaaltversnit (6—8 naaler) og har ellers en grynet struktur, som vistnok skyldes moser. Ingen av de angjeldende stykker viser andre tydelige plante-avtryk (f. eks. av levblader) Det sidste lille stykke har tydeligvis ligget i jorden, da det er chokoladefarvet og forvitret i overflaten. Det stemmer ellers paafaldende godt med de smaa tufbiter som jeg selv opdaget paa en ny forekomst ved Onset (ctr. det felgende). Furutufstykkene fra Eriksrud— Kraemmerodden er helt forskjellige fra begge de nævnte stuffer, og bestaar av lakunos, koralagtig eller cinteragtig tuf med utvisket mosetufstruktur. De bærer alle sammen tydelige spor efter at ha ligget oppe i dagen i den av Blytt omtalte ur; der vokser nemlig moser i smaa gruber paa dem alle sammen, likesom de er morke og for- vitret i overflaten. Et av stykkene er etikettert av Blytt selv. Jeg omtaler dette saapas utforlig fordi konservator Oyen i sin sidste avhandling beskriver Onsettuffen meget indgaaende, men vistnok uten at være opmerksom paa disse forhold. OYEN omtaler nemlig furutuffen ved Onset paa folgende maate: ,Furutuffen er derimot utviklet som en i los kalkjord liggende klumptuf over birketuffen, der danner storre blokker eller en mere sammenhængende tufbænk!. Den graagule furutuf, der som I Dette er, som nedenfor omtalt, ikke tilfældet. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 1 - regel er fast, viser dog ogsaa i den nedre del mosetuf av drypstensagtig "karakter med blader av Salix capræa, Populus tremula og Betula odorata, men her allerede med iblandet Pinus silvestris; senere blir den omend til- dels vekslende med noget jordagtig tuf, tildels noget graa, breccieagtig med skiferbiter, og her fandtes ved siden av de nu allerede nævnte ogsaa blad- avtryk av Vaccinium Myrtillus L. Paa mange steder ser man dog i den cinteragtige, graabrungule tuf kun spredte furunaaler uten spor av ind- blanding av lovtræblade, ja det samme træk gjenfindes paa sine steder Fig. 24. Breccieagtig kalktuf med bergartsfragmenter. Biri; Blytts samling (1/2). B. Larssen fot. selv der, hvor tuffen har noget mere præget av en mosetuf. Furutuffen er saaledes i det hele tat vel skilt fra de underliggende tufforekomster" (l. c. p. 260—261). Da der, som Brvrr uttrykkelig gjør opmerksom paa, bare findes et eneste stykke furutuf fra Onset i hans efterlatte sam- ling fra Biri, og dette stykke maa være et av de to som jeg ovenfor har beskrevet, maa denne Ovrws karakteristik vistnok bero paa en mis- forstaaelse. De nævnte stykker indeholder ingen lovbladrester, hverken av Salix caprea, Populus tremula eller Betula odorata. Og OYExS uttalelser om at furutuffen senere blir ,tildels noget graa, breccieagtig med skiferbiter, og her fandtes ved siden av de nu allerede nævnte ogsaa. bladavtryk av Vac- cinium Myrtillus", er for mig ganske uforstaaelig. I samlingen findes nemlig et solid stykke bestaaende av en mængde skiferbiter tæt sammenkittet av haard kalktuf, som er totalt forskjellig fra alle de øvrige stykker i Brvrrs 78 ROLF NORDHAGEN. M.-N. Kl. samling fra Onset. Det har ingen originaletiket; blaabaerbladet er ogsaa meget utydelig og hoist tvilsomt. I museets samling ligger et andet stykke fra , Biri" samlet av Reuscu, og dette viser en slaaende likhet med oven- nævnte, idet det er propfuldt av skiferfragmenter. Antageligvis stammer begge to fra samme sted og er sikkert opstaat paa den maate, at kalkholdig vand har passert en spræk med forvitringsmateriale, som kalken har kittet sammen, eftersom den blev utfældt (cfr. næste avsnit) Naar Oyen uten videre indfletter det nævnte tufstykke, som har en helt avvikende struktur, i sin omtale av furutuffen ved Onset og forsoker at gjøre det til en egen ,breccieagtig" facies av denne, saa er dette blot og bart et postulat. Det er for det første høist tvilsomt om stykket er fra Onset; det er ialfald hverken litet eller klumpformet, og har intet med furutuffen at gjøre. Det maatte da i tilfælde være fra Eriksrud—Kræmmerodden; men det ligner heller ikke de typiske furu-mosetufstykker fra dette sted. — Og Ovens sidste bemerkninger om furutuffen: ,,Paa mange steder ser man dog i den cinteragtige graabrungule tuf kun spredte furunaaler uten spor av indblanding av løvtræblader, ja det samme træk gjenfindes paa sine steder selv der, hvor tuffen har noget mere præget av en mosetuf", er mig likeledes ganske uforstaaelig. Denne beskrivelse passer nemlig aldeles udmerket paa styk- kene fra Eriksrud—Kræmmerodden (cfr. ovenfor). Man faar uvilkaarlig det indtryk, at Oven bygger sin karakteristik av furutuffen ved Onset paa et rikholdig materiale. Det er ialfald en levende umulighet at utlede hele denne utforlige beskrivelse av det ene lille furutufstykke som Brvrr har medbragt fra Onset og etikettert. At der her foreligger en misforstaaelse, er givet. Da det ikke er andre end Brvrr som har set forekomsten, maa man nødvendigvis holde sig strengt til BLyrrs egne veiledende oplysninger, og de er ikke til at ta feil -av. Naar Oyen desuten mener at kunne rekonstruere følgende sammen- hængende profil fra Onset: I. I bunden en tildels breccieagtig eller ogsaa ofte en konglomerat agtig tuf. 2. Derover en mosetuf, der som en egen avdeling dog nærmest. grup- perer sig under birketuffen og øverst fører Betula odorata sammen med den for avdelingen karakteristiske Hypnum sp. 3. Birketuf. 4. Noksaa tæt mosetuf, ogsaa tildels med furu under hvis sone den ogsaa nærmest hører som underavdeling. 5. Furutuf, saa maa jeg desværre erklære mig helt uenig ogsaa i denne tolkning. Det faktiske utgangspunkt for ræsonnementet, nemlig BLYTTs materiale, er her absolut avgjørende. OvEÉN forsoker altsaa at gjøre gjældende at Onset-tuffen er en autochten in situ-dannelse, og foretar desuten en opdeling i stratigrafiske 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 79 underavdelinger, noget som vi ikke finder antydet engang i BLyTtrs notiser. Furutuffen har jeg allerede omtalt utforlig ovenfor. Jeg har ogsaa gransket Brvrrs bladtufmateriale meget kritisk og omhyggelig, og det viser sig at dette lar sig inddele i forskjellige grupper av haandstykker, som utvilsomt horer sammen. ES En hel del vakre stuffer (r5—20 stykker) bestaar av en mosetuf- grundmasse, ofte meget grov, desuten med talrike lovbladavtryk av- D Fig. 25. Bladtufstykker fra Onset med valket overflate (Cyanofycé-tuf (1/2)). Blytts samling. B. Larssen fot. vekslende hermed. Deres overflatestruktur er ytterst eiendom- melig og viser en ytre, paafaldende glat og valket, fint lamellert sone, som skyldes kalkutskillelse ved blaagrenne alger (cyanofycé-matter) (ig. 25). Disse stykker er fremkommet ved opspaltning av en eneste storre blok, idet de lar sig satte sammen som en mosaik. Denne blok har ligget løs i jorden; overflaten er nemlig mørk og forvitret. 15 Større og mindre stykker med tildels den samme mosetuf-bladtuf- karakter, dog delvis mere kompakte, bærer visne paasittende recente moser i den forvitrede overflate; de maa altsaa faktisk ha stukket op av jorden. Det er altsaa klart at enkelte av Brvrrs bladtufblokker har ligget overst i jordlaget, tildels helt frit. En mængde stykker er mørkt chokoladefarvet i overflaten og har ligget lose i muldjorden (cfr. mine egne fund, som omtales i det følgende. 80 ROLF NORDHAGEN. M.-N. Kl. 4. Endelig findes der en serie med vakre stuffer bestaaende av avvekslende mosetufpartier og løvbladrike partier, som uten tvil er spaltet løs fra det indre av en eller et par blokker. De bærer nemlig tildels friske brudflater. Et par av dem indeholder skiferbiter. 5. Et par vakre mosetufstykker er tydeligvis halvrecent tuf, idet de bærer halvforkalkede, recente moser i overflaten. Denne gjennemgaaelse gir det bestemte resultat, at ,,birketuffen" ved Onset er en mosetufagtig, bladrik tuf (Alnus incana m. alm., des- uten Populus tremula, Salix capræa og Salix cfr. nigricans, Betula odorata alm.!). Den har, som Brvrr anfører, ligget los i jorden som større og mindre blokker. Vertikale facies (OvENs „breccieagtige (?) eller ogsaa ofte konglomeratagtige tuf" (?) i bunden, derover ,mosetuf'" som en egen av- deling under den egentlige ,birketuf") kan ikke paavises med nogen- somhelst sikkerhet Tuffen er tvertimot paafaldende mose- tufrikw"helt agjennem foe temmelig ens artet. Jeg har lagt meget arbeide paa denne gjennemgaaelse, fordi jeg mener at vi naar det gjælder disse omdisputerte stratigrafiske problemer, maa vere saa kritiske som mulig og eliminere alle dübiese eller hypotetiske momenter. Fremfor alt maa vi ikke la os forlede til forhastede slutninger og korrelationer paa grundlag av et usikkert materiale. At der her er antydning til en overensstemmelse med Gudbrands- dalens tuffer, er ganske klart. Men ingen kan vite om ikke de smaa furu- tufstykker ved Onset, hvorav Brvrr bare har medført en liten prove som fortæller svært lite, er av forholdsvis recent natur. I et av Bryrts stykker har jeg fundet nogen naaleformige avtryk, som utvilsomt skriver sig fra gran (Picea excelsa), og som altsaa maa vere av geologisk talt yngre datum. Dette stykke har vel ligget øverst i jorden sammen med de smaa furutufklumper.: Vi mangler ethvert sikkert middel til at tid- fæste disse lose tufbiter. Det samme gjælder furutuffen fra Eriks- rud —Kræmmerodden?, som forresten heller ikke ligner den virkelige typiske ,furutuf" i Gudbrandsdalen. Desuten kommer her et meget vigtig moment til, som Oyen ikke er opmerksom paa, men som jeg allerede har berørt under omtalen av fore- komsten ved Nedre Dal i Faaberg: Ligger tufblokkene der hvor de blev dannet,. eller befinder de sig paa sekundzrt ere sted? Er Onsettuffen autochton eller ikke? Under mit besok 1 Biri høsten 1920 lykkedes det mig at fremfinde en antageligvis for BLyrr ukjendt tufforekomst ved Onset. Denne er i flere henseender interessant og kaster ogsaa lys over det ovenfor opstillede sporsmaal. 1 Pollenanalyser bragte sparsomt pollen av Alnus, Betula og Pinus silvestris for dagen. 2 I likhet med forholdene paa den av mig opdagede nye tufforekomst ved Onset antar jeg at disse Brytts „lose stykker i uren" er faldt ned ovenfra hammeren (cfr. det følgende). 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 81 Forinden jeg gaar over til at omtale mine egne fund, maa jeg imid- lertid gaa ind paa nok et forhold av betydning, som Oyen har trukket ind i diskussionen, og som ogsaa hænger sammen med Brvrrs efterlatte sam- linger. OyEN mener nemlig at ha fundet avtryk av Dryas octopetala i et litet tufstykke, som Brvrr medbragte fordi det indeholdt en snegl (Ayalinıa petronella). ØYEN skriver, at dette lille stykke minder om det furutufstykke fra Onset som Bıyrr har etikettert, og antar, om end under nogen tvil, at der ved Onset ogsaa har været en ,Dryastuf (l. c. p. 259—260). Stykket FE Fig. 26. Øverst „Dryastufstykket“ fra Onset fotografert i to forskjellige belysninger. Billedet tilhgire viser tvergaaende forbindelsesnerver mellem de tre hovednerver. Nederst fragment av et tydelig Alnus-blad fra Onset til sammenligning. 1/1. B. Larssen fot. skal ifølge OvEN ogsaa indeholde et par furunaaler. Nu er det imidlertid at merke at det angjældende lille stykke ligger i en pakke som Brvrr selv har etikettert paa følgende maate: ,,Snegler fra birketuffen! ved Onset, be- stemt af frk. B. Esmark", og sammen med det ligger en del smaa lignende tufbiter med snegler. Jeg har selv gransket stykket meget indgaaende og er ogsaa kommet til et bestemt resultat. Ved første eiekast kunde man muligens ta avtrykket for at være tre grove Dryasblader paa rad, med midtnervene helt paralelle og med diffuse randpartier (cfr. fig. 26). Men ved noiere undersokelse ser man ganske tydelig at disse tre ,midtnerver" er forbundet ved 1 Uthævet her. Vid.-Selsk. Skr. I. M.-N. Kl. 1g21. No. 9. b 82 ROLF NORDHAGEN. M.-N. Kl. et tversgaaende anastomosenet; de hører altsaa sammen. Og ved sammenligning med et rikholdig løvbladmateriale er jeg blit over- bevist om at de tre utydelige ,,Dryasblader" kun er et bladfragment av Alnus incana, som er meget almindelig i bladtufblokkene fra Onset. Vi har her tre av de karakteristiske paralelle sidenerver og forbindelsesnerver lodret paa disse, hvilket netop særkjender orebladene (fig. 26). Dryas hører med til de lettest kjendelige av alle fossiler, og jeg anser det for helt utelukket at vi her har med blader av denne art at gjøre. Nogen sikre furunaaler findes heller ikke i stykket, kun et tvilsomt hulrum, som like godt kan være noget andet. Ifølge Bryrr skal jo stykket ogsaa være fra „birketuffen“ ved Onset og ikke fra furutuffen. Etiketten ,,snegler fra birketuffen" er utvilsomt rigtig. Oyen har selv karakterisert „Dryastuffen“ ved Onset som noget tvil- som; jeg er selv overbevist om, at den ikke har eksistert. Brvrr, som kjendte Dryas saa godt, har heller ikke opdaget noget bladavtryk av denne art. Og han har sikkert gransket materialet meget omhyggelig. B. Egne undersøkelser. Gaarden Onset i Biri ligger ved Mjosen i 40—50 meters hoide over denne. Like bak gaarden stryker et langsgaaende hoidedrag i retningen SØ—NV; det bestaar av den ejendommelige „Birikalk“, som her danner steile bergvægger, tildels med urdannelse under styrtningene. Den av Brvrr studerte tufforekomst har efter de oplysninger som jeg indhentet paa stedet, antageligvis ligget et steds ved foten av dette højdedrag i naerheten av en forfalden husmandsplads, som ligger et par hundrede meter sydvest for gaarden. Ret op for pladsen i den skogbe- vokste skraaning under hammeren lykkedes det mig bare at finde et eneste løst tufstykke, som jeg antok maatte være kommet ovenfra. Jeg klatret da helt op til bergvæggene, og her fandt jeg ganske rigtig en ny tufforekomst. Stedet laa ca. 60 m. hoiere end pladsen og denne omtrent 20 m. heiere end Onset, altsaa i alt ca. 75 m. over Onset. Mjøsen angives at ligge 124 m. o. h., og lokaliteten skulde efter dette ligge ca. 250 m.o.h. Dette tal er muligens noget for høit. Under de lodrette, tildels overlutende kalkklipper fandtes der her en meget brat skraaning med gran og løvtrær. Jordbunden bestod av sten- blandet muld med opragende fast fjeld og blokkemasser. Skraaningen var ca. 45%, tildels brattere. Ved gravning fandtes en mængde smaa tufstykker i jorden, de fleste sterkt forvitret og brune eller chokoladefarvet i overflaten. Profilet hadde følgende utseende: I Muldjord,2oxen: Il. Lose tufbiter i sort muldjord, især optil en mængde smaa biter, nedtil noget grovere stykker. Tilsammen ca. 50 cm. De 1921. No. o. KALKTUFSTUDIER I GUDBRANDSDALEN. 83 fleste. stuffer var helt fossiltomme, tildels flintagtig haarde og kompakte, ofte med smaa bergartsfragmenter indesluttet i kalken (breccieagtig). Videre fandtes flere slags mosetuf, tildels med utyde- lige thalløse levermosavtryk. I et større stykke saaes en nøtt av hassel (Corylus Avellana!), blad av Salix sp.(?) samt smaa furu- naaler. | et andet fandtes utydelige løvblader vistnok av byerk. Endelig indeholdt et par smaa tuffragmenter nogen avtryk, som an- tageligvis skriver sig fra grannaaler (Picea excel- sa); disse fandtes heit oppe i laget. Fælles for alle tuf- stykkene var mangelen paa skifrighet og deres haarde konsistens. Flere biter hadde cyanofycé- struktur. II. Derefter fulgte sten- blandet muldjord uten skarp avgrænsning c, med fra foregaaende lag, en del mindre tufstyk- ker; disse avtok stadig i antal nedad. Her saaes ingen bestembare fossi- ler. Tuffen var gjennem- gaaende flintagtig haard og kompakt. Dette „lag“ Fig. 27. Klipper av Birikalk ovenfor Onset med to kunde forfølges. til 50 mørke søileformige kalktufmasser nederst. Disse er cm.’s dyp under det fore- dækket av moser og cyanofycéer. Nordhagen fot. gaaende, men fortsætter nn sikkert dypere ned. Nogen tydelig stratigrafi kunde altsaa ikke paavises, heller ikke nogen skarp grænse mellem lag II og IIl. Men der er altsaa en anrikning av tufbiter optil, mot overflatens muldlag. Merkelig nok bar lokaliteten svake spor efter gravning, og jeg antok derfor først at jeg hadde fundet Brvrrs lokalitet. Men folkene paa Onset gaard fortalte at efter Bryrrs besok i 1892 hadde der været flere oppe og rumstert under fjeldet, vistnok for at se efter kalk til at forbedre aker- jorden med. Bryrr angir desuten „glacial-ler“ i bunden av sit profil, hvilket tyder paa at det er optat et steds længer nede ved foten av skraa- ningen. Overlærer Horwr, som ogsaa har avlagt besok ved Onset, antar ! Denne busk fandtes paa tuffindestedet ogsaa i nutiden. 84. ROLF NORDHAGEN. M.-N. Kl. at Bryrrs forekomst maa være ødelagt ved ras, hvilket er meget vel tænkelig. Men hvorfra skriver nu alle de lose tufstykker sig? En nærmere granskning av selve hammeren ret op for findestedet gav opløsning paa gaaden. Her fandtes nemlig et par meget interessante, halw- recente tufmasser avsat skalformig utenpaa de lodrette eller overlutende kalkklipper. Kalkholdig vand syntes at komme frem langs nogen revner i fjeldet, og langs disse hadde der bygget sig op soileformige eller ribbeformige tufansamlinger (cfr. fig. 27 og 28), som nu var klædt av en tæt pels med moser og cyanofycéer. Disse kalk- samlende organismer syntes at forkalkes langsomt og kontinuerlig. Da jeg besøkte stedet (20de oktober 1920), var mosene fugtige, men der var ikke rindende vand tilstede. Foruten disse pilarformige masser laa der under hammeren en svær tufblok, som tydelig nok var løsnet fra bergvæggen og faldt ned paa underlaget. Ogsaa paa denne var der svak mosetuf- dannelse (fig. 28). Den vigtigste tufdannende mos var Mollia æruginosa, som dannet svære kaker, men av et yderst sykelig utseende; den var meget sterkt forkalket, kun med faa opstikkende blader øverst. De øvrige arter dannet i grunden en serie med hensyn til sin kalksamlende evne: Swartzia mon- tana, Mollia tortuosa, Leersia contorta, Myurella apiculata, M. julacea og M. tenerrima følger nærmest efter ovennævnte art. Ditrichum flexicaule og Amblystegium protensum var meget svakere forkalket, Leucodon sciuroides uhyre svakt. Foruten disse ro arter saaes Hypnum sericeum, H. Bambergi og Solorina saccata paa den nedfaldne store blok; men disse arter vokste helt tørt og var uten spor av kalkansamling. Mellem mosene og paa disse fandtes store kvantiteter av kalksam- lende blaagronne alger. Molla eruginosa var ofte saa overtrukket av filtete traadmasser av Scytonema mirabile (BoRNET) at den var helt sortbrun og lignet mørke, korte tafser!. Foruten denne cyanofycé-art, som ogsaa dannet rene, smaa, filtagtige puter, var Chroococcus turgidus (NAEG.) rikelig tilstede samt flere andre Chroococcus-arter. Merkelig nok optraadte ogsaa en svakt likenisert Co//ema-art som brunlige gelé-klumper mellem mosene og cyanofycéene. Blandt Scytonema mirabile forekom ogsaa enkelte traader av Petalonema alatum (BERKELEY). Denne liste over kalktufdannende moser og cyanofycéer supplerer den av SERNANDER publicerte fortegnelse fra svenske forekomster (l. c. p. 165— 179). Av Sernanders arter har jeg i Norge kun gjenfundet Amblystegium filicinum? og Swartzia montana som recente tufdannere. De øvrige 9 mos- arter fra Onset er hittil ikke iagttat som kalksamlere i Sverige, hvor til gjengjæld en 5—6 andre arter er fundet. 1 Bestemt av assistent H. OrrvcoRoNa. 2 Cfr. Leine p. 14. IQ2I. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 85 Av recente kalktufdannende cyanofycéer anforer SERNANDER 3 arter: Rivularıa hæmatites (C. A. Ac.), Petalonema crustaceum (C. A. Ac.) og Dı- plocoleon Heppii (NarcJ). Desuten nævner han Chroococcus varius (A. Br.) og Chr. turgidus (NAEG.) som usikre kalksamlere. Til denne forholdsvis sparsomme skandinaviske liste kan vi altsaa nu foie Scytonema mirabile (BoRNET) og Petalonema alatum (BERKELEY). Des- uten bestyrker mine fund den av Sernander antatte kalktufdannelse hos Chroococcus turgidus. SERNANDER antar ogsaa at cyanofycéene leverer betyde- lige bidrag til kalkansamlingen i mostuene, at disse organis- mer altsaa supplerer hinanden. For Onsetforekomstens ved- kommende maatte man, hvis man anskuet forholdene plante- sociologisk, tale om en tuf- dannende Mollia eruginosa— Scytonema mirabile-association. De øvrige arter forekom ind- sprængt i denne eller dannet mindre bestand. Interessant var det at gjenfinde Mollia aeruginosa som recent tufdan- ner ved Borju-baekken nær Leine i Kvam (cfr. ovenfor p- 3). Denne synes vistnok at være almindelig paa norske tufforekomster. — Som en kuri- Fig.28. En stor kalktufblok, som har løsnet sig av ositet vil jeg nævne, at den fra klippevæggen. Paa avlosningsstedet sees mørke Collema-art som optraadte mel- polstere av Mollia eruginosa og Scytonema mirabile lem mosene ved Onset, ogsaa (øverst tilvenstre). Hammeren ved SE = 2ode oktober 1920. Nordhagen fot. syntes at bevirke kalkutskillelse, idet den flekvis var belagt med en kornet kalkmasse. Imidlertid var denne lavart som ovenfor omtalt svakt likenisert, eller rettere sagt: den JVosfoc-art som utgjer alge-komponenten i laven, var kun svakt omspundet av sop- hyfer, saa kalkansamlingen blir allikevel let forstaaelig. Hvad Leucodon sciuroides og Ditrichum flexicaule angaar, som begge var ytterst svakt kalksamlende ved Onset, og hvorav ialfald den første i almindelighet er knyttet til træstammer, maa man vistnok anta at kalk- utskillelsen omkring deres basaldel skyldes de tilstedeværende blaagronne alger (cfr. SERNANDER |. c. p. 179). Tufmassene ved Onset syntes at udmerke sig ved en temmelig træg vekst; ialfald var mosene svært lite frodige og tildels ganske kvalt av 86 ROLF NORDHAGEN. M.-N. Kl. algene. Jeg har derfor valgt at kalde disse tufpilarer og kaker for halv- recente, idet jeg tror at der har medgaat ganske lang tid til deres dannelse. Ret ned for disse kalkklipper, kun 2—3 meter lavere, laa den oven- for beskrevne masseforekomst av mindre tufstykker i jorden. Og det er ingen tvil om at disse skriver sig fra kalkklippene; de har faldt ned ovenfra i tidenes lop. Deres karakteristiske konsistens, mangel paa skifrighet, kompakte struktur etc.! faar ogsaa herigjennem sin naturlige forklaring: det skyldes altsammen den eiendommelige dannelses- maate. Disse tufstykker i jorden tyder paa at der har paagaat tufdannelse langs hammeren i betydelige tidsrum. Men da stykkene desværre er saa uhyre fossilfattige, fortæller de os saare lite om utviklingen paa stedet. Den merkelige ophobning av smaa tufbiter øverst i jorden under muld- laget betyr utvilsomt et eller andet. Men om fænomenet beror paa for- vitring og sterk avløsning av tuffragmenter langs den ovenfor værende klippevæg (under et tørt klima) eller skyldes rask tufdannelse paa dette sted, derom tør jeg ikke uttale mig. I lyset av disse fænomener, som knytter sig til denne nye forekomst ved Onset, blir den av Oyen omtalte tuf ganske dubios. Hvem vet om de av Brvrr fremfundne lose blokker befinder sig in situ? Det er meget mulig at ogsaa deres dannelsescentrum oprindelig har ligget et eller andet sted oppe i skraaningen eller under hammeren, og at de senere er faldt ned. Et par av Brvrrs bladtufblokker har som tidligere nævnt cyanofycé- struktur i overflaten, flere stykker indeholder ogsaa bergartsfragmenter, hvilket betegner likhetspunkter med den av undertegnede opdagede fore- komst Talfald er der hittil’ ikke levert noget bevis Tores Bivrs profil skriver sig fra en autochton tuf 1n situ ieee dette er gjenfundet og undersokt paany ute i naturen, kan tuffen ved Onset ikke tillægges nogen avgjorende betydning. Ræsonnementet blir nemlig staaende paa altfor svake føtter. I Likeledes forekomsten av bergartsfragmenter i tuffen. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 87 GENEREL'DEE: I den specielle del har jeg fremlagt hele det rent deskriptive materiale som vi nu raader over fra Gudbrandsdalens kalktuffer. Jeg har ogsaa forsøkt at paavise likheten og forskjellen mellem de enkelte forekomster, og like- ledes gjennemgaat de forskjellige tuflag og diskutert de stratigrafiske, genetiske og biologisk-plantegeografiske problemer som knytter sig til dem. I avhandlingens generelle del skal jeg gaa nærmere ind paa under- søkelsens almindelige resultater og forsøke at besvare følgende spørs- maal: hvorledes stemmer disse tuffer med andre i litteraturen beskrevne forekomster? Er de stratigrafiske fænomener som tuffene aabenbarer, av rent lokal eller mere generel natur? Hvorledes stemmer de plantegeografiske eiendommeligheter som Gudbrandsdalens tuffer opviser, med de resultater som torvmyrforskningen og andre palæobotaniske undersokelser har git os? Alt dette er centrale sporsmaal, som maa besvares forinden man kan gaa til en tidfæstelse av de enkelte lag. For at faa en tidsbestemmelse bakover i tiden blir det nødvendig at omtale isavsmeltningen i Gudbrandsdalen først. Jeg har ogsaa fundet det hensigtsmæssig at gi en oversigt over hvad man for tiden vet om den første flora og vegetation under avsmeltningstiden, da dette er av betyd- ning” for de efterfølgende avsnit. I. Isavsmeltningen i Gudbrandsdalen. Desværre foreligger der i norsk geologisk litteratur ingen samlet og fuldstændig fremstilling av isens avsmeltning i denne del av landet, kun spredte iagttagelser publicert av forskjellige forfattere. For Kristiania-fjordens omgivelser og traktene op til Mjøsen er for- holdene nu klarlagt paa en tilfredsstillende maate. Man adskiller her en række stadier i avsmeltningen, som vi med Oyen betegner som: er j Smaalenene— Jarlsberg-trinnet | Moss —Horten-trinnet Aasstadiet Aas-trinnet Ski-trinnet 88 ROLF NORDHAGEN. M.-N. Kl. | Nydals-trinnet Akerstadiet . ; | Maridals-trinnet i i | Skedsmo-trinnet Romerikstadiet I = | erger-trinnet (Oven 1914 1. 6,DJORLYEKE 1073 EN: At disse dobbeltrækker er oscillationsmoræner (OvEN 1904), dannet under fremstet av isranden, fremgaar av de intramorænale fore- komster av marint ler tildels med marine fossiler, som man nu har kunnet paavise i saagodtsom alle de nævnte morænerækker. Disse mange sving- ninger i brærandens stilling under tilbakerykningen er av stor teoretisk betydning for den absolute kronologi; det er nemlig vanskelig at avgjere hvor store tidsrum disse oscillationer repræsenterer. Man har her en ganske væsentlig feilkilde som maa tages med i beregningene. Nordenfor Romerik-stadiet moter vi en vældig morænerække foran Mjosen —Hurdalsvand —Randsfjorden —Spirillen, som man oprindelig betegnet som „indsjotrinnet“ eller det ,epiglaciale" trin (fig. 29). De fænomener som knytter sig til denne række, er omstridte. OYEN har 1 denne moræne fundet svære blokker av fint skiktet hav- ler op til 4—5 m. i diameter (1915 I. c. p. 310), hvilket viser at bræene her har rykket frem over en tidligere havbund og ploiet op lerlagene foran sig. I lermassene paa den romerikske slette som er avsat foran denne bræfront, gjorde Oyen sine opsigtvækkende fund av den yngste Portlandia arctica-fauna (1903 |. c.). Mens man kun har den ældre Portlandia ( Yoldia)- fauna (ældre og yngre Yo/dia-ler efter BRØGGERS terminologi 1900— 1901) utenfor raene eller i naer tilslutning til disse!, har man faktisk paa et langt senere stadium en fornyet opblomstring av Portlandia arctica (à en eiendom- melig mindre varietet) paa Romerikssletten. Man har villet forklare dette fænomen ved at anta at ishavsmuslingen trak sig tilbake fra Vànernbassinet og nordover og optraadte som relikt paa Romerike (DE GEER, Geol. Fóren. Förh. 1913 p. 308—309). Men dette er ingen tilfredsstillende forklaring paa det faktum, at Portlandia arctica her har en ny blomstringstid. Oyen har nu fundet den paa en mængde lokaliteter helt op til Elverum og Soler (Norsk Geol. Tidsskr. 1913 p. 2). En relikt, som tydelig avhanger av temperaturforholdene i vandet, opviser ikke uten videre en saadan paa- faldende levedygtighet og spredningsevne. En hel række andre kvartær-geologiske fænomener har fort Oyen til at opstille det saakaldte ,,Portlandia-nivaa“ som en egen avdeling i vort lands kvartærhistorie. En ældre og en yngre Portlandia arctica-forende avdeling var allerede tidligere kjendt fra Trondhjemsfeltet ved OveEns undersokelser, og viste sig at være ikke alene petrografisk forskjelligartet, men var ogsaa adskilt ved I Cfr. dog ØYEN 1915 l. c. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. Fig. 29. Kart over de vigtigste morænerækker i det sydøstlige Norge. Sydligst Rastadiets dobbeltrække, derefter Aas-stadiets to trin, nordenfor dem Aker-stadiets dobbeltrække og Romerik-stadiet. Fors Mjosen —Hur- dalsvand—Randsfjorden o. s. v. ,Indsjotrinnet". (Efter ØYEN rorr |. c.) 90 ROLF NORDHAGEN. M.-N. Kl. avsætninger hvis fauna hadde et noget mildere præg. Og da Oven gjenfandt noget tilsvarende i Kristianiafeltet og desuten opdaget den merke- lige tempererte og rike Mytilus-fauna ved Kristiania (1902) ved selve den marine grænse, maatte man uvilkaarlig studse. Ti alle disse fænomener stemte ytterst daarlig med det billede som man indtil da hadde opgjort sig av avsmeltningstidens natur. Paa den ene side hadde man altsaa den tempererte Mvyti/us-fauna (M. edulis, Mya truncata, Macoma baltica, Saxicava pholadis, Balanus crenatus!) i 221 meters hoide ved Kristiania, paa den anden side den yngste Portlandia-fauna i rik blomstring paa Romerike i et noget lavere nivaa, som dog korresponderer med en havstand som gaar op mot den marine grænse (som her forøvrig er vanskelig at fiksere). Naar saa hertil kom at allerede Brvrr (l. c. 1892) mente at finde spor i vore fjelddaler efter en yngre bræfremrykning (efter den egentlige avsmeltningstid), og Oyen ved sine tidligere studier 1 det centrale Norge, specielt Atnedalen, kom til det resultat, at store dalbræer her hadde be- væget sig nedover dalforene efter selve storbræens ophør (1899 I. c.), vil man forstaa at det laa noksaa neer at forsoke paa at kombinere alle disse feenomener. Dette har da Oyen gjort. Han antar at der efter Romerikstadiet fulgte en mildere periode, ,Mytilus-nivaaet", hvorunder bl. a. de rike banker ved Kristiania i 221 m. hoide blev dannet. Under denne tid trak bræene sig langt tilbake, men i hvor stor utstrækning indlandsisen avsmeltet, kan ikke avgjores med bestemthet. Oyen antar videre at havet nu gik ind i Mjesen helt op forbi Lillehammer. Denne periode paralelliseres med Brvrrs „ark- tiske“ tid. Efter denne mildere periode fulgte atter en depression av klimatet under ,Portlandia-nivaaets" tid. Bræene skjøt fra det centrale Norge ned- over hoveddalforene og helt ned til enden av de store indsjoer. Da hadde havet allerede sunket noget. Bræene ploiet op lerlagene fra Mvytilus- nivaaets tid, og disse blev indpresset i de store endemoræner foran Mjosen, Hurdalsvandet o. s. v. Denne periode paralelliseres med Brvrrs ,sub- glaciale" tid. Forholdene ved Lillehammer synes at stemme godt med denne opfatning. Allerede i 1895 omtaler nemlig REKSTAD nogen merkelige avleiringer ved Aaretta 1 km. syd for Lillehammer, ved Nyflot naer Losna o. fl. steder. Paa den første lokalitet saaes en veritabel moræne oppaa horisontale sandlag av betydelis megtighet (1895 1. c.p. 14); „Dissesang og lerlag maa rimeligvis være avsat under svingninger av bræstanden i slutningen av den sidste istid.“ Det hele tyder paa „at mildere klima er bleven fulgt av glaciale tilstande" (l. c. p. 14). Senere har overlærer HoLME iagttat lignende fine sand- og lerlag overleiret av glaciale avsætninger, til- I Flere av disse arter optrær i sydlige varieteter. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. OI dels ogsaa hvilende paa ældre moræner paa en række steder ved Lille- hammer og nordover til Myre st. Oyen, som ogsaa har undersekt for- holdene her, tolker alt dette som /Mytr/us-nivaaets dannelser overleiret av Portlandia-nivaaet (OYEN 1915 l.c. p. 307—310). BjoRLYKKE har ogsaa iagttat lignende merkelige stratigrafiske forhold ved Svanefoskanalen og ved Lena-elven paa Toten (de mellem morænene liggende lerlag var her 3,5 m. tykke) (BJoRLYKKE |. c. p. 144). Den yngste Portlandia arctica-fauna paa Romerike faar herigjennem sin naturlige forklaring. Ishavsmuslingen har hat gunstige livsvilkaar under denne nye kuldeperiode. Man mener ogsaa at ha fundet Myti/us-forende ler under Portlandia-forende ved Jesseim; men dette er endda ikke bevist. ByoRLYKKE mener at det motsatte er tilfældet (Ove: Nogle bemerkninger om klimatforandringer. Vid.-Selsk. Forh. 1904. ByoRLYKKE 1913 l. c. p. 151). Oyen har ogsaa senere fundet brudstykker av Portlandia arctica ved Skaadalen st., ca. 16 m. lavere end de ovenfor nævnte Mytilus-banker (1909 l.c. og 1915 |. c. p. 290). Han antar at drivis under Portlandia-nivaaets tid har stott mot stranden paa dette sted og trykket og knuget ældre sandlag med Mytilus-faunaen ind i lerlag med Portlandia-faunaen. De forstyrrede lag som blev fundet her, er ialfald vanskelige at forklare paa nogen anden maate. Saavidt vites har ingen anden norsk geolog forsokt at utrede denne forekomsts natur. Endelig fortjener det at nævnes at den store bre i Atnedalen, som fra Rondemassivet har skutt ned mot Østerdalen (ogsaa beskrevet av WEREN- SKIOLD 1911), ifølge OyEN maa ha dæmmet op for Glommen og tvunget denne til at rende østover mot Rendalen. Under denne periode skal , Jutul- hugget" være blit utformet!. Pashoiden over hugget korresponderer med de laveste seter i Østerdalen (cfr. HorMsEN 1915 p. 143), som likeledes tolkes som minder fra denne opdamning. Nu, alle disse fænomener som jeg her har referert, er tildels meget omstridt, og flere norske geologer stiller sig skeptisk, tildels avvisende overfor Mytilus- og Portlandia-nivaaet saaledes som disse teoretisk er ut- formet av Oyen. Paa Vestlandet har KarpHor (1909 og 1912 |. c.), delvis ogsaa KOLDERUP (Ig11) fundet forhold som stemmer med Oyens opfatning. Imidlertid kræves der endnu omfattende undersøkelser for at klargjøre forholdene. Vi kjender endda ikke sikkert lagfølgen paa den romerikske slette; vi vet heller ikke, hvor langt bræene trak sig tilbake indover mot det centrale Norge forinden de atter rykket frem til enden av de store indsjoer. Hvor stor rest av indlandsisen overlevet Mytilus-nivaaet, vites ikke; vi kjender heller ikke dette intervals varighet og hele oscillationens amplitude. Oyen har forsøkt paa grundlag av sine studier over ler- sedimentene i Trondhjemsfeltet at tidfæste bræsjø- og sete-perioden i det 1 Smlgn. ogsaa SCHETELIG (foredrag, referert i Norsk Geol. Tidsskrift B. 1. p. 44), og Reuscx (1917 1. c), hvor Jutulhugget omtales. 92 ROLF NORDHAGEN. M.-N. Kl. ostenfjeldske Norge. Han antar at denne avsluttedes hovedsakelig for Mytilus-nivaaets tid (1915 l. c. p. 294—297). Landisen maatte altsaa paa denne tid ha været sterkt decimeret. Hormsen mener derimot at en del av isresten i øst overlevet denne mildere periode, og at den atter vokste noget under Portlandia-nivaaets tid (samtidig med lokalglaciationen), da sne- linjen blev forskjøvet nedad. (G. Hormsen: Forskyvninger i snelinjens heide under avsmeltningsperioden. 1918 I. c.). Dette tvistepunkt er overordentlig vigtig. Svenske kvartærgeologer hævder nemlig i motsætning til OYEN, at indlandsisen i øst vedvarte et godt stykke utover i postarktisk tid, ja man ser gjennemgaaende paa svenske karter ogsaa indlagt en vedvarende polseformet isrest langt ind i Gud- brandsdalen. Dette punkt kommer vi tilbake til i de følgende avsnit. Kalk- tuffene er i denne forbindelse meget betydningsfulde. Ogsaa fra andre kanter i Skandinavien er der beskrevet eiendomme- lige avleiringer og fænomener som i flere henseender synes at stemme overens med Oyens tolkning. Dette gjælder først og fremst den saakaldte Allerød-oscillation i Danmark!, som nu maa betragtes som viden- skabelig fastslaat, idet alle de indvendinger som har været reist herimot, har vist sig at være ugrundet (Naturforskermøtets forhandlinger, Kristiania 1918, p. 418—421). ,Allered-tiden" har NoRDMANN og OYEN paralellisert med Mytilus-nivaaets tempererte periode („senglaciale klimatoptimum" JESSEN 1920 l.c), „den yngre Dryas-tid" med Portlandia-nivaaet. At der i Dan- mark har skedd store forandringer i vegetationsdækket under denne oscilla- tion, er en videnskabelig kjendsgjerning. I Sverige har Enousst i flere arbeider behandlet hvad han kalder „lokalglaciationen“. Han opdaget først (roro I. c.) at visse bræer i Herje- dalen— Jemtland tidligere har været betydelig større end nu; saaledes har Helagsfjeldets bræ engang skutt 1500 m. længer frem end i nutiden. Lig- nende fremstet markert ved endemoræner har han iagttat flere steder (i Norge har Hormsen omtalt en endemoræne fra Hummelfjeldet i Tolgen?). Senere mener Enouist at ha fundet spor efter intens lokalglaciation paa en række steder i det nordvestlige Skandinavien (1918 I. c.). Eiendommelig nok synes EnQuist ikke at kjende til den diskussion som man i norsk lit- teratur har ført om lokalglaciation (f. eks. BLytr 1892, ØYEN: „Kontinental- glaciation og lokalnedisning“ 1899 o. s. v. Hans opfatning av hele fæno- menet er ogsaa en anden end Ovens. Enouist antar nemlig at de av ham” studerte fænomener skriver sig fra den sidste istids avsmeltningsfase, specielt 1 Litteratur om Allerød-perioden: Hartz og MILTHERS Igor l c, Hartz 1903 |. c., JOHANSEN 1904 I. c.; NORDMANN IgI2 I. c., ØYEN 1915 |. c., DE GEER 1916 |. c., NoRD- MANN 1918 l. c., JESSEN 1920 |. c. bo 1915 og 1918 l. c. Enguist anfører ogsaa i et senere arbeide (1918 l.c.) (ifølge H. Sir), at der paa Knutsho, Dovre, skal findes en endemorzene som tyder paa lokal- glaciation. Antageligvis er dette den sidemoræne i 1500 m. hoide som Hotmsen har omtalt (1915 l. c. p. 189), og som ifølge ham skriver sig fra indlandsisen. 92T. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 93 fra dennes første del, da det sammenhængende isdække forsvandt fra visse omraader og gav plads for lokale bræer. Hans kart over isdækkets utbredelse under denne tid er imidlertid meget lite overbevisende og staar for Norges vedkommende i strid med hvad vi vet om isavsmeltningen i det trondhjemske, hvor en lang række med morænetrin er beskrevet og delvis sammenstillet med de ostlandske stadier. At lokalglaciationen netop skal svare til det tidspunkt, da bræene i det sydlige Norge stod ved raene!, er ogsaa i grunden bare et postulat. — De av Exouisr omtalte fænomener, specielt fra Herjedalen— Jemtland, kan, saavidt jeg forstaar, ogsaa meget godt tages til indtægt for Ovens lille atpaa-istid (Portlandia-nivaaet), som han sammenstiller med Bühl-Vorstoss i Alperne og med amerikanernes Post- Wisconsinperiode. Jeg har med vilje omtalt Myhlus- og Portlandia-nivaaene ganske ind- gaaende, fordi de spersmaal som knytter sig til dem, er ganske centrale i norsk kvartærgeologi. Saalænge der ikke opnaaes enighet paa dette punkt, kommer man ikke av flekken. Man maa haabe paa at disse problemer i frem- tiden blir underkastet en kritisk og indgaaende behandling og belyst fra for- skjellige sider; ellers kan der jo ingen diskussion bli. Mange svenske geologer negligerer desværre helt disse vigtige sporsmaal. Jeg for min del tror at dette i første række skyldes det forhold, at der i norsk litteratur ikke fore- ligger nogen tilfredsstillende klar og koncis fremstilling av disse aktuelle problemer. Polemiske og krigerske utfald mot anderledes tænkende fører her aldrig til maalet, men kun en kritisk og saklig utredning. Saalenge situationen ligger saaledes an, er det vanskelig at faa istand en overensstemmelse mellem de nyere svenske oversigter over isdækkets avsmeltning og de norske forhold?. Skal man gi en fremstilling av isavsmeltningen i selve Gudbrands- dalen, vil denne i hoi grad avhænge av den opfatning man har av Myti/us- og Portlandia-nivaaene. Man finder den ene morænerække efter den anden fra Lillehammer og helt op til Otta, hvilket utvetydig viser at bræene her i den sidste avsmeltningstid har bevæget sig nedover dalen (NV—S9), og at deres utgangspunkt har været i nærheten av landets hoideakse (REx- STAD 1895, 1896 og 1898). Isskillet har ligget ved grænsen mellem Dovre og Sel herred. De kartografiske fremstillinger som man finder i litteraturen, hvor en pelseformet isrest placeres over S. Fron, Ringebu eller Oier, er altsaa ikke rigtige. (Cfr. Ovens undersokelser ved Rosten 1899 l. c. p. 54—56 og Hoınsens stripekart 1915 l. c. p. 22). Man « I Disse er helt feilagtig indtegnet paa Enoursts kart. 2 Cfr. Oyen: Naturen 1916 p. 223 og Hoe i Geol. Foren. Förh. Stockholm 1916 p. 484. 94. ROLF NORDHAGEN. M.-N. Kl. har i denne del av Gudbrandsdalen overhodet intet tegn til at bræbevægelsen paa noget sted har været rettet opover dalføret, saaledes som f. eks. i Osterdalstraktene !. Hvis man nu akcepterer Portlandia-nivaaet som en egen avdeling karakterisert ved lokalglaciation i det centrale Norge, maa man anta at alle disse morænerækker i dalen er sammenskjovet av de sidste bræer i disse strok under Portlandia-nivaaets avslutningsfase, og at de markerer temporære stilstande eller mindre fremrykninger under den sukcessive av- smeltning. Ældre avleiringer er ogsaa tildels bevaret, men det er de sidste bræer som har sat de tydeligste merker efter sig. Anerkjender man derimot ikke Portlandia-nivaaet som nogen egen periode, blir morænerækkene at henføre til selve indlands-isrestens av- smeltningstid. Av morænenes placering og skuringsmerkene fremgaar det da at der her har været nedgaaende dalbræer fra isskillet nær landets hoideakse og ingen pelseformet isrest over stroket Fron—Oier. Da jeg selv ikke-har arbeidet med- disse ting, skal jeg her-bare neie mig med denne orientering i problemstillingen ?. I indledningen omtalte jeg de merkelige moræneavleiringer som op- bygger Leinebakkene i Kvam. Disse har som nævnt engang sikkert fyldt op hele den nedre del av.Veiklas nuværende dalføre, idet der anstaar rester av fyldningen ogsaa paa elvens østside. Den har sandsynligvis gravet sig ned gjennem disse og flyttet sig vestover. Moræneleren indeholder talrike blokker, fleresteds i tætpakkede lag (skyldes ogsaa ras). For om mulig at komme paa spor efter isbræens bevægelsesretning, medtok jeg en del bergartsprøver, som professor J. SCHETELIG har været saa elskværdig at undersøke. Det viste sig at være forskjellige sparagmittyper, kalksandstener, fylliter, desuten saaes blokker av en grov, rod eiegneis. Alle disse bergarter angives av BJoRLYKKE for traktene nord og delvis nordøst for Leine; den kalkrike morænelere forutsætter kalkholdige bergarter, og saadanne optrær ogsaa 1 naerheten. Oiegneis an- staar i foten av den lille top Gnedden nord for Leine og i Formokampen nord for Otta (BJoRLYKKE 1905 |. c.). Ved Kolloen nær Sjoa og Sandbovangen (fig. 30) litt højere oppe i dalen findes der store endemoræner, beskrevet av REKSTAD, og disse angir en bræ- bevægelse NV—SO (ut Hedalen og Ottadalen). Morænemassene ved Leine er ældre og vistnok avsat av en bre fra nord—nordvest; men om dette har været hovedbræen fra Ottadalen, som har presset sig sydestover 1 En undersokelse av blokkene i de undre moræneavleiringer paa de steder hvor man har intramorænale sand- eller lerlag (cfr. ovenfor), maa kunne gi oplysninger om man her nogen gang har hat blokkeflytning opover dalforet. (Cfr. FRôDINS utredning av Frösöfyndet. Geol. Fören. Förh. B. 38. 1916). Lo) Jeg har her ikke omtalt Dovretraktens bræsjo og de omdisputerte sete-dannelser aller overst i dalen. Tidsbestemmelsen vil her ogsaa avhænge av det standpunkt man ind- tar til Portlandia-nivaaet. r 1921. No.9. M KALKTUFSTUDIER I GUDBRANDSDALEN. (^, 161 krgr 9810N“ t 180[09%) SoSJoN :HADOOU A977) JO} avisxa» ‘HO 10j pAS uoSue AOqpug S poa SU. Iouropuo 9.1075 UIC] ‘of "Su 96 ROLF NORDHAGEN. M.-N. KI. Torgerkamp-plataaet |, eller om en mere nordøstlig bræ fra Rondemassivet Furusjoen har arbeidet sig sydover mot Kvam, vet vi foreløbig ikke. Blok- kene i leret gir ingen sikker besked herom. Moræneleren gaar op til 6 à 700 m. o. h., altsaa temmelig høit. WERENSKIOLD omtaler imidlertid side- moræner i S. Fron op til 600 m. heide (1911 |. c.). ^ Avsætningene ved Leine maa utvilsomt kunne tidfæstes i forhold til moræner baade sondenfor og nordenfor Kvam; men geologene har hittil merkelig nok ikke ofret dem nogen opmerksomhet eller diskutert deres alder. II. Nogen bemerkninger om den første flora og vegetation i under avsmeltningstiden. I ældre palæobotaniske oversigter finder man opført en saakaldt ,,Dryas- tid" for saagodtsom hele Skandinavien som den første epoke efter isens avsmeltning. Imidlertid har opfatningen paa dette punkt ændret sig ganske betydelig i de senere aar, eftersom forskningen er skredet fremover. I Danmark maa det nu ansees for fastslaat at man har hat en oprindelig »ældre Dryastid" med fuldstændig arktisk præg. Derefter følger den eien- dommelige „Allerod-oscillation“, som synes at udmerke sig ved aapne krat- skoger av bjerk, asp og vidjer (JESSEN 1920 I. c. p. 218). Under den , yngre Dryastid" synes atter de arktiske planter at ha hat overtaket. Oprindelig antok man at en lignende arktisk vegetation var fulgt efter isen nordover gjennem Sverige til Norge. Ogi det sydlige Sverige, hvor NatHorst gjorde sine klassiske undersokelser, har nok dette været til- fældet. Men jo længer nordover man kommer, desto mindre markert synes den arktiske floras blomstringstid at ha vaeret, desto mere opblandet er den med subarktiske arter (G. ANDERSSON 1906 |. c. p. 60). Rigtignok er arktiske planterester iagttat paa en række steder helt nord til Laxa 1 Mellem-Sverige, og ved Kristiania har Oyen bl. a. fundet Salix polaris i lerlag paa flere steder. Men forholdene stemmer i almindelighet, saavidt man kan se, ikke ganske med de i Danmark paaviste. Og en række bota- nikere og geologer synes at være av den opfatning, at da isen hadde trukket sig saa langt tilbake som op i Mellem-Sverige, hadde de klimatiske forhold ændret karakter; de var ikke længer arktiske, men tempererte. Man antar at en blanding av arktiske og subarktiske arter her tok landet i besiddelse (ANDERSSON |. c., WILLE Ll c. p. 325). For at kunne forklare den skandinaviske fjeldfloras tilstedevaerelse har man grepet til forskjellige teorier, som desuten forsoker at lose en raekke gaader som knytter sig til det samme flora-element. Brytr (1893 l. c. p. 21) og SERNANDER (1896 p. 117) har allerede for lang tid siden hævdet, at vi i Norge maa ha hat plantekolonier som paa isfrie nunatakker | Skuringsstripene paa Gudbrandsdalens østside i stroket Sel kirke — Otta st. — Bredevangen tyder paa dette (cfr. REKsTADs kart 1896 |. c.). 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 97 overlevet den sidste istid. Av nyere datum er teorien om den. isfrie kystrand under den sidste istid, med overlevende haardføre arter (HAn- SEN 1904, WILLE 1905, FRIES 1913, TENGWALL 1913). Denne teori kom- bineres nu ofte med nunatak-teorien, som jo ikke er væsensforskjellig fra den første (FRIES 1913, TENGWALL 1913). Fund av arktiske planterester i det trondhjemske og langs Norges vestlandskyst taler til gunst for denne opfatning, selv om de strengt tat ikke beviser andet end at isranden her i vest og nordvest blev efterfulgt av arktiske planter, saaledes som i Danmark og Syd-Sverige. Av stor teoretisk interesse er Oyens fund i det trondhjemske, specielt naar disse stilles i relation til isens avsmeltning i disse strøk. I sit arbeide om Trondhjemsfeltet (1915) paralelliserer Oyen den store ,,Ørlandsbanke" ved mundingen av Trondhjemsfjorden med „Stagnations-trinnet“ i Danmark — med andre ord: vi skulde i Ørlandsbanken ha grænsen for den sidste istids (Mecklenburgian) brædække i denne del av landet (cfr. UssinGs kart). Denne opfatning, som er basert paa de eien- dommelige faunistiske forhold som udmerker disse gamle avleiringer, der stemmer med tilsvarende avsætninger i Danmark!, medfører meget vigtige konsekvenser; der aapner sig da muligheter for en isfri, om end smal kystrand søndenfor Trondhjemsfjorden, ialfald mulig- beter for opragende fjeldpartier. Ved Ytterland fandt Oyen blader av .Sa/ix polaris (1901), hvilket viser at der paa Orlandet eller i dets nærhet har været en arktisk vegetation. Senere har Oyen kunnet forfølge denne arktiske flora eftersom den trak sig længer indover det trondhjemske. Sommeren 1900 fandt han nemlig Salix polaris ved Nidaros og Reitgjerdet teglverk nær Trondhjem og i 1901 Salix reticulata og Dryas octopetala i 164,4 m. hoide ved Sandsæter- volden nar Hommelvik (Mytilus-nivaaet. 1915 l. c. p. 291). I 1909 fandt BjørLYKkKkE Salix reticulata ved Reitgjerdet. Alle disse fund er fra en langt senere periode end Ørlandsforekomsten og maa ikke sammenstilles med denne, saaledes som EnQuist har gjort paa sit kart (1918 I. c. p. 82)2 De interessante fund av arktiske planterester som H. SmirH i den nyeste tid har gjort i Jemtland-Herjedalens fjeldom- raader (1917 I. c., 1920 I. c.), og som utvilsomt er meget gamle, danner paa en maate en fortsættelse østover av de ovenfor nævnte forekomster i Trond- hjemsfeltets marine avleiringer. Dog maa man medgi at en sikker tid- 1 Cfr. Portlandia arctica, Macoma Torelli, Macoma Loveni, Buccinum terrae novae, Sipho virgatus og S. Verkrützeni, Cylichna scalpta, Utriculus pertenuis, hoiarktiske bryozoer etc. (OvEN 1915 |. c. p. 177). 2 Her fremstilles alle norske fund av arktiske planterester tilsyneladende sans facon som synkrone. Ja, raene trækkes helt op til Kristiania, vistnok fordi Salix polaris er fundet i byens nzerhet, og fordi disse findesteder helst ,burde" ligge uten- for raene! Man maa virkelig ha lov til at spørre hvad meningen er med alle disse manipulationer? Naar man finder det umaken værd at indtegne findestedene paa et kart, bør man ogsaa studere originaloplysningene og citere forfatteren. Vid.-Selsk. Skr. L-M.-N. Kl. 1921. No. 9. 7 98 ROLF NORDHAGEN. M.-N. KI. fæstelse av arktiske plantefund i et hoifjeldsomraade er forbundet med ad- skillige vanskeligheter. Smirus tolkning virker dog meget tiltalende, og det maa vel nu betragtes som fastslaat at der har gaat en overordentlig vigtig indvandringsstrøm av fjeldplanter fra Norge i vest og østover ind i det centralsvenske høifjeldsomraade. I de bundlag som Smiru har analysert, fandtes der ikke spor av pollen hverken av bjerk eller furu. Dette stemmer med den av ANDERSSON og BIRGER fremsatte anskuelse (1912 l. c. p. 142): , Vi anse det således sannolikast att tallskog icke funnits eller åtminstone icke spelat någon roll våster om isdelaren så långe någon afsevård inlands- isrest ännu kvarlag.“ ANDERSSON antar ogsaa at bjerkeregionens arter senere vandret den samme vei østover ind i Sverige fra Norge i de an- gjældende trakter (1912 l. c. p. 141). Dette forutsætter med bestemthet en »bjerk-asp-periode" ialfald i visse deler av Norge (nordvestlige og centrale del) — et punkt av stor vigtighet, som vi senere kommer tilbake til. De mange interessante fund som HorwBor, REKSTAD og KOLDERUP har gjort paa Vestlandet, viser at ogsaa her har en rent arktisk vegetation holdt til langs isranden under avsmeltningstiden; men tidfæstelsen i forhold til bestemte avsmeltningsstadier er her meget vanskelig. Tu. C. E. Fries har i sit interessante arbeide fra det nordlige Sverige (1913) trukket frem en række nye plantegeografiske fakta som taler til gunst for en ,, overvintrende Mecklenburgo-glacial flora" paa visse stræk- ninger i Norge (cfr. hans inddeling av fjeldplantene i bicentriske arter, - vestarktiske arter o. s. v. 1913 l.c. p. 330). „Ob das eisfreie Land eben an der Küste gelegen war, lasse ich dahingestellt sein. Es sprechen in- dessen gewisse pflanzengeographische Verhältnisse dafür daß die eisfreien Nunatakken nicht an der Küste sondern weiter in das Land hinein gelegen Warenmill Cp. 215): Jeg hadde sidste sommer anledning til at gjore nogen iagttagelser fra et av de omraader i det nordlige, Norge, hvor baade Fries og TENGWALL tænker sig at der har været overvintrende Mecklenburgo-glaciale plante- kolonier, nemlig i stroket Saltdalen—Sulitjelma. Jeg vil her benytte an- ledningen til at nævne litt om forholdene i disse strok; de er nemlig ad- skillig mere problematiske end vistnok mange har tænkt sig. Jeg skal her kun opholde mig ved forekomsten av Carex scirpoidea og Saxifraga Aizoon, to arter som baade av Fries og TENGWALL regnes med tii de interglaciale overvintrere. Carex scirpoidea har sine eneste europæiske voksesteder ved Solvaag- tind i Junkersdalen (DvRiNG, 1900 |. c. p. 277). Den vokser her over en kortere strækning paa fjeldets sydøstlige side i 760 m. heide omtrent 150 m. over skoggrænsen. I 1916 blev arten ogsaa fundet paa vestsiden av Sol- vaagtind paa skraaningen av fjeldet Trækta av Dr. E. HAYRÉN (Finlandias Årsbok 1919 p. 57). Dette lave fjeld (g12 m.) danner den vestligste be- grænsning av Solvaagtinds skraaning mot Saltdalen. Det nye findested ligger 4 å 5 km. fjernet fra det ældste kjendte. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 99 Under et besøk paa stedet sommeren 1920 kunde jeg konstatere at fjeldskraaningene paa Solvaagtinds østside til og med i et hoiere nivaa end findestedet for Carex scirpoidea var belagt med erratiske blokker (tyndt morænedække). Og av hele topografien og isskuringen kan man se at bræ- massene her har presset sig fra Junkersdalen nordvestover netop i skaret EPS I Te 2 [ EN N AE Vandt) NN RN SIR A Zee? N RUN pem. Fig. 31. Kart over stroket Solvaagtind — Baatfjeld i Junkersdalen. Voksestedene for Carex scirpoidea er avmerket med +. mellem Solvaagtind og det ostenfor beliggende Baatfjeld. Naar man har hat anledning til at se Solvaagtinds besynderlig formede top fra forskjellige kanter, faar man indtryk av at den er tilslepet som en vridd kam av isen, der har glidd forbi paa østsiden og vestsiden. En ting er ialfald sikker: Carex scirpoidea kan umulig ha vokset paa de nuværende vokse- steder under den sidste istid. Planten synes ogsaa at være noget fordrings- fuld i valget av voksested. Den optrær paa smaa skraanende græsmyrer LOO ROLF NORDHAGEN. M.-N. KI. med Carex parallela, C. capillaris, C. alpina, C. rigida, Salix reticulata, Silene acaulis, Saussurea alpina, Polygonum viviparum, Bartschia alpina o. fl. samt en del eutrafente moser i bunden. Højere oppe paa skraaningen av tinden findes den ikke, og dennes nakne top med de steile styrtninger er aldeles uskikket for planten i nutiden, og endda mindre under et strengere klimat. Hvis Carex scirpoidea har overlevet den sidste istid 1 disse strok, maa det ha veret paa et andet sted. Det lae ogsaa tænke at denne eneste og merkelige forekomst av arten i Europa er de sidste rester av et tidligere større utbredelsesfelt. Specielt maa man Fig. 32. Utsigt fra Rosnevarre og sydover mot Salefjeldet og Skaitidalen. Lave, avrundede klipper. rete juli 1920. Nordhagen fot. tænke sig at den postglaciale varmetid med sin vældige forskyvning av skoggrænsene opad paa fjeldene har utryddet mange arter og indskrænket deres utbredelsesfelt (HANSEN 1904). Det er ogsaa forskjellige ting ved denne Solvaagtindlokalitet som synes at staa i forbindelse hermed. I nu- tiden er der netop paa estsiden av fjeldet og i skaret ved Solvaagvandet en voldsomt sterk vindvirkning, som presser skoggrænsen nedad. Denne yavtreekkanal” til og fra Junkersdal, som specielt i gamle dager, da ride- veien til Evenesdalen og Salten forte forbi her, var berygtet blandt befolk- ningen, har utvilsomt altid paavirket vegetationen paa stedet!, og sikkert > ogsaa under den hoiereliggende skoggrænses tid forhindret skogen i at 1 I Juli 1920 maatte man krype paa alle fire for overhovedet at komme gjennem passet mot Solvaagvandet. I92I. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. LOT sætte sig fast paa disse avblaaste skraaninger. Carex scirpoidea maa her ha hat specielt gunstige betingelser for at kunne overleve varmetiden og dens utryddelseskrig mot fjeldplantene. Problemet Carex scirpoidea og dens ,, overvintring" er vanskeligere at lose end vistnok mange har tænkt sig. Dette gjælder i endda hoiere grad Saxifraga Aizoon. Denne art har efter Læstanius”, SCHLEGEL og ARNELLS og i nyere tid overingenior KARLSONS undersokelser et litet utbredelsesfelt i det nordlige Norge nordøst for Carex scirpoidea, nemlig paa begge sider av Balvandet syd for Sulitjelma. Sidste sommer kunde konservator Ove Danur og undertegnede konstatere at planten fremdeles findes paa Balvandets østside (Læstanius” lokalitet »Balvandsryggen"), hvilket man har betvilet, idet den flere ganger har været eftersokt, men med negativt resultat. Baade paa Rosnevarre i nordvest for Balvand og paa Balvandsryggen (ved grænsen) optrær. Saxifraga Aizoon i forholdsvis lave nivaaer. Fjel- dene er ikke højere end 8 à 850 m., og planten overstiger neppe 800 m. Disse to fjeld- partier er paafaldende like. Fig. 33. Balvandsryggen nær Kvebilokskaret. Isskuret De er jevne og glatskuret av de med erratiske blokker. Saazfraga Aizoon-polstere : g E iforgrunden. Det kamel-lignende fjeld i bakgrunden er isen, som her er kommet fra . Nord-Saulo. Utsigt mot nordost. Den lille top tilhoire SO (cfr. Rexstap og Horw- erivirkeligheten en lang hoideryg, som her sees i profil. SENS kart 1917 l. c.). | Overalt rite juli 1920. Nordhagen fot. paa disse avrundede berg og jevne skraaninger finder man et tyndt bundmorænedække, saa tyndt at det væsentlig bestaar av utstrodde blokker, som ofte ligger placert paa de be- synderligste steder (cfr. billedene fra Rosnevarre og Balvandsryggen). Berg- grunden bestaar begge steder av kalkholdig glimmerskifer og baerer gjennem- gaaende en sparsom og aapen vegetation paa grund av manglende los- materiale. Her vokser Saxifraga Aizoon ganske talrik paa flate berg eller svake fjeldskraaninger i smaa sprækker og fordypninger, ikke paa hylder eller steile avsatser, som man gjerne tænker sig paa forhaand. Voksestedet er i det hele tat meget karakteristisk og eiendommelig. Det er nu ganske klart, at da planten kun optrær her i relativt lave nivaaer paa steder som har været isdækket lang tid utover i avsmeltnings- tiden, kan den umulig ha overlevet den sidste istid paa dette sted. Den synes at ha lette konkurrencevilkaar paa disse glatskurte klipper, idet den xerofile vegetation her er meget aapen. Dette er kanske en av aarsakene til at den holder sig netop her. Desuten kommer det 102 ROLF NORDHAGEN. M.-N. Kl. samme moment til som jeg omtalte for Carex scirpoidea, nemlig skog- graensen under varmetiden. Hverken paa de angjældende deler av Rosnevarre eller Balvandsryggen kan der ha vokset virkelig skog under varmetiden, som kan ha utkonkur- reret fjeldplantene paa stedet (f. eks. ved beskygning). Vi har her kanske en av aarsakene til at Balvandsryggen ogsaa ellers rummer saa mange sjeldenheter. Men hvorfra er da Saxifraga Aizoon kommet? Typiske nunatakformer (Turmskulptur, Enquist 1918 l. c.) findes ikke i naerheten, og partiet syd for Balvand (Argaladei—Salefjeldet o. s. v.) synes at ha været et bræcentrum. Planten forekommer heller ikke i store hoider. Man maa vistnok anta, at den har fulgt efter isen da denne trak sig tilbake fra Skjaerstadfjorden og indover landet, og at den oprindelig hadde et videre utbredelsesfelt end nu. Dens nuværende isolerte forekomst er oiensynlig betinget av vokse- stedenes eiendommelige natur. Baade for Carex scirpoidea og Saxifraga Aizoon er sporsmaalet om „overvintring under den sidste istid" ikke saa kurant som man kanske til en begyndelse skulde tro. Ovenstaaende utredning viser hvor uhyre van- skelig det er av en plantearts mere eller mindre isolerte forekomst i nutiden at trække slutninger bakover i tiden. Det nuværende alpine utbredelsesfelt er nemlig bestemt eller saa at si resultanten av en række faktorer, først og fremst: 1) plantens utbredelsesfelt før den postglaciale varmetid, 2) ind- skrænkninger og utdoen under den højereliggende skoggrænses tid, 3) even- tuelle nyere spredninger efter det klimatomslag som rykket skoggrænsene ned til sit nuværende leie, og som følgelig utvidet regio alpina. Jeg har her villet omtale disse fænomener fordi slagord som „nunatak- kolonier" og ,isfri kystrand" i de senere aar stadig dukker op i litteraturen, men uten at vi er rykket problemene nærmere ind paa livet. Special- undersøkelser mangler nemlig totalt. Og det nytter efter min mening ikke længer bare at ræsonnere mere eller mindre abstrakt over disse pro- blemer; ialfald kommer vi ikke videre ad den vei. I likhet med Hansen (1904) og Witte (1905) antar Fries at en del av den skandinaviske fjeldflora er indvandret fra øst i senglacial tid!; des- uten regner han med en indvandring fra syd. TENGWALL har fæstet opmerksomheten bl. a. ved Kobresia bipartita, Pedicularis Oederi, Campanula barbata, Gentiana purpurea og Ranunculus platanifolius, som han kalder sydlige fjeldplanter?. For disse antar han en sydlig indvandringsvei; men da de ikke har formaadd at sprede 1 Fries fordeler imidlertid de østlige indvandrere paa flere grupper (fjeldarter, bjerk- og naaleskogarter). Hans inddeling er saaledes en anden end de nævnte forfatteres og problemstillingen mere specialisert. 2 Til disse slutter Nigritella nigra sig. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 103 sig utover hele den skandinaviske fjeldkjede (de fire første findes bare i det sydlige Skandinavien), antar TENGWALL at den sydlige indvandringsvei har været mindre væsentlig. Man maa utvilsomt gaa ut ifra at der virkelig har indvandret fjeldplanter til det centrale Skandinavien fra syd (Alperne og Mellem-Europa) via Dan- Fig. 34. Kobresia bipartita's utbredelse i Skandinavien. Efter Tengwall (Enquist 1918 l. c.). mark og Sverige. Hvorledes skal man ellers forklare forekomsten av Ko- bresia bipartita, Gentiana purpurea etc. i Norge? Mens man oprindelig an- saa denne indvandringsstrøm for den vigtigste, slaar man nu over i den motsatte yderlighet. Nu skal nærsagt alle fjeldplanter enten være inter- glaciale eller østlige. Det ene behøver ikke at utelukke det andet. Naar Dryas og andre fjeldplanter har kunnet vandre helt op til 104 ROLF NORDHAGEN. M.-N. Kl. Laxä (indenfor den morænerække som svarer til raene), har de nok ogsaa evnet at komme sig op til Kristianiatrakten. Og i anledning av DANIELS- SENS interessante fund av arktiske planterester ved Kristiansand (1908, 1910, 1912 |. c.), ligger det snublende nær at anta en spredning over Skagerak fra Jylland, f. eks. med vinterstormene henover det tilfrosne hav (WARMING 1904 p. 13 og 18). Man antar jo nu at der i postarktisk tid har indvandret planter direkte fra England! og Danmark til Norge (Witte, Salmonsens leksikon XIII p. 503 og 1915 p. 101), og at der i nutiden paagaar en ind- vandring til Danmark i motsat retning (WARMING 1904 p. 15— 17). Saa- danne spredningsmuligheter har selvfølgelig altid "været tilstede og ikke bare været begrænset til noget enkelt tidsrum. At fjeldplanter fra sydøst eller sydvest er vandret helt op til Kristiania, fremgaar av Ovens fund av Salix polaris i Aker og Asker fra Portlandia- nivaaets tid’. Nordmarken ved Kristiania har topper som nu gaar op til over 700 m. o. h., og som var ca. 500 m. dengang havet stod ved den marine grænse. Da isen forsvandt herfra efter Aker-stadiet og Romerik- stadiet (cfr. ovenfor), har utvilsomt en arktisk vegetation hat gode be- tingelser paa disse koller og hoidedrag. Ovens fund av Dryas octopetala og Betula nana fra yngre avleiringer (som dog er vanskelige at tidfæste) ved og i Kristiania by, viser at fjeldplantene ogsaa har holdt sig her en stund utover i postarktisk tid (OvEN 1915 |. c. p. 35). Vi maa anta at den skandinaviske fjeldflora er blit rekrutert ogsaa fra syd, og det er foreløbig meget vanskelig at avgjore om enkelte arter har været interglaciale overvintrere, eller om de er sydlige indvandrere. Vort kjendskap til den vegetations beskaffenhet som fra syd fulgte efter det av- smeltende isdække opover mot det centrale Norge, er imidlertid uhyre mangelfuldt. De fleste er vel nu tilboielige til at anta at den var mere blandet arktisk-subarktisk end egentlig arktisk, og at vi i Norge kun har hat en egte ,Dryas-tid" i de deler av landet som allerferst blev isfrie (det trondhjemske, vestlandets fjordegne med tilstetende fjeldtrakter, kystranden nordover), og at de lavere landsdeler i syd og øst som blev blotlagt senere, og som laa aapne for den sydlige indvandringsstrom, ikke har hat nogen veritabel Dryastid av hoiarktisk præg. Her har ogsaa store strækninger ligget under hav i det kritiske tidsrum. Imidlertid er der her en mulighet som ikke bør oversees, og som Oyen har fæstet opmerksomheten ved. Hvis vi nemlig i Norge har hat en saadan senglacial klimatoscillation som Allerødperioden i Danmark (My- tilus-nivaaet) og betydelige deler av landet under denne tid var isfrie, maa dette ha været en gylden tidsalder for fjeldvegetationen (OvEN 1915 l. c. p. 296), som dog atter i betydelig grad maatte bli decimert, ialfald i visse 1 Norman (1855) er vistnok den første som har fremsat denne mening. 2 ØYEN 1907 B. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 105 strøk, under Portlandia-nivaaets nye bræfremrykning. Vi ser altsaa at ogsaa paa dette punkt er spørsmaalet om Myri/us- og Portlandia-nivaaets natur og specielt disse perioders klimatologiske valør av indgripende betydning. Det bør efter ovenstaaende utredning ikke virke særlig overraskende naar vi i bunden av Gudbrandsdalens kalktuffer ikke finder rester av arktisk-alpine planter. Imidlertid har der i den første tid efter isens ende- lige avsmeltning i disse strøk ikke været gunstige betingelser for kalktuf- dannelse. Som tidligere omtalt viser baade Leine- og Gillebutuffen at den første tid efter isens forsvinden har været meget kontinental, kanske arid. Og den første flora og vegetation har derfor ikke efterlatt sig noget spor i tuffene. Det kan for den saks skyld godt ha været fjeldplanter, det kan ogsaa ha været en mere blandet vegetation. Vi vet heller ikke hvor længe dette tidsrum, som er indhyllet i mørke, har varet. III. Gudbrandsdalens kalktuffer og Blytts teori. Brvrr tok kalktuffene til indtægt for sin bekjendte teori om de veks- lende tørre og fugtige perioder efter. den sidste istid (1876), ja han be- tragtet dem som vigtige støttepunkter for sin teori. Om denne har stridens bølger altid gaat meget høit. Man har kritisert Brvrrs torvmyrundersekelser, og med en viss berettigelse, idet de ikke tilfredsstiller nutidens krav. Men saa hadde Brvrr heller ikke det erfaringsgrundlag at bygge paa som senere forskere. — BLYTTs teori frem- stilles ogsaa undertiden i litteraturen som et slags ,skema", som vel i sin tid hadde heuristisk betydning, men som nu forlængst har passert henover tidens slipesten. Imidlertid vil enhver der ser objektivt paa forholdene, maatte indrømme at dette ikke er tilfældet. Den av Brvrr hævdede op- fatning er modificert paa mange maater; en hel del av hans meninger har tiden ogsaa visket ut. Men studerer man opmerksomt moderne skandinavisk kvartærgeologisk litteratur, skinner Brvrrs teori igjennem paa en række punkter. Dette gjælder saaledes læren om stubbelagene i torvmyrene. Ved nyere svenske, danske og norske (HOLMSEN 1919 og 1920 I. c.) under- sokelser har det vist sig at ialfald det yngste av Brvrrs stubbelag har generel betydning i Skandinaviens myrer. Under den hydrofile „yngre Sphagnumtorv" optrær en markert ,uttorringshorisont", som oftest i form av et stubbelag, hvis tilstedeværelse ikke kan forklares paa anden maate end ved den antagelse, at der dengang laget blev dannet, fremhersket et tørt klimat, saaledes som Brvrr antok. Disse to yngste lag i myrene benævnes nu almindelig den subatlantiske torv og den subboreale uttork- 106 ROLF NORDHAGEN. M.-N. Kl. ningshorisont!. Dette fænomen (den subatlantisk-subboreale kontakt) er nu beskrevet fra saa mange lokaliteter at man ingen grund har til at betvile dets generelle karakter. (Cfr. Brvrrs, SERNANDERS, VON Post’s og deres elevers arbeider, Jessens nye studier i Danmark, Hoimsens i Norge). Under det subboreale stubbelag optraer der 1 myrene gjennemgaaende sterkt hydrofile torvdannelser, som av de forskere der akcepterer BLyrr- SERNANDERS opfatning, benævnes „atlantisk torv", Og under denne kommer i mange tilfælder atter et avbrud, „det boreale stubbelag", som forovrig ikke synes at være saa sterkt markert som det subboreale (von Post 1918 l. c., JESSEN 1920). Disse fire hovedled i torvmyrenes opbygning (oven- fra nedad): subatlantisk torv, subborealt uttorkningslag, atlantisk torv, borealt uttorkningslag, gjenfinder man i alle de nyeste oversigter inden skandinavisk torvmyr- litteratur. Svenske forskere har ogsaa trukket frem en mængde andre fakta (bl. a. hydrografiske studier over avløpsløse sjøer i boreal og sub- boreal tid?) som bekræfter ovennævnte periodiske vekslinger. Hvad der ligger under det boreale lag, er derimot meget omdisputert. Bıyrr antok oprindelig at der her fandtes et ,subarktisk torvlag"; senere paastod han til og med at der under dette torvlag atter fandtes et ældre stubbelag (i de myrer som laa hoiest over havet), og han forandret da terminologien derhen, at torvlaget kaldtes „infraborealt“ og stubbelaget »Subarktisk" (sensu stricto). Imidlertid er det paafaldende, at ingen av de forskere som i nyere tid har arbeidet med torvmyrene, tydelig har gjen- fundet disse to horisonter. De ,praeboreale“ lag er forovrig lite bearbeidet (cfr. SERNANDERS uttalelser 1916 p. 136—138); men hvis forholdene hadde været saa markerte som Bryrr mente, vilde disse lag utvilsomt ogsaa faat sin rette plads i den kvartærgeologiske oversigt. De fleste palæobotanikere synes vistnok at helde til samme anskuelse som SERNANDER, nemlig at be- tegnelsen „subarktisk“ bør anvendes om alt det som er ældre end det boreale lag (altsaa Brvrrs oprindelige betegnelse), og at dette navn kun er et uttryk for mere eller mindre usikre fysiografiske forhold („glidende utviklingsmomenter"). Allerede Brvrr forsøkte at faa istand en korrelation mellem torvmyr- forskningens resultater og de marine nivaaforandringer i post- arktisk tid; dog hadde han et høist utilstrækkelig materiale at bygge paa (892 D c p.56). 1 WEBERS „graensehorisont“ (1910 I. c), som udmerker Nordtysklands myrer. 2 SERNANDER 1910 (utforlig litteraturfortegnelse) p. 205, 213—214. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 107 For Norges vedkommende har senest Oyen sokt at sammenstille resul- tatene fra disse forskningsgrener. Og det eiendommelige er, at mens i torv- myrene de „praeboreale“ lag er daarligst kjendt, er i grunden det motsatte tilfældet med de norske marine avleiringer. Ved ældre geologers og 1 nyere tid BRØGGERS og ØYENS vidtløftige studier er de avleiringer som ligger mellem den marine grænse og Tapes-nivaaet, meget godt kjendt (BRØGGER 1900— 1901, ØYEN (talrike avhandlinger)). Da bræene for sidste gang stod ved de store indsjøer i det østen- fjeldske Norge, hadde landplaten allerede begyndt at hæve sig en smule. Et klimatomslag begyndte nu at gjøre sig gjældende. Den yngste Portlandia- fauna dor ut, og isteden faar vi ZLifforina-mvaaets tempererte faunal. Dette nivaa er meget utpræget baade i Kristiania- og Trondhjemsfeltet og ud- merker sig ved. fremtrædende skjælbanker (littorale avsætninger), derimot ved svak akkumulation, hvorfor Oyen tolker denne periode som relativt kontinental. Landet fortsatte imidlertid at hæve sig, og vi kommer over i en periode hvis avsætninger følgelig ligger lavere end de foregaaende. Oven kalder dette karakteristiske nivaa for Pholas-nivaaet. Det udmerker sig ved fore- komsten av betydelige lerterrasser i Kristianiafeltet, altsaa en akkumula- tionsperiode. Det maa utvilsomt ha været en tid med rik vandforing og store slammængder i elvene, en relativt fugtig periode, hvis fauna var av sydvestlig præg og betydelig mere varmekjær end den foregaaende periodes. Endelig opfører Øven Mactra-nivaaet som det tredje led i rækken; det udmerker sig atter ved manglende akkumulation, ved skjælbanker og ved en varmekrævende fauna. Efter Mactra-tiden synes der at ha skedd en tydelig sænkning av landplaten, som dog er liten baade ved Kristiania og Trondhjem, men som maa paralelliseres med ,Littorina-sænkningen” i Sverige og Danmark. Denne fører os over i 7apes-nivaaet (sensu stricto), den fugtige atlantiske tid, atter med akkumulation og dannelse av lerterrasser. At Tapes-nivaaet og den ,atlantiske periode" falder sammen, derom synes nu alle kvartærgeologer at være enige. Under denne periode skal da det atlantiske torvlag i myrene være dannet. Og OYEx paralelliserer da helt naturlig Littorina-nivaaet med Brvrrs subarktiske tid (sensu stricto) Pholas-nivaaet — infraboreale tid Mactra-nivaaet = = boreale tid. Vi ser altsaa at de norske marine avleiringer stemmer med Brvrrs opfatning av de præboreale lag, og Oyen finder derfor anvendelse for Brvrrs engere opdeling av den oprindelige ,subarktiske" tid i to forskjel- lige avsnit. OvENs nivaa-inddeling for disse ældre postarktiske tidsrum er fast underbygget og anerkjendes nu av saagodtsom alle norske geologer (cfr. 1 Dette nivaa maa ikke forveksles med „Littorina-tiden“ i Sverige og Danmark. 108 ROLF NORDHAGEN. M.-N. Kl. JJORLYKKE 1913, BRØGGER 1914). Saa meget er ialfald sikkert, at hvad de marine avleiringer angaar, saa kan vi i Norge meget vel karakterisere avsnittet mellem den marine grænse og Tapes-nivaaet, saavel faunistisk som klimatologisk. Men da kjendskapet til torvmyrenes præboreale lag er mangelfuldt, er det al grund til at være forsigtig og ikke generalisere ovennævnte resultater uten videre. Fremtiden faar avgjøre om vi ogsaa i præboreal tid har hat perioder synkrone for hele Skandinavien. De avleiringer som er yngre end Tapes-nivaaet, er ogsaa meget inter- essante baade i Kristiania- og Trondhjemsfeltet. Oven har her indført be- tegnelsen ,,771via-nivaaet" efter et „faunistisk kompleks". (Trivia europea, Lima loscombi og Conulus millegranus), som udmerker skjælbankene i et nivaa lavere end Tapes-nivaaet. Av faunaens utpræget sydlige og varme- kjære karakter, den manglende akkumulation etc. utleder Oven at Trivia- nivaaet betegner den aller varmeste og aller tørreste del av den postglaciale varmetid. Dette gjælder tildels ogsaa første del av det efterfølgende nivaa, som Oyen kalder Ostræa-nivaaet, som falder i et ældre og et yngre avsnit. Skillet mellem disse avsnit ligger ved en havstand av ca. II m., og Ostræa-nivaaets yngste avdeling synes at ha været relativt fugtigere og noget kjøligere end det ældre avsnit mellem 11 m. 08.22 mo... Nu skulde man tro at Oyen vilde paralellisere sit Trivia-nivaa og første del av Ostræa-nivaaet med Bryrrs „subboreale“ periode, som jo karakteriseres som varm og tor, og den anden del av Ostræa-nivaaet med den ,subatlantiske periode". Imidlertid har Brvrr i den korrelationsover- sigt som han utarbeidet, sat graensen mellem disse to perioder ved en havstand 9,4 m.—13 m. subboreal 15,7 r3 m. Oh: subatlantisk 9,4— om. o. h. (Brvrr 1882 l.c. p. 8, 9, 12 13 og 1892 p. 44 eh Og til trods for at Ovens nivaaer hvad strandlinjens beliggenhet angaar, ellers stemmer meget daarlig med Brvrrs (paa et mangelfuldt materiale baserte) beregninger”, lar han her Brvrrs angivelser gjøre utslaget og paralelliserer kun Ostræa-nivaaets første del med Bryrrs subboreale og det samme nivaas senere del (under rr m.) med Brvrrs subatlantiske periode. Paa denne maate blir Trivia-nivaaet staaende igjen uten relation til nogen av Drvrrs perioder, til trods for at det er mere markert konti- nentalt og varmt end Ostræa-nivaaets første del. Trivia-nivaaets strandlinje gaar nemlig helt op til 47 m. o. h. Følgen av det hele blir da den, at ØYEN blir nødt til at indføre to nye betegnelser: ,neoboreal" for Trivia-nivaaet og „neoatlantisk“ (= sub- I Ostreea-nivaaets ældre avsnit skal dog ifølge Oven være en smule mere maritimt be- tonet end Trivia-nivaaet. 2 Cfr. OvEN 1915 l. c. p. 99. 1921. No. Q. KALKTUFSTUDIER I GUDBRANDSDALEN. 109 boreal + subatlantisk) for Ostræa-nivaaet for at faa orden paa tingene. Men disse nye betegnelser, hvorav den sidste ,neoatlantisk" likefrem bryter med hele traditionen 1 Brvrrs nomenklatur, idet her ordet atlantisk (5: fugtig, maritim) anvendes som fællesbetegnelse baade paa en tør (subboreal) og en fugtig (subatlantisk) periode, bidrar bare til at øke nomenklaturvanskelig- hetene. Det store spørsmaal blir da om baade Trivia-nivaaet og første del av Ostræa-nivaaet skal paralelliseres med Brvrrs ,subboreal". En kombi- nert studie av skjælbanker og lerlag mellem Tapes-nivaaet og nutidsstrand- linjen paa den ene side, og torvmyrer med utviklet subboreal—subatlantisk kontakt i det samme spatium paa den anden side, kan her alene si det av- gjørende ord. Hvis nemlig Trivia-nivaaet, saaledes som ØYEN antar, har været den varmeste og mest kontinentale periode efter isens avsmeltning, maa torvmyrene utvilsomt bære vidnesbyrd herom i form av et stubbelag. Dette bør være meget markert, ialfald vel saa markert som den horisont som Ostræa-nivaaets første avsnit har efterlatt sig (,subboreal" i OvExs mening). Men hvis nu Trivia-nivaaet og Ostræa-nivaaet I begge har været hovedsakelig av kontinental natur, burde man a priori bare vente at finde ett yngre stubbelag (eller uttørkningshorisont) som vidnesbyrd om begge disse to avsnit! — hvilket jo ogsaa er tilfældet. — Paa dette punkt er korrelationen mellem de marine avleiringer og torvmyrene temmelig usikker. Nedenstaaende skema viser korrelationen mellem OYExs nivaaer og Brvrrs perioder: Mytilus-nivaaet? — arktisk Portlandia-nivaaet? — subglacial Littorina-nivaaet — subarktisk (sensu stricto) Pholas-nivaaet — infraboreal Mactra-nivaaet — boreal Tapes-nivaaet — atlantisk Trivia-nivaaet — Ostræa-nivaaet I | — subboreal Ostrea-nivaaet II | — subatlantisk. Jeg skal ikke her gaa naermere ind paa disse detaljer. Sammenlignes OYvENs opfatning med de svenske torvmyrforskeres (SERNANDER, VON Post etc.), er der for saavidt en vigtig overensstemmelse som ØYEN meget be- stemt henlægger det postglaciale klimatoptimum til tiden efter Tapes-nivaaet, mens man tidligere antok at den atlantiske tid betegnet klimaks$. Likeledes er det meget paafaldende at mens Tapes- nivaaet (sensu stricto) utpræger sig som en fugtig akkumulationsperiode, synes Trivia-nivaaets (og tildels første del av Ostræa-nivaaets) avleiringer 1 Altsaa en ,neoboreal-subboreal" fælleshorisont efter OvENs terminologi. bo Denne periode er tidligere omtalt under kapitlet ,Isavsmeltningen i Gudbrandsdalen". [^ Cfr. BRØGGERS redegjorelse hos SERNANDER 1910 |. c. p. 226 — 227. 110 ROLF NORDHAGEN. M.-N. Kl. at vidne om kontinentale klimatforhold, som atter synes at slaa om ved rr meters strandlinjen, dog uten voldsomme ændringer. Imidlertid harmonerer dette ikke videre godt med den nyere svenske opfatning (SERNANDER, VON Post o. fl.), hvor den varme og tørre „sub- boreale" tid henlægges til den yngre stenalder og bronsealderen, den fug- tige ,subatlantiske" til overgangen mellem bronsealderen og jernalderen. Oven maa nemlig forlægge sit Trivia-nivaa og Ostræa-nivaa I meget længer bakover i tiden, da Trivia-nivaaets strandlinje ved Kristiania og Trondhjem gaar op til mellem 40 og 50 m. o.h., mens strandlinjen i bronse- alderen synes at ha indtat omtrent samme stand som i nu- tiden (BRØGGER 1905 |. c.). Imidlertid kan vi f. eks. i Kristianiafjorden kon- statere et andet omslag ved overgangen til nutidsstrandlinjen; en række syd- lige og sydvestlige former utdor, og Mya arenaria indvandrer (OyENS Mya-nivaa = recent tid). Denne er ikke fundet fossil over nuværende hav- stand (OvEN 1913 l.c. p. 381). Den marine faunas utvikling vidner dog ikke om nogen voldsomme ændringer. Hvorledes disse divergenser skal utjevnes, blir det den fremtidige forsknings sak at avgjore. De stratigrafisk-biologiske fænomener som ligger til grund for hele denne lære om vekslende klimatiske perioder, er i begge tilfælder de samme, og alle ting tyder paa at vi har hat synkrone perioder for hele Norden. For saavidt skulde problemet ha utsigt til at bli endelig løst. Men dertil kræves nye undersøkelser og atter nye under- søkelser. Brvrrs teori og SERNANDERS videre selvstændige utformning av samme har i likhet med Oyens opfatning i disse sporsmaal været gjenstand for til- dels voldsom kritik og imøtegaaelse. Og jeg kan saa godt forstaa at mange forskere finder den anførte inddeling og karakteristik av den postarktiske tid altfor indviklet. Det var meget lettere for videnskapen hvis alle disse mange perioder kunde undgaaes! Men undersøkelsene ute i marken viser os atter og atter at forholdene har været meget komplicerte. Og læser man med opmerksomhet de nyere avhandlinger f. eks. av G. ANDERSSON, som kanske mere end nogen anden har stillet sig i opposition til klimavekslingsteorier, vil man finde at han ogsaa ganske tydelig maa ta sin tilflugt til variationer, ikke bare i temperatur, men ogsaa i nedbør, for at kunne forklare stratigrafiske og biologiske for- hold. - Saaledes skriver ANDERSSON (1909 S. G. U. Årsbok p. 77): „in the Baltic bassin after a period that was warmer and drier than the present, during the latter part of the Ancylus age, there followed gradually under the Littorina-age, an equally warm but much wetter period" (senere an- fører han en antat aarlig nedborhoide av ca. 1000 mm.). Samme forfatters uttalelser p. 67 og specielt i note 2 paa samme side er ogsaa ganske paa- I92I. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. TT STRANDERNAS VEGETATION ansatser til en klimavekslings- as bb c M und s SEK faldende. Man har her tydelig teori, selv om periodene ikke —— blir helt synkrone med andre SUB. 1 forfatteres. ATLANTISK LOS TURF = a Gaar vi derefter over til SEES SER ee e aa ln N kalktufstudiet i norden, N saa har det ogsaa bragt en lang række stratigrafiske og SUB- 3 plantegeografiske eiendomme- SOREAR KA Uhl ligheter for dagen, som viser à at forholdene efter den sidste ~ istid ikke har veeret helt enkle. à BLL NEN Ue c NOS. - RN Efter Brvrrs avhandling i 1892, som maa siges at være a klassisk inden denne forsk- ningsgren, er der specielt fra ; svensk side kommet en lang ON række monografiske arbeider ATLANTISK wee ra d over svenske tuffer (HurrH, = KURCK, SERNANDER, HALLE, d KJELLMARK o. fl). Av disse “ er kanske Skultorptuffen ^ z i Västergötland den som for- $500 år t tjener størst opmerksomhet, da den gir det mest sammen- œ e > m Er > a a TALLSKOG hængende og uforstyrrede Mn Een billede av utviklingshistorien. KS == = LE . Uu E Benestadtuffen i Skaane AMBLYSTECIUM -TUFF M ES obs hee interessant SUB- OCH BLEKE > as r ogsaa uhyre interessan ANSE NE . . > «m og teoretisk betydningsfuld. à à = i Om Jemtlands tuffer maa DURS FE i: : à 1500 år fine UT: = man naermest si at de strati- SET EIER A a4, grafiske forhold der er mere problematiske og vanskeligere Fig. 35. Skultorptuffen. (Sernander 1916). at tolke. Det av Bıyrr for Gudbrandsdalens tuffer paaviste fænomen, at avsæt- ningen ikke har paagaat kontinuerlig, men intermitterende, har senere vist sig at ha nærsagt generel betydning. Saaledes konstaterte HurrH for Skultorptuffen 2 markerte avbrud, karakterisért ved optræden av humus- render i tuffen eller tydelige forvitringsfænomener. Huzrx fandt 3 tyde- lige tufdannende perioder og 2 uttørkningshorisonter, og det laa da nær 112 ROLF NORDHAGEN. M.-N. Kl. at paralellisere disse med de av Biyrr og SERNANDER antatte klimatiske epoker (HurrH 1899 I. c.). At saagodtsom hele den postarktiske tid var repræsentert i Skultorpprofilet (fig. 35), fremgik av floraens gradvise for- andringer; selv ikke de arktiske elementer manglet i bunden. Av Kumcks (1901) og senere SERNANDERS studier (1916 |. c.) fremgaar det at ogsaa Benestadtuffen har 2 avbrud; men paa grund av en omfattende eksploitering av denne kalkforekomsts øvre del, er de yngre lag, som indeholder det yngste (,subboreale") avbrud, fjernet over næsten hele omraadet og der- for vanskelig tilgjængelige (cfr. dog profilet fra Skvattemållan, SERNANDER 1916 l.c. p. 160). — Endelig har vi Hates arbeide over den floristisk heist interessante Botarfve-tuf paa Gotland (1906 |. c.), som foruten en del smaa lokale avbrud viser én markert muldstripe gjennem hele tuffen. Da findestedet har ligget under hav til langt ut i den postglaciale varmetid, burde man her ogsaa a priori vente at finde bare ett distinkt avbrud, idet nemlig ældre lag svarende til ovennævnte tuffers undre deler, ikke har kunnet komme til utvikling paa stedet. Ogsaa fra andre deler av Sverige er der beskrevet mindre kalktuffer med humusrænder. Av nærværende avhandling vil det ogsaa fremgaa at Gudbrands- dalens tuffer, saaledes som vi nu kjender dem ved Ovens og HorwEs samt undertegnedes nye undersøkelser, taler et meget bestemt sprog og stemmer godt overens med de resultater som svenske kalktufforskere er . kommet til. Ja, undertegnedes studier over Leinetuffen har til og med git det for- bløffende resultat, at denne stemmer meget bedre med klimavekslingslæren end BLYTT selv ante. Bryrr var selv til en begyndelse meget i tvil om hvorledes Leine- tuffen burde tolkes. I sin første beskrivelse (Naturen 1891) tolker han furutuffen som synkron med det yngste torvlag 1 myrene (sub- atlantisk). Dryastuffen blev da subboreal og birketuffen samtidig med det næstyngste torvlag, altsaa atlantisk: Furutuf — subatlantisk Dryastuf og kalkler — subboreal Birketuf — atlantisk. Imidlertid bragte kalktuffen ved Nedre Dal ham bort fra denne tolkning; han ansaa det nemlig heist usandsynlig at en birketuf av subalpint praeg paa saa lavt nivaa som Nedre Dal kunde skrive sig fra en saa ung periode som den atlantiske, der tvertom, efter andre undersokelser at dømme, syntes at ha været varmere end nutiden. Bıyrr forkaster derfor den første forklaring og hævder at tuflagene maa være ældre (1892). Den nye kor- relation blev da: Furutuf — atlantisk Dryastuf — boreal Birketuf — infraboreal. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 113 Imidlertid maa dette siges at være en temmelig dristig tolkning; for konsekvensen av det hele blir at der i Gudbrandsdalen ikke har været nogen tufdannelse under den sidste av Brvrrs fugtige perioder, den sub- atlantiske tid. Med andre ord: Torvmyrenes subatlantiske torv- lag og subboreale uttørkningshorisont, som jo netop har vist sig at vere de mest generelle, skulde altsaa ikke ha nogen ækvivalent i Gudbrandsdalens tuffer. At Brytt selv har undret sig over forholdet, fremgaar tydelig av det citerte arbeide. Han skriver nemlig (l. c. p. 23): ,,Man maa jo ogsaa let tænke sig at kalkgehalten i grunden kan uttømmes saa at de senere fugtige tider kan gaa hen uten tufdannelse. Ja da vi ved Nedre Dal saa at furu- tuffen laa ved siden av birketuffen-og ikke over den, er endog den mulighet forhaanden, at yngre tuflag kan findes baade ved Nedre Dal og Leine!, ihvorvel jeg anser dette for lite rimelig." Omtrent 30 aar efter at disse uttalelser fremkom, lykkedes det imid- lertid undertegnede ved Leine virkelig at fremfinde et yngre tuflag (Alnus- tuffen), som hviler diskordant paa furutuffen. Og vi kan nu med be- stemthet si at den subboreale uttørkningshorisont og det subatlantiske torvlag har sin fuldstændige stratigrafiske motsvarighet inden Leinetuffen. Denne kalktuf tvinger os nu simpelthen ind i BLyrrs tankegang: Alnus-tuf — subatlantisk Forvitring og diskordans — subboreal Furutuf — atlantisk Xerofil Dryasmatte og diskordans — boreal Bladtuf og mosetuf — subarktisk (1 videste forstand). Som jeg for har nævnt, bygger Alnus-tuffen paa en udmerket maate bro over til nutidsforholdene, hvilket ogsaa befæster ovenstaaende kor- relation. Jeg var selv oprindelig temmelig skeptisk overfor Brvrrs tolkning av tuffene, idet jeg nemlig i likhet med mange andre fandt hele dette indvik- lede system av perioder en smule usandsynlig. Og jeg fandt ogsaa det fænomen, at de to sidste perioder, som andre steder i Skandinavien er de mest markerte, skulde ha gaat sporløst hen over dalens tuffer, noget mystisk. Men naar man saa en vakker dag finder netop det som Brvrr savnet, men hvis tilstedeværelse han i grunden har forutsagt, er dette altfor paafaldende til at bero paa nogen tilfældighet. Naar man videre ser hen til at neiagtig de samme perioder og av- brud synes at komme igjen i Gillebu—Tingvoldprofilene (OyEN 1920) (avleiringene fra den sidste periode dog i en noget modificert, men ut- præget form), maa man uvilkaarlig studse. I likhet med Skultorp og Bene- 1 Uthævet her. Vid.-Selsk. Skr. I. M.-N. Kl. 1921. No. 9. | 8 114 ROLF NORDHAGEN. M.-N. Kl. stadtuffen viser baade avsætningene ved Leine og Gillebu — Tingvold 3 tyde- lige opsvulmninger av de virksomme kilder og 2 avbrud i avsaetningen. Overensstemmelsen med torvmyrforskningens resultater og de marine av- leiringers vidnesbyrd er likeledes paafaldende. Alt i alt maa man ogsaa indrømme, at klimavekslingsteorien paa en utvungen maate formaar at lose alle disse stratigrafiske problemer. Vi har for tiden ingen anden arbeidshypotese som er bedre!. Og akcepterer man ikke denne forklaring, blir Gudbrandsdalens kalktuffer en eneste lang række av sporsmaalstegn, en indviklet serie av merkelige og uforklarlige, men lovmaessige vekslinger. Jeg stiller mig skeptisk overfor mange av de konsekvenser som BLyTr i sin tid trak av sin teori. Saaledes tror jeg at hans floristiske grupper tildels er grove skematiseringer, og at vor flora ogsaa gjemmer problemer som Brvrr ikke var opmerksom paa. Hans plantevandringslære indeholder sikkert ogsaa store overdrivelser og mange ensidige synsmaater. Men hvad der for undertegnede i denne forbindelse staar som hoved- saken, er selve klimavekslingslæren som kvartærgeologisk arbeids- hypotese. Til trods for de mange divergerende opfatninger som her ogsaa gjør sig gjældende, maa man dog indrømme at denne fremdeles er et . . (7 aktuelt centrum — eller stormcentrum — i nordisk kvartergeologi ^. Korrelation. | Brvrrs perioder | Leine Gillebu — Tingvold Nedre Dal Recent tid. . . . . . | Forvitring, svak Forvitring Forvitring mosetufdannelse Subatlantisk Alnus-tuf Erosion med Utglidning ? avsætning av grus og tufstyk- ker paa sekun- dært leiested 1 Cfr. SANDEGRENS oversigt over svensk kvartærgeologisk forskning i sidste hefte av Geol. Fören. Förh. Stockholm 1921, hvor den Brvrr-SERNANDERSKE teori og dens store betydning belyses paa en udmerket maate. 2 Henrik PRINTZ har i sit netop publicerte store arbeide over ,The vegetation of the Siberian— Mongolian Frontiers" (1. c.) git en række interessante oplysninger om klima- tiske forandringer i de angjældende trakter av Asien i nutiden (forskyvninger i steppens utbredelse paa skogens bekostning som en følge av klimaets utvikling i tør retning). Printz synes ogsaa at ville søke forklaringen herpaa i Brvrrsk retning, og hans arbeide turde faa betydning for diskussionen om den ,,subboreale" periodes klima og plantevekst. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. ITS —————————————————————————————UeMoOeOoeeoveoveeoveernÓ Brvrrs perioder | Leine Gillebu — Tingvold Nedre Dal Eubboreal - . . . .. Forvitrings- Forvitring ? horisont Emanüsk. ...-... | Furutuf | Furutuf | Furutuf or USE lose: Dryastuf og Jordstripe Diskordans diskordans Snbarküsk. : . … . . | Bladtuf og Bladtuf Bladtuf mosetuf (I Gudbrandsdalen Rød lere Forvitret ? 2 forskjellige av- moræne, anrik- snit, det ældste ning av jern- meget kontinentalt) forbindelser Sidste isbræ . . . Moreenelere Morænegrus Moræne med blokker IV. Bemerkninger om Gudbrandsdalens plantevekst i postarktisk tid. I det følgende skal jeg behandle de enkelte avsnit i kalktuffenes ut- viklingshistorie mere indgaaende og omtale de konsekvenser som oven- staaende korrelation medfører. A. Den subarktiske tid. Jeg anvender her Bıyrrs oprindelige og videste betegnelse, idet jeg ikke føler mig helt overbevist om at Brvrrs »infraboreale" og ,,subark- tiske" (sensu stricto) perioder er av generel natur. Paa dette punkt maa man avvente torvmyrforskningens resultater med hensyn til de ,præ- boreale" lag. Jeg har allerede under gjennemgaaelsen av tuffene omtalt den konti- nentale periode umiddelbart efter isens endelige avsmeltning i dalen, som udmerket sig. ved forvitrings- og oksydationsfænomener i overflatelagene. Vi har her et forhold som er av stor betydning for diskussionen om tuffenes alder og opstaaen. ANDERSSON og BIRGER, som omtaler baade Jemtlands og Gudbrands- dalens tuffer i sit store arbeide om Norrlands flora (1912), uttaler fel- gende herom: 116 ROLF NORDHAGEN. M.-N. KI. »Det torde kunna starkt ifragasättas om ej kalktuffernas i tiden uppen- ‘barligen skarpt lokaliserade förekomst, kan stållas i samband med den stora- mangd grundvatten som tillfürdes dessa kalktrakter just i samband med isens afsmältning. - Tuffbildningen skulle, om ofvan framkastade måj- lighet visar sig riktig, icke státt i samband med någon ,våt" period, som flera forskare förmodat, utan med afrinningen af den sista delen af den i inlandsisen under årtusenden magasinerade nederbürden” (l. c. p. 144—145). Om Jemtlands tuffer uttaler forfatterne senere: „Enligt har håfdade upp- fatning skulle de egentliga kalktufferna till alldeles öfvervägande del bildats under nägra ärhundraden alldeles vid tiden för de sista isresternas defini- tiva afsmältning.“ Leine og Nedre Dal „ligga i ungefär samma läge till dessa trakters isdelare, som de jämtländska tufferna (fig. 20) och ha en i alla detaljer fullständigt motsvarande flora" (l. c. p. 145), og forfatterne synes at ville utstrække den samme forklaring til ogsaa at gjælde disse norske tufforekomster. Av redegjerelsen i nærværende arbeide vil det imidlertid fremgaa at tufdannelsen i Gudbrandsdalen slet ikke har begyndt 7 tik slutning til isavsmeltningen, men først senere. Ders markert og eiendommelig interval imellem, som antageligvis ikke har været helt kortvarig. Den av ANDERSSON og BIRGER hævdede opfatning maa alt- saa forkastes. Desuten er baade Leine-. og Gillebu—Tingvold-avleiringene saa avvekslende og indviklede, at det bare av den grund er en umulighet at anta at altsammen er dannet i løpet av nogen aarhundreder, ved den tid da de sidste isrester avsmeltet. Paa forfatternes kartskisse (fig. 20 I. c. p. 138), hvor isskillet og kalktuflokalitetene er indlagt, er isskillet over det østenfjeldske Norge ogsaa indtegnet feilagtig; det er placert like nord for Nedre Dal, passerer altsaa ret over Gillebu i Øier herred. Og Leine er anbragt et godt stykke nordvest for isskillet, hvilket altsammen ikke stemmer med de faktiske forhold, saaledes som disse for længe siden er klarlagt av REgkstan og Oyen. Isskillet laa nemlig flere mil hoiere oppe i dalen end Leine, saaledes som jeg før har omtalt. Da Gudbrandsdalen i nutiden har et utpræget kontinentalt klimat, sam- menlignet med andre deler av vort land, er det forbundet med adskillig risiko at ville generalisere den kontinentale periode hvorom tuffenes under- lag bærer vidnesbyrd. Fordi om forholdene var ekstreme oppe i dalen, behøver dette ikke at ha været tilfældet andre steder i landet. Da Øvens Littorina-nivaa repræsenterer den første tid efter isens endelige avsmeltning, og udmerker sig ved svak akkumulation og typisk skjælbankedannelse baade i Kristiania- og Trondhjemsfeltet, betragter ØYEN forvitringshorisonten i bunden av kalktuffene som et hermed overensstem- mende og synkront fænomen, med andre ord: perioden skal ifølge ØYEN allikevel ha været av generel natur (1920 |. c. p. 335). | Hvorledes Gudbrandsdalens plantevekst var beskaffen i den allerførste tid efter isens forsvinden, er uvisst. Da kildene begyndte at springe frem 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 1307 som en folge av oket nedbør, fandtes der en subarktisk lavtrævegetation baade ved Leine, Gillebu og Nedre Dal. Ved Leine har vistnok enkelte fjeldplanter været tilstede. Man faar et levende indtryk av at Gudbrands- dalen maa ha frembudt et billede som et av vore subalpine dalfører med frodige bjerkelier tilblandet asp, heg og Salices (baade grønne og graalodne). Forekomsten av furupollen kan bero paa en sporadisk optraeden av furu paa specielt gunstige lokaliteter; men som for nævnt er langflugt ikke utelukket!. Flere ting vidner ialfald om at furuen maa ha været lov- trerne helt underlegen. Ved Gillebu dækkes tuffen og bækkedalens omgivelser i nutiden av en blandet furu- og granskog, som er meget vakker. 'Terrænget passer ogsaa udmerket for furu (utvasket morænegrus); at granen her som alle andre steder har presset sig frem paa furuens bekostning, er en sak for sig.. Vi har ogsaa set at under furutuffens tid har findestedet hat typisk uruskog. Hvis nu furuen under subarktisk tid hadde været almindelig i Oier rundt omkring findestedet, hvorfor skulde den da ,tilfeldigvis" mangle netop paa denne lokalitet, hvor den i den efterfølgende periode (furu- tuffens tid) synes at trives fortrinlig, til trods for at jordbundsfor- holdene hele tiden er de samme, og likeledes i nutiden? Det samme gjælder Leine. Under furutuffens tid har lerbakkene og tufkildens nærmeste omgivelser været rigtig et onskested for furuen, at dømme efter den kolossale masse med avfald som tuffen indeholder. Skal ogsaa her den typiske bladtufbaenk, uten makroskopiske fururester, skrives paa tilfældighetenes regning? Mang}er furuen her bare fordi der ,tilfæl- digvis" stod en hel del lovtrær „iveien“ netop paa tuffindestedet? Hvis fænomenet kun hadde været karakteristisk for én av lokalitetene, kunde et saadant standpunkt forsvares. Men ogsaa tuffen ved Nedre Dal, som ligger paa dalens sydside like i nordvest for Lillehammer, med østlig eksposition, viser den samme mægtige bladtuf. Alt dette tyder med be- stemthet paa at vi her i det centrale Norge i subarktisk tid har hat en dominerende subalpin løvtrævegetation, en klimatisk betinget bjerk—asp- periode, selv om furuen sandsynligvis allerede paa dette tidspunkt var indkommet til dalen. Spørsmaalet om pollenets langflugt er endda ikke tilfredsstillende utredet. At man ikke bør negligere denne feilkilde, fremgaar kanske bedst av HESSELMANS forsøk paa fyrskibene utenfor Sveriges kyst, hvor pollen- regnet paa havet var ganske paafaldende (1919 I. c.). Det omdisputerte furupollen paa Novaja-Zemlja bør ogsaa mane til forsigtighet.. Jeg har selv under en geologisk ekskursion til Finse (september 1914) indsamlet løvblader av asp, bjerk og or (eller hassel) paa Hardangerjøkelen flere 1 HoLmsEns opsats om pollen i kalktuf har ikke været mig tilgjængelig under manu- skriptets utarbeidelse (trykt i sidste hefte av Norsk Geol. Tidsskrift 1921). 118 ROLF NORDHAGEN. M.-N. Kl. mil fra de nærmeste forekomster baade i ost og vest!. Fra Alperne er lignende fund (bøkeblader) fra en række bræer omtalt i SchrötErs „Das Pflanzenleben der Alpen" (p. 738). Bekjendt er ogsaa ,salthaglen" paa Gotthardt i 1870; de saltkrystaller som her faldt til jorden (op til 0,76 gr.), maa mindst ha passert 250 å 300 km.s veilængde (fra Genua eller Venedig), kanske betydelig længer. Ytterst interessant er likeledes KERNERS oplys- ning (Pflanzenleben I, 1888 p. 36) om, at han i alle de prøver av „rod sne" som han har undersokt fra Alpernes gletschere, har fundet pollen av forskjellige naaletrer. Fordi om furupollen er fundet i bladtuffen ved Leine, er det forhastet at trække den slutning, at træet har vokset i nærheten. Blomsterstovet kan med opstigende luft- strømmer være kommet længer nedenfra dalbunden, kanske langveisfra 2. Spørsmaalet om der i Skandinavien har været en almindelig ,bjerk asp-periode", saaledes som STEENSTRUP oprindelig antok, er i den senere tid hyppig diskutert. STEENSTRUPS opfatning (1842 l. c.) synes nu mere og mere at maatte op- gives. Allerede i 1894 undlot SERNANDER i sine „Studier 6fver den got- làndska vegetationens utvecklingshistoria^ at medta nogen bjerk—asp-tid for denne e, da han ikke fandt beviser herfor i Gotlands myrer. Hoops fremhæver i 1905 med bestemthet at hverken i Nord- eller Mellem-Europa har bjerk og asp alene været dominerende efter isens avsmeltning, men furuen har fulgt like efter de nævnte træsorter, ialfald ubetydelig senere. L. von Post mener paa grundlag av pollenanalyser helt at maatte stryke bjerk—asp-perioden i det sydlige Sverige (1918 I. c.). Og helt nylig har K. JESSEN for Sjællands vedkommende hævdet at ,Rene Birke—Bævreasp- skove i den Forstand, at Skovfyr manglede i dem, synes ikke at have været eneherskende i Nordøstsjælland. Baade makroskopiske Rester og anseelige Mængder af Pollen af Fyr er fundne saa dybt i den alluviale Gyttje som til nogle faa cm. fra Dryaslerets Overkant“ (l. c. p. 221). Horw- SENS nye undersokelser i Norge synes ogsaa, saavidt jeg har kunnet erfare av de foredrag han har holdt, tildels at gaa i samme retning. Baade Hoın- BOE (1903) og WILLE (1915) opfører imidlertid en ,,Bjerkeperiode" for Norge. Da det STEENSTRUPIANSKE skema ogsaa i andre henseender ikke synes at svare til de faktiske forhold (von Post 1918 I. c), er der ingen grund til at holde paa det. Men jeg tror dog, at Gudbrandsdalens tuffer paa dette punkt taler et sprog som ikke helt kan negligeres. Der synes i det centrale Norge virkelig at ha været en bjerk—asp-periode, I Konservator J. Lip, Kristiania, har meddelt mig, at han flere ganger har konstatert at løvblader blaaser over fra Hardanger til Voss. 2 En pollenundersøkelse av den slaggagtige mosetuf (allerunderste horisont ved Leine), bragte uhyre sparsomt bjerkepollen for dagen, og i de Io præparater (dækglas 18 X 18 mm.) som blev gjennemset, fandtes kun et eneste pollenkorn av furu. Dette kan skyldes forurensning og kan ialfald ikke tillægges nogen avgjørende betydning. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. IIO om end ikke saa decidert som palæobotanikerne i sin tid antok!. Det er ingen grund til at anta at forholdene i Gudbrandsdalen har stemt fuld- stændig overens med forholdene paa Sjælland eller i Mellem-Sverige; i nutiden er jo forskjellen betydelig mellem disse omraader. Brvrr har i sin avhandling trukket en hel del konsekvenser av den subarktiske bladtufs forekomst i bunden av tuffene. Han har utvilsomt ret i at klimatet dengang var koldere end nu (1892 p. 27); ti alle de iagttatte planter og snegler er subalpine, tildels alpine; ingen sydlig art er fundet. Dette er saa meget mere paafaldende som baade Leinebakkene, Gillebuskraa- ningen og lien ved Nedre Dal i nutiden opviser en mængde sydlige, varme- kjære arter. Men naar Brvrr desuten paa grundlag av de manglende makro- skopiske fururester haevder at hele Gudbrandsdalen fra Mjosen av har ligget over furuens grænse i denne første tid, kan neppe dette ræsonnement be- tragtes som overbevisende, selv om det er fuldt logisk konsekvent. Furu- pollenets forekomst staar her iveien og maner til forsigtighet. Jeg skulde anta at Leine har ligget over furugrænsen, og at denne har ligget betydelig lavere end i nutiden; men opfatningen paa dette punkt maa nødvendigvis bli noget subjektiv. Den subarktiske bladtufbænk er meget vigtig, idet den viser os at allerede denne periode hadde bræene ı det centrale Norge trukket sig tilbake til heifjeldet. En vedvarende ispelse over midtre del av Gudbrandsdalen helt til boreal tid er saaledes en levende umulighet; vi har her frodig lovskog hele veien fra Kvam til Faaberg. Under omtalen av Jemtlands tuffer kommer jeg tilbake til dette vig- tige punkt. En speciel interesse knytter sig til forekomsten av Æippophaës rham- noides ved Gillebu og den undre Dryas-horisont ved Leine. Hippophaés og dens indvandring vil bli nærmere behandlet i det specielle avsnit »,Hippophaés-problemet". Hvad vi her særlig skal merke os, er at denne busk er en av de planter som har lettest for at tape i konkurrencen med andre trær og busker. Av hele dens forekomstmaate i nutiden har en række botanikere trukket den bestemte slutning, at Æippophaës i hoi grad er lyselskende, og at dens værste fiende er tætte bestander av skog- dannende trær. Derfor formaar den i nutiden kun at hævde sig dels paa strandkanter langs Nordeuropas kyster, hvor andre planter ikke kan gjøre den rangen stridig (flyvesand, storstenet strand, overalt lokaliteter hvor konkurrenceforholdene er lette), desuten langs flodbredder og gruset-stenete bækkedaler i Mellemeuropa og Centralasien, hvor likeledes konkurrenceforholdene er lette paa grund av den urolige jordbund. I kli- matologisk henseende er den indifferent i hoi grad, idet den kan trives saavel langs Norges og Englands nedborrike kyst som i Asiens I Allerede ovenfor (Generel del, avsnit II) har jeg berørt dette problem under omtalen av plantevandringer fra Norge og ostover ind i det centrale Sverige. 120 ROLF NORDHAGEN. M.-N. KI. orkentrakter (Körren l. c. p. 644). Den gaar i Himalaya 5000 m. o. h., i Alperne r9oo m. o. h. (ifølge meddelelse fra Dr. H. Gams, München). Forekomsten av Hippophaés i det centrale Norge i subarktisk tid viser at forholdene her har været ganske eiendommelige, og taler til gunst for den opfatning, at lysaapne bjerkeskoger har været fremherskende. Det er likeledes hoist interessant at Æippophaës blir mere sporadisk opover i bladtuffen, og at den forsvinder med denne, altsaa for furutuffens dannelse begynder. Da jordstripen ved Gillebu maa tolkes som boreal, kan man med god grund paastaa, at Hippophaés i Gudbrands- dalen utder under boreal tid eftersom furuskogen tykner till og at vi netop i furuens sukcessive dominans har aar- saken til artens utdoen (beskygning)!. I det hele tat kaster Hippo- phaés et eiendommelig lys over denne subarktiske periode. Livskaarene maa for plantene tildels ha været ganske ekstraordinære, og dette tidsrum gjemmer utvilsomt paa mange botaniske hemmeligheter som nok kunde gi os noklen til forstaaelsen av visse arters eiendommelige utbredelse i nutiden. Den undre Dryashorisont ved Leine supplerer Æippophaës paa en ud- merket maate. Rigtig type end Hippophaés, men begge er lyselskende, og det er ganske paafaldende,.at det ved Leine er furuen som 1 sluftenre boreal (senboreal) tid gjer ende paa fjeldplantene 1 likhet med Hippophaés ved Gillebu (cfr. den lokale „klidagtige“ förna-tuf ved Leine med de sidste Dryas-blader). I furutuffen finder man hverken Dryas, Salix reticulata eller Hippophaës. Der er her en lovmeessig paralellitet til- stede mellem furuens tiltagende kvantitet (fra subarktisk til senboreal tid) og ovennævnte fotofile planters avtagende frekvens og utdoen, som ikke beror paa tilfældigheter. Og disse rent biologiske forhold bekræfter efter min mening den opfatning som jeg ovenfor har gjort gjældende med hensyn til Gudbrandsdalens plantevekst i subarktisk tid. Disse fænomener er ogsaa av den største betydning naar vi senere skal prøve at sammenbinde Jemtlands og Gudbrandsdalens kalktuffer. gnok er Dryas octopetala økologisk set en noget anden B. Den boreale tid. Under boreal tid har tufavsætningen stadig avtat og snart ophørt saa- godtsom fuldstændig, og isteden indtrær forvitring baade ved Leine og og Gillebu. Samtidig med denne avtagen i fugtighetsforholdene ændres vegetationens karakter. En xerofil Dryasmatte utbrer sig ved Leine paa den fugtige bjerkeskogs bekostning eftersom lerbakkene tørres mer og mer ut, og til slut finder vi her en meget aapen og spredt bjerk-furuskog, som har tillatt en bundvegetation av fotofile arter. Furuen gjør nu sin indtræ- 1 Cfr. Srecrisr, R.: Die Auenwälder der Aare l. c. Her findes ypperlige eksempler paa hvorledes furuen langs flodbredder i Schweiz dræper Hippohaés-bestandene (p. 156 — 157). 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. T2T delse paa findestedet, utvilsomt som en følge av gunstigere klimatiske for- hold (højere sommertemperatur), og fordi den subalpine lovskogs magt nu er brutt. Ved Leine er vi videre i den heldige situation, at vi kan kon- statere hvorledes furuen utvider sig jevnt og sikkert og til slut bringer Dryas og de andre fjeldplanter til undergang paa grund av den tiltagende beskygning (i senboreal tid). Det samme har utvilsomt været tilfældet ved Gillebu, hvor Hippophaés møter samme skjæbne. Imidlertid fortæller den jordstripe som her ækviva- lerer Dryastuffen, intet om periodens plantevekst. Brvrr betragtet Dryasmatten ved Leine som et lokalfeenomen, beroende paa lokalitetens store heide over havet (l. c. p. 11). Og mine undersøkelser har vist at vi ikke noget andet sted i Gudbrandsdalen har antydning til nogen Dryastuf. Derimot finder vi stratigrafisk og genetisk likeværdige horisonter i form av jordstriper eller diskordanser. Dryastuffen ved Leine er imidlertid betydningsfuld i flere henseender. Jeg har tidligere nævnt at lerbakkene i boreal tid maa ha frembudt et enestaaende syn. Specielt er denne masseoptræden av Dryas interessant, naar man tar i betragtning at planten i nutiden hverken findes i lerbakkene eller paa skiferklippene heiere oppe, eller i skraaningen under Tunsbergfjeldet. Paa den anden side er det utænkelig at Dryas, dengang den vokste paa tuffindestedet, ikke ogsaa fandtes paa skiferklippene. Disse har 1 boreal tid sikkert været dækket av en Dryasmatte. Følgende plantearter, som allesammen vokser paa klippene i nutiden (cfr. fortegnelsen i den specielle del p. 11), indgaar i Dryadeta octopetalae som jeg har studert baade ved Finse og paa Sylene: Antennaria alpina Gentiana tenella Astragalus alpinus Juncus trifidus Carex capillaris Poa alpina Carex sparsiflora Poa cesia Cerastium alpinum Parnassia palustris Cetraria nivalis Polygonum viviparum Draba hirta Potentilla verna Draba incana Selaginella spinulosa Gentiana nivalis Veronica saxatilis Flere av disse er til og med typiske indikatorer paa denslags los, smuldrende skiferbund som Dryas netop ynder. Antageligvis er flere av disse arter at betragte som associations-relikter fra den tid da Dryadeta i boreal tid dækket skraaningene. I motsætning til Dryas selv har de klart sig under varmetiden med dens hævning og ekspansion av furuskogen i disse trakter. Dog er det mulig, at enkelte arters forekomst i dette nivaa ogsaa skyldes senere nedvandring, i tiden efter det klimatomslag som gjorde ende paa varmetiden og rykket skogen nedover. igjen. En ting er ialfald sikker: Dryas selv døde her ut under furuskogens første tid og har endda ikke 122 ROLF NORDHAGEN. M.-N. Kl. formaadd at spre sig paany til disse skiferbakker eller længer ned- over lien. Naar situationen for Leines vedkommende faktisk var den, at Dryas, Salix reticulata etc. i boreal tid hadde en meget større utbredelse end i nutiden, maa man ha lov til at generalisere dette fænomen ogsaa for andre højereliggende strækninger i dalen. Den boreale tid synes at ha været gunstigere for fjeldplantene end nutiden; antagelig- vis har regio alpina dengang været storre end den nu- værende. Alting tyder paa at isen under denne tid var avsmeltet omtrent til sin nuværende lokale utbredelse i norsk hoifjeld, og fjeldfloraen synes i denne tid for skoggrænsen begyndte at bevæge sig opad, at ha hat glimrende betingelser. Dryastuffen ved Leine kan ikke tolkes paa nogen anden maate. At furuen her kommer til sammen med Dryas, viser at vi her saa at si befinder os i den undre grænse for fjeldplantenes domæne. Ned til Gillebu og Nedre Dal har de ikke evnet at komme. Sporsmaalet om ,regio subalpinas" og ,regio alpinas" tidligere ut- strækning under de postarktiske perioder sammenlignet med nutidsforhol- dene, er blit mere og mere aktuelt i de senere aar. Da furuen som bekjendt under varmetiden (specielt under optimum) gik 150—300 m. hoiere tilfjelds end nu, antok man oprindelig at ogsaa bjerkens ovre grænser var for- skjovet opad i tilsvarende grad, til trods for at de paleeontologiske fakta ingenlunde kunde siges at bevise at saa hadde været tilfældet. Fund av fossile bjerkerester ovenfor grænsen for fossil furu er nemlig meget sjeldne (BIRGER 1908, SMITH 1911, FRIES 1913, SMITH 1920), og hele spørsmaalet er saagodtsom ikke utredet (cfr. TENGWALL 1920 I. c. p. 285). Desuten hviler den tankegang som ligger til grund for denne analogi-anskuelse, paa et postulat, nemlig at bjerkens og furuens avhængighet av sommertemperaturen ikke er væsensforskjellig, kun kvantitativt forskjellig (furuen synes at kræve betydelig hoiere sommertemperatur end bjerken). Imidlertid er svenske botanikere ved sine nyere undersokelser kommet til det resultat, at skoggraenseproblemet er vanskeligere at lose end man oprindelig tænkte sig (FRIES 1913, 1918, TENGWALL 1920, SMITH 19201. c.). Det ser nemlig ut som om ikke alene sommertemperaturen for bjerkens vedkommende bor vaere over et visst minimum; bjerken synes desuten at kræve en vegetationsperiode av en viss længde, som ikke maa avknappes (2: bjerken kræver for at kunne leve en minimumstid i hvilken den kan utfore alle sine normale livsfunktioner, hvilket selvfølgelig forut- sætter at ogsaa temperaturen den hele tid befinder sig over et visst lav- maal. Man har nu videre tænkt sig, at kanske varmetidens klima (ialfald under optimum) var av den natur at vistnok den gjennemsnitlige sommer- temperatur har været hoiere end nu, men selve vegetationsperioden (tiden mellem lovspraet og løvfald) behøver ikke at ha faat en tilsvarende for- længelse, med andre ord: furugrænsen kan ha bevæget sig opad 150— 300 m. hoiere end i nutiden (hvilket er konstatert), men vi har ingen ret 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 123 til at slutte det samme om bjerken. Bjerkegrænsen kan for den saks skyld gjerne ha ligget relativt stille eller kun undergaat svingninger i mindre skala. Ja, man maa regne med den mulighet, at i postglacial tid har kanske furuen, altsaa et naaletræ, dannet baade .skoggrænsen og trægrænsen i de skandinaviske fjeldtrakter 1 likhet med forholdene i Alperne, Sibirien o. s. v. i nutiden. Det nuværende bjerkebelte eller ,regio subalpina" skulde da i overensstemmelse hermed være et forholdsvis recent fænomen, opstaat efter varmetidens slut (furuen har rykket ned, mens bjerken er blit staaende, eller har ialfald ikke rykket saa langt ned som den første; de har opført sig forskjellig og uavhængig av hinanden). Dette ræsonnement, som i første række skyldes Dr. TH. C. E. Fries’ epokegjørende studier i Torne lappmark, er ialfald teoretisk set meget vigtig og skjærper problemstillingen i hoi grad, likesom det angir retnings- linjene for den fremtidige forskning. Selv om Gudbrandsdalens tuffer, paa grund av furuens noget tvilsomme stilling i den første tid, ikke taler et helt avgjørende sprog paa dette punkt, synes det mig dog tvingende nødvendig at anta at vi i subarktisk (vistnok ogsaa 1 boreal) tid, altsaa før den egentlige varmetid, har hat en subalpin bjerkeskogsregion i det centrale Norge likesom i nutiden, fremkaldt av et subalpint klima, men med andre grænser end i nutiden. Om regio alpina, hvis utstrækning hænger paa det noieste sammen med regio subalpinas, uttaler SERNANDER som sin mening (Herjedalen roro l. c. p. 208) at „regio alpina icke en gång omedelbart efter isens afsmåltande kunnat vara mera utstråckt ån i nutiden, utom tvårtom mycket snart måste genom skogens uppryckning ha reducerats i sådan skala at troligen många af de först inkomna fjållvåxterna utdótt". Dryastuffen ved Leine og det ræsonnement som jeg har fremført i anledning av de merkelige skifer- klippers vegetation, fører dog til det resultat, at fjeldplantene i det mindste i begyndelsen av boreal tid har hat en større utbredelse end i nutiden. Jemtlands kalktuffer synes at vise det samme. lalfald har vi her et inter- essant fænomen som vi bør stoppe op for og ikke negligere. Vi bør være taknemmelige for ethvert lite indblik vi faar i disse gamle perioders plante- vekst og klimatiske forhold. For endda er de i stor utstrækning indhyllet i mørke. For det sydlige Skandinavien antar man med rette at den boreale tid indvarsler de varmekjære løvtrærs æra i norden og i det hele tat ind- vandringen av sydlige og sydøstlige typer, som saa i løpet av varmetiden spredte sig vidt utover landet baade nordover og vestover (BLytt, HANSEN, SERNANDER Il. c.). En sammenligning mellem Gudbrandsdalens og Jemtlands kalktuffer. En korrelation mellem Gudbrandsdalens og Jemtiands tuffer er tildels vanskelig at gjennemfore. Oyen behandler dette problem i sit sidste arbeide, og angriper her baade SERNANDERS og Ha tes tolkning av de jemtlandske 124 ROLF NORDHAGEN. M.-N. KL forekomster. Men nogen tilfredsstillende forklaring faar man dog ikke; i grunden lar OYEN spørsmaalet staa fuldstændig aapent. Imidlertid aapner HALLES interessante undersokelser nye muligheter for en korrelation mellem disse norske og svenske tuffer. Harre har trukket frem en række nye stratigrafiske og biologiske momenter (1915 l. c.), som er av den allerstørste værdi, og som i al korthet kan resumeres i følgende punkter: 1. I bunden av Jemtlands tuffer er der i de ældste tuffer antydning til en smal undre sone uten fururester; jalfald er furuen her sparsommere end ellers. D Dryas octopetala og Hippophäes optrær i denne undre sone i stor mængde og karakteriserer den. De forsvinder opad eftersom furuen øker. 3. Hoiere oppe 1 lagrækken dominerer furuen. Granen mangler. Forskjellen mellem disse tuffer og de norske ligger i forekomsten av bladtufbænken i Gudbrandsdalen, hvilket baade ANDERSSON og BIRGER (1912 l.c. p. 145) og HALLE (1915 p. 38) finder paafaldende og vanskelig at forklare. Saaledes stiller altsaa saken sig set med svenske eine; for os, som har arbeidet med de norske tuffer, er netop den manglende bladtuf i Jemtland vanskelig at forstaa. Men børtset fra denne undre tufbænk, er likheten meget fremtrædende. Likesom i Jemtland følges Dryas og Hippophaës ad ogsaai de norske tuffer og forsvinder samtidig. Rigtignok er de her endda ikke fundet sammen, men dette betyr ikke saa meget da stratigrafien ved Leine og Gillebu stemmer fuldstændig overens. — I begge til- fælder er det en okning i furuens frekvens som er utslag- givende og skjæbnesvanger. SERNANDER har senere i overensstemmelse med Harrrs fremstilling tolket den Dryas-matte som optrær i bunden av visse jemtlandske tuffer, som en „senboreal hede" (1915 I. c. p. 540), og det ligger i det hele tat snublende nær at sammenstille denne med Dryastuffen ved Leine, som vi ikke finder anden plads for end netop i den boreale tid. Men hvorfor er der da ikke ogsaa utviklet en bladtuf i Jemtland? Dette kan hovedsakelig bero paa to ting: enten har de klimatiske forhold her lagt hindringer iveien for tufdannelsen i den forste tid efter isens av- smelining, eller*rester av indlamdsisen har persistert lemerz i denne del av Skandinavien end i det centrale Norge. Ved studiet av Ragundasjoens uttapning har svenske geologer (DE GEER 1915 l. c. p. 191) forsokt at fiksere tidspunktet for den østlige isrests tvedeling (bipartition) i en nordestlig og en sydvestlig del, og man er nu tilboielig til at ville henlægge denne begivenhet til boreal tid (SERNANDER 1916 p. 539). At der i det centrale Norge umulig kan ha ligget igjen nogen isrest 1 boreal tid, har jeg allerede ovenfor omtalt. Det store sporsmaal I92I. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 125 blir da hvorledes disse opfatninger skal kombineres sammen. Hvis virkelig isrestens bipartition først skedde saa sent som i boreal tid, hvor stor ut- bredelse hadde da den tilbakeblivende sydvestlige del av isen? DE GEER synes at være fuldt opmerksom paa at der .her er vanskeligheter tilstede, idet han paa sit kart (1915 l. c.) over isens bipartition ikke bringer den søndre islobe til nogen naturlig avslutning vestover i Norge. Jeg skal her ikke gaa nærmere ind paa dette problem, som er meget vanskelig. Svenske og norske opfatninger divergerer paa dette punkt ganske sterkt. Mytilus-nivaaet og Portlandia-nivaaet spiller her ind paa norsk side, likeledes tidfæstelsen av de brædæmte sjoer (cfr. avsnit I) o. s. v. Men at der efter HALLES undersokelser er banet vei for en korrelation mellem de norske og svenske forekomster, anser jeg for givet. Mange gode grunder taler for at Dryas-Hippophaës-sonen i Jemtlands tuffer skriver sig fra boreal tid, og dette bekræfter den mening som jeg ovenfor har hævdet, nemlig at denne periode maa ha været specielt gunstig for fjeld- plantene. Aarsakene hertil kan dog ha været forskjellige. Furutuffen i Jemtlands-forekomstene tolkes av SERNANDER som atlantisk, nærmere betegnet som gammelatlantisk (l. c. p. 540). Forfatteren tænker sig at tufavsætningen her er blit avsluttet forholdsvis tidlig „genom det öfversilande vattnets sjäfdränering i distinkta erosionsfáror". Imidlertid er det al grund til i fremtiden at undersoke det muld- eller humuslag neiagtig som pleier at overdaekke furutuffen; for efter den erfaring som undertegnede har gjort baade ved Leine og Gillebu, er det meget let ved en hastig grav- ning at overse eventuelle forvitrede yngre tufrester i jordlaget. Disse er ofte forsvindende smaa, men kan allikevel gi vaerdifulde oplysninger (cfr. Alnus-tuffen ved Leine og de ubetydelige furutufrester i visse profiler ved Gillebu). Hippophaës-problemet. I den foregaaende fremstilling er Æippophaës rhammoides nævnt flere ganger. Denne arts merkelige utbredelse i nutiden og dens fossile fore- komst paa Gotland, i Jemtland og Äsele lappmark har siden lang tid til- bake sat plantegeografenes fantasi i bevægelse. Meningene om dens ind- vandringsveier til Skandinavien har været noget delte, og flere teorier har været opstillet i sakens anledning. Paa kartet fig. 36 er alle kjendte norske og svenske lokaliteter for nulevende og fossil Hippophaés indtegnet. For Finlands og Danmarks ved- kommende er fremstillingen noget ufuldstændig, men hovedlinjene i plantens utbredelse trær dog tydelig frem. Langs Tysklands Østersjøkyst er bare nogen faa lokaliteter indlagt. Aippophaës forekomst i Kurland er tvilsom (ældre angivelser hos Körpen |. c., men ikke gjenfundet i nyere tid). Av de fossile findesteder er F = Fröjel paa Gotland (G. ANDERSSON 1895 l. c. p. 45), G = Gillebu i Oier (OYEN 1917). De jemtlandske lokali- 126 ROLF NORDHAGEN. M.-N. Kl. teter er ifølge HALLE (1915) folgende: Raftkälen (NatHorsr 1885 |. c.), Digernäs (SERNANDER 1899 |. c.), Sikaskälen (CAarısox ifølge HALLE 1915 p. 39), Gaxsj6 (CARLSON), Filsta (G. ANDERSSON), Tracksta i Hallen (Kjeır- MARK), Gulästjärn (HALLE |. c.). Den nordligste lokalitet i Sverige er Lang- sele i Dorotea sogn, Asele lappmark (NATHORST 1883, planche 18). Hippophaës-pollen er paavist i sandlag med arktiske planterester paa Snasa- högarna og V. Enadalshöjden av H. SwrrH (1920 |. c. p. 138); disse lokali- teter er ikke indtegnet paa kartet, da der vel kan disputeres om hvor stor vegt man skal tillægge forekomsten av pollen av en vindbestover. Forevrig slutter disse forekomster sig meget smukt til de ovrige. Ütbredelse 1 sy erie murıden. Norrbotten: Neder-Kalix skärgärd; Luleå skärgard: Junkön, Smäskären o. S. v. (BACKMAN og Holm p.247) Seskaröen ( /7 1899 E. HAMMARÉN Hb. Ups... Haparanda skärgärd (J. A. Z. BRUNDIN 3 7 1900 Hb. Ups). Piteá skärgärd: Hunden 7/6 1892 E. LuxpBERG Hb. Ups), Buskin (1870 A. N. Lunpstrém Hb. Ups.) Mellerstön, Kluntarne, ‘Rebben, Svartnås, Trundón; Neder-Lulea: Alhamn (1917 E. Mankruxwp l.c. p. 796). Kalix skärgärd: Granón (27/6 1906 F. E. A. Block Hb. Ups.). Västerbotten: Umea: Tafla (1887 N. L. Andersson Hb. Ups.). Medelpad: Bràmón; Njurunda: Galtstróm mellem Furuskär og Sathamn, Björköbyn, Bjórkóviken;: Alnón: ej långt från Spikarna, Rödön, Lillkalven, Granón; Tynderó: Skilsakersmalen, Astón sóder om Kalvhällberget (Cor- LINDER p. 118). Hälsingland: Gnarp: Ragvaldsnás fram till Medelpadsgransen; Jätten- dalkredsands allmänning. — Fleresteds dyrket „sasom vid Ljusdal, Hudiks- vall etc." (WisrRÓx). Gästrikland: Gevle: Brynäs (/7 1823 herb. Wahlenberg in Hb. Ups.), Brobänken (4/6 1852 R. F. Fristept & F. J. Björnström Hb. Ups.) Iggön (/1 1895 Torsten Arnett Hb. Ups), Granón (16/7 1894 T. Arnett Hb. Ups.) Miramar (/6 1885 C. O. ScurvrER Hb. Ups.). Uppland: om Hippophaés’ utbredelse i Uppland cfr. E. ALMQUIST 1921 l. c.!. Den er her almindelig ned til Grisslehamn; sondenfor er den betydelig mere sjelden. De sydligste lokaliteter er Nickó 1 Ljusteró og Svartlóga i Blidö, beliggende ved ca. 599 35° (E. Arwovisr in litt). Lokalitetene paa kartet er indtegnet efter et kartkoncept utfærdiget av Arwovisr. I Uppland træffes den mange steder paa enger, langs veikanter o. s. v. i kystens nær- het, undertiden flere km. fra nuvaerende strand (kulturpaavirkede steder). Bohuslän: Oxevik i Dragsmark sn. (/7 1884 G. Wa tity Hb. Ups.); Dragsmark (/7 1889 A. U. Jonsson Hb. Ups); Tanum: 0,5 km. sydvest for Tanums jernbanestation (MaGnusson Sv. Bot. Tidskr. 1918 I. c. p. 472); Svenneby: Spänslätt (12/8 1869 G. M. L. GErkE Hb. Goteb., ifølge Macnus- 1 Denne avhandling vil bli publicert 1i Svensk Bot. Tidskrift 1921. KALKTUFSTUDIER I GUDBRANDSDALEN. 1921. No. 9. voksesteder Fröjel paa Gotland. Kart over Hippophaés rhamnoides i Fennoskandinavien. Fig. 36. Gillebu, F. = G. © = fossilforekomster. 1 nutiden. 128 ROLF NORDHAGEN. M.-N. Kl. son l. c. vistnok spontan); Morlanda: Hermanön (PaLm£r Sv. Bot. Tidskr. 1920 p. 89)!. Denne oversigt er sammenstillet av Fil. mag. R. STERNER, Uppsala, som elskvaerdigst har stillet den til min disposition. Utbredelse 1 Finland. I Finland er /7ippophaés noie knyttet til den Bottniske Bugt, hvor den optrær paa strandkantene fra Torneå i nord til Alandsarkipelet i syd. Syd- grænsen paa fastlandet er Nystad, i skjargaarden (Aland fraregnet) øen Enskår i Gustafs sogn i Åbo-skjærgaarden (, regio aboéænsis" efter Herbarium Musei Fennici’s inddeling 1889). Lokalitetene er indlagt efter oplysningene i PALMGRENS monografi (1912), hvor al litteratur vedrørende Hippophaés i Finland citeres. Utbredelse 1 Danmark. I Lance: Haandbog i den danske Flora (1886 —88) anføres folgende om plantens forekomst: Strandklinter (paa ler og kalk) og sandklitter; i den nordlige del av Jylland alm., sjeldnere mot syd (Ris skov ved Aarhus) og paa gene. Fyen: Vedelsborg. Sjælland: Refsnæs, Lerchenborg, Stevns klint, Møens klint i stor mængde. Falster: Mellem Korselitze og Grønsund og mellem Tromnæs og Bøtø. Laalland: Oreby strand, Aalholm strandklint. Bornholm. WARMING (1907 — 1909) har en mængde oplysninger om Hrppo- phaés' utbredelse og økologi. Folgende findesteder omtales her: Almindelig i klitterreeng nord for Limfjorden, ogsaa ved dennes kyster, f. eks. ved Kaas, og inde i landet, f. eks. omegnen av Vildmosen, ved Tolne og Vogn bakker, Lerup kirke. Mot syd paa vestkysten mere spredt og sjelden, bl. a. i Nissum- Husby klitter, Holms!ands klit, Nymindegab. Han omtaler den videre fra Skagens nordstrand, Uggerby og Tversted aaer og Rubjerg Knude vest for Hjørring. Videre: i mængde f. eks. paa Møens Klint, paa Refsnæs og paa nordøstkysten av Falster. Paa kartet er de av disse lokaliteter ind- lagt som jeg har kunnet fiksere nøiagtig. UtbredelsemNonce: S. Trøndelag og N. Trøndelag fylke: Inderoen: ved Borgentjorden nær Sund (!/7 1918 I. Jorsrap). SCHÜBELER anfører følgende: Paa Inder- øen 5 m. hoie trær. 2 stammetversnit maalte 13 cm. med 54 aarringer og 20 cm. med 44 aarringer (uten bark). — Værdalen: Helgeaaens bredder nær Hagagaard ved Nes (J. W. Zerr.). — Skogn: paa stranden mellem Tynes og Levanger i sterste mængde (J. W. Zerr.); Holme (A. Br) — Skatval: i hammeren mellem Velvang og Olderen ved kalktuffen (juni 1913 Rorr NORDHAGEN). — Stjerdalen: Suttereen (Horrsrap). — Frosta: Tautra m. 1 Litteratur over Hippopha?s’ utbredelse i Sverige: Backman, C. J., og Horm, V. F.: Elementarflora öfver Västerbotten och Lapplands fanerogamer och bräkenartade växter. Upsala 1878. MARKLUND, E. Svensk Bot. Tidskrift 1917. CoLLINDER, E., Medelpads ~ Flora. Norrländskt handbibliotek III. Upsala roro. Wisrrôüm, P. W.: Förteckning öfver Helsinglands fanerogamer och pteridofyter. Wimmerby 1898. 192 I. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 129 alm. paa strandkanter (A. Br.); Frosta (!!/s 1875 A. Br.); Holmberget (?!/e 1915 I. Jorstap). — Strinda: Dævlehavnen og østover (1869 STORM); Saksvik (1876 Ove Dax); Tinveden (Br. 1897); Strinden (OxaaL); Trond, hjem (M. N. Bryrr). — Skjern: Eid (2/7 1915 I. Jorstan). — Orlandet: mellem Fladnes og Hovde rikelig over den flate utmark (Norman 1883); Beian (Boeck & Koren. Herb. Kristiania); Berg og Ostraat (1900 Horr- STAD); Ostraat (Koren). — Bjugn: nær grænsen til Orlandet (Norman- Storm). — Aafjorden; Melem fleresteds; Kven- gjerdet; Valdersund (Nor- MAN, Brvrr); Hyldenesset (storvoksen) (NoRMAN); Valso (Norman); Lovo og Oian (1900 Horrsrap); Lysø (Ancstrom). — Stok- sund: Hosen paa flyvesand (1900 Horrsrap). — Nero: prestegaardstrakten (Nor- MAN 1883). Nordland fylke: Al- sten: Strandaasen nar Sandnessjoen (Ove Dani 2911); Horvnesodden. — Tjøtta: Lovonesset, et helt litet krat av indtil mands- hoie busker (Ove Daur 1911). — Hero: Nordviken paa Donna (Ove Daur 1911). — Meisfjorden: Lei- nes (Ove DAHL I911). — Salten: Fiskvaagflauget Fig. 37. Fra Junkersdalsuren. E. HAYREN fot. (SOMMERFELT; A. Lanp- MARK har senere fundet den her omtrent roo m. o. h. ctr. Brvrr 1892 1. c); Kvitberget øverst i Jordbrudalen ca. 600 m. o. h. (Ove Daur og R. Norp- HAGEN 7/7 1920); Junkersdalsura (Frıprz, Boutin, DYRING (1900), ipse!). — Bodo: nedenfor landskirken ved søen paa flaten dominerende busk, steril i 1876, blad 6,5 cm. langt (SomMERFELT, Norman). — Steigen: Engeleen ved Laskestad paa Prestkontindens fot i nøken grusbakke 111 m. o. h., 137 m. o.h. og 20 m. nedenfor birkefeltets midtlinje, undtagelsesvis i blomst 9/6 1867, steril i 1881 (HaukLann, Norman, Norte 1/7 1912). Hippophaös’ forekomst i Salten, det eneste omraade i Skandinavien hvor arten nu findes i indlandet og ikke paa strandkanter, er meget inter- essant og lærerik. I Junkersdalsuren blev den opdaget i 1889 av Vid.-Selsk. Skr. I. M.-N. Kl. 1921. No. 9. 9 130 ROLF NORDHAGEN. M.-N. KI. R. Friptz (Dyrinc 1900 I. c.). ,Junkersdalsura" er en storslagen kanjon- dannelse, noget over en halv mil lang, hvis nordside. falder av mot elven i lodrette stup, som naar op til 500 m. o. h. Under disse findes der væl- dige urdannelser, som paa en række steder antar formen av imponerende, instabile rasmarker, hvor der vaar og høst gaar svære skred ut i elven. Paa disse steder, som befolkningen kalder ,flaug" (fig. 37), mangler vegetatiønen oftest helt, og de alternerer med mere stabile urpartier, hvor det kalkrike jordsmon og den heldige eksposition fremkalder en frodig og meget inter- Fig. 38. Hippophaés paa en hylde i Junkersdalsuren. Utsigt mot vest. Arctostaphylos uva ursi i forgrunden. ste juli 1920. Nordhagen fot. essant plantevekst. Bjerk (baade Betula odorata og verrucosa), furu, heg, graaor (Alnus incana), rogn, selje o. fl. optrær skogdannende, og i bunden findes en lang række græs og urter, hvoriblandt mange sydlige relikter, som har gjort denne lokalitet berømt (ANDERSSON og BIRGER 1912 p. 120). Hippophaës derimot optrær i ganske stort individantal netop paa et av de midtre flaug oppe i en svær rasmark, hvor andre trær og busker ikke kan trives. Voksestedet er for saavidt aldeles typisk: det er de lette kon- kurrencevilkaar som bevirker at planten her kan hævde sig. Selv formaar den trods det instabile substrat at holde sig, takket være den sterke vegetative formering som udmerker arten (rik skuddannelse paa rottene). Desuten findes Hippophaés ogsaa i en ganske liten koloni noget længer vest i uren paa en hylde allerøverst under selve den lodrette berg- væg, paa et næsten ubestigelig sted (fig. 38). Nedenunder strækker der sig I92I. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. ESE en flere hundrede meter lang rasmark, kanske den farligste i hele uren. Den danner her et litet krat paa en 45° skraanende hylde i 4-500 m. hoide. Sammen med den findes et par buskformede individer av Betula odorata, desuten Dryas octopetala, Salix reticulata, Arctostaphylos uva ursi (se billedet), Rubus saxatilis og Campanula rotundifolia, men intet sammen- hængende dække. I juli 1920 var den her aldeles steril og ca. 0,5 m. hoi. Sammen med konservator Ove DaxL foretok jeg ogsaa samme sommer en ekskursion til den saakaldte Jordbrudal i Salten vest for Russaanes, hvor Russ- aaen over en længere strækning har underjordisk løp (kalksten). Vi besteg da det merkelige tempelformige ,,Kvitberget" (fig. 39), som paa sin sydside har svære urdannelser av nedraset forvitringsmateriale. Paa denne ytterst gunstige lokalitet møter man tildels de samme arter som i Junkersdalsuren (Cypri- pedium, Epipactis, Braya gla- bella etc.), og det lykkedes mig ogsaa at opdage et litet bestand av Hippophaés oversti den stor- stenete ur like ovenfor skog- grænsen (i 600 meters hoide). Den var her ikke mere end 0,3 m. hei og steril. Hippophaës maa utvilsomt tolkes som relikt paa disse Fig. 39. Kvitberget i Salten. Hippopha?s-lokaliteten 7 d længst tilvenstre, øverst i uren. 7de juli 1920. forekomster (cfr. | nedenfor). Nordhagen fot. Specielt i Junkersdalsuren er skredene saa at si fast institution, som ikke viser tegn til ophor, og baade konkurrenceforholdene, den kalkrike bund! og ekspositionen er her gunstig for planten og letter dens kamp for tilværelsen. Paa Kvitberget fører den en mere hensyknende tilværelse. Voksestedene paa Helgelandskysten er -utelukkende kalkforekomster nær stranden, hvor vegetationen oftest er noget aapen, men artsrik. Den vokser fleresteds sammen med Dryas og andre fjeldplanter, som her op- trær i havets nivaa paa kalk og dolomit (cfr. Ove Danr op. cit.). Forekomstene i Trøndelagen stemmer gjennemgaaende med danske og svenske lokaliteter. Interessant er findestedet Hosen i Stoksund, hvor Horr- srAD fandt Hippophaös paa flyvesand saaledes som i Danmark. „Her dannede H. et krat af omkring 0,5 (op til 1) meters hoide med aapne mellem- 1 Om plantens forkjærlighet for kalk cfr. PALMGREN |. c. 132 ROLF NORDHAGEN. M.-N. Kl. rum. Inde i krattet fandtes sterile skud af Galium boreale & verum rikelig, des- uten spredt Convallaria majalis og Vicia cracca, hvilken sidstnævnte under- tiden naaede op over H. buskene. Op gjennem krattet stak desuden Festuca ovina, men især Centaurea Scabiosa, enkeltvis ogsaa Knautia arvensis og Elymus arenarius.“ (Horrstap 1900 l.c. p. 20.) Ved selve Trondhjems- fjorden fra Orlandet og ind til Inderøen danner Æippophaës mere eller mindre aapne krat eller smaa bestander paa strandkantene. Paa Skatval- halvøen har jeg set den i en brat hammer ca. 150 m. o. h. ved Velvang (kalkholdig underlag). I Bryrr: Norges Flora anføres Hippophaés for ,,Indviken i Nordfjord paa strandbredder (ifølge KroGH)"; men den er senere aldrig omtalt herfra og ingen herbarieeksemplarer foreligger, saa forekomsten er meget tvilsom, men slet ikke usandsynlig. PALMGREN har i sin store monografi over Hippophaös paa Ålandsøene git en detaljert skildring av artens utbredelse baade i Europa og Asien, samt diskutert plantens livskrav (forhold til lys, temperatur, nedbør, biotiske faktorer, specielt konkurrencen med andre arter o. s. v.), og plantens økologi maa nu i det hele tat siges at være tilfredsstillende utredet. Om utbredelsen skriver PALMGREN folgende (Il. c. p. 27—28): „Der Seedorn wird, an Flüssen und Bächen in Gebirgsgegenden sowie an Seen und am Meer auftretend, von der Mongolei im Osten bis nach England, Frankreich und Spanien im Westen angetroffen. Die Art ist am nörd- lichsten in Europa in Norwegen unter 670 55^ nördlicher Breite, in Asien im südlichen Sibirien gefunden worden, während sie am südlichsten in Europa am Mittelmeer und in Asien am Himalaya unter etwa 30° nörd- licher Breite vorkommt. In Europa steigt der Seedorn bis in eine Höhe von 2000 m., in Asien sogar bis 5000 m. über dem Meeresspiegel. In Europa umfaßt die Verbreitung des Seedorns ein südliches Gebiet, welches einen bedeutenden Teil der Gebirgsgegenden Mittel-Europas sowie Teile von Spanien, Italien, und der Balkanhalbinsel in sich schließt, und ein nördliches Gebiet, welches einen Teil der Küstenstrecken des Englischen Kanals, der Nordsee, der Ostsee und der Westküste von Norwegen um- spannt. Innerhalb dieses nördlichen Verbreitungsareals ist der Seedorn eine ausgeprägte Küstenpflanze — — — —." Om Hippophaös’ merkelige utbredelse skriver Kórrrw (l. c. 1888— 89 p. 644): „Diesmerkwürdige Verbreitung des; Sanddormes tas: sich auf klimatische Ursachen durchaus nicht zurückführen!; denn er findet sich unter sehr verschiedenen Temperatur-Bedingungen und anscheinend auch unter sehr differenten Feuchtigkeits-Verhältnissen; so dürften die "natürlichen Bedingungen unter denen er einerseits in Norwegen bis zum 680 n. Br. und andererseits auf der der Hami-Wüste zugekehrten 1 Uthævet her. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. TS3 vorderen Terasse des Nan-schan (unter dem 40° n. Br.) wächst, sich außer- ordentlich von einander unterscheiden; dort findet er sich in der ausge- sprochensten maritimen, hier dagegen in der kontinentalsten Lage. Es scheint da& der Standort, den der Sanddorn bevorzugt, am ehesten seine eigen- tümliche Verbreitung erklären könnte. Ich habe Eingangs bemerkt, daf es die Meeresküsten und die Ufer der Gebirgsbäche hauptsächlich sind an denen dieser Strauch sich ansiedelt. Die geringe Entwicklung der Meeres- kisten im europäischen Rufsland (abstrahirt von dem klimatisch für den Sanddorn unzugänglichen Küsten des Eismeeres, desgl. des Weissen Meeres), so wie die fast vollständige Abwesenheit von Gebirgen auf dem kolossalen Raume, den die russische Tiefebene einnimmt, — diese beiden Factoren dürften hauptsächlich das Fehlen des Sanddornes auf der letzteren bedingen.“ PALMGRENS undersokelser paa Åland bekræfter fuldt ut hvilken betydning voksestedet og specielt konkurrenceforholdene har for Hippophaés!. Den taaler til en viss grad saltbund bedre end andre trær og busker, og langs den Bottniske Bugt, hvor der paagaar landhævning i nutiden og nyt land stadig dukker op, har den udmerkede betingelser, idet ingen andre vedplanter formaar at utkonkurrere den. Paa de længst fra strandlinjen liggende lokaliteter (de ældste) dør den efterhaanden ut og for- trænges av andre planter. I Uppland indtar den ogsaa et smalt spatium paa strandkantene, mellem den uroligste del av stranden (med koloniartet vegetation) og strandkrattene av or længer inde (SERNANDER 1905 |. c.). I det hele tat er der nu gjort saa mange iagttagelser i sakens anledning at man kan slaa fast følgende: 1. Hippophaés er indenfor temmelig vide grænser klimatologisk indifferent (baade hvad temperatur og nedbør angaar). 2. Planten optrær nu kun paa lysaapne voksesteder, hvis natur er saadan at en sluttet vegetation specielt av trær og busker er utelukket (stenet strand, flyvesand o. 1. ved kystene; rasmarker, sandige elvebredder etc. i indlandet). 3. Desuten er Hippophaés noget kalkyndende. Oyen har i flere av sine nyere skrifter omtalt Hippophaés* og polemi- serer her sterkt mot en række svenske forfattere som har ytret sig i an- ledning av Hippophaés-problemet. Han konkluderer selv med den bestemte mening, at plantens utbredelse, fremrykning og tilbakegang styres av kli- matologiske lover, og henfører dens indvandringstid til sit Pho/as-nivaa. 1 Cfr. NatHorsts uttalelser 1886 l. c. I september 1921 har jeg hat anledning til at iagtta Hippophaés paa utallige steder i Alperne, og mine erfaringer bekræfter fuld- steendig ovennævnte tolkning. — SERVETTAZ synes i sin monografi over Elaeagnaceae (1909 l. c.) tildels at ha misforstaat Hippophaés’ økologi; han hævder at naar planten formaar at spre sig til lokaliteter utenfor fugtige elvebredder, saa er det altid til kalkfattige voksesteder. Dette er fuldstændig misvisende, likeledes paastanden om at planten foretrækker fugtig bund (cfr. SiEGRIST 1. c. p. 122). 2 Videnskapsselskapets Skrifter og Svensk Bot. Tidskrift op. cit. 134 ROLF NORDHAGEN. M.-N. Kl. Da dette faunistisk set er av utpræget sydvestlig karakter, tolker han ogsaa Hippophaés som sydvestlig. „Den synes derfor at være paa det neieste sammenknyttet med den her omhandlede periodes hele klimatpræg, der var av utpræget sydvestlig karakter" (1920 |. c. p. 322). Oyen indtar altsaa et standpunkt som er diametralt motsat KóPPENS, PALMGRENS og andre botanikeres. Imidlertid synes Oyen ikke at kjende til disse hovedverker inden Hippophaös-litteraturen; han citerer dem ialfald ikke. Han berorer ikke plantens biologi i nutiden, og nogen diskussion: av forskjellige forklaringsmuligheter finder man ikke. Da jeg ovenfor tilstrækkelig har belyst sporsmaalet om Hippophaös’ forhold. til klimatiske faktorer, skal jeg her kun omtale plantens relation til Pholas- nivaaet. Da Hippophaés ved Gillebu er knyttet til bladtufbænken. og denne av Oyen tolkes som „infraboreal“ og synkron med hans Pho/las-nivaa (cfr. oversigten i avsnit III, er Ovens standpunkt forstaaelig. Men ved Gillebu moter vi det merkelige fænomen, at Hippophaés faktisk har sit maksimum allerede 1 bladtufbænkens aller underste del (tuffens underside). Den har været tilstede i store mængder netop da tufdannelsen begyndte; blokkenes underside viser os et avtryk av markens overflate paa dette tidspunkt. Man maa derfor anta at denne art har været tilstede eller indvandret allerede under den konti- nentale periode umiddelbart efter isens avsmeltning, som sik forut for tufdannelsens begyndelse. Jalfald er der ikke levert noget bevis for at Hippophaés først er indvandret under den periode som udmerker sig ved bladtufdannelse. Heller ikke paa dette punkt virker Ovens fremstilling overbevisende. Sammenholder man Hippophaös’ fossile forekomst paa Gotland (G. An- DERSSON 1895 |. cJ), i Jemtlands kalktuffer, i Långsele sydligst i Lapp- marken og ved Gillebu i Norge, kommer man til det resultat, at denne art maa ha hat en vid og vistnok temmelig sammenhængende utbredelse over hele den skandinaviske halvø i subarktisk og utover i boreal tid for furuskogene (i syd skoger av ædle lovtrer) begyndte at faa overtaket!. Dog er det mulig at den i indlandet har foretrukket kalktrakter. Allerede i boreal tid begyndte ned- gangen, og litt efter litt døde den ut baade i det centrale Norge og i Jemtland—Lappmarken. Kun langs kystene og paa et par specielt gun- stige indlandslokaliteter i Nordlands fylke har den evnet at holde sig til nutiden. Ved den Bottniske Bugt synes den at like sig bedst, takket være landhzevningen i disse trakter. Det er ingen grund til at anta at denne kystutbredelse i og for sig er et sekundert fænomen. G. Anperssons fund av fossil Hippophaés paa Alnön i Medelpad i „littorina- gyttja“ viser, som forfatteren selv gjor opmerksom paa (1895 p. 45), at den 1 Cfr. G. ANDERSSON 1896 p. 455. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 135 i lang tid har været kystplante. At sænkninger av landplaten langs andre kyststrækninger i postglacial tid maa ha været skjæbnesvanger for Hippo- phaés og utryddet den over visse strækninger, har HALLE tidligere gjort opmerksom paa (I. c. p. 43). Da Hippophaés i klimatologisk henseende er indifferent, er det bare naturlig at den i nutiden forandrer og utvider sit utbredelsesfelt og an- lægger nye kolonier!. Hvis forekomsten i Bohuslàn er av geologisk talt ung alder og staar i forbindelse med det danske utbredelsesfelt (cfr. kartet), hvilket enkelte forfattere har hævdet (ARNELL 1912 p. 232), kan det godt hænde at Æippophaës i fremtiden vil faa en renæssance langs Kattegat- Skagerakkysten. Selv om problemet Æippophaës nu kan betragtes som løst i hoved- saken, er det faktiske billede vi for tiden kan gi av dens tidligere ut- bredelse, mangelfuldt. Men fremtidige fund vil nok utfylde hullene. Spørs- maalet om arten er indvandret til Jemtland fra Norge eller fra øst, to alternativer som HALLE diskuterer, staar fremdeles aapent. HALLE synes at helde til den første antagelse. Ialfald er det nu en kjendsgjerning at planten har vokset i det centrale Norge i subarktisk tid?, og naar saa mange andre planter har vandret fra Norge ind i Sverige (cfr. SERNANDER 1910), kan dette ogsaa meget vel ha været tilfældet med Hippophaés. Om denne art oprindelig fulgte efter det avsmeltende isdække fra syd eller ost eller fra flere kanter samtidig, er omdisputert?. SCHWELLENGREBEL betegner Hrppophaéæs som en asiatisk steppeplante av østlig type (1905 I. c. p. 191). Warmine skriver (Dansk plantevekst II Klitterne 1907 p. 150) at den kunde ,maaske være indvandret til Sverrig nord om den Botniske Bugt fra Steppér i Vestasien og Ostrusland, mens den vel er kommet til Østersøens andre Kyster og til Vesterhavets fra Mellem-Europa, i hvis Bjerge og langs hvis Floder den vokser." Da denne sak er meget van- skelig at avgjøre, skal jeg her ikke diskutere den nærmere. Alt i alt er Æippophaës’ fossile forekomst meget interessant, idet den viser os at den aktualistiske tolkning av denne art som en plante for hvem konkurrenceforholdene og derigjennem de edafiske forhold er de ut- slaggivende, er fuldstændig korrekt. Fortiden supplerer her nutiden og omvendt. Og naar Oyen i Hippophaés mener at ha fundet et typisk 1 BucHEnau har fra de ostfrisiske øer omtalt hvorledes Hippophafs i slutten av det rode aarh. har bredt sig østover; den har endda ikke naadd øene Spiekeroog og Wangeroog (Abh. naturw. Vereins Bremen XVII 1903). 2 SmirH (1920 l.c. p. 139) antyder ogsaa en vestlig indvandringsvei for Hippophaës til Jemtland (cfr. denne forfatters pollenfund). 3 SwrrH (1920 l. c.) fremsætter den antagelse, at Hippopha®s har overlevet den sidste istid paa Norges vestkyst. Dette er dog usandsynlig. Den høiarktiske fauna som er fundet paa Ørlandet, viser at klimatet paa nunatakker og isfrie omraader langs vest- kysten maa ha været meget strengt. — Desuten viser ‘forekomsten paa Gotland at Hippopha’s her har fulgt efter isranden fra syd eller ost. Til Gillebu er den utvil- somt ogsaa kommet søndenfra. 136 ROLF NORDHAGEN. M.-N. Kl. eksempel paa hvorledes planteartenes utbredelse rent generelt styres av klimatologiske lover (I. c. p. 323), saa maa dette eksempel siges at være meget lite lykkelig valgt. Hvis ikke Æippophaës hadde været kjendt i fossil tilstand, vilde menin- gene om dens indvandringstid og indvandringsveier utvilsomt ha været endda mere divergerende. Med utgangspunkt i hvad vi nu vet om denne art, kunde det spørsmaal reises, om vi ikke inden vor flora ogsaa har andre arter som endda ikke er fundet fossile, men hvis historie har faldt sammen med /7ippophaés. I Gudbrandsdalen maa man i denne forbindelse specielt tænke paa ,klaariset", Myricaria germanica. Den er meget sterkt av- hængig av de edafiske forhold og utkonkurreres meget let av andre trær og busker hvor bunden er stabil; kun paa sandige og stenete elvebredder som oversvømmes i flomtiden, danner klaariset egne krat. Planten har i Skandinavien et nordlig utbredelsesfelt i Tromsø—Finmark fylke og et centralskandinavisk fra Hønefoss til Namdalen (med forgreninger over til Sogn og Nordfjord). Fra det trondhjemske har dette felt en utløper ind i Sverige (ialfald tilsynelatende), hvor Myricaria langs Indalselven naar frem til den Bottniske Bugt. Man maa anta at denne art i tiden efter isens av- smeltning og før furuskogenes tid har hat specielt gunstige livsbetingelser og rike spredningsmuligheter. Men desvæfre vet vi endda intet om dens ind- vandringstid!. I Central-Asien optrær den ofte sammen med Hippophaés?; saaledes skriver DruDE: ,/Zippophaés rhamnoides, noch am Kuku-nor bis 3600 m. Höhe ansteigend, wird bis 20 Fuß hoch; oft begleitet ihn die in Hochtibet am höchsten steigende Myricaria germanica“ (Handbuch der Pflanzengeographie 1890 p. 409). En anden merkelig art av subarktisk præg er Aster subintegerrimus (Resv. & OSTENFELD), som i nutiden har et meget isolert utbredelsesfelt ved Aursunden nord for Røros. Ifølge dr. ResvoLL er planten sterkt av- haengig av de edafiske faktorer; den er knyttet til et parti av den gruset- sandige strand hvor skogen ikke gaar ned til sjoen$. Netop av denne grund frygter man for at reguleringen av Aursunden kommer til at bety plantens død; den magter nemlig ikke at trænge sig ind i sluttede natur- lige samfund. — Hvis Hippophaés ikke hadde eiet sin merkelige klimato- logiske plasticitet og sin evne til at taale en god portion salt i substratet, vilde den i nutiden utvilsomt ha fristet en ytterst kummerlig tilværelse. Den er utdød over milevide strækninger fra Oier og helt til Lappmarken. 1 Cfr. ANDERSSON & BIRGER 1912 p. 167. 2 Dette er vistnok ogsaa tilfældet et par steder ved Trondhjemsfjorden og i nærheten av Sundsvall. For Tysklands vedkommende cfr. GRAEBNER: Die Pflanzenwelt Deutsch- lands 1909. I Schweiz optrær disse to arter ofte sammen, f. eks. i Tessin, hvor jeg mellem Mesocco og Bellinzona har set vakre blandede krat paa elvenes grusavleiringer. 3 Cfr. TH. ResvoLL & OSTENFELD: Den ved Aursunden fundne Aster. Nyt Magazin f. Naturv. B. 54. 1916 p.-6. per 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 137 Hvem vet om ikke Aster subintegerrimus, som synes at være daarlig rustet i kampen for tilværelsen (ialfald i nutiden), tidligere har hat en noget mere sammenhængende utbredelse? (Cfr. ResvorL & OSTENFELD 1. c. p. 6, hvor ogsaa denne mening fremseettes)!. Det nærmeste voksested ligger nu i det nordøstlige Finland. I denne forbindelse vil jeg ogsaa fæste opmerksomheten ved den merkelige ansamling av østlige planter som vi nu for tiden har i selve Fig. 40. Aster subintegerrimus paa stenet sandstrand ved Aursunden. Desuten sees Astra- galus alpinus. TH. R. ResvoLL fot. Gudbrandsdalen. Athyrium crenatum, Cystopteris sudetica og Atragene sibirica har her hver for sig et isolert skandinavisk utbredelsesfelt (fig. 41). Eiendommelig nok ,hopper" alle tre fra den finsk-russiske grænse og til Gudbrandsdalen. I. Athyrium crenatum: Utbredelse i Finland—Rusland: fra Ponoj- og Imandra-Lappmarken i nord til Tavastehus i sydvest; østover gjennem Ladoga-Karelen, den kareliske land- stripe mellem Ladoga og Onega og Nowgorod (HERMANN: Flora 1912). Sibirien, Mon- goliet, Sakhalin. Utbredelse i Norge: Sel: Rosten ovenfor Laurgaard (Mor). Nord 1 En anden art som i biologisk-økologisk henseende minder om Aster subintegerrimus, er Carex bicolor, som foruten et nordlig utbredelsesfelt i Skandinavien har 2 meget isolerte forekomster i Centralskandinavien, nemlig i Foldalen i Norge (sandige elvebredder) og i Hårjedalen. wu 8 ROLF NORDHAGEN. M.-N. KI. for Kringen langs veien (M. N. BL). Kvam: Storuren (Norman Herb. Krist.). Ringebu: ved Laagen nedenfor Randklev bro fleresteds i mængde (KAALAAS); Elstad paa den anden side av elven like overfor gaarden (Orsanden if. A. BrLvrr). Den vokser her , ved foten av bergene paa skyggefulde muldete steder blandt raatne omstyrtede stammer ogsaa paa greesbund i selskap med subarktiske planter saasom Polypodium Phegopteris, Stellaria nemorum, Aconitum, Geranium silvaticum, Ranunculus acer etc." (haandskrevne notiser av. À, BL. 1 BL Ne BL): Mangler i det ovrige Europa. 2. Cystopteris sudetica: Rusland: Nowgorod (HERMANN I. c.). Desuten i Karpaterne. Norge: ved Vinstraelven i Gudbrandsdalen ret overfor Kongsli, i dype vanskelig tilgjængelige kløfter i selskap med Cystopleris montana og Cinna pendula (KAALAAS 1897). 3. Atragene sibirica: Finland—Rusland: Onega-Karelen og Nowgorod og i lerkeskog i Onegadalen (HERMANN I. c., WILLE l. c. p. 251). Nord- og Mellemrusland, Ural, Sibirien, Mongoliet, Turkestan. Paa begge sider av sjoen Losna i Gudbrandsdalen (ved gransen mellem Mier og Ringebu herreder), paa østsiden mellem gaardene Enge og Vedum, paa vestsiden ved Hoglien og ved Rugakersætrene (op til over 900 m. o. h. WILLE USE SELE Alle tre arter er av subarktisk type og viser en ganske frappant over- ensstemmelse hvad utbredelsen angaar. Vi har her kanske en av de storste gaader som vor flora gjemmer. Da alle tre er urteagtige eller ialfald visner ned som urter, er chancene for at finde fossile rester av dem uhyre smaa. Men et eneste fossilfund kan her si det avgjorende ord. For Atragene sibirica s vedkommende har Wire (1917 I. c.) fremsat den anskuelse, at den er indkommet til Gudbrandsdalen ved tilfældig spredning i nyere tid, hvilket er meget vel tænkelig. Imidlertid mener jeg ogsaa de to andre arter maa tages med i ræsonnementet, og med henblik paa Hrp- pophaës og dens utdøen over hele Centralskandinavien, maa man indrømme, at der her foreligger muligheter for at ovennævnte arter, som nærmest er av subarktisk type, ogsaa kan ha hat en kompliceret historie i det lange tidsrum som ligger mellem isens forsvinden og nutiden. Men opfatningen paa dette punkt maa selvfølgelig bli subjektiv; noget videnskabelig bevis kan man jo ikke levere. C. Den atlantiske tid. Denne periode har i Gudbrandsdalen udmerket sig ved tætte furu- skoger. Antageligvis har sydlige løvtrær spillet en viss rolle ialfald i dalens nedre del paa gunstige lokaliteter (hassel, alm, muligens lind)!. Av hasselnottfund i torvmyrer vet vi at Corylurs Avellana har hat en noget større utbredelse under den postglaciale varmetid i dalens sydlige del (cfr. Horw- BOE 1903). Ulmus-pollen, som det har lykkedes mig at paavise i smaa mængder i furutuffen ved Gillebu, er meget interessant, men gehalten er altfor ube- tydelig til at kunne tillægges nogen større betydning. Fundet av Tofieldia palustris ı den atlantiske tuf ved Leine viser at enkelte fjeldplanter ogsaa under denne periode har hat tilhold i Leine- I Ulmus montana har nu sin nordgrænse i Faaberg. Gaardsnavnet Alme i S. Fron viser ifølge A. M. Hansen (1914 l.c. at den er i tilbakegang. Acer platanoides gaar til Faavang, Corylus og Tilia til Ringebu, men er meget sparsomme i sin optræden. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 139 bakkene. Muligens har dette bare vaeret tilfzeldet med alpine eller subalpine myr- og kildeplanter. Dryas, Salix reticulata og de øvrige som dominerte i boreal tid, er ialfald nu forsvundet. — Forekomsten av fjeldplanter i Jemtlands kalktuffer har SERNANDER oprindelig villet forklare som atlantiske nedvandringer (1899 |. c., 1916 I. c.). Imidlertid tyder Harrres undersokelser, specielt paavisningen av den smale Dryas-Hippophaés-sone i bunden, paa at den mere sporadiske optræden av fjeldplanter hoiere oppe i furutuffen paa de jemtlandske forekomster snarere er en reminiscens fra boreal tid. f at klimatet har været gunstig, IN Ved Leine røber Fraga- ria vesca og Detula verrucosa ialfald ikke daarligere end i nutiden. / Hansen har med styrke fremhævet hvilken stor betyd- Des nique | ning den postglaciale varme- ae tid med dens hævning av \ v \ Vins skoggrænsene har hat for à | d e fjeldvegetationen (1904 I. c.). À Sen Under denne tid er mangt ei N ees et kontinuerlig utbredelsesfelt AUR ) x blit splittet ad og mange ark- HE tisk-alpine arter bukket under 21 hvor fjeldene ikke var hoie Lillekamnev SR M nok. Tuffene vidner tydelig om denne utryddelseskrig, specielt av fotofile arter under atlantisk tid (cfr. Dryas og Fig. 41. Kart over Gudbrandsdalen med indlagte vokse- steder for Atragene sibtrica (X), Athyrium crenatum (@) Hippophaés). og Cystopteris sudetica (2). D. Den subboreale tid. Om dette interessante tidsrum fortæller kalktuffene i dalen ikke andet end at kildene torket ind, og at der indtraadte en forvitring av den tid- ligere dannede tur. Som ovenfor omtalt er torvmyrforskerne kommet til det resultat, at det »postglaciale klima-optimum", altsaa selve varmetidens klimaks, har indtraadt efter atlantisk tid, nemlig under den tørre og varme subboreale periode. De marine avleiringer baade i Kristiania- og Trondhjemsfeltet viser ogsaa, som ØYEN har gjort opmerksom paa, at vi ingen grund har til at sætte Tapesnivaaet (sensu stricto) som kulminationspunkt; Trivia-nivaaets og del- vis Ostræa-nivaaets fossilrike avleiringer vidner nemlig om ytterst gunstige klimatiske forhold, ogsaa efter Tapes-nivaaet. I avleiringer paa Frogene, utenfor Trondhjemsfjorden, fra Trivia-nivaaet fandt jeg i 1915 foruten 140 ROLF NORDHAGEN. M.-N. Kl. Trivia europea og en mængde andre sydlige typer ogsaa Solecurtus can- didus Ren. Desm., en musling som nu for tiden ikke findes nordenfor den Irske Sjø (NORDHAGEN 1917 l. c.). Dette og andre tidligere fund i de norske marine avsætninger viser hvilke voldsomme forandringer og forskyvninger vi har at regne med i havets dyreverden i postglacial tid. Og landfloraen har gjennemgaat tilsvarende, om ikke større ændringer (cfr. ANDERSSON 1902 |. c., SERNANDER 1908 |. c., MALMSTROM 1920 |. c.). En række med plantearter av sydlig eller sydøstlig, varme- kjær og kontinental type, som nu har sin nordgrænse i Gud- brandsdalen paa gunstige loka- liteter (sydskraaninger med kalkholdig og tør bund) er utvilsomt at opfatte som relikter fra subboreal tid. Dracocepha- lum Ruyschiana og Brachy- podium pinnatum (fig. 42 og 43), to arter som STERNER (1921 l. c.) specielt har studert, horer til denne gruppe (cfr. den specielle del p. 9). Den sidste seetter ikke moden frugt ved Leine, saavidt jeg har kunnet konstatere; men den har rik vegetativ formering. Da Leine- bakkene i nutiden huser saa mange rariteter, maa man anta at de i subboreal tid hadde en meget interessant vegetation. Fig. 42. Dracocephalum Ruyschiana 1 Skandinavien. Desveerre er der ikke opbe- Efter STERNER (1921). For Norges vedkommende er varet hverken tuf eller andre voksestedene sammenstillet av R. NoRDHAGEN. Dette 3 1 gjælder ogsaa Brachypodium pinnatum. rester fra dette tidsrum ". E. Den subatlantiske tid. Den merkelige Alnus-tuf og gruskeglen ved Gillebu vidner om store forandringer efter den subboreale tid. Fugtige orekrat lik de nuværende har udmerket Leinebakkene, men furuen har dog fremdeles været tilstede. Gillebutuffen fortæller intet om vegetationens karakter i Oier under denne periode. 1 Jeg har tidligere omtalt de divergenser og vanskeligheter som knytter sig til beteg- nelsen „subboreal“. Noget bidrag til denne periodes tidfæstelse kan kalktuffene i Gud- brandsdalen selvfolgelig ikke levere. 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. I4I Man antar nu at granen indvandret til Norge i subboreal tid (Horw- SEN 1919 og 1920 |. c.), og det er for saavidt merkelig at rester av denne “art mangler i den subatlantiske tuf ved Leine. I nutiden er dog granen sjelden i de øverste bygder i Gudbrandsdalen (f. eks. i Lesje, hvor den betragtes som en raritet og bindes til kranser, omtrent som barlind andre steder i landet. Den holder sig her mest til bakliene (Hrrrawp |. c.). Dette tyder paa en relativt sen fremtrængen i dalens nordre del, selv om kanske klimatiske forhold i nutiden ogsaa spiller ind. — Jeg har forøvrig tidligere præ- cisert at den negative kjends- gjerning at granrester mangler ved Leine, ikke behøver at bety saa meget. Da Alnus-tuffen er sterkt forvitret, ligger det nær at tænke sig at tufdannelsen i subatlantisk tid væsentlig har paagaat i periodens første del. Yngre lag er muligens ogsaa helt forvitret. I subatlantisk tid rykket skoggrænsene paa fjeldene atter ned fra det hoitliggende nivaa og til det nuværende. Regio alpina blev herigjennem sterkt utvidet, og nye sprednings- muligheter aapnet sig for fjeld- plantene. De fjeldarter som vi finder 1 lerbakkene i Kvam i nutiden, er vistnok subatlantiske og recente nedvandrere. Ler- Fig. 43. Brachypodium pinnatum i Skandinavien. skredene i nyere tid maa saa- ae ser, ledes som tidligere omtalt, ha skapt gode vilkaar for fjeldplantene ved at blotlegge nye arealer og skape lette konkurrencevilkaar og rik lystileang!. En art som Dryas octopetala har dog endda ikke formaadd at gjenerobre det tapte terræng. Omvendt har sydlige typer under subatlantisk tid undergaat store for- skyvninger. Naar dette gjælder arter som hassel, Trapa.natans etc., saa maa man ha lov til at generalisere forholdet. Dog er det mulig at for- skyvningene i den varme og lune Gudbrandsdal har foregaat i mindre skala end mange andre steder. ! Denne aapne plantevekst i skraaningene er ogsaa hensigtsmæssig for de sydlige relikte typer, som her ikke har saa let for at bukke under i konkurrencen med andre arter. 142 ROLF NORDHAGEN. M.-N. KI. I dalens vegetationshistorie har den subatlantiske tid været en av de allervigtigste, idet granskogene litt efter litt har presset sig frem, specielt paa furuens bekostning. Dette har været mere fremtrædende i dalens nedre del end i de øvre trakter, hvor granskogen væsentlig er knyttet til de fugtigere og skyggefulde baklier med nordlig og østlig eksposition. Endelig har mennesket i historisk tid paavirket vegetationen paa utal- lige maater, likeledes vandflommene og lerskredene. Alt i alt kan vi for Gudbrandsdalens vedkommende adskille tre epoker i skogenes historie: 1. Den første subarktiske bjerk-aspeskogs tid. 2. Furuskogenes tid. 3. Granskogenes tid. Under den postarktiske varmetid har antageligvis ogsaa ædle løvtrær spillet en viss rolle paa gunstige lokaliteter, saaledes som ovenfor antydet. Denne inddeling sigter kun til de dominerende træslag; det er saa at si en kvantitativ inddeling, og den falder ikke sammen med den over- sigt som andre forskere opstiller paa grundlag av undersøkelser i Danmark, Syd- eller Mellemsverige og det sydlige Norge. Her har forholdene været anderledes, ikke alene kvantitativt, men ogsaa kvalitativt. I det hele tat er det umulig at fastsætte en viss postarktisk „norm“ for hele Skandinavien grundet paa palæobotaniske principper, saaledes som ældre plantegeografer antok. Forholdene har variert be- tydelig i de forskjellige deler av Skandinavien, om end visse sterre geo- grafiske provinser med et visst fællespræg i vegetationshistorien kan ut- skilles. For Norges vedkommende er disse sporsmaal endda lite studert. Fortegnelse over de fundne plantearter og snegler. Karplanter. Equisetum variegatum Avv. Uhyre alm. i mosetufbænken ved Leine (BLvrr 1891); ogsaa i den undre Dryashorisont og i Dryastuffen. Equisetum hiemale L. Furutuffen ved Leine, men især alm. i Alnus- tuffen. . Nedre Dal i mængde i bladtuffen (Brvrr 1892), muligens ogsaa i furutuffen. | Pinus silvestris L. I furutuffen ved Leine, Gillebu og Nedre Dal i uhyre masser (naaler, bark, grener, kongler); i Dryastuffen ved Leine spar- somme naaler, nederst kortere og smalere, men allerede i Dryastufkom- pleksets midtre del lange og brede (cfr. BLyrr 1892) Sparsomme naaler i Alnus-tuffen ved Leine. Pollen i bladtuffen ved Leine og Gillebu og i bladtufblokkene ved Onset. I9Q2I. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. I43 Picea excelsa (Law.) Link. Nogen naaleformige avtryk i et par smaa stykker fra Onset (BLyrrs samling) og i undertegnedes samling av lose tufbiter i jorden sammesteds tilhorer vistnok denne art. — Mangler i Gud- brandsdalens tuffer. Kun ved analyse av forvitret furutuf fra Gillebutuffens everste del har jeg set et par pollenkorn av gran, hvilket utvilsomt skyldes recent tilforsel med nedsivende vand. Populus tremula L. Bladtuffen ved Leine, Gillebu og Nedre Dal (BLvrr 1892); Dryastuffen, furutuffen og Alnus-tuffen ved Leine; furutuffen ved Gillebu. Onset i bladtufblokkene (OYEN 1920). Salix caprea L. Ved Leine, Gillebu og Nedre Dal alm. i bladtuften (BLvrr 1892). Ved Leine sparsomt i Dryastuffen, desuten i furutuffen og Alnustuffen sammesteds. Salix nigricans Sm. I bladtuffen ved Nedre Dal (Brvrr 1892); vist- nok ogsaa i bladtuffen ved Leine og Gillebu; i bladtufblokkene ved Onset (OvEN 1920). Salix cfr. phylicifolia Sm. I bladtuffen ved Leine og i Dryastuffen samt i bladtuffen ved Gillebu forekommer en del blader som maa henføres til denne art; men bestemmelsen av fossile Salices er meget vanskelig. Salix arbuscula L. Ved Leine i den undre Dryashorisont, men især i Dryastuffen almindelig (Brvrr 1892) I et profil er den iagttat nederst i furutuffen. — Planche I, fig. 8. Foruten blader har jeg set smale C-rakler av denne art (planche II, fig. 2). Salix hastata L. Et par blader fra bladtuffen ved Leine (Brvrr 18921. Denne bestemmelse er utvilsomt rigtig. Salix glauca L. Bladtuffen ved Leine temmelig alm. (Brvrr 1892) Kollodiumavtryk av et vakkert opbevaret avtryk viser at epidermis har været sterkt haaret. Bestemmelsen er ganske sikker (planche I, fig. 6). Salix cfr. lanata L. Et par mindre avtryk fra bladtuffen ved Leine tilhører muligens denne art, men bestemmelsen er meget usikker. Salix reticulata L. Dryastuffen ved Leine (Brtvrr 1892). Brvrr fandt bare to blader; men da jeg selv har fundet r3 avtryk, er arten neppe sjelden i dette lag (planche III, fig. 2). Salix herbacea L. Av denne art har jeg fundet et fragmentarisk, men typisk bladavtryk (planche I, fig. 7) i Dryastuffen ved Leine. Karakteristisk for denne art er at bladets hovednerve (midtnerve) ikke løper distinkt ut til bladranden, men svækkes og blir mere utydelig et stykke fra randen. Den fine tanding og bladets smaa dimensioner stemmer likeledes med denne art. Foruten de anførte arter har jeg fundet avtryk av andre Salices; men det er ikke mulig at bestemme dem med sikkerhet. Betula odorata Becust. Alm. i bladtuffen (og mosetuffen) ved Leine, Gillebu, Nedre Dal (BLyrr 1892). Ogsaa i Dryastuffen, og i furutuffen paa alle tre forekomster, desuten i Alnus-tuffen ved Leine. Onset i bladtuf- blokkene. — Foruten blader og bladfragmenter i store kvantiteter har jeg ogsaa fundet forkalkete Q-rakler. 144 ROLF NORDHAGEN. M.-N. Kl. Betula verrucosa Eur. Bryrr anfører et bladfragment fra furutuffen ved Leine (dobbelttandet, næsten lappet rand), dog under tvil, likeledes et langstilket blad fra furutuffen ved Nedre Dal (usikkert). Jeg har selv i furutuffen ved Leine fundet et bjerkeblad med langt uttrukket spids og dobbelttandet rand, som maa henføres til D. verrucosa. Betula cfr. intermedia Tuom. ,Dryastuffen ved Leine, meget usikker" (BLyrr 1892). Betula cfr. nana L. „Et brudstykke av et blad, meget usikkert fra Dryastuffen ved Leine" (Brvrr 1892). Betula cfr. alpestris Fr. „Leine, den nederste” del av birketuffen. Et eneste blad uten top, hvorfor bestemmelsen er usikker" (BLYTT 1892). — Jeg har selv hat anledning til at se de angjældende avtryk av 5. nana og intermedia og finder dem hoist usikre. I mine egne samlinger har jeg heller ikke fundet spor av disse former. Alnus incana DC. Brvrr anfører et par fragmentariske bladavtryk fra birketuffen ved Leine som ,cfr. Alnus incana"; men bestemmelsen er meget usikker da randen mangler. I Alnus-tuffen ved Leine uhyre alm., ogsaa en hel del G-rakler. Bladstorrelsen varierer adskillig (planche V). — Alm. i bladtufblokkene ved Onset (Brvrrs samling. OYEN 1920). Corylus Avellana L. Avtryk og hulhet efter en nott i et lost tufstykke i jorden ved Onset. Alder ubestemt. Ribes cfr. rubrum L. Bryrr anfører et haandnervet blad fra birke- tuffen ved Leine. Noget usikker artsbestemmelse. Sorbus Aucuparia L. I furutuffen ved Leine et bladfragment (planche II, fig.3). Cotoneaster integerrima Mepic. Bıyrr opfører et blad fra Dryastuffen ved Leine; men bestemmelsen er usikker. Prunus Padus L. „Den nedre del av et blad 0,04 m. bredt paa midten, fra birketuffen ved Dal" (Brvrr 1892). Dryas octopetala L. Blader og hele stammer med paasittende blad- rester i store masser i Dryastuffen ved Leine (Bryrr 1892). Desuten i den undre Dryashorisont. Et enkelt blad i bladtuffen. Forskjellige eiendomme- lige kalkkjerner og avtryk (blomster 1 begyndende frugtstadium (planche I, fig. 1), blomsterbund med merker efter smaafrugtene (planche I, fig. 2, 3, 4, 5)) skriver sig ogsaa fra denne art. Fragaria vesca L. I furutuffen ved Leine fandtes et mindre, trekoblet blad, som i ett og alt stemmer med jordbærblader. Desværre var bladet saa skjort at det under transporten til Kristiania blev noget odelagt. Av planche III, fig. 1 ser man at de tre deler er fossilificert i forskjellige planer. (Ulnaria pentapetala, Ribes rubrum og Rubus saxatilis er utelukket, hvilket den direkte sammenligning paa findestedet dengang avtrykket blev frem- fundet, viste.) Hippophaës rhamnoides (L.) AscHers. Bladtuffen ved Gillebu, i maengde- vis i tuf baenkens bund og paa dens underflate (OvEN 1917, det. NoRDHAGEN), sparsommere opad. — Y 1921. No. 9. KALKTUFSTUDIER I GUDBRANDSDALEN. 145 Pyrola cfr. minor L. I Dryastuffen og furutuffen ved Leine flere blader og en hel forkalket liten plante av en Pyro/a, som stemmer godt med P. minor; men artsbestemmelsen er ikke helt sikker. Vaccinium vitis idæa L. I furutuffen ved Leine m. alm. og Nedre Dal alm. (BLyrr 1892); ved Gillebu sparsom baade i bladtuffen og furutuffen. Brvrr anfører den ogsaa, om end noget usikkert, fra Dryastuffen ved Leine. Vaccinium uliginosum L. I bladtuffen ved Nedre Dal et eneste blad (BLvrr 1892). Furutuffen ved Leine flere blader. Cfr. Arctostaphylos uva ursi (L.) SPRENG. Brytr anfører et usikkert brudstykke (den nedre halvdel) av et blad fra Dryastuffen ved Leine. Bestemmelsen er heist usikker; jeg har selv fundet smaa glatte bladavtryk i Dryas- tıffen som ligner baade Cotoneaster og andre arter med helrandete blader, men som vistnok bare er avtryk av Salıx arbuscula, hvor det øverste kalklag (med nervaturavtrykket) er avspaltet eller ut- vis Hegetoalente dor Lam, Modem) = En. ther tnlaeise als mrackkambrisch/ oder ZZ A er veractohnet, troie Sand, Schotter u.Lelm der Cegemvart | E baa. Geologische Kartenskizze der Gegend von Plzenec. 1:30000. Nach C. Purkyne, ergänzt v. J. V. Zelizko. I. Kreyci und K. FEISTMANTEL!, die sich auch mit den geologischen Verhältnissen der Umgebung von Plzenec befaßten, sprechen nirgends von Versteinerungen. 1 Orographisch-geotektonische Übersicht des silurischen Gebietes im mittleren Böhmen. Archiv der naturwiss. Durchforschung von Böhmen. Bd. V. No.5. Prag 1890. 1921. No. Io. ÄQUIVALENTE DER UNTERSILURISCHEN EULOMA-NIOBEFAUNA. 5 Als ich nach Beendigung meiner Forschung auf der Hurka im Jahre 1912 bei Plzenec zufällig Schiefer der Komorauer Stufe (d 1 8) mit über- raschender, meistens bisher unbekannter Fauna!, welche der Hauptgegen- stand der vorliegenden Arbeit ist, entdeckte, besuchte ich anläßlich der Durchforschung neuer Lokalitäten Plzenec noch im Jahre 1913 und 1915. Daf ich die Forschung mit solchem Erfolg zustande brachte, wie später gezeigt wird, dafür bin ich in erster Reihe dem lóbl. Verwaltungs- ausschusse des Museums des Königreichs Böhmen, welcher mir zu diesem Zwecke im Jahre 1913 eine Subvention aus dem Barrande’schen Fonde gewährte, verpflichtet. Die Schloenbachstiftung der k. k. geol. Reichsanstalt ermöglichte mir dann im Jahre 1914 eine Studienreise nach Skandinavien zur Besichtigung dortiger altpaläozoischer Ablagerungen, sowie der diesbezüglichen, zum Vergleich der von mir bei Plzenec festgestellten Fauna wichtigen Samm- lungen. Während meiner Anwesenheit in Plzenec war Herr Ing. Run. Cisar stets ein opferwilliger Teilnehmer meiner Arbeiten, wofür ich ich ihm an dieser Stelle herzlich danke. Gleichfalls danke ich dem p. t. Gemeindeamte in Plzenec für die Erlaubnis zur Durchforschuug der der Gemeinde gehórenden Lokalität »U Blazeje«. Ferner ist es mir eine angenehme Pflicht, Herrn Prof. C. RITTER voN PurkyNE für die allseitige, meinen Forschungen im westlichen Böhmen jahrelang gewidmete Unterstützung zu danken. Schließlich bin ich Herrn Prof. Jon. Kiær in Kristiania, welcher sich meiner Publikation freundlichst annahm und dieselbe zur Veróffentlichung in »Videnskapsselskapets Skrifter« empfahl, besonders zum innigsten Dank verpflichtet. 1 L V. Zerizko. Neuer Beitrag zur Geologie der Gegend von Pilsenetz in Böhmen. Ver- handlung der k. k. geolog. Reichsanstalt. No.5. 1913. 6 T'Y; ZELIZKO. M.-N. Kl. Schiefer der Bande D—d1? deren Liegendes und Hangendes. a) Die Schiefer »U Blazeje«. Westlich von Plzenec, an dem linken Ufer der Uslava, zieht sich eine aus der Ferne gut sichtbare Lehne, genannt »U Blazeje«, welche mit einer ziemlich hohen felsigen, nordwestlich streichenden Bóschung endet. In einer Schlucht der betreffenden Lehne, an dem rechten Ufer eines unweit des Eisenbahnwächterhauses No. 269 fließenden Bächleins treten dünngeschichtete, verwitterte Schiefer zu Tage, die bei flüchtiger Besich- tigung an die Schiefer der Osek-Kväner Stufe (d 1 y) erinnern, welche be- kanntlich auf der gegenüberliegenden Hurka vertreten sind und scheinbar auch auf das linke Uslavaufer übergehen. Diese Schichten, welche teilweise von Diluvialablagerungen bedeckt sind, hat Herr Prof. PURKYNE in seiner Karte! ursprünglich als der Osek- Kväner Stufe angehörend verzeichnet, später jedoch? die Ansicht ausge- sprochen, daß dieselben wahrscheinlich dem Eulomahorizonte der Stufe dı zuzurechnen sind. Bei näherer Untersuchung der besprochenen Schiefer fand ich, daß der petrographische Charakter derselben ein anderer ist, als die typischen schwarzen Schiefer von Hurka aufweisen. Das Gestein besteht im frischen Zustande aus graugrünem, feinkörni- gem, glimmerigem und festem Schiefer, welcher verwittert eine lichte, graue oder gelblichbraune Farbe aufweist. Die Flächen der Schieferplatten sind häufig von Eisenhydrooxyd verschiedenartig gefärbt. Genannter Schiefer erinnerte mich schon auf den ersten Blick an einen ähnlichen, den ich im J. 1906 bei Klabava, zwischen Pilsen und Rokycan sah, von wo ein Jahr früher Herr Prof. B. Horak einige neue Versteine- rungen für das städtische Museum in Rokycan erworben hat, und welche mir zur späteren Bearbeitung zugesandt waren. Als dieses Material bald 1 Geologicka mapa zastupitelskeho okresu Plzensköho, 1:30 000. Pilsen 1910. 2 Geologie okresu Plzenskeho. S. 52. Pilsen 1913. 1921. No. 10. AQUIVALENTE DER UNTERSILURISCHEN EULOMA-NIOBEFAUNA. 7 darauf durch die Aufsammlungen Horuss bedeutend vermehrt wurde, habe ich auf Ansuchen des Herrn Horus, welcher die Zugehörigkeit der Funde zu einem für Böhmen neuen Eulomahorizonte nachgewiesen hat1, ihm den betreffenden Teil zur Bearbeitung überlassen. An der Exkursion nach Klabava im J. 1906 habe ich mit Herrn Prof. Horak und Purkyne ausschließlich zur Untersuchung der geologischen Verhältnisse der Lokalität teilgenommen, denn zum Suchen nach Fossilien war damals die nötige Zeit nicht vorhanden, infolgedessen konnte man natürlich von diesem Ausflug keinen besseren Erfolg erwarten?. Die auffallende petrographische Übereinstimmung des Schiefers von Klabava mit dem des Fundortes »U Blazeje« bei Plzenec veranlaßte mich zu emsigerem Suchen nach Versteinerungen, was tatsächlich nicht ohne Erfolg blieb. Auf diese Weise wurde neuerdings bestätigt, daß es nicht immer richtig ist, den petrographischen Charakter eines Gesteines zu unter- schätzen, welches nach dem oberflächlichen Ansehen nicht fossilführend zu sein scheint. Nach längerem geduldigem Suchen im neuen Fundorte gelang es mir endlich überzeugende Beweise zu gewinnen, daß die hier zutage tretenden Schichten auch faunistisch mit jenen von Klabava übereinstimmen, d.h. daß sie eine Fazies der Stufe dıß bilden. In teilweise festem, teilweise halbverwittertem, tonigem Material wurden neben undeutlichen Graptolithen auch mehrere Stücke von Brachiopoden, die den bereits von BARRANDE angeführten Linguliden, und zwar der Lin- gula sulcata? und der Lingula rugosa* und anderen verwandten Formen angehören. BARRANDE bezeichnete als Fundort beider Arten K/abava (»Vallon de la Klabava — dr — au nord de Rokitzan«). Außer diesen Versteinerungen kommen im neuen Fundorte bei Plzenec auch bekannte enge, den Orthoceren ähnlich gegliederte Bildungen, und undeutliche Trilobitenreste vor. Noch besser aufgeschlossen findet man fossilienführende Schiefer einige Schritte nordwestlich von der obenerwähnten Stelle, nämlich hinter dem Kreuz »U Blazeje«, wo die Lehne in einer ziemlich steilen Böschung ab- lauft Da an dieser Stelle das Gestein öfters zum Schottern ausgebrochen wurde, sind die besprochenen Schichten überall gut zugänglich. 1 K. Horus. Nova fauna spodniho siluru v okoli Rokycan. Rozpravy Ceské Akademie. Jg. XX. Nr. 15, Prag ıgır. — Doplnky ku faune eulomového horizontu v okoli Rokycan. Ibid., Ig. XXI, Nr. 33, 1912. 2 K.Horup. Nova fauna etc., pag. 1. 3 Systeme Silurien. Vol. V, Pl. 106, Fig. III (2, 3). 4 Ibid. Pl. 152, Fig. V (2, 3). 8 J. V. ZELIZKO. M.-N. KI. Dieser Teil der Lehne wurde vom Herrn Prof. PURKYNE als präkam- brische Schiefer aufgenommen. Auf der alten, handkolorierten Karte der k. k. geol. Reichsanstalt (Z. 7 C. TX. Pilsen und Blowitz) ist der an dem linken Ufer des Uslava- flusses liegende Schichtenkomplex überhaupt als pråkambrischer (Pribramer) Schiefer B bezeichnet. Das Gestein in dem nordwestlichen Zipfel der Lehne »U Blazeje« bildet nordwestlich zwischen 30—40° einfallende, feste und unregelmäßig mächtige Bänke, die besonders gegen NW allmählich in ganz dünne blätt- rige Schichtchen übergehen. Auch an dieser Stelle glückte es mir nach längerem Suchen einige schön erhaltene Versteinerungen im gelbbraunen halbverwitterten, sowie im festen, graugrünen Schiefer zu gewinnen. Während meiner dreijährigen Forschung fand ich hier zahlreiche Brachiopoden, einige Orthoceren, Ptero- poden, namentlich aber schön erhaltene Graptolithen in Form von bis über 40 cm. langen Büscheln und Ruten (Taf. V), mit deren Bearbeitung sich soeben Herr Dr. PERNER beschäftigt. Am besten erhaltene Exemplare haben große graugrüne Schieferplatten geliefert. Schließlich sollen noch einige neue Z7ilobiten als Seltenheit erwähnt werden. Die Schichten der Stufe d1 8 an dem linken Uslavaufer sind von Diluvialablagerungen der III. Terrasse PunkvwE's bedeckt. Dieselben kann man von dem Hauptfundorte »U Blazeje« auch noch gegen WSW, sowie gegen O, wo sie quer über den Fahrweg etwa in halber Entfernung zwischen der Stelle »U Blazeje« und Plzenec an einigen Punkten zum Vor- schein kommen, verfolgen. b) Die Schiefer in Plzenec. Dieselben untersilurischen Schiefer der Stufe d 1 8 wie in der Lehne »U Blazeje« kommen auch an einigen Stellen in Plzenec, wie z. B. hinter dem Bräuhaus und südöstlich von diesem auf der Stelle »U krizku« (= beim Kreuzchen) noch an dem linken Uslavaufer vor. Das Gestein ist aber größtenteils verwittert und an der Fläche rostig gefärbt. Das Liegende der oberwähnten untersilurischen Schiefer des linken Uslavaufers bilden die präkambrischen Schiefer, welche überhaupt südöstlich von Plzenec einen ausgedehnten, häufig von Lydit- und Spilitstreifen und Inseln durchtretenden Komplex einnehmen. Sie sind entweder von Diluvial- oder Alluvialablagerungen bedeckt, und da sie leicht verwittern, verwandeln sie sich oft in mächtige eluviale Tonschichten. Ein solches Beispiel liefert am besten die Umgegend von Spälené Porici (Brennporitschen) südöstlich von Plzenec, wo man Schiefer 1921. No. 10. AQUIVALENTE DER UNTERSILURISCHEN EULOMA-NIOBEFAUNA. 9 in eine beträchtliche Tiefe so stark zersetzt fand, sodaß es oft schwer ist das ursprüngliche Gestein durch einige feste Bruchstücke nachzuweisen !. Das eigentümliche Aussehen dieser tonigen Schichten lockte vor einigen Jahren verschiedene Privatunternehmer zur Schürfung nach Kohle in un- mittelbarer Nähe von Spálené Porici, was, wie sich denken läßt, erfolglos blieb. Die mir damals zugesandten ca. 26 m. in die Tiefe reichenden Bohrproben zeigen wenigstens in wie weit der Zersetzungsprozeß der Schiefer vorgeschritten ist, wie folgt: 1. Probe. Vollkommen zersetzter, in grauen, sandigen Ton verwandelter Seliefers er a 508 FA ease «DIS: RSA MD 2. — Derselbe von einer dunkleren Farbe . . . . . » 16 > a SS Derselbe von schwarzgrauer Farbe . . . . „. „sr I7 » 4. — Grauer Sandiger Schiefer = 2 2% mE Ie TO > 5. — Schuppen von schwarzen glänzenden Schiefer mit @Quarzkornerm Radar ML ee ee ae S. uev > JETER 6. — Dunklere Schiefermasse mit größeren Schieferbruch- Sie doit M tasse Vem Ste oh ess. in OE 7. — Dieselbe mit kleinen Quarzkôrnern . . . . . . » 21 » 8. — Gemisch aus Bruchstücken des schwarzen Schiefers, Grunstemes und Owuarzes —.. X9 4 NV UR 25. d 22.5 9: — Schwarzer Schiefer mit Quarz und vielem Pyrit » 23 » 10. — Bruchstücke des festen schwarzen Schiefers . . . » 24 » EI. — Grausehwarzer Schiefer = ^2 ne. X TT. ^w 25 » Nox — Fester, schwarzer, glänzender Schiefer . . . . » 26 » c) Die Schiefer bei Sedlec. Daß man Schiefer der Stufe d 1 auch an dem rechten Uslavaufer verfolgen kann, davon kann man sich bei Sedlec, einem ca. 1.5 km. óstlich von Plzenec entfernten Dorfe überzeugen. Nördlich von dem genannten Dorfe, beim Kreuz auf der linken Seite der nach Timákov führenden Strafe, sowie an einigen anderen Punkten in Sedlec selbst, kommen meistens verwitterte, dünngeschichtete gelbbraune, nw. bis nww. unter einem 35—40? einfallende Schiefer zum Vorschein. Da dieselben in einer ziemlichen Tiefe zersetzt sind, konnte ich darin bloß undeutliche Graptolithenspuren und Bruchstücke von einer Lingula, und einigen lànglichen Konkretionen finden. Die besprochenen Schiefer der Stufe dıß bilden die Unterlage der konkordant liegenden schwarzen Schiefer der Stufe d 1 y von Hurka. 1 F. KATZER. Geologie von Böhmen, pag. 636—637. IO TV, ZELIZRO, M.-N. Kl. Die genaue Grenze zwischen beiden Stufen festzustellen, verhindern die die Schiefer bedeckenden Diluvialablagerungen. Es scheint, daß die in den Schluchten des südöstlichen Teiles von Hurka, näher gegen Sedlec, später gefundenen Versteinerungen wahr- scheinlich jenen Schichten angehören, auf welchen unmittelbar Schiefer der Stufe dif ruhen. Die fossilienführenden Schiefer des südöstlichen Teiles von Hurka sind stark verwittert und zerfallen in dünne, durch Eisenoxyd rostig gefärbte Blätter und Plättchen. Die Farbe derselben ist meistens schmutziggrau, im Gegensatz zu den dunklen und festen Schiefern aus der höheren Lage der Hurka. Wie es der Erhaltungszustand der Versteinerungen zuläßt, habe ich folgende Arten bestimmt: ]. Trilobiten. Placoparia Zippei Boeck. sp. Einige kleine, vollkommen erhaltene Exemplare, isolierte Kopfschilder und häufige Thoraxteile. Das Vorkommen dieses Trilobites ist um so merkwürdiger, da derselbe in der zwar reichen Fauna von Plzenec! in keiner der höheren Lagen dıy bisher nachgewiesen wurde. Aeglina rediviva BARR. Ein größeres und ein kleineres Pygidium. Aeglina cf. sulcata Barr. Ein Abdruck und der Gegenabdruck eines kleineren Pygidiums. Il. Cephalopoden. Orthoceras expectans BARR. Einige Bruchstücke. Ill. Brachiopoden. Strophomena primula Barr. Einige Exemplare. Paterula bohemica Barr. Zwei Exemplare. iocur, ic. a pag. 3. IQ2I. No. 10. AQUIVALENTE DER UNTERSILURISCHEN EULOMA-NIOBEFAUNA. ET IV. Gastronoden. Pleurotomaria (Lophospira) viator BARR. Einige Exemplare. Pleurotomaria (Lophospira) nov. sp. Ein negativer Abdruck eines etwas größeren Exemplares als ich im J. 1909 anführte (Faunistische Verhältnisse der untersilurischen Schichten bei Pilsenetz in Böhmen. Verhandl. d. k. k. geolog. Reichsanst. No. 3). Helicotoma ? nov. sp. Ein Abdruck und der Gegenabdruck mit erhaltener feiner Schalen- skulptur. Außerdem noch einige Reste wahrscheinlich verschiedenen P/euroto- marien angehörend. V. Pteropoden. Hyolithus sp. Ein Abdruck und Gegenabdruck eines seitlich gepreßten, längs der Schale mit feinen Rippen verzierten Exemplares. Conularia exquisita BARR. Einige kleine Bruchstücke und ein Fragment eines größeren Exemplars mit gut erhaltener Skulptur. VI. Lamellibranchiaten. Leda bohemica Barr. Ein Bruchstück einer Doppelschale und ein kleines, vollkommen erhal- tenes Exemplar. VII. Crinoiden. Einige undeutliche Stengelreste. Die oben beschriebene Fauna liefernden Schichten gehóren wahr- scheinlich ein: und demselben Horizonte d 1 y der nördlich liegenden Lokali- täten bei Ejpovic! an, wo wie bekannt Placoparia Zipper als häufigstes Fossil vorkommt. Kj 1 I. V. Zelizko. Weitere neue Beiträge zur Kenntnis der Fauna des böhmischen Untersilurs. Verhandl. d. k. k. geolog. Reichsanst. No.2. 1902. — Zur Paläontologie der unter- silurischen Schichten in der Gegend zwischen Pilsen und Rokycen. Ibid. No. 16. 1908. 12 J. V. ZELIZKO. M.-N. Kl. Das Liegende der Schiefer der Stufe d1ø bilden bei Sedlec die auf den pråkambrischen Schiefern ruhenden Krusnáhoraschichten (dr «). Zum Schluß möchte ich noch bemerken, daß die Verbreitung der Schiefer dif in der Gegend von Plzenec viel größer ist als in dieser Publikation behandelt wird, dafür sprechen meine neuerlichen Forschungen, über welche ich anderorts berichten werde. Paläontologie der Bande D—d1 £. Trilobiten. Asaphellus bohemicus ZEL. (Tat bie atl Rupe 2») Es liegen zwei grofse, fast vollstándig erhaltene Exemplare vor, wo- runter ein im positiven sowie im negativen Abdruck vorhanden ist. Zu derselben Art gehórt auch ein Gegenabdruck eines Rumpfes mit Pygidium und ohne Kopfschild. Alle Stücke sind durch Schichtendruck einigermaßen geprefst, sodaß manche Merkmale schwer nachweisbar sind, dessen ungeachtet låfst sich doch ihre Gattungszugehórigkeit bestimmen. Das erste vollständige Exemplar (Taf. I) ist 12 cm. lang. Das halb- kreisformige, mit kurzen Wangenstacheln endende Kopfschild ist mit einem sehr breiten, flachen und glatten Randsaum umgeben, und fast doppelt so breit wie hoch, denn seine Breite betrágt 83.5 mm. und die Hóhe 42 mm. Die Grenze zwischen den Wangen und Glabella ist schwach angedeutet. Die halbmondförmigen, ursprünglich erhobenen, ziemlich großen Augen sind abgewetzt. Die Glabella ist leider größtenteils abgeschält, sodaß sich ihre gleich- mäßig breite, oben abgerundete Form nur nach dem Umrif feststellen läßt. Der Abstand zwischen der Stirn und dem Oberrand ist ziemlich betráchtlich. Der aus acht Segmenten bestehende Thorax samt Pleuren stimmen in ihrer Form mit denen bei verschiedenen Asaphiden-Gattungen überein. Das Pygidium ist halbelliptisch, mit ‘sehr breitem und glattem Rand- saum umgeben, 69 mm. breit und 43 mm. hoch. Die beschädigte Axe ist lang, ziemlich schmal und erstreckt sich kaum in zwei Drittel des Pygi- diums. Die ursprüngliche Segmentierung der Axe und der Seitenlappen ist verwischt, nur bei dem zweiten, fast genau so großem Exemplare (Taf. II) ist dieselbe sehr schwach angedeutet. Bei diesem aus einem Abdruck und einem Gegenabdruck bestehenden Asaphellus nimmt die lange, schmale Axe mehr als ein Fünftel der Gesamtbreite des Pygidiums ein. 1921. No. 10. AQUIVALENTE DER UNTERSILURISCHEN EULOMA-NIOBEFAUNA. 13 Das im negativen Abdruck erhaltene Pygidium samt den aus fünf Segmenten und Pleuren bestehenden Thoraxteilen des bereits oben ange- führten dritten Exemplares, weist gieichfalls dieselbe Form und Größe auf, wie die zwei vorher beschriebenen Stücke. Von dem Kopfschild der beiden Abdrücke des zweiten Exemplares hat sich bei dem negativen Abdruck (Taf. II, Fig. ı) nur ein Teil der linken Wange mit dem Stachel und ein undeutlicher Abdruck der Innenseite vom Hypostom erhalten, die übrigen Teile waren abgelöst. Bei dem positiven Abdruck (Taf. II, Fig. 2) sind beide Wangen und ES fast tadelloses Hypostom vorhanden, bekanntlich eines der wichtigsten Merkmale zur genauen Bestimmung dieses Trilobites. Das in situ befind- liche Hypostom ist 25.5 mm. lang, hat einen eifórmigen, gegen den Ober- rand verschmälerten Umrif und ziemlich breite Randsäume. Die eigentliche Einbuchtung in der Mitte des Hinterrandes scheint vorhanden zu sein, jedoch ist die genannte Stelle zufállig so mangelhaft erhalten, daß eine präcise Feststellung schwer durchführbar ist. Nach allem aber war die Einbuchtung nicht zu groß. Die übrigen Merkmale lassen sich aus unserem Bilde, wo der Umrif mit weißer Farbe ange- deutet ist, am besten erkennen. Der Form nach erinnert unser Hypostom am meisten an den von Asaphellus Homfray var. aus dem Untersilur (Tremadoc) von Cape Breton in Dritisch- Amerika, wo derselbe nach MATTHEW! in den sogen. Bretonian (c>-Asaphellus-Zone) vorkommt. Das mehr als um ein Drittel kleinere Hypostom der amerikanischen Art weist einen fast kreisförmigen Umriß und ziemlich breite Randsäume auf, die in der Mitte des Unterrandes eine mäßige Einbuchtung bilden. Der von MATTHEW abgebildete voilständie Asaphellus Homfray var. (I. c. 1902 und 1903, PI. XVII, Fig. toa), welcher mehr als um eine Hälfte kleiner ist als der von Plzenec, ähnelt diesem insofern, daß sein Kopf- schild und das Pygidium die gleiche Form besitzen, während die Rand- säume beider Körperteile schmäler sind, infolgedessen die Stirn bedeutend mehr zum Oberrand des Kopfschildes und die schwach segmentierte Axe mehr zum Hinterrand des Pygidiums geschoben sind. Die Glabella ist ebenfalls fast gleichmäßig breit, hat eine abgerundete Stirn und das Kopfschild mäßig lange Wangenstacheln. Das Hypostom des Asaphellus Homfray aus den sogen. » Shineton shales« von Shropshire in Wales, dessen oberer Teil faunistisch dem norwegischen 1G. F. MarrHEWw. Additional notes on the Cambrian of Cape Breton. Bulletin of the Natural History Society of New Brunswick, Canada, No. XX, Vol. iv, Part v. — Report ' on the Cambrian Rocks of Cape Breton. Geological Survey of Canada, 1903. 14. J. V. ZELIZKO. M.-N. Kl. Euloma-Niobe-Horizonte entspricht, hat dieselbe Form wie der gleich- namige amerikanische Asaphellus!. Als Begleitfauna des amerikanischen Asaphellus ist unter anderen Parabolinella, Triarthrus, Bellerophon angeführt. Der von Satter beschriebene typische Asaphellus Homfray Saxt.? aus dem englischen Untersilur (Upper Tremadoc) von Wales stimmt nur teilweise mit dem von Plzenec überein. Das Hypostom des Asaphellus bohemicus erinnert auch an einige von BRoGGER bei den skandinavischen Megalaspiden beobachteten Hypostome ?, welche durch ihre Form den Asaphellus-Hypostomen ähneln, eine zur Be- stimmung der Untergattung des Asaphellus mafagebende Charakteristik, wie auch beim Asaphellus bohemicus neuerdings bestätigt wurde. Was die Stellung der Asaphiden (Asaphus, Ogygia, Niobe) anbelangt, soll hier vor allem auf die Studie BroGGers »Über die Verbreitung der Euloma-Niobe- Fauna (der Ceratopygenkalkfauna) in Europa«* hingewiesen werden. Die neueste amerikanische Literatur RAvwowps zur genaueren Definition der Asaphiden ist mir leider infolge des Weltkrieges nicht ein- gelangt. An unseren Asaphellus bohemicus erinnert ferner einigermaßen der mit breitwangigem Kopfschild versehene riesige Asaphellus glabratus SALT., welchen FRECH aus dem Asaphus-Schiefer (Mittleres Untersilur) von Cabrières in Frankreich abbildete?, der aber einen ausgesprochenen Asaphellus- Habitus aufweist. Da in demselben Schiefer (vom Alter des Llandeilo- Flags) auch Placoparia Tourneminei RouAuLT vorkommt?, welche der böhmischen Placoparia Zippei nahe steht, entspricht der betreffende Horizont der böhmigen Stufe dıy. Der von FRECH aus zwei verschiedenen Exemplaren kombinierte Asaphus glabratus ist durch kurze Wangenstachel und deutlich segmentiertes Pygi- dium gekennzeichnet. 1 CH. Cattaway. On a new Area of Upper Cambrian Rocks in South Shropshire, with a Description of a new Fauna. The Quarterly Journal. S. 663. Pl. XXIV. Fig. ı London 1877. 2 I, W.SALTER. A Monograph of the British Trilobites. S. 165—166. Pl. XXIV, Fig. 6—ı2. London 1864 — 1883. 3 W.C.BroGcer. Ueber die Ausbildung des Hypostomes bei einigen skandinavischen Asa- phiden. Sveriges geologiska Undersükning. Afhandlingar och Uppsatser. Ser. C. No. 82. K. Svenska Vet. Akad. Handlingar. Bd. 11. No. 3. Stockholm 1886. 4 Nyt Magazin for Naturvidenskaberne. Grundlagt af Den Physiographiske Forening in Christiania. Bd. 36. 1897 — 1898. 9 F. Frecu. Ueber die Entwickelung der silurischen Sedimente in Böhmen und im Süd- westen Europas. N. Jahrb. f. Min., Geol. u. Pal. Jg. 1899. Bd. Il. 6 F. Frech. Die palaeozoischen Bildungen von Cabrieres (Languedoc). Zeitschr. d. deutsch. geolog. Gesellschaft. S. 395. Berlin 1887. 1921. No. 10. AQUIVALENTE DER UNTERSILURISCHEN EULOMA-NIOBEFAUNA. Dt Von den bisher bekannten Asaphiden aus dem böhmischen Untersilur entspricht überhaupt keiner dem Asaphellus bohemicus von Plzenec. à Asaphellus insignis ZEL. (Taf. III, Fig. 2.) Eine 46 mm. lange Form, welche durch einen sehr breiten gleich- mäßigen Randsaum des halbkreisförmigen Kopfschildes mit langen abste- henden Wangenhörnern gekennzeichnet ist. Die übrigen Merkmale des Kopfschildes sind verwischt, nur die Wangennähte sind schwach angedeutet. Die acht Segmente und Pleuren des deformierten Rumpfes sind schlecht erhalten. Das kreisförmige, abgerundete Pygidium ist gleichfalls teilweise be- schädigt. Die in die Hälfte des Pygidiums reichende Achse nimmt kaum ein Viertel seiner Breite ein. Die Segmentierung ist nirgends sichtbar. Daß es sich um eine neue Asaphellusart handelt, verrät schon auf den ersten Blick die eigentümliche Bildung des Kopfschildes und die Form des Pygidiums. Asaphellus sp. (Taf. III, Fig. 1.) Einen isolierten Abdruck und ein Gegenabdruck der linken Wange mit einem sehr langen Stachel. Ob dieselbe einem großen Individuum von Asaphellus bohemicus oder vielleicht einer anderen Form angehört, läßt sich auf Grund des fragmen- tarischen Körperteiles schwer nachweisen. Niobe (Ptychocheilus) sp. (Lat: 1H, Pigs.) Ein Abdruck des rechten Teiles eines abgebrochenen Kopfschildes mit einigen deutlichen Rumpfsegmenten und Pleuren. Die Glabella ist abgeschält. Die Form des Randes mit vorhandenem schmalem und schräg ab- stehendem Wangenstachel, sowie der Verlauf der schwach angedeuteten Wangennähte erinnern an eine Niode, wie sie z. B. NovAK-PERNER! aus der Stufe dry von Nové Dvory abbildeten. v 1 Trilobiti pasma D—d 1 y = oboli prazského. Palaeontographica Bohemiae. S.47. Taf.III, Eig I. Nr. EX. Ceská Akademie, Prag. 16 J. V. ZELÍZKO. M.-N. KI. Cephalopoden. Orthoceras tenuis ZEL. (Taf. IV, Fig. 6.) Eine schlanke, auf die Art der Hyolithen ziemlich scharf zugespitzte, ca. 50 mm. lange Form, wie sie unsere Tafelabbildung darstellt. Dieselbe war möglicherweise noch etwas länger; ihre Oberfläche ist glatt, die Wohnkammern reichen von der Spitze fast in die Hälfte der vorhandenen Schale. Außer diesem Stück wurde noch ein Fragment mit fehlender Spitze und ohne Wohnkammern gefunden, von welchem man unmöglich sagen kann ob es auch der obigen Form angehört. Die Oberfläche beider Stücke ist teilweise vom Eisenoxyd rostig- braun gefärbt. Brachiopoden. Von den zahlreichen größeren und kleineren Linguliden und anderen Brachiopoden habe ich nur folgende herausgenommen, welche eine nähere Bestimmung zulassen. Lingulella sulcata Barr. HAN etre) vay 962) Diese bereits von BARRANDE (Syst. Sil. V PI. 106) aus der Stufe dıß von Klabava angeführte Art, welche neuerdings nach Horus (l. c.) in dem Euloma-Niobe-Horizont bei Rokycan nachgewiesen wurde, kommt auch bei Plzenec ziemlich häufig vor, und zwar in dem halbverwitterten lichtgrauen Schiefer unterhalb des Kreuzes »U Blazeje«, sowie in den festen grau- grünen Graptolithenschiefern des am westlichen Ende der Lehne sich befind- lichen Steinbruches. Es sind schön geformte, mit feinen Radialrippen versehene Exemplare oder glatte Steinkerne vorhanden, deren Wirbel mehr oder weniger zu- gespitzt ist. Die konzentrischen Lamellen sind nur bei einigen Exemplaren erhalten (Fig. 1a, 2a). Die Schale ist schwarz und glänzend, der halb- kreisförmige Stirnrand hie und da mit einem engen Saum versehen. Die Form der von BARRANDE von Klabava abgebildeten Exemplare (Sys. Sil. V, Pl. 106, Fig. III, 2, 3) scheint mir mit den Originalen, die ich seinerzeit untersuchte, nicht genau übereinzustimmen. 1921. No. 10. AQUIVALENTE DER UNTERSILURISCHEN EULOMA-NIOBEFAUNA. iu Lingulella rugosa Barr. (Taf IV, Fig. 4, 4 a) Es finden sich meistens Steinkerne mit nur teilweise erhaltener Schale. Dieselbe ist breit und verhältnismäßig kurz, der Wirbel abgestumpft. Die Oberfläche weist eine Reihe scharf hervortretender, schütter situierter Radialrippen auf; konzentrische Lamellen sind nicht überall entwickelt. Kommt in beiden Lokalitàten »U Blazeje« vor. BARRANDE führt diese Art gleichfalls von Klabava (Syst. Sil. V Pl. 152) und Horus aus derselben Gegend an. Lingulella amygdala Zen. (Dar AIN Biss, 5a.) Die Schale der vorhandenen Art unterscheidet sich von beiden oben beschriebenen Linguliden durch eine mandelartige Form. Der Stirnrand ist breit, halbelliptisch abgerundet, die Schale allmählich verschmälert und mit einem stumpfen Wirbel endend. Es sind nur einige Stirnkerne mit stellenweise erhaltener Schalen- kruste vorhanden. Sonst ist die ursprüngliche, aus feinen Radialrippen und konzentrischen Lamellen bestehende Skulptur ziemlich gut sichtbar. Kommt in beiden Punkten »U Blazeje« vor. Lingulella pusilla Ze. (Rat. IN Eio 9, oa 9892) Von den bei Plzenec häufig vorkommenden kleinen Linguliden sind hier zwei typische Exemplare abgebildet. Die ca. 3—5 mm. lange Schale ist schmal, glänzend und mit spärlichen Lamellen, welche nur unter der Lupe sichtbar sind, versehen. Der Umriß ist elliptisch oder schwach verschmälert, eiförmig, die Schale flach gewölbt oder gegen den Wirbel zu ein wenig erhöht. Die besprochene Art wurde nur in den graugrünen Schiefern »U Blazeje« gefunden. Acrothele? nov. sp. (Tat IN, Fig. 7, 7a, 7b.) Eine fast kreisrunde, ziemlich hoch gewölbte Schale, in einem Durch- messer von 8 mm., deren Oberfläche hornig, glatt, glänzend und unregel- mäßig konzentrisch gestreift ist. Eine kleine Einbuchtung des Schlofsrandes erinnert, wie aus unserer vergrößerten Abbildung (Taf. Ill, Fig. 7) ersichtlich ist, an eine ähnliche schlitzformige Öffnung bei der Discina oder Trematis. Vid.-Selsk. Skrifter. I. M.-N. KI. 1921. No. ro. 2 18 J. V. ZELIZKO. M.-N. KI. Daß das hier beschriebene Fossil jedenfalls zu der Familie Discinae gehört, ist auf den ersten Blick sichtbar. Dasselbe stammt gleichfalls aus dem graugrünen Schiefer. Obolus? sp. Zwei sehr kleine an Obolus minimus Barr. (Syst. Sil. V, Pl. 5) erin- nernde Individuen aus demselben Fundort »U Blazeje«. Spirifer sp. Ein ca. 6 mm. langer und 7 mm. breiter, hoch gewölbter Steinkern, welcher dem Habitus nach wahrscheinlich der oberwähnten Brachiopode anzugehören scheint. Dieselbe stammt aus dem lichtgrauen Schiefer unterhalb des Kreuzes »U Blazeje«. Pteropoden. Conularia pygmaea ZE1.. (Taf. III, Fig. 5) Eine sebr kleine, unvollständig erhaltene Art, deren Länge ca. 17 mm. und die Breite bei der Mündung ca. 7 mm. beträgt. Die ursprüngliche Epidermis hat sich nur in einer Partie bei der Spitze erhalten. Sie besteht aus nur unter der Lupe sichtbaren, gleich großen und gleichmäßig aneinander situierten Wärzchen rundlicher Form. Diese Wärzchen waren senkrecht aneinander, also mit der vorhandenen parallel laufenden Medialfurche gereiht. Der den Abstand zwischen den Wärzchenreihen bildende Raum längs der Schale ist schmal, jedoch ist derselbe durch-den Umstand, daf die Wärzchen gleichmäßig dicht geordnet sind, gut sichtbar. Durch die geschilderte Schalenskulptur ist die Conularia pygmaea von allen aus dem älteren Paläozoikum Böhmens bekannten Formen sofort zu unterscheiden. Conularia sulca Tele (Textabbildung. Taf. III, Fig. 4.) Auf demselben Gestein, wo sich die oben beschriebene Art befindet, kommt neben derselben ein Bruchstiick einer 14 mm. langen Schalenwand vor, deren Skulptur aus einer Reihe auftretenden Querrippen besteht, die in einem kaum 1 mm. messenden Abstand voneinander getrennt sind. Zwischen den Rippen findet man keine Granulation oder sonstige Ver- zierung. Diese Skulptur stimmt mit der mir im Jahre 1906 von Herrn 1921. No. 10. AQUIVALENTE DER UNTERSILURISCHEN EULOMA-NIOBEFAUNA. 19 Prof. Horak zur Bestimmung geschickten Conularia aus den bereits ange- führten d 18-Schichten von Klabava überein. Da dieses Fossil bisher weder beschrieben noch abgebildet ist, móchte ich dasselbe hier kurz behandeln. Es ist ein Abdruck und ein Gegenabdruck einer teilweise erhaltenen, ziemlich großen Schale mit deutlicher Skulptur vorhanden. Die Verzierung besteht aus groben, ziemlich tiefen Querfurchen, welche in Abständen von I—I.5 mm. von einander entfernt sind. Die Granulation oder andere Ver- zierungen fehlen. Dem Schalenumrisse nach scheint, daß das vollkommene Exemplar 8 cm. hoch war und seine Breite bei der Mündung höchstens 3 cm. betrug. — / y i NS bs 3 ES IQ» Lue X MUERE SS a Eine ähnliche, aus Querrippen und Furchen bestehende Skulptur wie sie das Schalenfragment von Pilsenetz und das Exemplar von Klabava auf- weist, besitzt auch die von mir seinerzeit beschriebene Conularia Purkynet} von Sira-Cekov (dry). Die erwähnten Rippen und Furchen, welche gleichfalls einfach und ohne Verzierung sind, treten sehr scharf hervor, und je mehr sie der Spitze zulaufen sind sie feiner und seichter. Bei der Mündung entfallen von diesen 15—17, bei der Spitze 28—30 auf 5 mm. Stellenweise fließen auch zwei Rippen in eine langlichrunde Leiste zusammen. Gleichfalls die von Osek (d ry) bekannte Conularia robusta BARR? weist nur teilweise ähnliche Schalenskulptur wie unsere neue Form von Plzenec auf. 1 Neue Pteropoden des älteren Paläozoikums Mittelböhmens. Jahrb. d. k. k. geol. Reichs- ans Ton Bd 61, p.45. Taf. UL; Kiez za, FD: 2 Syst. Silur. Vol. III, p. 51. Pl. 16, Fig.ro—r1. 20 J. V. ZELIZKO M.-N. Kl. Conularia sp. Ein zerdrückter positiver und negativer Abdruck einer unvollständigen, 24 mm. langen, nach vorn gekrümmten Schale. Die Seitenleisten sind gut sichtber, die Medialfurche sowie die aus ursprünglich rundlichen Quer- streifen bestehende Skulptur ist nur schwach angedeutet Dieselbe Skulptur fand man auch bei einem Bruchstücke eines anderen Exemplars. Außerdem wurde noch ein Abdruck eines kaum ı cm. langen Ge- häuses mit erst unter der Lupe erkenntlichen Seitenleisten und Medial- furche gefunden. Orthotheca? n. sp. (Taf. II, Big6.) Ein stark zerdrücktes, 17 mm. langes Gehäuse ohne Spitze. Der Mund- rand ist abgebrochen, die Längsleisten sichtbar und die Oberfläche glatt. Ein daneben befindliches isoliertes, 4.5 mm. langes und 2 5 mm. hohes Operculum scheint demselben Stücke anzugehören. Dasselbe bildet ein gleichschenkeliges Dreieck mit abgerundeten Ecken. Was die anderen Merkmale des Deckelchens, dessen Innenseite vorhanden ist, anbetrifit, ähnelt dasselbe dem von Novak abgebildeten!, aus verschiedenen Fund- stellen des böhmischen Obersilur und Devon herrührenden Orthothecen am besten. Obwohl die untersilurische, aus den Quarzkonkretionen der dr;- Schichten von Särka stammende Orthotheca Särkaensis? von Novak als fraglich bezeichnet wurde, so ist es doch nicht ausgeschlossen, dafs die Verbreitung dieser von Novák gestellten neuen Pteropodengattung auch in das Untersilur hineinreicht. Da unser Exemplar allerdings vielmehr Verwandtschaft mit der Ortho- theca als mit den aus dem bóhmischen Untersilur bisher bekannten Bactro- theca- oder Hyolithusgattungen aufweist, so habe ich dasselbe auch provi- sorisch zur Orthotheca gestellt. Schließlich sei noch bemerkt, daf es nicht ausgeschlossen ist, daß der von BRØGGER? aus dem norwegischen Kambrium angeführte Hyolithus pli- catus nach Novak? zur Gattung Orthotheca gehóren kann, weshalb diese Gattung auch schon in primordialen Ablagerungen vertreten wäre. | Zur Kenntnis der Fauna der Etage F—f 1 in der palaeozoischen Schichtengruppe Böh- mens. Sitzungsber. der königl. böhm. Gesellsch. d. Wiss. Prag 1886. Revision der palaeosoischen Hyolithiden Bühmens. Abhandl. d. k. böhm. Ges. d. Wiss. VII. Folge, 4 Bd. Math.-nat. Cl. No.6, p. 44. Prag 189r, und I. c. Taf. II, Fig. 29. 3 Om paradoxides-skiferne ved Krekling. Nyt Mag. for Naturvidenskaberne. XXIV. Christiania 1877. abc: bo I921I. No. ro. AQUIVALENTE DER UNTERSILURISCHEN EULOMA-NIOBEFAUNA. 2I Graptolithen. Unter allen Fossilien der d1f-Schichten bei Plzenec sind die Grapto- lithen am hàufigsten vertreten. Wie ich schon vorn angeführt habe, kommen dieselben besonders in dem nordwestlichen Teile der Lehne »U Blazeje« im festen, graugrünen Schiefer vor, dessen grofse spaltbare Platten mit langen, schón entwickelten, ruthenfórmig verzweigten oder buschigen Exemplaren bedeckt sind. Da ich das ganze Material meinem Freunde, Herrn Dr. PERNER zur Bearbeitung übergab, móchte ich nur im Kurzen auf einige Graptolithen hinweisen, die ich seinerzeit Herrn Prof. S. L. Tornouist in Lund zur Vergleichung mit schwedischen, dem åltesten Ordovician entstammenden Arten eingesandt habe. Durch die Güte des Herrn TGRNQUIST wurden folgende Arten bestimmt: Didymograptus. Scheint zwischen Didymograptus balticus Lapw. oder Didym. artus ELLES AND Woop zu stehen, ohne mit dem einen oder dem anderen identifiziert werden zu kónnen. Nahestehende Formen kommen in schwedischer Zone mit Didymograptus balticus TULLBERG vor}. Jener von PERNER in seiner Monographie über die Graptolithen des böhmischen Untersilurs von Sárka und Osek (dry) beschriebene Didv- mograpius nanus weist einen anderen, von unser Art ganz abweichenden Charakter auf. Tetragraptus quadribrachiatus HALL und außer diesem entweder Jetragr. serra BRONGN., nach der Auffassung Törnovists (= Tetragr. Ami ELLES AND Woop?), oder Tetragr. serra BRonGn, ELLES AND Woop?. Vielleicht ist es auch eine andere nahestehende Form. Eine verwandte bóhmische Art 7etragraplus caduceus SALTER beschreibt PERNER von Klabava (d: f). Außer diesen Graptolithen wurden bei Plzenec auch Fragmente ent- weder von einem gabelfórmigen Didymograptus oder Bryograptns gefunden. Nach der vorlàufigen Mitteilung des Herrn dr. PERNER überwiegt in dem ihm von Plzenec eingesandtem Material Dichograptus und Holograptus 1 Sven LrowH. TóRNQuisT. Researches into the Graptolites of the Lower Zones of the Scanian and Vestrogothian Phyllo-Tetragraptus Beds. I. Lunds Universitets Årsskrift. Bd 37. Afdeln. 2. Nr. 5. Königl. fysiografiska sällskapets handlingar. Bd.12. Nr.5. Lund igor. Lo I. PERNER. Studie o ceskijch graptolitech. Cast II. Monografie graptolitu spodního siluru. Palaeontographica Bohemiae. N. IIIb. Prag 1895. 3 Sv. LEonH. TónNQuisr. Researches into the Graptolites etc. II. Lund 1909. — Derselbe. Nagra anmärkningar om indelninger inom Sveriges kambro-silur. Geolog. Foren. För- handl. Bd. 35. H. 7, p. 416. Stockholm 1913: J. V. ZELIZKO. M.-N. KL D (Temnograptus); siehe Taf. V. Außerdem findet man darin Holograptus ( Trochograptus) sp. off. Deani Lapw. und einige schwer bestimmbare Reste, die an Loganograptus und Azyograptus erinnern. Die aus der Bande d—dif angeführten Fossilien. Trilobiten. Asaphellus bohemicus ZEL. Asaphellus insignis ZEL. Asaphellus sp. . Niobe (Ptychochoilus) sp. Cephalopoden. v Orthoceras tenuis ZEL. Brachiopoden. Lingulella sulcata Barr. Lingulella rugosa Barr. Lingulella amygdala Ze. Lingulella pusilla Ze. Acrothele? nov. sp. Obolus? sp. Spirifer sp. Pteropoden. v Conularia pygmaea ZEL. Conularia sulca ZEL. Conularia sp. Orthotheca? n. sp. Graptolithen. Didymograptus. Tetragraptus quadribrachiatus Haut. (? Tetragraptus serra BRoNGN. (= Tetr. Ami ELLes AND Woop) oder Tetr. serra BRoNGN. ELLES AND Woop). Dichograptus. Holograptns (Temnograptus) sp. Holograptus (Trochograptus) sp. off. Deani Larw. 1921. No. 10. AQUIVALENTE DER UNTERSILURISCHEN EULOMA-NIOBEFAUNA. 23 Schlussfolgerungen. Die unmittelbar unter den schwarzen Schiefern der Stufe dıy mit vorherrschenden Placoparia Zippei bei Sedlec auftretenden dr 8-Schichten bilden stratigraphisch sowie faunistisch einen selbständigen Horizont der Bande D—dıß. Nach der in der Lokalität »U Blazeje« festgestellten Fauna scheint dieser Horizont jünger zu sein als der Eu/oma-Horizont bei Rokycan !. Deshalb wird es bei weiterem Studium der Ablagerungen der Stufe dif notwendig, eine ähnliche Zonengliederung derselben vorzunehmen, wie solche KLoucek ? in den dry-Schichten durchführte und für deren Aufnahme für die drB-Schicheten auch die Graptolithenstudien PERNERS® sprechen. Diesbezüglich können uns auch die von mir Herrn Dr. PERNER zur Bearbeitung übergebenen Graptolithen von Plzenec gewiß ein positiveres Resultat liefern. Was einen vorläufigen Vergleich der seinerzeit von Herrn Professor Törnouıst von Plzenec untersuchten Graptolithen mit jenen von Schweden anbelangt, geht aus dem nachstehenden, mir von Herrn Prof. TORNQUIST zur Verfügung gestellten schematischen Gliederung des ältesten schwedi- schen Ordovician am besten hervor: d) Zone mit /sograpíus gibberulus NicH. Unterer Didymo- c) — » Phyllograptus densus Torna. graptus-Schiefer b — >» Didymograptus balticus TULLBERG. | a) — » Tetragraptus phyllograptoides Linrs. Niobe-Euloma- region, auch Ceratopygenkalk als Kalkfazies und Dictyonemaschiefer Dictyonema- | als Schieferfazies. region genannt Der von Plzenec angeführte 7etragraptus serra kommt in der Zone a und 7etragraptus quadribrachiatus in der Zone 6 vor. Nach den vorhergehenden Erörterungen scheinen die fossilführenden Schiefer von Rokycan und Plzenec teilweise dem obersten Niveau des unteren Didymograptusschiefer (Zone a und 6) zu entsprechen. I je 2 C.KLoucek. Predbesnä zpráva o dvou novych horizontech v pasmu D—dry. Vestnik kräl. ces. spol. nauk. Prag 1908. — O vrstvach Dry, jich trilobitech a nalezistich. Roz- pravy Cesk& Akademie. Ig. XXV. N.39. 1916. | 3 I. PERNER. Studie o ceskych graptolitech. Il. Monografie graptolitu spodniho siluru. Cesk& Akademie. Prag 1895. 24 J. V. ZELÍZKO. M.-N. KI. Daß die in Rede stehenden Schichten vom stratigraphischen und paläontologischen Standpunkt aus älter sind als die der Bande D— dry und jünger als die der Bande D — 1f, dafür sprechen unsere bisherigen Erfahrungen bei Plznec und noch besser die Fossilienfunde Horues! aus der Gegend von Rokycan. Horus fand hier, wie bekannt, eine den Uber- gang zwischen dem obersten Kambrium und untersten Silur bildende Fauna, die BRØGGER als Euloma-Niobefauna bezeichnete?. Außer Lrachiopoden (auch Lingula sulcata und L. rugosa wie bei Plzenec), neuer bisher noch nicht bestimmter Graptolithen, Pleropoden und underen Fossilen, sind aus der Gegend von Rokycan bis heute folgende 7rzloditen beschrieben: Agnostus splendens, Agnostus consors, Asaphellus Perneri, Aspidaeglina miranda, Euloma Bohemicum, Euloma inexpectatum, Lichas praecursor, Megalaspides cuspidatus, Nileus pater, Aeglina Dróggeri und Barrendei primula. Horug, welcher die bóhmische Fauna mit der norwegischen, französi- schen, englischen und bayrischen verglich, bemerkt, trotzdem sich die von ihm bei Rokycan gefundene Fauna mit der alten skandinavischen Euloma- Niobefauna nicht vollkommen identifizieren läßt, ist es doch notwendig, dieselbe als ein Âquivalent der übrigen europäischen Eulomaschichten zu betrachten. Dasselbe gilt auch der von mir entdeckten Fauna bei Plzenec. Aus den Forschungen BReGGeErs und TónNouisrs geht gleichfalls hervor, daß wir nur an wenigen Punkten der Erde eine mit der nordischen Eu/oma- Niobe-Fauna näher übereinstimmende Fauna vorfinden, nämlich: in Shropshire in den Shineton shales, » North Wales in den Tremadoc-Schichten, » Bayern die Leimnitz-Schichten bei Hof?, » Südfrankreich die Schichten von Caunes und St. Chinian in Languedoc. Aus dem Grunde, daß in Böhmen Äquivalente der Euloma- Niobe- Fauna jetzt nachgewiesen wurden, muß natürlich die alte Definition BRoGGERS*, »daß ein unzweifelhaftes Äquivalent zu der Euloma-Niobe-Zone (Ceratopygen- kalkzone za) des skandinavischen Nordens in Böhmen bis jetzt nicht nach- gewiesen ist und deshalb zu fehlen scheint«, entfallen. BRØGGER selbst war nicht der einzige, der an die Existenz der älteren ordovicischen Ablagerungen in Böhmen zweifelte. Ive ABC A pr4 3 I. BARRANDE. Silurische Fauna aus der Umgebung von Hof in Bayern. 1868. — I. F. Pompecny. Ein neuentdecktes Vorkommen von Tremadoc-Fossilien bei Hof. 4 Über die Verbreitung der Euloma-Niobe-Fauna p. 224. 1921. No. 10. ÄOUIVALENTE DER UNTERSILURISCHEN EULOMA-NIOBEFAUNA. 25 Schon Linnarsson im J. 1873 hat auf die fehlende Übereinstimmung zwischen den böhmischen und nordischen Ablagerungen aufmerksam ge- macht; er sucht dies teils auf eine mögliche Landsperre zwischen den böh- mischen und dem nordosteuropäischen Silurmeer während der Zeit dieser Ablagerungen zu beziehen. Auch TóRNouisr hat sich dafür ausgesprochen, daß Böhmen mit Frank- reich, Portugal und Spanien, während dieser Zeit ein von dem nordischen ordovicischen Meer getrenntes Absetzungsgebiet ausgemacht haben muß, während aber die Graptolithen beweisen, daß jedenfalls bisweilen »das nord- europäische Graptolithenmeer< sich auch über dies Gebiet ausdehnte'. Diese Vermutung hat sich jetzt durch die Funde bei Rokycan und Plzenec tatsächlich bestätigt. Bezüglich der Entwickelung der silurischen Sedimente in Böhmen und im Südwesten Europas sei hier auf die gleichnamige Arbeit FREcHs? bzw. auf die Monographie Broccers? hingewiesen. Obwohl die Trilobitenfauna von Plzenec gegen die von Rokycan bis zum heutigen Tage nicht so mannigfaltig ist, scheint mir wenigstens das Vorkommen des Asaphellus bohemicus für den betreffenden Horizont nicht chne Bedeutung, denn, wie bekannt, die ersten Vertreter der Asaphiden sind für die untersilurischen Ablagerungen ebenso charakteristisch wie z.B. Agnostus, Paradoxides und Olenus für das Kambrium. Deshalb repräsen- tiert Asaphellns bohemicus auch bei Plzenec ein charakteristisches Leitfossil ähnlich wie der gleichaltrige Asaphellus Homfray in den Shineton Shales in Shropshire, und in dem Lower u. Upper Tremadoc in North Wales, sowie im Tremadoc von Cape Breton in Britisch-Amerika und Asaphellus Wirthi in den Leimnitzschichten bei Hof. Jedenfalls aber ist es wünschenswert die dıß-Schichten bei Plzenec einer weiteren Durchforschung zu unterziehen, was nach meinen bisherigen Erfahrungen eine làngere Zeit in Anspruch nehmen wird, wenn die Fos- silienliste um weitere für die betreffenden Schichten ebenso charakteristische Trilobitenformen vermehrt werden soll. Wie schon oben erwáhnt wurde, bilden die Ablagerungen der Stufe dı? bei Plzenec einen faunistisch scharf abgesonderten Horizont gegen- über den schwarzen fossilienreichen dıy-Schiefern, die als Hangendes der grünlichgrauen d 1 8-Schiefer zu betrachten sind. 1 Ibid. p. 223. 2 Neues Jahrbuch für Min., Geol. und Pal. Jg. 1869. Bd. II. — Auch Die geographische Verbreitung und Entwickelung des Cambrium, von demselben Autor. Congrès géolo- gique international, 7me session Russie 1897. St. Petersbourg 1899. 3 Die silurischen Etagen 2 und 3 im Kristianiagebiet u.s.w. Kristiania 1882. 26 J. V. ZELIZKO, M.-N. KI. In welchem Verhåltnisse die letztgenannten Schiefer zu den Krusnå Hora Schichten (d1 4), welche neuerdings eine häufigere Fauna lieferten !, stehen, das festzustellen wird wiederum eine andere Aufgabe sein. Zum Schluß dieser Arbeit fühle ich mich verpflichtet, Herrn Direktor Prof. A. JELinek in N. Bydzov, für den größten Teil von ihm aufgenom- menen Originale meinen herzlichsten Dank auszusprechen. Wien, November 1917. 1 C. Kroucer. Novinky z Krusnohorskych vrstev. I—III. Rozpravy Ceské Akademie 1915 u. 1917. 1921. No. 10. ÄQUIVALENTE DER UNTERSILURISCHEN EULOMA-NIOBEFAUNA. 27 Erklärung zu den Tafeln. Tafel I. Asaphellus bohemicus Zer. Natürliche Größe. II. Fig. n LÀ n I. Asaphellus bohemicus ZEL. Negativer Abdruck. 2. Asaphellus bohemicus Zer. Positiver Abdruck mit erhaltenem Hypostom Natürliche Größe. I. Åsaphellus sp. Isolierter Abdruck der linken Wange. Natürliche Größe. 2. Asaphellus insignis Zer. Natürliche Größe. 3. Niobe (Ptychocheilus) sp. Natürliche Größe. 4 Conularia sulca Zev. Eine vergrößerte Schalenpartie. Conularia pygmaea Zev. Eine vergrößerte Schalenpartie. a u Orthotheca? n. sp. En wenig vergrößert. 7: D bye , M Le 4 inar aui D | E uat cm 26405 Cle »P FOREWORD. The author much regrets the late appearance of this treatise. It has been written and printed with manv interruptions due to various circumstances over which he had no control. The greater part of the manuscript was ready for the press more than eighteen months ago. He wishes to express his sincere gratitude especially to the Norwegian geologists Professor Jacob Schetelig, Professor V. M. Goldschmidt, and Mr. Adolf Hoel, University Reader in geologv, also to the Swedish geo- logist Professor A. G. Högbom, for much valuable information and advice. A special word of thanks is also due to the. publisher Jacob Dybwad by whose courtesy a number of illustrations from the author’s book "En Ferd til Spitsbergen" are reproduced here. The letter o used in Norwegian names is equivalent to oe and is pronounced somewhat similarly to the letter o in the English words Son or "work". Lvsaker, December 1922. GONTENTS: Page I; Introduction. 1: en ee ur ete ee ERE RR DTE ENTERS I ITheoriestoffthetsgenetie origo the strandilat, <=... "C 4 Ill. The’ effect of the subaëérial denudation in the ‘coastal’ zone... "en 16 FAR Glaciali«erost01125: AM ere Ce ee le CRE 20 Iheserosion? ofstheselaciers Tofte Finland acer. ee 20 Mheñerosiontot local elaciens te d ene ER RE SENEC EE CIE 25 Mik Marine denudation: 'Shorererosion byalrost 2 ee cree Te CORTE 28 VLZ-Therdevelopment of the Norwegian strandilat 999-22 9 922 222 43 When was the Norwegian strandflat developed. nn. re ee 46 ihe height of thes Norwegian strandllate er ce CCE 49 The partial absence of a strandflat along some parts of the Norwegian coast 49 SO Eh gems de OR CE aie, ERRORS IE OCT JD D oc 52 VII. The strandflat of the Norwegian west coast from the region of Sogne Fjord to thesnerionmohsdardan cers ky Onder acre EE ET 55 The strandilatrolsSogme lord en ee ee RN OCR 57 lhessenetic orleinzor the,strandflat in Sogne Monde na ee 66 The strandflat north and south of the mouth of Sogne Fjord ............ 69 Rhesrecion cot (lindas seeninsulay RER EC COCO 71 The re sonet ØEN LP are fo cll we ense tie Cr ER RER 73 Re ero of BETTER ae ere ee eee meneur Dole ee EE 79 Region tofrSottan are ee ee à connus eee ee RL 81 Islands between Kors Fjord and” Hardanger Horde cc - eee 83 ardangverskjordsand! Bommels yond: 9.999 3-9. CC een 84 VIII. The strandflat of the southwestern and southern coast of Norway .......... 91 iresuceoionsomarmogiem-s stc eis ee ee RG eA GIG TER 91 IrhesStavange region. «ares ewe one aie rere Var anne NEC TE S SCENE 93 Relation between the geological structure of the coast and the occurrence of tes train dia te ce pde Rote s ee ee is TERRE Nome EUER EET Folk eS SERRE o8 Een n NERO ERE ROT ROT TOT ES ees 100 Mnethieh/steepicoastbetween tæderen and Wister 2.2. EE 102 ÉromaestentomthenNazeNEmuesnes) ie 19793: 1 1: RE CE 104 le SouthémmandsSouth-easternicoas EEN EP CE CCE 105 The inverse Gavel Oi @hrısbiamıa El] Ode EEE ER CE EC EC 107 IX. The strandflat along the coast from Sogne Fjord to Vikten ................ 113 lihemmesionwolsSandijord u Nordhord sand) State PR ee e Ju The region of A EC hats key T P MEE Ie xc SPE dieses Joe 113 he renonsotSmelen, Elitteren andere lens T E E 120 Lxomerondhjem sejondstomvaiktens. iy RE 1 9] 4 E 3-004 SE 126 VII Page ieulihesstrandfüatrofit northenn® Norway: 239 9 ee RE 129 CABINE ee et ne Ne nt ER de hey 129 Jh hem N NP RE eke cide un EEE EE 143 Relation between the differences in the surface topography of the submerged plateaus and differences in the nature of their rocks .................... 147 Coast of northern Helgeland and the east coast of West Fjord ........... 152 Eorotentand Vesterålen ee EUREN E 156 Senjenistos RIN SV ASO Aa euo eee reuse RE chop ore aay ie en TUTTA TY. 163 BR RE A NE A oem eter e o ee ara Ror oe pee ad Eee kac ae cu ere 163 SWesEbesstrandflat of Bear Island. wei... Sl: rst. weit an res Se ES 165 I ERR ES strandilat of Spitsbergen 1.914 alo dep MOM ew eo ke me r3 rs 178 N vu cete e Rr DO ee MM ER 178 Relation between the development of the strandflat and the geological struc- türexonktbeslanda scr. e E ME Ut ds ern ciet Io poms Bin deco 185 EancegsGharlesuBorelandiee 2. en S 185 Wiest coast of ‘Spitsbergen! south of Ice Ejord 2e E 192 Capes Guissezaing Crossover I SUCTUS ea 193 Cape Mitre Peninsula and the north-western part of Spitsbergen ......... 193 Reindeer, Eandıs 3-7 5t. Le AER re lo cites eee RAN . 196 The peninsula between Liefde Bay and Wijde Bay ..................... 197 East coast of Wijde Bay, and Verleegen Hook .... ............... 200 Noxthowesencoast ot@Northr east) Band ST et ee IRE LE 203 HREMTIONAS ENES E ne diese ele pP Ne 203 whe age and genesis of the strandflat of Spitsbergen ............22.2.... 204 RAISE Ge SUOLE-HNES eee sane) ee ete OR RETE 207 REG forms ate hishwlevels. 55m re een er) ore a eel Cotter 208 XIII. The strandflat along the coast inside and outside the arctic regions.......... 2II ‘helcoasts of ‘Siberia. Greenland, ands Alaska 0 sos aoc ome ole 211 Shetland NISIands «46 Nr Seel en ee tet S 214 INT V The levels of the strandflat and. their development... rero ees 2T Summary of the results of our investigations of the strandflat ............ 217 ihesemersedstrandtilat d eee eee ce ce eee ire I ERE ES 217 he Submersed strandflat of Norway Se ee ce eee soe eee 218 hes three levels” oflthesstrandilater sa 219 Causes oMfhe changes in the ‘level of ‘thes strandflati. 20.2... «es 220 The nature of the rocks and the topography of the strandflat and the conti- Rentals helene ee Cr meter ER ele Le ET Ce M de 225 BSVEREDE continental shelf) andsitsatormation® = > zum = aioe ee 227 Fluctuations in sea-level caused by the formation of ice-caps .............. 229 "he stbickness of the Tee Caps RE ne che ene eet ECS 230 Shifts of sea-level and shore-line caused by changes in the volume of the (D (CEE Te RE A GE SIDE ON DID CE D CL AE CR DE ee CE 233 The lowering of sea-level during the glacial periods and the surface of the contimental*shelhi«. (e E el MEN tae eR te ee EEE 237 The deposition of sediment has gradually raised the general sea-level...... 239 XVI. The strandflat and the late-glacial and postglacial submergence of Fenno-Scandia 245 The late-glacial and postglacial upheaval of Sogne Fjord ................. 246 The late-glacial and postglacial upheaval in the region of Nord Fjord ...... 248 Gradient of the late-glacial and postglacial upheaval of the west and north COS OR Henn oO SCAN AMEN NAN TS DRS SS yo: ee 251 Relation between the inclinations of the two conspicuous raised shore-lines of Northern Norway and: the Kola: Peninsula... -... 2 s+ ie oe 256 VIII Relation between the altitudes of the two conspicuous raised shore-lines in the Tromsø — Hammerfest districts ................. PN Rh 259 Relation between the altitudes of Tanner’s shore-lines /e and //A in Finmark 262 The upper limit of late-glacial submergence and the Tapes level on the Kola Peninsula sn. are ana Diesel CODO aie red Add Re die ee de SE SLAGSEN 266 The upper limit of submergence and the Tapes level along the Norwegian Coast south of the Dromise’ district. yc este arse Pete elm euere lets ES ee 269 The uniform character of the late-glacial and postglacial upheaval along the west. and nonth Coast of Renno-Scandia 1, CO CRU ee Aie Tir 273 The late-glacial and postglacial submergence and emergence in central and eastern Fenno-Scandia and in) Jutland! 2 Sn 2 ee -.- CORTE 275 The present crustal movements in the regions round the Baltic Sea and the Guit-of Bothntiarn. 2.2.22 ae SY "has ea eet one qa Sr SES ee CU En 276 The possibility of a strandflat along the Baltic and Bothnian coast ...... 276 The reasons why the postglacial crustal movements have been retarded in the regions round the Baltic Sea and the Gulf of Bothnia ............. 280 Relation between the heights of the Tapes level and of the upper marine limit in central and Southern Kenno-Seandiamn. ssc MN eS E men The cause of the transgression of the sea in the Tapes-Littorina period ..... What may have been the cause of a rise of the sea-level during the Tapes- XVM Ceci cC DM Mr a le, ous lke) ae aloe E icec- ThestheorysobusoSUas ye c Let ee reste ee N The Crusts capacity offmsostatie readjustment) un. ae EC EE How are the isostatic vertical movements of the lithosphere effected ...... How long a time does the earth's crust require to reach its new isostatic What is the extent of the smallest area within which isortatic movements ua Oey mo cr PO omnis sao Maca noo oon ooo ee nics S's - Tsostasve and) CnoSio nies cte ee ee ne Sicha à ne eee eee Fig. 1. Strandflat at Lille Molla (535 metres high, to the right) and Skråven (281 metres, to the left), south side of Lofoten. (July 2nd, 1912.) PANTRODUCHOIN The Norwegian “strandflat” extends as a low flat foreland, and an often broad belt of thousands of low islands, skerries, and rocks (the “Skjergard’’) in front of the high, mountainous land, along the west and north-west coast of Norway, from Lindesness to Finmarken. It is backed by the escarpment of the mountains which often ascend abruptlv from the inner margin of the strandflat to altitudes of hundreds of metres. The width of this strandflat may vary much, from a few k lometres in some regions to 60 kilometres (37 miles) in the region of Hitteren and Froia, and 46 to 50 kilometres (29 to 31 miles) in Helgeland (region of Heroi, Donna, and Træna). The degree of development of the strandflat may also vary a great deal. Along great parts of the coast it is extremely conspicuous and sharply defined, but in other regions it is less striking, and in some places it may even be difficult to trace out or to distinguish from the low hills of the land inside. Where it is well developed, its characteristic features are: (1) the remarkably horizontal plane formed by the flat summits of its thousands of low skerries, islets, and peninsulas, rising to a certain low height above the sea, looking at a distance as if they had been cut off and planed down to this level along a ruler. (2) The horizontal and sharply defined in- cision which this plane forms in the mountain side of the land, often oversteepened and rising abruptly from the inner margin of the plane. Fig. 2. Strandflat on Arsteinen, east of entrance to Raftsund, Lofoten. (July 2nd, 1912.) Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. 11. il D FRIDTJOF NANSEN. M.-N. Kl. (3) Hills, or mountains, or mountainous masses, surmount here and there the plane of the strandflat as more or less isolated ‘stacks’ or ‘monadnocks’, often with very steep sides. No observant travellar can avoid being struck by this peculiar for- mation so dominant in many regions, and Norwegian geographers long ago, e. g. H. Mohn [1877], called attention to it. But Hans Reusch was the first geographer in literature [1894] who described it as a uniform and important morphological feature in the topography of the Norwegian coast and propounded a general theory of its genetic origin. He gave it the name "strandflat" (i. e. shore plane). The English term “coastal plain" I do not consider appropriate for this formation, because, as a rule, it 1s not a plain, and in my opinion never has been. It is, and always was, composed of numerous low islands and peninsulas, separated by sounds and fjords of varving, often con- siderable depth. Moreover, any plain in the coastal region, also formed more or less of loose material formerly deposited in off-shore water, is often called coastal plain. “Coast platform" might be a better term, but I consider it to be pre- ferable to keep the Norwegian “strandflat” as a name for this formation, so characteristic of the Norwegian and other northern coasts, but which does not occur in its typical form outside regions which have formerly been glaciated or exposed to severe climates. After Reusch's important paper of 1894, much attention has been paid to the strandflat in scientific literature, and a lively discussion has been going on about its nature, origin, and age. A brief account of the literature concerning this subject has been given recently by Hans W:son Ahlmann [1919, pp. 93—98]. Prof. W. C. Bregger, who in 1893 accompanied us as far as Tromse on our way out with the Fram-Expedition, was struck by the peculiar, flat formation of the many low islands along the coast of Nord- land. He gave a lecture on the subject in the Geological Club of Christiania on December r4th, 1893, and expressed the view that this level formation is a plane of marine denudation. During the Fram-Expedition the writer also found that an extensive and strikinglv flat, low foreland is a very dominant feature of the topo- graphy along the north coast of Sibiria, especially the west, north, and east coast of the Taimyr Peninsula. In a later report [Nansen 1904, pp. 20, 39, 42, 71, 75, 90, 102 ff.] the strandflats of northern lands were described and discussed at some length. Since that time I have occasionally studied the strandflat in various regions. During cruises with my yacht “Veslemoy” in the summers of 1904 and 1909 along the south and west coast of Norway as far as the region of Ålesund, observations of the strandflat were made, although the main object of the cruises was oceanographic research. 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 3 Fig. 3. Strandflat near Kunna (593 metres high), Northern Helgeland. View north-eastwards from off Meloivær. (September oth, 1912.) In the summer of 1911 a cruise was made with the “Veslemoy” along the south and west coast of Norway, as far as the region of Sogne Fjord, and also to Shetland, with the special purpose of studying the strandflat and measuring its heights. A cruise with the “Veslemoy” in 1912 along the coast of Norway to Bear Island and Spitsbergen, gave an opportunity of studying the strand- flat in those northern regions. | An expedition from Norway through the Kara Sea to the Yenisei river in 1913, gave a new opportunity of studying the coast formations in those regions. In the following report I shall try to give the results of the obser- vations concerning the strandflat, made during these cruises, especially that of 1911. I regret that other work has prevented that this was done before. Much that was in mind when the many observations were made, has certainly faded from memory now so many years afterwards. But nevertheless, I venture to hope that the observations as they are, may still be of some interest to geographical students. In a recent book on the cruise to Spitsbergen in 1912 [1920, 1921] I have already described some results of my study of the strandflat on Bear Island and Spitsbergen. 4 4 FRIDTJOF NANSEN. M.-N. Kl. II THEORIES OF THE GENETIC ORIGIN SE THE STRANDFLAT. The views as regards the genetic origin of the strandflat have varied much, and have chiefly been the following: Reusch explains the strandflat as being a plain of marine abrasion, chiefly due to wave erosion, but the general subaërial denudation, imme- diately near sea level, has also been of some importance. The plain was formed chiefly in Tertiary time along a but slightly dissected coast, but it was also to some extent formed during “that portion of the glacial period when our country was comparatively free from ice”. E. Richter [1896] also maintained very decidedly that the strand- flat was formed by wave erosion, but in interglacial time. J. H. L. Vogt [1900, 1907] is strongly in favour of the view that the strandflat has been formed by wave erosion along a practically un- dissected coast. He thinks that in Helgeland (and northern Norway) the strandflat was cut in this manner into the massive block of land to a width of about 45 kilometres, long before this land was dissected by the numerous deep valleys, fjords, and channels now existing. The layer of solid rock thus cut away, had a thickness of at least 400 metres along the inner zone of the strandflat, and in some regions even more. Vogt assumes that the development of the strandflat may have gone on ever since the time of the Jurassic dislocation on Andoi till the beginning of the first Ice Age. The view that the strandflat is a plain of marine abrasion (wave erosion) has also been held by Davis [1899], Rekstad [r9r2, 1915], Sa blst.o m or ED SAW johns om roro) and others. Andr. M. Hansen [1894, 1898] assumed that the Norwegian strandflat had been formed during the later part of the first Great Ice Age, partly by wave erosion and partly by the scouring of the drifting ice along the shores of the sounds. The coast had then already been dissected by numerous fjords and channels, greatly increasing the line of attack. The mode of formation of the strandflat was supposed to be practically the same as that of the shore-lines. The broad strandflats are simply several shore-lines which have met and united, advancing from different sides of the islands and peninsulas. 1921. No. 11. THE STRANDFLAT AND ISOSTASY. . 5 Hansen considers that the glacial erosion has also been of much im- portance, particularly for the denudation of the low level surface of the skerries. He also pointed out that during the time mentioned, when the margin of the first inland ice still remained in the fjords, the climate greatly favoured subaerial erosion. Amund Helland, and later F. Nussbaum [1909], maintained that the strandflat and the low skerries have been formed by the erosion of the inland ice, advancing over the outer coast. A view different from most others is held by Gerard de Geer [1912] who considers dislocations to have been of great importance for the formation of the strandflat. This theory has been carried still further by J. J. Se derholm [1913] who sees dislocations everywhere along the inner margin of all shore-planes, and he tries to explain the ‘stacks’, sur- mounting the plane of the strandflat, as horsts bounded by numerous lines of dislocations, in a most artificial and complicated manner. But strand- flats do with certainty occur in many regions where there are no traces of dislocations near their inner margin, and Hogbom [1913] has in several places in Nordland been able to trace conspicuous layers, with gentle seaward dip, from the mountain slopes and on the sharply defined plane of the strandflat without any break, which proves finally that the formation of a strandflat is not conditioned by dislocations. On the other hand, investigations of Norwegian geolists have proved that dislocations may often occur within the region of the Norwegian strandflat, without showing any relation to its limitation, or to the border lines of the stacks On the contrary the plane of the strandflat often continues across the lines of dislocation without a break. By bringing weaker rocks in the shore-region in level with more resistant rocks further inland, dislocations may naturally fascilitate the formation of sharply defined shore-planes, but they cannot form them. In the report [1904] mentioned above, and in a later paper [1905], the present writer maintained that the Norwegian strandflat had been formed by the joint action of subaérial denudation and marine denudation, after the time when the coast had been dissected by the numerous fjords and channels, which now split it up into its innumerable peninsulas and islands. The subaérial denudation was supposed to have been of the greatest importance for the denudation of the coast land, while the marine denudation had been important for the levelling of the strandflat. During the glacial periods the subaérial denudation of the coast land was essen- tially increased by the disintegrating effect of the frost on land. The marine denudation was due to wave erosion and also to the disintegrating effect of frost on the shore that was wetted by tide and waves. The transport of matter by ice, formed on the beach, was also of some im- portance. 6 FRIDTJOF NANSEN. M.-N. Kl. It was emphatically maintained that a broad strandflat, like that of northern Norway (Helgeland), cannot have been formed by wave erosion, during a reasonable time, before the coast had been dissected by deep fjords and channels, but it must have been formed after that time. This was especially for two reasons: On the one side, the erosive effect of the waves on the shore would be much reduced in the extremely shallow sea over a submerged, nearly horizontal strandflat, along an undissected coast, where the waste would have a difficult way to travel in order to reach deep water. While along a dissected coast the line of attack of the marine denudation is immensely increased, and the waste is easily washed into the deep channels and fjords. The subaërial denudation is also much increased because on all islands and peninsulas the waste has got a short way to travel to reach the sea. On the other side, the total quantity of rock that had to be worn away from the small islands and peninsulas of a dissected coast, like the present one, would be only a small fraction of the quantity that must have been cut away from a high and solid coast. For the above reasons, I reached the conclusion that the Norwegian strandflat cannot be of preglaciale age, but must have been developed especially before, during and after each glacial period when the rough moist and cold climate highly favoured an active subaërial denudation, as well as an active marine denudation. Although I shall later go more fully into this question, let me here at once correct what I consider to be a mistake. The development of the strandflat cannot, as a rule, be assumed to continue during the late part of a glacial period, when the glacial margin is retreating from the coast, and not for a considerable period after that time, because, near the end of a glacial period, the land along the greater part of our coast, has most certainly been depressed by the weight of the extensive ice-sheet, far below any level of the strandflat, and it took a long time before the land had again returned to its natural level. Let me in this connection also correct another mistake. It was as- sumed that the slow oscillation of the shore-line during the glacial periods may have been of importance for the formation of the strandflat. These oscillations were “caused by the isostatic movements of the land under the pressure of the ice-caps” as well as “by the accumulation of water in the ice-caps by which the volume of the ocean was altered; and also, though slightly, as a result of the raising influence exerted on the sea- level by the attraction of the ice-masses on land" [1904, p. 109]. , A characteristic feature of the strandflat is, however, the great width and the nearly perfect horizontality of its levels, which indicate that it must have been formed during several long periods, when the level of the shore-line remained fairly stable. It has not been formed during periods of isostatic movements of the land due to the load of the ice-caps, 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 7 when, however, the raised beaches were formed. A characteristic diffe- rence between the strandflat and the raised beaches is that, the former is horizontal, and indicates stable levels which the land has had during long periods, while the latter are tilting and indicate the levels of the shore-line during a temporary submergence of the land. As being of importance for the development of the strandflat it was also pointed out that by each advance of the glaciers of the glacial periods the waste was carried away seawards from the land and the shores, leaving bare rock surfaces for attack when the glaciers retreated. I still hold similar views on most points regarding the nature and formation of the strandflat, as I did at that time; but I now am of the opinion that the shore-erosion by frost is of even much greater importance for the marine denudation of the strandflat than I thought then. Nearly the same views regarding the nature and genetic origin of the strandflat, as put forth in my report, have also been held by Thorolf Weoet (1912; 1914], Otto Nordenskjeld [i9r2, 1914], A. -G. Hogbom [1913], and others. In his admirable paper, Hogbom proves, by numerous convincing evidences, the untenability of the above mentioned tectonic theory of De Geer and Sederholm, explaining the strandflat as formed by dislocations. He points out that the coast land must have been dissected by the fjords before the strandflat was developed, and had been so much lowered by subaerial denudation that there was not very much left for the marine abrasion to cut away in order to form the strandflat. He thinks that this last quantity of rock may thus have been at most ten per cent of the quantity calculated by J. H. L. Vogt as having been cut away by marine abrasion. I would be inclined to reduce even this figure considerably. In his recent publication “Geomorphological studies in Norway" [1919] Hans W:son Ah! mann has discussed the nature and ‘genetic origin of the Norwegian strandflat. As his views in this respect differ from those of previous writers I shall have to mention them at some length ?. Ahlmann arrives at the somewhat startling conclusion that a Nor- wegian strandflat (or “coastal plain" as he calls it) does not really exist. In the first part of his paper he assures us that the formation, previously called so, has nothing to do with marine denudation. It is a base-levelled plain formed solely by subaërial denudation, in some places assisted by glacial erosion. He therefore thinks that the name of “coastal plain”, or strandflat, for this formation is inadequate, and proposes to call it “the distal base-levelled plain”. * Just as this manuscript is going to press I have received from Prof. A. G. Hog - bom a paper [1920] discussing Ahlmann’s views. Hogbom’s points are to a great extent the same as mine, but he has also mentioned some other sides of the subject which I have not paid attention to. 8 FRIDTJOF NANSEN. M.-N. Kl. There seems, however, to be no sufficiently weighty reason for such a change of name, even if there had been some probability in favour of A.’s theory of the genetic origin of the strandflat, which is not the case according to the view of the present writer. As theory is not so revolutionary as he seems to think. Some previous writers, especially A. G. Høgbom [1913] and the present writer [1904, 1905], had suggested that the strandflat had been formed chiefly by the conjoint action of subaérial denudation and marine denudation. and also to some extent glacial erosion. By far the greater part of the denuding work was supposed to have been accomplished by subaérial denudation, while the marine denudation was supposed to have finally planed off the low coastal zone of islands and peninsulas, and had thus developed that nearly horizontal plane of the strandflat which is so very conspicuous in many regions of the coast. Now A. postulates that this finishing planing by the marine denudation is not necessary, as the sub- aérial denudation alone may have accomplished the whole work. His evidences are, however, hardly convincing, as we shall see. Like most geomorphologists A. considers marine denudation to be solely due to wave erosion, and as, according to his view, the waves can- not possibly cut very broad and nearly horizontal plains along an open undissected coast, nor can have much erosive force along the protected shores in narrow sounds, inlets, and fjords, a strandflat or “coastal plain" cannot be formed by marine denudation. His argument is that the formation of a strandflat in this manner would be such an extremely slow process, that, during the long time required, the coast land would be planed down to base level by subaërial denudation. He therefore considers it to be probable that, what is called the strandflat, has been formed in the latter manner, during preglacial time before the coast had been dissected by the many deep fjords and channels, deepened during the glacial periods, and now traversing this plain. Already on this point A. seems to come into a serious conflict with himself, in as much as, in the last part of his treatise [1919, pp. 237—239], he describes very broad and nearly horizontal plains in northern Norway, in the regions of Veroi, Rost, and probably Træna, which he thinks are “unmistakable results” of marine denudation (7. e. wave erosion). On Veroi, these plains are cut as much as two or three kilometres landwards, into the mountain side, forming cirques one kilometre and a half broad. He says [1919, p. 239] that on Rost “marine abrasion and other atmospheric agencies of destruction have broken down all land so that only isolated parts survive”. He thinks that this “took place during the last Ice Age outside the inland ice. At that time too the subaérial destruc- tive agencies in the regions, situated just outside the inland ice, were undoubtedly extraordinarily powerful. The land area was rapidly broken 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 9 down through the combined force of atmospheric weathering and marine abrasion". A.s views as regards the formation of these coast platforms are obviously identical with the views of the formation of the Norwegian strandflat held by the present writer [1904] and by Hogbom [1914] and are expressed almost in the same words. It is, however, hard to see why A. assumes that the joint action of marine denudation and atmospheric weathering, so effective in this special region, and during so short a t me as the last glacial period, should have had practically no effect during the same period, not to speak of the much longer preceding glacial periods, along the rest of the Norwegian coast, where he assumes that there was also a border lying “outside the inland ice". We may naturally ask, what have these agencies, so effective on Værøi, Rost, and Træna, been doing in other regions during all that time with climatic conditions favourable for erosion? Is it conceivable that they should have left no traces of their activity? As far as I can see, no answer to this question can be found in As paper. He assures us that Væroi Rost, and Træna are very like each other, and are “markedly different from the rest of the coast region of Norway” without explaining what this marked difference chiefly is. If it is an exceptional evenness of the strandflat, this might seem to be sufficiently explained by the fact, also pointed out by A., that these 1slands were pro- bably not covered bv ice, or have at least not been much attacked by ice erosion, during the last glacial period, while other regions of the strand- flat have been more or less eroded by glaciers. And what is then to be said about other parts of the Norwegian strandflat, which are also very level — e. g. on Sandoi, south of the mouth of Sogne Fjord, or in the regions of Smolen and Froia, Bronoi, Heroi, Donna etc.? It 1s also difficult to see any marked difference between the strandflat of the Lofoten Islands, Fig. 1 and 2, and the strandflat along the coast of the mainland, Fig. 3. As views as regards the importance of marine denudation, do not, however, seem to be quite consistent, for mentioning the region of Smolen. west of Trondhjem Fjord, he says that he does not “wish to denv that abrasion has at some time occurred here, but only as a final smoothing process. The inland ice has also been of great importance in the planing of the ground" [1919, p. 197]. The question is how great the importance of this “final smoothing process" has been? It can hardly have been insignificant if it is chiefly of preglacial age, and has been able to survive the erosion of the glacial periods. But it is very difficult to understand why the marine denudation has only occurred “at some time”, if it is due to wave action? One would expect that the waves have always been at work along the coast of Norway, where it was not covered by ice. It also seems highly improbable that the inland ice has had a planing effect upon IO FRIDTJOF NANSEN. M.-N. KL the ground. As a rule its effect has been the other way, as will be mentioned later. In his anxiety not to admit too much to the effect of marine denu- dation, A. assumes that only “the innermost part” of the strandflat ("shelf") on Værøi (and Rost) has been thus formed, while “the extensive outer part, which now lies beneath the surface of the water” is a perfectlv different formation, due to subacrial denudation, and belonging “to the initial topography as a foreland, equivalent to that round the islands of Vesterälen and Lofoten” [1919, p. 238]. How is this to be understood? Is the outer part of the strandflat a preglacial formation while the inner part is late glacial, and is it to be supposed that the levels of these two platforms, formed in so entirely different manners, and during periods so remote from one another, should coincide to such a degree, that the one platform forms a direct continu- ation of the other? This does certainly not sound very probable. Or is it after all so that this initial foreland has also been “smoothed” by marine denudation? If so the effect of this smoothing process may have been quite considerable, unless we assume that the level of the shore-line during the long preglacial time happened to be nearly the same as, or slightly lower than, that of the late-glacial shore-line. In order to avoid misunderstanding it may at once be pointed out that I do not attribute so much planing effect to the wave erosion as A. does in the case of Væroi and Rost, and probably Træna. Though im- portant the erosion of the waves may have been during the enormously long time they have had to work in, still I hold that during the glacial periods, and during the cold time preceding them, the shore erosion by frost has been much more effective for the planing of the strandflat along the Norwegian coast, while the chief importance of the wave action has been its transport of debris from the shores. The topography of the low and flat Radoi, north of Bergen, which Ahlmann describes in much detail, is in his opinion a convincing evidence proving that the strandflat is a base-levelled plain formed by subaërial denudation, without the aid of marine erosion. He describes, however, two distinct levels of this strandflat which is in conformity with what has been observed in other regions of the Norwegian coast, and these levels are in some places very conspicuous as will be described later. Quite apart from the improbability that planes, as horizontally level as these, can be formed by subaérial denudation alone, it is hard to see how two such distinctly different levels, in some regions appearing as nearly horizontal benches cut in solid rock, have been formed by base- levelling. If we imagine that the shore-line has remained fairly stationary during very long periods (in preglacial time?), first at the upper level, and later at the lower, and obviously younger level, it might be expected that the subaerial denudation, while base-levelling the land towards the 1921. No. rr. THE STRANDFLAT AND ISOSTASY. TT lower level, would wear away more or less the traces of the upper level, and would produce a gradual transition from it towards the lower one. But this is not the nature of the two levels. By marine denudation, working conjointly with subaérial denudation, we get a simple explanation of the two levels of the strandflat. The plane of the lower one is cut backwards under the upper one, and both may exist simultaneously, because the latter one will not disappear till it is entirely cut away by the lower level; and a more or less abrupt transition between them may be found, unless it has been much modified by later erosion. An important reason why A. thinks that the Norwegian strandflat has not been formed by marine denudation, is that a plane thus formed could not slope so very gently from its inner margin, at the foot of the moun- tains, towards the outer skerries, as does the strandflat. Its inclination must have become steeper, for else the waves would not have got suf- ficiently deep water to work in. Nevertheless he thinks that the innermost parts of the very flat platforms on Værøi, Rost, and probably also on Træna, are formed by wave erosion. A. is obviously right in his view that wave erosion alone cannot, as a rule, form wide planes sloping as gently as these; but he has not considered the effect of shore erosion by frost. Where this process, as described later, plays the leading róle in marine denudation, wide and nearly horizontal planes, like those of the Norwegian strandflat, may certainly be formed along a much dissected coast. On the other hand A. objects that, because in some places, e. g. in the region of Rorvik, north of the Trondhjem region [1919, p. 197], the low coastal border-land is not flat, there is no strandflat. For if this "had been formed, wholly or mainly, through marine abrasion, the plain would everywhere have the same main character," but “at Rorvik, and at many other places, there occur, in complete contrast to this, all stages from the most broken topography to the groups of small level islands." This is, however, just what might be expected to be a characteristic feature of a strandflat formed by the joint action of subaérial denudation and marine denudation, and also glacial erosion, along a much diss?cted coast. Its degree of evenness will naturally depend on the degree of maturity to which it has been developed. The less mature the more ridges, hills, and stacks will surmount the general marine level. Where the rocks are relatively resistant, or where initially relatively great masses of rock surmounted sea-level, many islands and hills may remain more or less incompletely levelled, and their summits may vary much in height. On the whole, the surface of the strandflat may seem to be remarkably level, considering that it has also been exposed to considerable glacial erosion, perhaps during several periods, which has scoured the islands and hills, rounding off their edges and summits, and also considering 12 FRIDTJOF NANSEN. M.-N. Kl. that the strandflat has been developed during long periods, with different levels of the shore-line. A most characteristic feature in the topography of the Norwegian strandflat, is its incision into the mountain side of the land behind, forming an often sharply marked line of demarkation between the level strandflat and the mountains ascending abruptly and steeply, often hundreds of metres. As far as I have seen, Ahlmann has made no serious attempt to explain how such a horizontal incision could have been formed by the vertically working subaérial denudation, although this would naturally have been of essential importance, if his theory should have been made more plausible. Nor does he try to explain how the vertically working subaérial denudation alone can possibly develope such extremely flat, and nearly horizontal planes, as occur e. g. in Smolen, Froia, Hergi, Donna, Risver, and Solver. In the case of Smolen he himself has ob- viously had a notion that it was necessary to open some opportunity of a finishing touch by a horizontally working agency, the marine denudation, as was mentioned on a previous page (9), but, as if to weaken the effect of this admission, he also draws in the erosion of the inland ice, as having a planing effect, which I consider very unfortunate, as will be discussed in a later chapter. If the assumption that the strandflat is a base-levelled plain, due to subaérial denudation, be correct, we might expect that this process would have had the greatest facilities in developing a broad strandflat in southern and south-eastern Norway, where the initial land was low, and sloping gently towards the coast, — while it would require infinitely longer time on the initially high west coast, especially if it be assumed, with A., that his “distal base-levelled plain” was mainly formed before this coast was dissected by the many deep fjords, channels, and valleys of the glacial periods, 1. e. at a time when a very much greater mass of rock had to be worn away before the land could be base-levelled. We find, however, just the contrary: an often broad and well developed strandflat along the steep and high west coast of Norway, while there are only slight indications of such a formation along the southern and south- eastern coast. It is, however, not always easy to grasp what A. exactly means by his base-levelled plain, for in some regions, e. g. in southern Norway, it may have a relief of a hundred metres above the sea, and in that case it would still be much rock to plane away before we reach the strandflat. If the Norwegian strandflat is solely a “‘base-levelled plain," it would also be extremely difficult to understand why subaérial denudation has not developed similar strandflats along any old coast, where the coast-line has remained stationary during a time necessary for base-levelling, and why it is that, on the contrary, typical strandflats occur chiefly in regions that have been covered by ice-caps, or have at least had verv cold climates 1921. INo. v3. THE STRANDFLAT AND ISOSTASY. 13 We might have expected to find this “distal base-levelled plain” most perfect in those milder regions, where its surface has not been attacked by glacial erosion. A. has made no attempt to help us out of this serious difficulty. It might be objected that along the east coast of India there is a very broad (up to 75 kilometres broad), extremely flat and low plain, backed by steep mountain walls. But unfortunately, this is just a region with very little rain-fall, and where therefore the subaërial denudation has been so insignificant that this magnificent plain of marine abrasion could be developed so perfectly, and remain relatively undisturbed, and backed by oversteepened hills, because it was only sligthly attacked by subaërial denudation. A.’s views as regards the formation of his “distal base-levelled plain” has been wel! expressed in his description of the region of Smolen, where he says [1919, p. 197]: “On the mainland opposite Smolen there occurs a broad denudation surface with about the same height above sea-level as that on the island, and abruptly attached to a steep fell-side about 500 m. high. In certain places this surface seems to continue in islands and terraces at the side of fjords, which towards the east pass into a mature valley-generation.” From this he draws the conclusion that the broad denudation surface of Smolen and the mainland has been formed by base- levelling in the same manner as the floor of his base-levelled valley generation, which he describes so well. His view is obviously that the broad valley floors have joined together in front of the high land and have “formed a peripheric base-levelled plain” [1919, p. 221]. To me it would have seemed more logical to argue that, the low is- lands and ledges along the sides of the fjords have obviously been levelled by the same process as the flat and very even surface of the strandflat of the coast outside, and that this process has been marine denudation of some kind, because the islands and ledges in the fjords have, in most cases, little resemblance to what might have been expected to be remnants of the floors of base-levelled valleys, that have been exposed to the erosion of several glacial periods. Besides in several places the floor-level of A.’s preglacial valleys differs distinctly from the level of the strandflat in the same locality, e. g. in Sogne Fjord, as will be mentioned later. Another difficulty is also connected with As views as regards his base-levelled valleys. For the same reasons which the present writer has pointed out [1904, pp. 44 f., 54 ff., 151 ff. etc.] A. also assumes that the preglacial fluvial valleys of the land has been continued across the floor of the now submerged continental shelf, e. g. outside the coast of Romsdal, Trondhjem Fjord, and Helgeland, at a time whén the land stood about 250 to 300 metres higher than now. A. is obviously of the opinion that these valleys too were base-levelled: but if so how is this fact reconcilable with his theory of the valleys and strandflat as having been base-levelled 14 FRIDTJOF NANSEN. M.-N. Kl. at about present sea-level? If, after that great elevation (250—300 metres higher than now) when the valleys were base-levelled on the continental shelf, the land was submerged, the valleys were naturally also more or less submerged, and their floors would be below sea-level near the coast. There would thus be no possibility of base-levelling the valleys in this coast zone, as they were already deepened below base-level. It might then be assumed that the elevation of the land occurred after the valleys of the present land-surface had been base-levelled and ‘the distal base-levelled plain’ had been formed. But if so the land must have stood at that higher level for a considerable time, sufficiently long for the base-levelling of the fluvial valleys of the shelf, and after that the land has again sunk to its previous level, or the shore-line has returned to the same level which it had during the very long period when A.’s old valley generation was base-levelled. But what kind of movements is it that has changed the level of the shore-line in this peculiar way, and after such a long time brought it back to its original level? A. cannot be seen to have considered this difficult question, which his theory must inevi- tably raise. There is also another difficulty which he does not mention. He thinks that the inner part of the continental shelf “constitutes an imme- diate continuation of the coastal zone, thus belonging to the peripheric base-levelled plain” [1919, p. 211]. But how is this to be understood? Was the plain of the continental shelf base-levelled at the same time as his old valley generation further inland was base-levelled? But the level of the latter, is now near present sea-level, and is considerably higher than that of the former. How then could extensive formations, so sharply marked as the strandflat, and the floors of his old valley generation, be so well developed at this base-level, when there was also another lower base-level (before or after?), represented by the inner part of the con- tinental shelf? A.’s ideas do not seem to be very clear on this point. His views of the genetic origin of the continental shelf shall not be taken up for discussion here. A factor of much importance for this and other questions dealt with in A.’s treatise, is the isostacy of the earth’s crust, which, however, he does not mention. The conclusions arrived at concerning Ahlmann’s views of the nature of the Norwegian strandflat, may be summarized as follows: A. is right in assuming that the subaérial denudation (1. e. atmo- spheric weathering, frost disintegration, and fluvial erosion) has been of chief importance for the denudation of the Norwegian coast land, as well as for the land slope within. This is in full accordance with the views of several previous writers. A. is wrong in assuming that the Norwegian strandflat, forming often a sharply marked horizontal incision in the mountain slope, has been 1921. Ne. ri. THE STRANDFLAT AND ISOSTASY. I5 developed solely by base-levelling of the subaërial denudation, without the aid of marine denudation. A. is also wrong in assuming that the present strandflat has been formed mainly in preglacial time before the coast land had been dissected by the numerous fjords and channels now traversing the strandflat. Profiles of the strandflat and the high land behind it, like those given in Chap. VII and VIII, and also the numerous profiles given in my report of 1904 [Pl.s XII—XX], demonstrate how very level the strandflat may be in some regions, and what sharply defined horizontal incision it may form in the steep mountain side of the land. It is hardly conceivable that level planes like these, can have been formed exclusively by a vertically working process, like the subaërial denudation. We must assume that they have been finally levelled by some process working horizontallv. The writer has recently [1920, 1921, Chap. VIII] mentioned several processes that may have a planing effect upon a land surface, even above sea-level. But their levelling effect is small compared with that of marine denudation in cold regions, where an active shore erosion is produced by the disintegrating activity of the frost, in and just above the shore-line, as will be described later. Let us, however, first examine more closely what importance the various denuding processes may have for the denudation of the coast land and for the development of the strandflat. 16 FRIDTJOF NANSEN. M.-N. Kl. III. THE EFFECT OF THE SUBAERIAL DENUDATION IN THE COASTAL ZONE: If a land-surface sloping gradually towards the coast, be exposed to subaerial denudation during sufficiently long periods, and without being disturbed by other processes, it is obvious that a base-levelled plain may finally be developed along the coast, and according as the sloping land- surface is denuded, this plain will extend landwards. Fig. 4 demonstrates very roughly the development. SL is sea-level and gab the initial land slope, which by subacrial denudation is lowered to cd, and then to e f, and the base-levelled plain ace is thus developed. It is here supposed that the rate of subaérial denudation as well as the resistance of the rocks have been the same in all regions of the land slope, which of course is, not the case, as a rule. The transition between the land slope and the base-levelled plain would naturally be very gradual, and there would not be a sharp break as in the figure. b d E HS SD S. == ees OE oO ne Fig. 6. Cirque-glaciers on the west coast of Cross Bay, Spitsbergen [from Nansen, 1920]. dy RE» Fig. 7. Future picture of the coast in Fig. 6 [from Nansen, 1920]. would here move with consirably greater velocity along the fjords and sounds then over the islands between them, and it would go on deepening them at a very much greater rate than it could erode the surface of the islands. The velocity of its movement along these channels may have gone on increasing with increasing depth, and its erosive effect would increase very much more. How then would it be possible that the inland ice could have planed the surface of the islands and peninsulas to practically the same level, while it has excavated the sounds between them to very different depths? The inevitable effect of the erosion of the inland ice in this region must be that, not considering its smoothing and rounding of the local rock surfaces into roches moutonés, it will make the whole land surface much more uneven than it was before. For this reason, according to my view, and as has also so clearly been pointed out by Hogbom [1913, p. 57], it is impossible that the deep sounds and channels, traversing the strandflat and dissecting it into its many islands, can have been formed after this plane had been levelled. If the sounds were deepened, to some considerable degree, by the glaciers of the inland ice, this deepening process could not in that case have left the plane between the sounds as undisturbed as it actually has. A glacial erosion, to that degree selective, is not conceivable on a flat plain. If the sounds and channels have been formed chiefly by atmospheric and fluvial erosion, then as Hogbom has pointed out, it becomes still more absurd to think that they could have been eroded without the inter- vening plain being dissected by deep valleys, sloping towards the floors of these sounds. But this is not the case. 1921. No. ET. THE STRANDELAT AND ISOSTASY. 25 Fig. 8. Inner Norway Island, north coast of Spitsbergen [from Nansen, 1920]. Any profile of the Norwegian strandflat gives the impression that the land, rising between the sounds and submerged channels, has been truncated and planed after the latter had been formed, and that there have been relatively slight modifications of the relief after this happened. The Erosion of Local Glaciers. Another form of erosion is due to the activity of small “botten’’- glaciers or cirque-glaciers, and of snow and ice accumuiated in depressions and hollows of the rock surface, and remaining during the summer, or at least a greater part of it. Along the edges of these glaciers and snow- accumulations, the frost will have a strong disintegrating effect on the rocks during the season when the snow is melting, and when there are perpetual oscillations of temperature between frost and thaw. All joints and fissures in the rocks are here kept fuil of melting wtaer, ready to burst the rocks at each frost, that may even occur several times during the day and night. The rocks are therefore rapidly eaten away and thumbling down on to the glaciers or snow-heaps which carry them off. This erosion is thus a combination of glacial erosion and atmospheric weathering (mainly by frost) which is especially powerful in glacial cli- mates, and may be studied now at full work in Spitsbergen [cf. Nansen, 2920, 1921, Chap. VIII]. Fig. 6 represents cirque-glaciers now at work on the west coast of Cross Bay, Spitsbergen. Fig.7 illustrates the probable future effect of this erosion when the cirque-glaciers have got time to cut through the mountain walls behind them. Ås was already pointed out by Amund Helland and Lorange, there must also be a very active vertical erosion under the cirque-glaciers 26 FRIDTJOF NANSEN. M.-N. Kl. Figs. 9 & 10. The Buchanan and Murray Glaciers along the est This may, to some great extent, be due to the alternating melting and freezing of the ice and water, at the under side of the glaciers, caused by sudden changes in pressure, as was mentioned on a preceding page. It may also be caused by melting water coming from above in the summer, and again freezing under the ice. As Werner Werenskiold has first pointed out to me, the pressure under water filling holes in the ice, will be greater than under the ice at the same level, owing to the considerably higher density of the liquid water. If the temperature is at melting point, the ice may thus melt under the water, and this may continue down to the bottom of the glacier, provided that the holes remain full of water. But as soon as the pressure is reduced, the water will again freeze under the glacier. Such holes, more or less filled with melting water, may often be formed along the edges of the glaciers, between the ice and the rock, and in this manner the disintegration of the rock may be increased. At the bottom of crevasses often formed near the inner edge of the cirque-glaciers there may also be frequent changes of temperature above and below freezing point, causing rapid disintegration of the rocks [cf. W. D. Johnson, 1904]. It is, however, obvious that the cirque-glac.ers also erode the ground by their movement. Although in most cases the movement of these small glaciers may not be considerable, we find that they have scoured and polished the rocks on the floor of their cirques, they have smoothed the edges and have plucked stones. Moreover their motion is of importance by carrying away debris and detritus formed by the erosion. The whole process described above, may have a general denuding effect upon the land surface where it works, which is considerably greater than the average erosion of the inland ice. There is also this difference, that it will be mainly limited to the land surface which is above the sea. Given sufficient time, it might therefore be able to denude the coast land towards sea-level and might transform it into a fairly low, though uneven plain, provided that the climatic conditions allow the cirque-glaciers to descend to the sea. In Lofoten the cirques have actually been eroded to some depth below present sea-level [cf. Helland, Thorolf Vogt, 1912, Ah'- 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 27 A Kan Lam i, coast of Prince Charles Foreland. Spitsbergen [from Nansen, 1920]. mann, 1919]. It is conceivable that, where the cirque-glaciers are suf- ficiently thick, they may be submerged to some extent, but, as a rule, they will not descend much below sea-level. It is obvious that, in the manner described above, the local erosion of small cirque-glaciers and accumulations of snow on the mountain sides along the shores, may help to form low coastal borders, backed by over- steepened mountain walls, as demonstrated by Fig. 8. I have observed in Spitsbergen that several cirque-glaciers, after having eroded themselves down nearly to sea-level, may be widened by horizontal erosion, until they meet and their glaciers unite and form one continuous, nearly horizontal ice-sheet, covering a fairly flat shore land in front, with a mountain wall ascending steeply behind. Figs. 9 and 10 illustrate some glaciers of this kind, covering the low shore land along the east coast of Prince Charles Foreland, Spitsbergen. In the same manner as a cirque-glacier, the flat shore glaciers may have | an ability to eat themselves backwards into the mountain side, by the frost erosion along their inner edge. The remaining ridges between the original | cirques may thus gradually disappear, and few traces of them may be left. As the flat glacier, by the pressure of the snow, each year accumulating on its surface, will be moved slowly towards the sea, it may gradually carry away the débris. In this manner we might imagine that a kind of strandflat, with an &bruptly ascending, oversteepened mountain acclivity behind, can be formed. But the plain thus arising cannot be expected ever to become very broad, nor very level and regular, and there are in fact no indications that the strandflat of Norwav, has to any appreciable extent been formed in this manner. In southern Norway there are very few traces of cirques having ever been formed near present sea-level; though this does not prove that it may not have been the case during the Great Ice Age. Any how, it cannot be doubtful that, in regions with the necessarv climatic conditions, as it now is in Spitsbergen, the above mentioned form of glacial erosion may have been of importance for the development of a low shore land, although it has not been able to form a typical strandflat. 28 FRIDTJOF NANSEN. M.-N. KL V. MARINE DENUDATION. SHORE EROSION BISEROST There remains then no other process for the planing of the strandflat but the marine denudation. Most writers assume that this denudation is chiefly due to wave erosion. But if the wave erosion has been able to cut the plane of the broad and nearly horizontal strandflat along the coast of Norway, it must certainly have been able to cut similar planes, at least to some extent, along more southern coasts, exposed to the full fury of the ocean during sufficiently long periods, even though those coasts were less dissected. But, as a rule, no real strandflat occurs along the coasts of milder regions. Considering the extremely slow progress of wave erosion alone on a coast built up of solid rock, it is conceivable that during the very long time which the wave erosion will need for cutting a fairly broad strandflat, the land will be so much denuded and dissected by the atmospheric weathering and fluvial erosion, and will be so much raised by the isostatic elevation thus caused, that the traces of the strandflat may be more or less ob- literated. The striking fact is that the typical strandflat is a characteristic feature of high northern and southern latitudes. It occurs preeminently in regions that have formerly been subjected to glacial conditions or have at least had very cold climates, like the coast of Siberia. It seems, there- fore, to be a natural conclusion that the formation of typical strandflats have, as a rule, had some connection with low temperatures. S.W.Cushing [1913] has described a remarkably smooth emerged plane of marine denudation along the east coast of India, wh'ch is like a strandflat. It is backed by “an ancient sea wall,” rising steeply to an average height of over 650 metres above sea-level, in some regions even to 2300 metres in an almost vertical wall. Numerous remnants of quartzite rise in the shape of steep-sided ridges or stacks, often with flat summits, above this plane. Their bases are not unfrequently marked by sea caves, and there seems to be room for little doubt, but that this plane, in places about 75 kilometres broad, is actually formed by wave-erosion [cf. D. W. Johnson, 1919, p. 231]. The plane has been developed over meta I921. No. rr. THE STRANDFLAT AND ISOSTASY. 29 morph:c structures mainly, represented by numerous schists, gneisses, and quartzites. "Because of its low lving attitude and meager rainfall it has been little dissected." Cushing does not give the height above sea-level of the inner margin of the plane, but it might be inferred that it cannot be much over 70 or 80 metres; and the plane dips gently seawards to the low, flat shore. It is conceivable that, in a region with very meager rainfall, and con- sequent slow subaérial denudation, the wave erosion may, in the length of time, be able to develop sharply defined planes backed by oversteepened sea walls. But in regions with a more abundant rainfall, the subaërial denudation will work faster than the wave erosion. During the long time which the latter would require for the development of a broad plain of marine abrasion, the subaerial denudation would certainly denude the land surface much more, and it would wear down the sea wall (the cliff), and give it a gentle slope. If the plain of marine abrasion be elevated (by isostacv) above sea-level, its surface would gradually be more or less dis- sected by the subaérial denudation, and after some time there may be no very sharp boundary between the marine plain and the more undulating surface inland, especially as the whole land would gradually be elevated, by isostatic movement, at about the same rate as it was denudet, and nearly the same amount. Hence, as a rule, we will find no typical and sharply defined strandflat in regions with an active subaérial denudation, unless there have been especially favourable conditions for its development, like those prevailing in regions exposed to severe climates. After having had an opportun:ty of studying the process of marine denudation and its effects more closely, especially in Spitsbergen, I have modified somewhat mv earlier views [1904, 1905] as to the manner in — which the strandflat has been developed (mentioned on pp.5 f.). I have been lead to the conclusion that the wave erosion has been of but little direct importance for the planing of the strandflat of northern regions, compared with the erosion effected by frost in and just above the shore-line, which process I have found to be even much more effective in an arctic climate, than I formerly believed (cf. above p. 5). As the general expression ‘marine denudation’ is by most writers combined with wave erosion, I prefer to use the expression shore erosion by frost for this special’ form of marine denudation. When sea-water freezes (at —1° to —1.9°C.) it does not expand so suddenly in the moment it is transformed into ice, as fresh-water does at o? C. But at sinking temperature the ice of sea-water goes on expanding gradually [cf. O. Pettersson, 1883]. According to my observations, this continues as long as the sea-ice holds in its pores liquid brine which is gradually transformed into ice. New sea-water ice is also soft, porous, 30 FRIDTJOF NANSEN. M.-N. Kl: L f d : , [TR | ams fl Fig. 11. Shore at Cape Elisabeth, Bear Island (after a photograph by J. G. Andersson). and flexible, and very different from the hard, solid, and brittle fresh: water ice. For this reason the sea-water, when it penetrates into the fissures of the rocks and freezes there, has not as great a disintegrating power as the fresh-water, and there is a material difference in this respect even if the water contains comparatively little salt [cf. ©. E. Schiøtz, 1894]. One might, therefore, expect that the sea-water cannot by freezing produce a very powerful erosive effect on the shores, especially if it is not much diluted with fresh-water. It is an obvious difference in this respect between the shores of a lake and the shores of the sea. It has, however, to be considered that in the fiords, and sounds, and enclosed parts of the sea, especially in the Arctic or glacial regions, the sea-surface is generally covered by layers that are very much diluted by river-water, and by the melting water of glacier-ice carried into the fjords, often producing nearly fresh surface-layers. Moreover, nearly fresh surface-layers are quite commonly formed in Arctic seas by the melting during the summer of the ice, formed in the sea during the winter. If the sea is sheltered against waves by floating ice, or by islands, this fresh surface-layer may remain more or less un- stirred during the summer and autumn, till it again freezes next winter. In this manner, the disintegrating power of the sea, caused by freezing, will become more vigorous along sheltered coasts, either in fjords and sounds, or where the coast is sheltered by floating ice. In a somewhat different manner the sea has, however, a much greater erosive effect along the shores in cold climates. As was mentioned before, glaciers or patches of snow may, by alternate thaw and frost, have a vigorous disintegrating effect upon the rocks along their edges. Similar conditions prevail along coasts in an Arctic or glacial climate. Ice is formed on the beach or along the shore-line, just above high-tide 1921. No. rr. THE STRANDFLAT AND ISOSTASY. 3I in fon LR RAS ni 2 A ae t a ER N N mi Mm KAF | Fig. 12. Northwest shore of Reindeer Islands (Kjellman Islands), coast of Siberia. (August 20, 1893). level, and is covered by snow-drifts during the winter. This ice and snow remain in greater or smaller patches on the beach, above high-tide level, during the summer, or at least during the greater part of it (cf. Figs. 11 and 12). Along their edges, especially on their inner side, a very effective erosion goes on during the melting season in the manner mentioned on p. 25. As the dark shore cliff absorbs the light heat-rays, the melting will begin very early at its base. All cracks, fissures, and pores in the rocks are kept full of melting water, ready to freeze at the slightest frost, and will split r the rocks [cf. Nansen, 1920, 1921, Chap. VIII]. As the masses of melting snow and ice, as well as the cold sea surface, keep the air temperature near the freezing point of water, a slight fall of temperature may be sufficient to cause frost. Alternations of thaw and frost may therefore occur almost every day and night during a great part of the year. Owing to its dark surface the rock will absorb the light heat-rays to a much greater extent than the snow and ice surface. Every time the rock is exposed to direct sun-shine it may, therefore, be heated to temperatures much above the freezing point of water, although the air-temperature in the shade is very low. The snow and ice, especially along the vertical always dark rock-walls, will then be melted, and the fissures and cracks of the rock kept full of liquid water. As soon as the direct sun-shine disappears from the rock surface, this water will freeze at once. This process may be repeated several times during the twenty four hours, and may begin very early in winter or spring, as soon as the sun rises sufficiently high to have an appreciable effect. In not too northern latitudes it may even occur, more or less, during the whole winter. In polar regions I have observed drops of liquid water being formed on the surface of white ice cliffs in this manner when the air-temperature was below — 15? C. In regions where the sea is covered by ice during the winter, it is also of importance in this respect that, during late winter and spring, the atmosphere is generally very clear, and there may be continual sun-shine 32 FRIDTJOF NANSEN. M.-N. KI. Fig. r3. ‘Ice-foot’ (shore-ice) formed above the upper fucus-limit, and above the average sea-level, at Holstensborg, Greenland. [K. J. V. Steenstrup, 1907.] during a great deal of the time, till the sea is opened, and fogs become frequent. The result is that the rocks are rapidly disintegrated and crumble to pieces. The tide may also be of importance by alternately submerging some part of the shore twice every day and night, even during the cold winter. This may cause alternate melting and freezing of the water in the fissures and depressions of the rocks, wherever the shore is not covered by more permanent layers of ice. Thus an active disintegration of the shore rocks may be produced even by the sea-water. During the time of the vear when the sea is more or less open, the wave action will wash away from the shore the débris formed by the frost disintegration. This is of the greatest importance for the continued shore erosion by frost. The waves and the tide may also break loose the ice formed on the beach, and may carry it away with the débris, accumulated on its surface from the cliffs above. The ice formed at low water, on small water pools left by the tide on the beach, may also be of some importance in this respect. Mineral particles and small stones enclosed in this ice, may be carried along with it when the tide rises [cf. O. E. Schiøtz, 1894]. The waves may help to break the ice loose, and thus the shore erosion may be increased. The socalled ‘ice foot’, or thick layer of solid ice, formed along Arctic shores during the winter, may also carry along with it enclosed stones, or stones and débris fallen from the cliff on to its surface, where it is broken loose in the spring or summer [cf. Knutsen, 1889, p. 249]. But according to my observations, this transport by the ‘ice foot’ is less than might be expected, because on the one hand, a great deal of the ‘ice fcot’ lies above the average high-tide level, and melts gradually in situ, without being carried away by the sea, and on the other hand, the ice on the lower 1921. No. rr. THE STRANDFLAT AND ISOSTASY. 33 7 y 5j; V2 4 eh Hp MAY) AN - $1 IRI) i 1^ XB D V ^U DTE PA PAMELA IM / +e FA MA [M TA uo. ei) T py jn / i ME i- B TM d uL 1 a $5 (4 ze D DS y y n Næ ^ ^ii, VA pv Fig. r4. Picture of the future, showing how the 'ice-foot' in Fig. 13 may erode a shore-ledge in the length of time. beach may be so firmly frozen in between the stones, and boulders, and rocks, that it cannot be broken loose by the waves, but is graduallv worn away or melted in situ. I have seen ice remaining during the summer in this manner between the stones on the sea bottom along submerged beaches. In a different manner a transport of débris may be effected. The stones loosened by the disintegration of frost from the cliff and the steep mountain side, will fall down on the sloping snow surface of the ‘ice foot’ and thumble, or gradually glide, down this slope to the shore where they may reach the surface of the sea 1ce and be finally carried away by this ice. Or they are.deposited in or near the water, and when they have been suf- ficiently disintegrated by frost and waves, are finally washed away. In this manner a terrace of loose stones and débris may often be formed along the shore outside the bench cut in solid rock. The accumulations of ice and snow along the shore will year by year eat themselves landwards, making the shore-bench broader, and forming a higher and higher cliff, or mountain wall, of crumbling rocks inside: Thus the typical shore of Arctic lands is developed. This may even occur along steep coasts where the mountain side falls abruptly into the sea, as is demonstrated by Figs. 13 and r4. Figs. 13 illustrates a small ‘ice foot” formed above the upper sea-tang (fucus) limit and above the average high-tide level at Holstensborg in Greenland [K. J. V. Steenstrup, 19071. Fig. r4 illustrates how a shore-bench might be formed in the length of time by the frost erosion of the accumulations of ice and snow at this level. The rate of the erosion will greatly depend on the resistance of the rock to the disintegrating effect of the frost and ice. In places where the rock is relatively less resistant, small cirques may be formed. Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. 11. 3 34 FRIDTJOF NANSEN. M.-N. Kl. LE d ons Fig. 15. An old shore cliff at the inner margin of a strandflat of low level, on Verleegen Hook, Spitsbergen [Nansen, 1920]. During storms with high-water, especially in late summer and autumn, the débris accumulated on the bench may be more or less washed away. The débris will also be moved outwards by the creeping motion in the accumulations of ice and snow themselves, and by the transport caused by the alternate melting and freezing of water along their inner margins. It might be objected that the ice formed on the beach is sea-ice and will not therefore have much erosive power. But on the one hand, the sea in these regions is often covered by nearly fresh surface-layers, as mentioned above, and on the other hand, when the sea-ice grows old, especially during summer, the brine gradually sinks out of it, and its melting water becomes practically fresh, so that, for instance, it makes excellent drinking water. Moreover, the ice on the beach is generally covered by deep snow-drifts which remain during a great part of the summer. This form of shore erosion may be studied at work in its different phases in Spitsbergen. We may there see how it 1s now forming ledges along the present shores, and we may see how it has been able to form broader benches or small strandflats as demonstrated by Fig. 15, where there is an old vertical shore cliff of disintegrated rock, with an erod ng accumulation of snow at its base, on the inner side of a quite low strandflat. After this chapter on the formation of the strandflat, had been written, my attention has been called to a paper by Thorolf Vogt [1917] which he has kindly sent me. It is of great interest for our subject as it de- scribes recently formed shore-ledges, cut just above high-tide level in very steep rock walls along the coast of Kvænangen Fjord in northern Norway. 1921. No: TI. THE STRANDELAT AND ISOSTASY. 35 UN Nett : (A TN NN i, À RN N JER SS il } | [ TIN \\ N i WW N vl DE : SNS . MA eap. Ir = sae | Fig. 16. Shore-ledge cut in gabbro with bands of syenite, at Simalanga, Kveenangen Fjord [after a photograph by T. Vogt]. A more convincing demonstration of the manner in which the shore-erosion by frost actually works, could hardly be found. The ledges are 8 and 12 metres broad, the one is cut in gabbro with bands of syenite (Fig. 16), the other in dolomite. Their outer edges rise generally between half a metre and one metre, or a little more, above the level of their floor inside, which lies perhaps half a metre above the upper fucus limit, and slightly above average high-tide level. The floor of the ledges may probably be flooded at spring-tide. As Vogt maintains, these ledges are obviously formed by frost dis- integration in recent time and at present sea-level. He thinks that the eroding work has to a great extent been performed by accumulations of snow on the ledges, which have frequently been soaked with spray from the waves, and have afterwards been frozen. In this manner he finds an explanation of the height of the ledges above the average high-tide level. I think, however, that it is the alternate mélting and freezing of the ice and snow accumulated on the ledges, which have had the chief erosive effect on the rock in the manner described on a preceding page. The ice has been formed on the ledges at spring-flood and at exceptional high water, as well as by water washed up by the waves in cold weather, and on top of this ice snow-drifts have been accumulated (cf. Fig. 14). Because of the salt contained in the sea-water the soaking of the snow by the spray from the waves may reduce somewhat the disintegrating effect of the melting and freezing snow. 36 FRIDTJOF NANSEN. M.-N. Kl. Y / DY a f. "m n = ? h 1 IT Cg aid e "Mn Ur à == ==] i pem un A. Be 5, 2 MSA: Fig. 17. Shore-ledge 8 metres broad cut in argilaceous shist on the Fornebo Peninsula. The actual occurrence of such shore-ledges, recently eroded by frost in solid rock and at present sea-level along shores where a considerable wave action has been working simultaneously, as is the case in Kvænangen Fjord exposed to the stormy Loppen Sea, is a convincing evidence that, where the necessary conditions are present, the shore-erosion by frost is much more effective than the wave erosion, and it is able to cut shore- benches in solid rock in a much shorter time. It might be objected that the mountain sides of Kvænangen Fjord, where Vogt’s ledges have been cut, are so very steep with so deep water just outside (a depth of 22 metres onlv 4 metres outside the shore) that the wave erosion would, in any case, have very little effect on such a nearly vertical rock wall. But the fact is, as Vogt points out, that the loose stones as well as the projecting solid rocks on the rough surface of the ledges are angular, and show no appreciable traces of having been rounded by the waves. While the disintegrating effect of the frost has been able to cut these ledges 8 and 12 metres broad into the steep mountain wall, the wave erosion has not even been able to produce any appreciable effect upon the outer edge of these ledges. The wave action has, however, obviously been of importance by helping to carry away the débris. Similar shore-ledges, formed by shore-erosion by frost, also occur in more southern latitudes. Along the shore outside my house on the Fornebo Peninsula (at Lysaker), in the inner end of Christiania Fjord, relatively 1921. No: TE: THE STRANDFLAT AND ISOSTASY. 37 N 227 ZA Bp ae re MEE Fig. 18. Shore-ledge 18 metres broad, cut in argilaceous shist near Fornebo Harbour. broad ledges have been formed in this manner, in recent time and at present sea-level. Figs. 17 and 18 represent some parts of these shore-ledges. They are cut in solid rock and are from 8 or 9 metres (Fig. 17) to 18 and 20 metres broad (Fig. 18). The rock consists chiefly of ordovician clay- slates, alternating with bands of lime-stone, occurring in series of lenti- cular nodules with intercalated shales [cf. Werenskiold, 1911]. This formation is intersected by numerous dykes of diabase. The general floor of these ledges is perhaps half a metre above average sea-level. The tide is insignificant in the inner end of Christiania Fjord, and the sea does not often rise sufficiently to flood the ledges. In som places the outer part of the ledge, near its edge, may be somewhat higher than the floor inside. In Fig. 17 the outer edge of the ledge is about 0.6 to 0.8 metre above average sea-level, while the floor inside is 0.2 to 0.3 metre lower. In some places rocky nabs occur near the outer edge rising as much as I metre above the floor of the ledge (see Fig. 18). These pro- jecting nabs and ridges near the edge of the ledges, are in some cases formed by dykes of diabase, which has been more resistant to the erosion than the argilaceous shists and lime-stone, but they may also, as in Figs. 17 and 18, consist of the same kind of rock as the inner part of the ledges. In the nab in Fig. 18, there is relatively much lime-stone. These ledges have obviously been formed by shore erosion by frost, in a similar manner as that described on the preceding pages. When the fjord was covered by ice in the early winter, as it always used to be except in late years when the fjord is kept open by ice-breakers, the ledges were covered by thick layers of ice formed at high water. When this ice melted, all fissures and depressions of the rock surface would be kept filled with water, which would freeze and disintegrate the rock at each frost. 28 FRIDTJOF NANSEN. M.-N. Kl. The argilaceous shists and shales are easily denuded in this manner, The nodules of lime-stone may be more resistant, and they therefore often project somewhat above the surface of the surrounding shales. As Fig. 17 shows, the rock of the higher parts of the ledges has the very rough surface typical for rocks disintegrated by frost. In some places where the rock surface is extremely rough the relief of the many projecting ridges and blocks may amount to nearly one metre. The edges of the projecting rocks, on the outer part of the ledges as well as further in, are but slightly rounded by the wave action, which has obviously been of very little direct importance for the original formation of these ledges. The surf at high water has, however, been of great indirect importance by washing away the débris formed by the frost erosion. Where the ledges are low, and slope gently seawards below average sea-level, as in some part of the shore represented in Fig. 18, the solid rock- surface is more or less covered by a layer of stones of different sizes. It is possible that the wave erosion may here have denuded somewhat the outer part of the ledges. The stones are rolled up and down the beach by storms from the south and south-east, which always cause high-water and may have great effect by a vigorous surf. The rock-surface of the lower levels show indications of wave erosion, though it has also to some extent been disintegrated by frost. The stones have obviously been broken loose from the solid rock by frost disintegration. There are all stages from a great number of angular stones recently disintegrated, and consisting to a great extent of diabase, to rounded, wave-worn pebbles, which greatly consist of the more resistant parts of the argilaceous shist, especially the calcareous nodules. These ledges have been developed in recent time after the land had been elevated very nearly to its present shore-level; and there has obviously been no appreciable elevation of the land after their formation. The sur- face of the ledges shows no traces of glacial erosion, but the surface of dykes of diabase in several places projecting in the shore-line at the outer edge of the ledge is rounded and striated by glacial erosion, and so is the upper surface of the dyke of diabase to the right in Fig. 17, forming the cliff backing the ledge. The low skerry seen in the background, behind the bath-house to the right, is also rounded and striated by glacial erosion. In many other places along this shore one also finds rock-surfaces, chiefly of dykes of diabase, which are rounded and striated by glacial erosion. They are sometimes situated near sea-level outside the shore- ledge, and sometimes above it. This shows that the rocks of the shore had been scoured and rounded by the glaciers of the last glacial period, before thev were attacked by the shore-erosion, after the shore had been elevated to its present level. The argilaceous shists were then easily disintegrated by frost, and were cut back by the shore-erosion, while the dykes of diabase were much more 1921. No. rr. THE STRANDFLAT AND ISOSTASY. 39 resistant. The ledge illustrated in Fig. 17, was cut back till the erosion stopped against the nearly vertical wall of the dyke of diabase to the right in the picture. This wall rises about 1.7 metre above the floor of the ledge. The level upper surface of this dyke is about 2.2 metres above the sea, and seems to be part of a shore-ledge formed before the last glacial period. A little further inland there is a higher ledge at about 3.1 metres above the sea, which is 40 to 50 metres broad, and partly cut in solid rock, partly formed of loose material. In the region of Fig. 18 there was no dyke of diabase to stop the shore erosion, and the shore-ledge has here been cut back about 18 metres to the foot of the cliff of argilaceous shist, which in some places is nearly vertical, 4 to 6 metres high and even Io to I2 metres high. In one place (at Godthäb) there is a broad dyke of syenite-porphyry along the shore, in which the shore-ledge has been cut, and it is to some extent backed by a cliff of argilaceous shist. This porphyry is traversed by numerous fissures and was easily disintegrated by frost. The effect of the shore erosion differs much with the height above sea-level. At the lowest levels of the shore, where the rocks emerge only at low water, the recent shore erosion has been insignificant. One may even find rocks of argilaceous shist scoured by the glaciers, which have kept their rounded polished surface, where the glacial striation is still visible. The reason is obviously that the rocks at these low levels have been protected by the water against the disintegration by frost, while the wave-erosion has had no appreciable effect. They are a convincing demon- stration how the former process has been essentially more effective than the latter one. The disintegrating effect of alternate thaw and frost may be most vigorous just above average sea-level, where ice is formed at high-water, but where the freezing of the water during frost is not too frequently disturbed by submergence. The shore-ledges have therefore been developed at this level! In some places the ledges are, however, as much as a metre, or even 1.3 metre, above average sea-level, and are rarely submerged. It is there- fore a question whether the shore may not have been slightly elevated since their formation. If so it can, however, only be a fraction of a metre. These ledges on the Fornebo Peninsula demonstrate on a small scale very clearly how the shore erosion by frost, assisted by the wave action, works, and how it is able, in relatively short time, to cut fairly broad shore-ledges. The planing effect of this erosion may differ much ac- cording to the resistance of the rocks and other circumstances. The result is an often very uneven rock surface, varying somewhat in height in dif- ferent places. We cannot therefore expect that a plane of abrasion thus formed, will ever become quite level. 40 FRIDTJOF NANSEN. M.-N. Kl. If W. C. Brøgger [1905] is right in assuming that the coasts of Christiania Fjord were still rising during the first part of the Bronce- age, but attained their present level towards the end of that age, we may assume that the ledges of the present shore of the Fornebo Peninsula have had about 2500 years for their formation. The ridges along the outer edge of the shore-ledges, rising above their inner floor, which are so conspicuous on the ledges in Kvænangen Fjord (Fig. 16) and of which there are also traces on the ledges of the Fornebo Peninsula (Figs. 17 and 18), appear to be a common feature on shore- ledges formed by frost erosion. They occur frequently on the lateglacial and postglacial raised beaches of Norway, where especially O. E. Schiøtz [1894] has called attention to them. They are also mentioned by other Fig. 19. writers. J. H. L. Vogt and J. Rekstad [Vogt, 1900, p. 73] state that near the outer edge of the shore-ledges in Helgeland, 10 to 20 metres broad or more, rocky nabs frequently rise one or two metres above the general floor of the ledges (e. g. on Leka in Helgeland). They are obviously formed by the greater effect of the disintegration by frost on the inner part of the ledge, where the accumulation of ice and snow remains longer, while it is more easily washed away by the waves along the edge. On the inner part of the ledge the accumulation of ice and snow (Fig. 19, 1) may thus erode the rock down to a lower level without being disturbed by the waves, as is demonstrated in Fig. 19, A and D. The raised beaches of Norway have obviously, as a rule, been formed by shore erosion by frost, in a similar manner as the strandflat, but during relatively short periods. Already Feilden and De Rance [1878] pointed out very clearly the great importance which the disintegration by frost and the ice-foot must have had for the formation of the many raised beaches or shore- ledges in Arctic regions. Mw 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 4T Blytt [1881] considered the elevated shore-lines to have been formed by the freezing of the sea-water in regions with a great range of the tide. H. Knutsen [1889, p. 249] thought that the shore-lines were chiefly formed by the transport of the ice-foot (see above), and J. H. L. Vogt joins this view [1900, pp. 75 f.; 1907, p. 25], he also thinks that the dis- integration by frost in the shore is of great importance. O. E. Schiotz [1894] maintained that the raised shore-lines have been formed by the disintegrating effect of the frost, and also by the transport of mineral material by the ice formed on the shore-ledge. He pointed out that sea-ice must have less erosive effect than fresh-water ice, because the sea-water does not expand so suddenly when freezing as fresh- water. P. Schei [1904, p. VIII] strongly maintained that the ice-foot, in Ellesmere Land up to 100 metres broad, was of the greatest importance for the formation of shore-lines. Thoulet has mentioned the erosive effect of the freezing sea-water on the shore-line in Newfoundland. J. Rekstad [1907, 1916] maintains that the elevated shore-lines have been formed by frost and the ice-foot, and by the transport of stones with this ice-foot when loosened. He also points out that there are often small cirque-like depressions in the mountain slope, above the raised shore-lines, and the thinks they have been formed by small cirque glaciers [1916, p. 16]. Some writers have held the opinion that the raised beaches should have been formed chiefly by the erosion of drifting ice. Judging from my observations of the effect of the drifting ice on Arctic shores, I hold it for impossible that shore-ledges can be formed in this manner. The drifting ice has in fact an insignificant erosive effect. During ice pres- sures the ice-floes may be piled up against the shore, and may push up stones and gravel on to the beach, but will have very little effect upon the solid rock. The transporting effect of this drifting ice is also insignificant, except that it may transport detritus and gravel carried down on it by water or small snow-slips from the shores, or it may occasionally carry stones enclosed by freezing. It has also been maintained that the raised beaches have been formed by wave erosion; but we have already seen that the waves work extremely slowly on the shore, compared with the frost. The wave action is, however, of much importance for the formation of the shore-ledges, by washing away the débris formed by the frost erosion. But in some places where the coast is open and the surface water of the sea is salt, the wave action may have been a hinderance to the development of the shore-ledges by washing away the ice and snow on them. This may especially have been the case in postglacial time when the climate was less severe. 42 FRIDTJOF NANSEN. M.-N. Kl. On the other hand, the waves will have a greater erosive force on exposed coasts. But as the wave erosion will attack a vertically more extended surface of the shore cliff than does the shore erosion by frost, it will not cut a sharply marked incision in the mountain side, as has been pointed out by T. Vogt [1917]. Thus we may have an explanation why raised beaches are less con- spicuous and seldom observed along the open coasts of Norway, while they are often very conspicuous in the fjords and sheltered sounds, especially in northern Norway, where the climatic conditions have been favourable for their formation. The lower salinity of the surface layers of the sea in the fjords and sounds may also have been of some importance in this respect. A striking difference between the strandflat and the ledges of the raised beaches, besides the difference of extension and width, is that the latter are tilted, having always a dip seawards, while the plane of the strandflat is very nearly horizontal. It is obvious that the strandflat is a formation that has been developed during long periods when the shore- line was standing at a very nearly stable level, while the ledges of the raised beaches have been formed during relatively short periods when the shore-line had only temporary levels. Va ee 1921. Noer THE STRANDFLAT AND ISOSTASY. 43 VI. THE DEVELOPMENT OF THE NORWEGIAN STRANDFLAT. It seems to be probable that the shore-ledges have been formed by the same process as the strandflat, and that they are in a way embryonic strandflats, that might have developed into more mature ones, if they had been allowed the necessary time. But how may these narrow ledges develop into the broad planes of the strandflat? The wave action is obviously of much importance for this develop- ment. While the frost is disintegrating the rock by the alternate melting and freezing of ice and accumulated snow above the average high-tide level — widening the ledges into broader benches and at the same time lowering their floor — the waves attack the outer edge of the benches, assisted to some limited extent by the frost, and in the length of time they will manage to wear down this edge, even below low-tide level, and will thus get access to the inner floor of the benches. There may here be plenty of débris and loose stones for the surf to work with, rolling them forwards and back- wards, and thus gradually wearing down the outer part of the benches, and make them slope gently into the water, in the manner which may be studied on a small scale on the shore-ledges of the Fornebo Peninsula (cf. Fig. 18). In this manner the sea, headed by the sharp teeth of the frost of an Arctic climate, and following with the roaring surf, may eat itself land- wards and create a gradually broadening low and flat shore-plane, sloping very gently seawards, and with its inner part emerged above high-tide level. Landwards this plane will be bounded by a more or less vertical cliff, con- tinually retreating before the attack of the frost. When the shore-plane attains a certain width, the waves may lose their force in the shallow water over the outer submerged part of this shore-plane, before they reach the emerged shore, and their kinetic energy will then to a great extent be expended in transporting the gravel on the flat sea-floor [cf. Nansen, 1904, p. 182]. But by so doing they will erode the sea-floor, and will continue to do so as long as the shallowness of the water prevents them from attacking the emerged shore with their ful! 44 FRIDTJOF NANSEN. M.-N. Kl. energy. Thus both processes, the horizontal shore erosion by frost and waves, and the vertical wave erosion on the submerged part of the shore- plane, will go on simultaneously, and will continue their gradual march landwards. This is the probable genesis of the typical Arctic shore, which we find in many regions where the sea-level has remained fairly stable for a suf- ficiently long time. I may instance the north coasts of Russia and Siberia. Wilhelm Ramsay describes [1900, pp. 59 f.] an illustrative example of such a flat shore formed at present sea-level on the northern coast of the Ribachi Peninsula (Fisher Peninsula, Murman Coast). This shore-plane (Fig. 20) is emerged at low-tide to a breadth of 50 metres, and is cut in black clay-slates, which is easily disintegrated by frost. This coast has a severe climate, but is at the same time exposed to the violent surf of the open and stormy northern ocean. Although the frost is the chief causal agent for the formation of the shore-ledges, the aid of an effective wave erosion is thus necessary in order to develop these ledges into broader shore-planes, because on the one hand the waves must wash away the débris of the frost erosion, and on the other hand they must denude the outer part of the planes sufficiently to get access to their inner parts. Though the shore-ledges may be easily formed in fjords and sheltered sounds, it is thus obvious that the best conditions for the development of extensive shore-planes must be along the open, outer coast, exposed to the full force of the wave action of the open sea, and where also the land generally is lowest and most dissected into islands, so that there is much less rock to be cut away. The rate of the wave erosion increases very much with the storminess of the sea, it being proportional to something between the third and the sixth power of the velocity of the wind [cf. Nansen, 1904, pp. 181 f.] pro- vided that the latter has a steady landward direction. Thorolf Vogt, in his valuable paper on recent shore-ledges [1917, p. 121], has already given expression for a view of the formation of the strandflat which is similar to what has been here described. He says: “The forces developing shore-lines, work qualitatively very sharply limited without removing very much rock, while the surf combined with frost disintegration removes much greater quantities of rock without working so sharply limited as to level. Where there is a vigorous surf in connection with an intense disintegration by frost the necessary conditions prevail for an abrasion of great dimensions, and this may be the point of view from which one has to consider the development of the strandflat." In the above discussion of the development of the strandflat by the joint action of frost disintegration and the breakers, the sea-level was supposed to remain stable. If, however, the coast be slowly submerged during this process, it is obvious that the frost disintegration as well as 1921. No: x. THE STRANDFLAT AND ISOSTASY. 45 Fig. 20. Shore-plane formed at present sea-level, on Ribachi Peninsula. The picture is taken at low water [after W. Ramsay, 19001]. the wave erosion on the shore may be much increased horizontally. The sea will then get freer access to the shore-ledge. It will gradually raise the level of the disintegration by frost, and the breakers will reach the actual shore with greater force, less energy being expended in deepening the submerged part of the shore-plane. Hence the combined erosion of the frost and the breakers may advance landwards at a greater rate. The result will be a wider but more sloping shore-plane. The effect of the erosion will be extended more horizontally, but the vertical erosion will be less. If the coast be slowly emerging during the process, the result will be the opposite. The effect of the combined erosion will be extended less horizontally, and more vertically. It will lower the seaward part of the shore-plane, and the result will also in this case be a more sloping plane, but narrower, standing on the whole at a lower level. During those periods when, according to my view, the Norwegian strandflat was mainly developed, the sea-level was for a long time fairly stable, or the coast was being quite slowly submerged, owing to the weight of the accumulating ice-caps (cf. infra). During the periods of emergence of the coast, after the ice-caps had been removed, the land was much sub- merged. Then the raised beaches were formed, while the strandflat was lying below sea-level. The climatic conditions may then, to a great extent, have been less severe and less favourable for the shore erosion by frost. The ability of the shore erosion, described above, to develop a strand- flat along a coast, will depend on the relative length of the shore-line and on the heigth of the land (i. e. the quantity of rock to be removed), not considering the power of resistance of the different kinds of rock. Along a relatively undissected and high coast the effect of the shore erosion in this respect, will be very little, and unless the rocks be very 46 FRIDTJOF NANSEN. M.-N. Kl. weak, it would hardly be able to form a strandflat of much width, even though it could work during the longest geological time we might possibly imagine. Along a much dissected coast, like the west and north-west coast of Norway, the conditions are, however, entirely different. The length of the shore-line has been enormously increased, the islands and peninsulas will be attacked by the shore erosion from all sides, and its effect will be increased accordingly. Moreover, along this dissected coast the greater part of the denudation towards sea-level has already been accomplished beforehand by the sub- acrial denudation and the glacial erosion, which have worn away enormous quantities of rock, and there is comparatively little work left for the shore erosion, in order to plane off the small and low islands and peninsulas more or less to sea-level, and thus form the strandflat; especially as during the cold periods, when this plane was in my opinion mainly given its pre- sent flat surface, the atmospheric weathering and the local glacial erosion by frost denuded the surface of the dissected coast land vigorously. On the greater and higher islands, or where the rocks were more resistant, it would take longer time for the shore erosion, assisted by the atmospheric weathering and the local glacial erosion by frost, to denude the land to sea-level. In such places mountains or smaller knolls and ridges may still be left, surmounting the level of the strandflat, often as isolated stacks or ‘monadnocks’. The result of the whole process, gradually developing the planes of the strandflat by the erosion of the shores of the islands, will be that a quite common shape of many islands and even of small skerries, is more or less similar to that of a hat swimming on the sea with the brim near sea-level and a rounded crown forming the central part. When was the Norwegian Strandflat developed. The conclusions arrived at on the preceding pages regarding the mode of formation of the strandflat, make it probable that the Norwegian strand- flat has been developed to its present form chiefly before and during the quaternary glacial periods. We do not know what the climatic conditions may have been along the coast of Norway in late tertiary time, and whether they may have been favourable for an active shore erosion by frost, so essential for the formation of a strandflat. This is, however, hardly probable, as the climate may have been too mild. Towards the beginning of the first quaternary ice age, the temperature sank, and a more effective shore erosion began when frosts became more frequent. As time went on the climatic conditions grew more favourable — a 1921. No. rr. THE STRANDFLAT AND ISOSTASY. 47 for the shore erosion by frost, and at the same time the subaërial de- nudation became more effective, as the disintegration of the rocks by frost increased. Provided that the level of the shore-line was then approximately the same as during later interglacial periods, a more active formation of the strandflat may have begun. But as the coast had not yet, at that time, been dissected by the glacial erosion, it is hardly probable that the development of the strandflat could make much progress. After the valleys of the coast had been deepened by the erosion of the Great Ice Age, and the coast land had been dissected by the numerous deep fjords and channels, intersecting the coast and splitting it up into the many islands and peninsulas the conditions were essentially changed, as has been pointed out on a preceding page. It therefore seems probable that the Norwegian strandflat has chiefly been developed to its present shape after that time. It is possible that in interglacial times there may have been periods with climates sufficiently severe for shore erosion by frost so essential for the formation of the strandflat; but the climatie conditions preceding, accompanying, and succeeding each glacial period were especially favour- able for this erosion. At the same time the subaërial denudation of the outer coast land was-also very effective. For the development of the strandflat it was, however, also essential that the shore-line was stable during long time and standing at Or near the level of the strandflat. This was probably the case during a great part of the interglacial times and at the beginning of the glacial periods, while during the glacial periods the land was gradually depressed by the weight of the growing ice-caps, as was pointed out above. The strandflat cannot therefore have been developed during the late part of the glacial periods or during the time of submergence after these periods, even though the ice had retreated from the outer coast. The development of the strandflat could not begin until the land had again been elevated nearly to its normal level. But at that time the climatic conditions would not, as a rule, be favourable for the shore erosion by frost. We are thus lead to the conclusion that the strandflat has been de- veloped chiefly during interglacial periods with cold climates, and especially during the very cold time preceding each glacial period, and during its first part, before the outer coast was covered by the inland ice, and as long as the level of the shore-line still remained nearly stable. This may have lasted some time, because the level of the ocean was lowered by the accumulation of water in the ice-caps on land. The gradual sinking of the land caused by the growing load of the ice-cap, may thus for a long time have been more or less counterbalanced by the sinking of the shore-line. It should also be considered that the depression of the land began in its interior parts where the ice masses first accumulated, and did 48 FRIDTJOF NANSEN. M.-N. KL not extend to the outer coast before after some time. During the last glacial period some part of the outer coast was probably never depressed, as will be mentioned later. We do not know how many quaternary ice ages there have been in Norway. But if there have been only two, as is generally assumed, we are lead to the conclusion that the present plane of the strandflat has been developed chiefly during the cold time preceding the last glacial period, while its formation may already have begun during the time preceding the first, great Ice Age. There are, however, indications which, according to my view, make it probable that there have been several glacial periods in Norway, and that the strandflat has been developed during several dif- ferent periods, as will be mentioned later. We must then assume that during each interglacial time the ice-caps of Norway have almost entirely disappeared, so that the coast has been able to rise to its normal level at which the strandflat has been developed. Oxaal [1914, pp. 42 f.] has maintained that there were three glacial periods in Norway, and that the upper level of the Norwegian strandflat, in about 40 to 50 metres above sea-level, has been planed by marine abrasion during the first interglacial period, while the planes of the lower levels of the strandflat, in about 10 metres or even less above the sea, have been developed during the second interglacial time. My investigations have lead to similar conclusions, which will be mentioned later, after the observations and measurements of the strandflat in various regions have been described. Some writers have maintained that the strandflat must have been formed before the fjords, because there are no traces of a strandflat along the coasts of the latter. The answer is: Firstly, that there are actually strandflats in the fjords, not only in their outer parts where there are often beautifully developed planes, e. g. in the mouth of the Hardanger Fjord; but there are small strandflats also in their inner parts, as will be described later. Secondly, the shore erosion will need a relatively very long time for the development of a strandflat in most fjords, especially in their inner parts, because the fjord sides are as a rule very steep and high, and consist of resistant rocks. Thirdly, the fjords have been much excavated and deepened by the glaciers during each glacial period, and the strandflat along their sides would then be more or less obliterated by this erosion, especially in the inner parts of the fjords. Fourthly, if the strandflat was to some extent developed during the first part of each glacial period, before the land was too much submerged — the inner parts of the fjords were then soon filled with glaciers, while the planing of the strandflat may still have continued along the outer coast. The fact that nevertheless small strandflats do occur along the inner coasts of the fjords, is a convincing evidence that the fjords had been formed before the strandflat was developed. 1921. No. 1T. THE STRANDFLAT AND ISOSTASY. 49 The Height of the Norwegian Strandflat. Several writers, like J. H. L. Vogt, Thorolf Vogt, and A. G. Hogbom, make the height of the inner margin of the Norwegian strandflat, at the foot of the steep mountains, especially in Helgeland and Lofoten, to be near 40 metres above sea-level, Oxaal says between 4o and 50 metres, perhaps nearest the former height, while H. Reusch and Andr. M. Hansen put it at 100 or even 120 metres. The reason why the latter writers have got such great heights is obviously that they have taken the benches of raised beaches as belonging to the strandflat. As was pointed out on p. 42, there is, however, this striking difference between the strandflat and the raised beaches, that the planes of the former are very nearly horizontal and have obviously been developed during times with a more or less stable sea-level, while the raised beaches are tilted and have been formed during periods of submergence of the land, when the shore-line was staving at temporary levels for relatively short periods. It ought therefore to be sharply distinguished between the two kinds of formation, although they are formed more or less by the same process of erosion; and may often lie nearly at the same levels. But even if we stick to the planes of the real strandflat it may be difficult to determine the exact height of their upper limit because, on the one hand, this limit between the strandflat and the steep mountain side is not often very sharply marked, as the upper planes of the strandflat are old formations, which have been much modified and dissected by later glacial erosion, and on the other hand, the level of the shore-line has not remained quite stable during the development of the strandflat, and its planes are obviously formed at somewhat different levels. Amongst other things it may then to some extent depend on the resistance of the rocks which plane has become most conspicuous. Nevertheless there is a fair agreement between the estimations of most writers of the height of the upper limit of the strandflat, but at the same time distinct lower planes of the emerged strandílat have also been described. We shall return to this subject after our investigations of the strandflat have been described. We will then also have to consider another question: Why it is that these nearly horizontal levels of the strandflat are now raised above present sea-level? The partial Absence of a Strandflat along some Parts of the Norwegian Coast. A difficult question of much interest is: Why there are so great dif- ferences in the development of the strandflat along the various parts of the Norwegian coast? While the high and steep west coast of Norway has a well developed and broad strandflat, in some places nearly 40 kilometres broad, there are, Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. 11. 4 * 50 FRIDTJOF NANSEN. M.-N. Kl. for instance, only slight indications of such a formation along its southern and south-eastern coast, although the land is there very much lower, sloping gently towards the coast, and there would consequently have been much less rock to denude in order to form a strandflat. As far as I can see, one main reason may have been that during the cold interglacial periods, when the strandflat was to a great extent de- veloped, the climatic conditions were much less favourable for the shore erosion by frost along the south and south-east coast of Norway than they were further north, and therefore the strandflat could not be developed to any considerable extent in those southern regions. It is the same reason why in postglacial time, shore-ledges, cut in solid rock by shore erosion by frost, have been so well developed in northern Norway while they have not been formed along its southern coasts. In the inner part of Christiania Fjord, where there was more of an inland climate with colder winters, a strandflat has been developed, as will be described later. During the glacial periods the climatic conditions may have been favourable for the shore erosion also in southern Norway, but then the south and south-east coast was relatively soon submerged, while the outer west coast was only slightly submerged, if at all. As Andr. M. Hansen [1895] has already pointed out, the south and south-east coast was also soon covered by ice, and during most part of the glacial’periods there was no border of bare land similar to that existing outside the fjords of the west coast. There is still the possibility that the big glacier that filled the sub- merged Norwegian Channel round along the coast, and excavated it to depths of 500 and even 700 metres below present sea-level, may also have eroded the outer part of the coast, and may more or less have cut away parts of any strandflat that had been developed, provided that there have been several ice ages, when the Norwegian Channel was filled by a big glacier. It is, however, much more difficult to account for the absence of a strandflat, near present sea-level, along the coast of Finmarken. In this region the strandflat suddenly ends, just with the extension of the igneous and possibly Archæan rocks outside Ringvadsoi, Rebbenesoi, Grotoi, and northern Kvaloi. These islands consist of igneous and so-called Archæan rocks, extending north-eastwards along the coast from Vesterälen and Senjen. Outside these islands as far as north of Kvaloi, there is a submerged strandflat with a great many skerries, sunken rocks, and shoals. But north-east of Kvaloi this strandflat suddenly ends. Vannoi, east of Kvaloi consists partly of sedimentary rocks (schists) and partly of ‘Archean’ rocks. Fugloi, east of Vannoi consists entirely of schists. North of these two islands there are some scattered submarine platforms with sunken rocks and shoals (in 70? 36' N. Lat.), which may be considered as sito 5 1 n — ban ant: 2. IIQI. No. 11. THE STRANDFLAT ANID SOSTASY. SE belonging to the strandflat, and which are probably built up of harder ‘Archean’ rocks [cf. Nansen, 1904, pp. 42, 117 ff.]. East of this region, which coincides with the western boundary of Finmarken, the typical strandflat, near present sea-level, entirely dis- appears. The outer coast is here chiefly built up of sedimentary rocks and crystalline schists, less resistant to shore erosion than the igneous and so-called Archæan rocks to the west and south-west. The coast suddenly changes character at this boundary line between the geological formations. There is no typical ‘skjzrgard’ along the Finmarken coast; only in some few places, round Ingoi and outside the north-west corner of Mageroi, where more resistant ‘Archean’ rocks occur, are there indications of a 'skjergárd' and a strandflat at sea-level. The only explanation I can find of the absence of a strandflat, near present sea-level, along the coast of Finmarken, and of the remarkably close relation of this absence to the change in the geological structure of the coast, is that the sedimentary rocks and schists of Finmarken have offered relatively little ristance to the vigorous shore erosion of this northern region and to glacial erosion. During periods with a low shore- line, the rocks of the outer coast have therefore been denuded to deeper levels. They have also been cut away by glacial erosion. The outer coast of Finmarken is to a great extent very steep and precipitous, forming high shore cliffs, with much oversteepened, some- times almost vertical mountain walls, often some hundred metres high. This is especially the case in East-Finmarken where the coast consists chiefly of series of dolomite-bearing sandstones and shales of great thick- ness [cf. O. Holtedahl, 1918]. This coast has obviously got its typical con- figuration by a vigorous and very effective shore erosion. If in this region the formation corresponding to the strandflat along the Norwegian coast to the south-west occurs, it may therefore be looked for at lower levels, below the sea-surface, where submerged platforms actually occur at depths of between 40 and 9o metres [cf. Nansen, 1904, pp. 117 ff.]. It may, however, be difficult to distinguish between these platforms and the inner part of the continental shelf. It is obviously a general feature that coasts built up of relatively weak rocks, offering little resistance to shore erosion, never have a typical ‘skjeergard’, while this formation always occurs along coasts consisting of harder Archæan or igneous rocks, and formerly exposed to glacial erosion. As examples of coasts without a ‘skjaergärd’ besides Finmarken, I may mention the coasts of Bear Island, Spitsbergen, and Iceland. These coasts are mostly built up of rocks which offer relatively less resistance to shore erosion, such as sandstones, shales, dolomite, limestones, basalts, etc. But wherever harder igneous rocks occur, there are generally indications of a ‘skjergard’, e. g. outside the north-west corner of Mageroi, at the north- 52 FRIDTJOF NANSEN. M.-N. Kl. west corner of Spitsbergen, in the region of North Cape on North-east Land and the Seven Islands, at the south-west corner of Barents Island, &c. It might be objected that Franz Joseph Land, the Faroes as well as Shetland are not built up of very resistant rocks, but are none the less dissected into a great number of islands. The fact is, however, that thev are not surrounded by a typical “skjærgärd”, with numerous low islands, skerries, sunken rocks, and shaals, like those along the coast of Norway and Greenland. The above mentioned coasts, consisting of relatively weak rocks, e. g. on Bear Island, Iceland, and the Faroes, have as a rule high pre- cipitous shore cliffs, showing that the coasts have been exposed to a vigorous shore erosion. By our above discussion we are led to the conclusion that the absence of a strandflat near present sea-level along the outer coast of Finmarken in northern Norway is chiefly due to a too vigorous erosion on a shore of relatively weak rocks, while the insignificant development of the strandflat along the south and south-east coast of Norway, has partly an opposite reason, a too ineffective shore erosion in regions where the climatic conditions as a rule were too mild. Summary. Summarizing the results of the above discussion we may describe the cycle of the formation of the Norwegian strandflat as follows: During preglacial, probably postmiocene (or possibly still longer) time the coasts of Norway, as well as its land-surface on the whole, were much denuded by subaërial weathering and fluvial erosion. The land- surface and the coasts were to some extent dissected by fluvial valleys which may even have descended below present sea-level, on to the now sub- merged continental shelf the plain of which they have probably traversed [cf. Nansen, 1904, pp. 54 ff., 58, 151 f., Ahlmann, 1919, pp. 209 f.]. When these submerged valleys were formed is difficult to decide. During a great part of this very long preglacial time the marine de- nudation was not by far so effective as during the quaternary glacial and interglacial periods, because probably milder climates did not favour the shore eros‘on by frost, at least not along the greater part of the Norwegian coast, and the marine denudation was therefore chiefly limited to wave erosion. When the time of the first quaternary ice age approached, the climate became colder, and more favourable conditions for shore erosion by frost as well as for a more active subaërial denudation (greatly increased by frost) extended southwards along the coast of Norway. A more active development of a narrow low foreland along this coast may have begun. 1921. NOTE. THE STRANDFLAT AND ISOSTASY. 53 An essential condition for the formation of the present strandflat of Norway did, however, not exist before the coast had been eroded and dis- sected by the glaciers of the Great Ice Age. The preglacial fluvial valleys were then much deepened, the coast was dissected by numerous deep fjords and channels, and was split up into thousands of peninsulas and islands, the length of the shore-line, 7. e. the line of attack of the shore erosion, was enormously increased. The waste on the land was swept away, and bare rock-surfaces were exposed to the attack of the erosion, especially the disintegration by frost. During interglacial times there may have been cold periods favouring erosion by frost, at least along some parts of the Norwegian coast. But especially the climatic conditions preceding and accompanying each glacial period, greatly increased the subaërial denudation as well as the shore erosion, in all regions not covered by the inland ice, i. e. especially the outer coastal border along western and north-western Norway. During these periods, as long as the level of the shore-line remained fairly stable, before the land was too much submerged by the weight of the inland ice, the strandflat was chiefly developed, along the much dissected coast, by the joint action of subaérial denudation, particularly by frost, and local glacial erosion on the peninsulas and islands outside the inland ice, and finally by the shore erosion by frost and wave action. The two first mentioned processes were of main importance for the denudation of the land towards sea-level; because they attacked the whole land-surface, while the shore erosion gave the thus denuded uneven islands and peninsulas their nearly horizontal plane. By the repeated advances of the margin of the inland ice and its glaciers all waste was swept away seawards from the land, and bare rock-surfaces were exposed to fresh attacks of the erosion when the glaciers retreated. But as the shore-line was not quite stable, at least not during some part of the time, when the final planes of the strandflat were developed — because, for instance, the sea-level was gradually lowered by the accu- mulation of water in the ice-caps on land — the strandflat was not finallv planed at a perfectly fixed level of the shore-line. Besides this, it is also probable that when the land had again attained its level of isostatic equi- librium, after each glacial period, the shore-line may have stood at a level somewhat lower than that of the preceding interglacial time, owing to the removal of a great deal of rock material and waste by the eros’on during each glacia! period, as will be mentioned later. It is not, therefore, to be expected that the strandflat as we now see it, should forın one definite and sharply marked plane. The level of its surface may vary somewhat according to circumstances. Then it has also to be considered that during each glacial period the strandflat has been largely exposed to a vigorous glacial erosion which may have modified its surface more or less, and made it more uneven. 54 FRIDTJOF NANSEN. M.-N. Kl. The degrce of maturity to which the strandflat may have been de- veloped in the various regions, will naturally depend upon the time during which these various processes of denudation, especially the shore erosion, have had to work, and also upon the initial height of the land and the power of resistance of the rocks. Some islands may have been entirely levelled, others more or less, leaving higher hills and mountains in their interior parts, etc. We may therefore expect to find all different stages, from almost perfectly flat and level planes of low islands and peninsulas, to regions with more varying and undulating heights, and only some islands and peninsulas here and there have been nearly planed, or have planed borders round their shores. As the strandflat has been eroded by glaciers, at least during one, and probably during two glacial periods, we cannot expect to find very sharp lines of demarkation between the planes of the strandflat and the shore cliffs of the surmounting ridges and stacks, as these have been rounded off by the glaciers. On Værøi and Røst in Lofoten, and probably also on Træna, the strandflat was not eroded by glaciers during the last glacial period. Hence the emerged strandflat on some of these islands is very level, but hardly more so than we may also find in other regions. UT — il 1921. No. rr. THE STRANDFLAT AND ISOSTASY. [911 O1 VII. THE STRANDFLAT OF THE NORWEGIAN WEST COAST FROM THE REGION OF SOGNE FJORD FOFTHE REGION OF-HARDANGER. FJORD. The heights of the strandflat given in the following descriptions were determined by levelling. In the summer of 1911, in the Sogne Fjord, along the Norwegian coast, and on the Shetland Islands, a small levelling telescope and a levelling rod (4 metres long) were used. In the following summer, on Spitsbergen, the same rod was used, but the levelling instru- ment simply consisted of a U-shaped glass tube containing coloured water. Where there was an opportunity, the level was also determined by the horizon of the sea. This is not a very accurate method, but as the distances within which the measurements were made were never con- siderable, the final error of a levelling thus performed hardly ever ex- ceeded a metre. If the distances are greater the use of a telescope would greatly increase the accuracy of the measurement. The accuracy with which the heights of the strandflat may be deter- mined, does not, however, as a rule depend on the levelling method employed. The real difficulty is in most cases to decide where the actual level of the strandflat is. Seen at a distance this level may look at if it were quite sharply defined; but coming near one often finds the surface of the strandflat to be uneven, with depressions and elevated ridges, causing doubt as to what actually indicates the general level, and whether it should be put perhaps one metre higher or lower, and sometimes even more. As the strandflat has been denuded by glacial erosion after its final formation, it may be preferable in most cases to be guided more or less by the elevated ridges, if their summits are lying approximately at equal heights. But on the other hand, the surface of the strandflat may originally have been fairly rough, and the ridges may have been higher than the generallevel. It will, therefore, often be a question of personal judgement what the correct height should be estimated to be. Another difficulty is the determination of the present shore-line on which the levelling is based. Most observers have used the upper fucus limit in the shore as a base, which may have great advantages. But this Ki es 1921. No. rr. THE STRANDFLAT AND ISOSTASY. 57 Fig. 21. Map of Norwegian west coast between Sogne Fjord and Bommel Fjord. The Strandflat is marked black where the author has investigated it. A is the inner continuation of Sogne Fjord. Scale 1:1 000000. I mm. equal to 1 kilometre. ı Sogndal Fjord. 2 Norum Fjord. 3 Tjugum. 4 Ese Fjord. 5 Vangsnes. 6 Balestrand. 7 Kvamsei. 8 Tangen. 6 Hoiang Fjord. tro Fuglset Fjord. ır Ardal. 12 Holmen. 13 Akre. 14 Sorevik. 15 Matsnes. 16 Eike Fjord. 17 Oppedal. 18 Risne Fjord. 19 Brekke. 20 Vadheim Fjord. 21 Afsnes. 22 Mjelleli. 23 Torven. 24 Ra. 25 Ringer- eide. 26 Lavik. 27 Brendingsdal. 28 Bo. 29 Næsje. 30 Rutletangene. 31 Dingenes. 32 Inner Sulen island. 33 and 34 Two southern peninsulas of the latter. 35 Næs Island. 36 Northern peninsulas of Inner Sulen island. 37 Buskoi. 38 Faroi. 39 Sakrisoi. 40 Luten Island. 41 Skivenes. 42 Hisoi. 43 Store Vatsoi. 44 Sandoi. 45 Bjortnes Island. 46 Kversei. 47 Grimen Island. 48 Vardetangen, northwestern extremity of Lindås Peninsula, 49 Store Tangen. 50 Lindås Peninsula. 51 Fens Fjord. 52 Rautingen. 53 Kjelgaulen. 54 Bakoi. 55 Njotoi. 56 Fosen Island. 57 Lygre Island in Lygre Fjord. 58 Radoi. 59 Feie Island. 60 Henoi 61 Lyngoi. 62 Forhjelmen. 63 Sæløi or Hjelmen. 64 Alvoi. 65 Hjelte Fjord. 66 Fedjeosen or Fedje Fjord. 67 Bredviksoi. 68 Blomsoi. 69 Holsenoi. 70 Askoi. 71 Herloi. 72 Toftoi. 73 Gjernes on Holsenoi. 74 Salhus. 75 Bergen. 76 Nordasvand. 77 Lille Sotra. 78 Store Sotra. 79 Litärnet. 80 Häkensund. 81 Glesvær. 82 Toftoi. 83 Kors Fjord. 84 Hundevagoi. 85 Horge Island. 86 Mogster and Akre Islands. 87 Hufteroi. 88 Fugloi. $89 Selbjorn Island. go Reksteren Island. or Selbjorn Fjord. 92 Slotteroi Lighthouse. 93 Fondoi. 94 Stord Island. 95 Tysnes Island. 96 Langenuen Sound. 97 Lervirk. 98 Bommel Fjord. 99 Hardanger Fjord. 100 Hamaren. 1o1 Haukanes. 102 Silden Island. 103 Ænes. 104 Akrehavn and Akre- holm. 105 Ulvanes. 106 Steinane. 107 Ölve. 108 Snilstveitoi. roo Husnes. rro Huglo Island. rrr Halsnoi. 112 Fjelbergoi. 113 Borgundoi. 114 Tittelsnes. 113 Valestrand. 116 Moster Island. 117 Hjartholm. 118 Ekelandsnes. 119 Nesheim and Nordbo. 120 Southern peninsula of Bømlo Island. 121 Bømlo Island. 122 Ryvarden Lighthouse. 123 Lyngsoi. line is not always easy to determine, especially not in the fjords. The upper limit of high tide has also been used, but that is still more uncertain, as the marks of high water may be much influenced by the waves and by storms. I have, therefore, started from what I estimated to be the mean level of the shore-line, as marked by the colour of the rock-surface and bv the organic life in the shore, balanes, snails, &c., and also the sea-weed. I admit, however, that this way of estimating may be more or less arbi- trary, and I consider the upper fucus limit to be preferable as a base wherever it is fairly distinct. The Strandflat of Sogne Fjord. Along both sides of Sogndal Fjord and Norum Fjord, in the inner region of Sogne Fjord (see Figs. 21 and 22), there are very conspicuous low, flat points (promontories) and benches, being obviously parts of a strandflat, cut in solid rock at the base of the steep mountain sides. They have an equal altitude of about 10 metres above sea-level. The rocks in this region are partly crystalline schists overlying phyllite, partly gabbro. 58 FRIDTJOF NANSEN. M.-N. Kl. Standflat al Hetmans- vetk, Leikanger. Fig. 22. Sogndal Fjord and Norum Fjord, in the inner part of Sogne Fjord. At Kjørnes, the flat, rocky point (crystalline schist) between Sogndai Fjord and Eids Fjord, there is a very level plane cut in solid rock, and forming a distinctly marked incision in the mountain slope (see Fig. 23). The level of its flat surface is 9:84 metres above the sea. At Pallenes, in Norum Fjord (Fig. 24), a distinct horizontal ledge lies at about 10 metres above sea-level, and is the same formation as the plane observed at Kjornes. The rock is here gabbro. At Vines (gabbro), farther out in Norum Fjord, a distinct plane is cut in solid rock forming an incision in the mountain slope at about the same level as at Pallenes and at Kjornes. The small islets, the Vines Holms, outside the shore, form a continuation of this plane (see Fig. 25). The small peninsula, on the other side of the fjord, just opposite the Vines Holms, forms a very distinct strandflat at an average level of some- Fig. 23. Kjornes Point, between Sogndal Fjord and Eids Fjord. Strandflat 9.8 metres above sea-level. (July 29, rorr). On! Ne) 1921. No. TE. THE STRANDELAT AND ISOSTASY. MUN RON NAN Fig. 24. Pallenes in Norum Fjord. Strandflat about ro metres above sea-level. After photograph. (July 29, rorr). Fig. 25. Vines and the Vines Holms in Norum Fjord. In the background to the right the low peninsula at Nordnes. After photograph. (July 30, rorr). what less than 10 metres above the sea, but the highest ridge of this pen- insula approaches 10 metres. The low peninsula (crystalline schist) at Nordnes (see Fig. 25) further out in the Norum Fjord, shows no distinct horizontal level, but the outer- most portion which has obviously formed a round islet, has on its outer side indications of the same level nearlv at ro metres above the sea. At Övre Slinde (crystalline schists), near the mouth of Norum Fjord, the level of the strandflat is 12.4 metres above the sea. Along its inner margin it forms a distinct incision in the mountain slope, indicating that its plane has been developed by shore erosion (Fig. 26). At Hermansverk, in Leikanger, there is a very distinct strandflat at a level somewhat lower than ro metres above the sea (see Fig. 22, lower right corner). The rocky point at Hamre (phyllite), west of Hermansverk, shows the same distinct strandflat at nearly ro metres above sea-level. This strandflat at about the same level is observed on most points and headlands in this region more or less irrespective of their geological structure. Both sides of the outer part of Sogne Fjord, outside Leik- anger, consist entirely of Archæan rocks. Fig. 26.. Strandflat at Övre Slinde in Sogne Fjord, near mouth of Norum Fjord. After photograph. (July 30, rorr). Fig. 27. Vegarnes in Tjugum, seen from Ekedal. After photograph. (Aug. ro, 1911). 60 FRIDTJOF NANSEN. M.-N. Kl. Fig. 23. Ekedal with the tower of the church in Tjugum and the Ese Fjord behind, seen from Vegarnes. (Aug. Io, 1911). In Tjugum, Balestrand, on the north side of Sogne Fjord, the strand- flat is represented by the peninsula Vegarnes (Fig. 27) and by the flat narrow foreland (Fig. 28) on which the church of Tjugum is situated, under the steep mountain slope. In the outer part of Vegarnes there is a wide plain or level rock-surface about ıı or 12 metres above sea-level. The ridge of the peninsula reaches 25.05 metres above the sea. The platform at Tjugum church (Fig. 28) has a level surface at about 12 metres above sea-level, but the rock rises gently higher and has its highest level near the foot of the mountain slope, at 20 metres above the sea. A projecting rock-knoll rises 3.8 metres higher, giving a total height of 23.8 metres. The islet at Kvamso, between Malsnes and Kvamme, shows a distinct strandflat at between 12 and 20 metres above sea-level. The same plane is continued along the coast inwards along Balestrand, and the houses and farms are lying on this plain. Vangsnes (Framnes), on the other side of Søgne Fjord, rises to a flat rocky plain at 25.82 metres above sea-level. But the top of the pen- insula is 32.15 metres higher, at a level of 57.97 metres above the sea. At Tangen, on the south side of Sogne Fjord, opposite Hoiang Fjord, there is a well-marked strandflat (Fig. 29) on which the houses are situ- ated. The level of this plane at the houses of Tangen, was measured to be 17.2 metres above the sea. Farther to the west the plane is a couple of metres lower, whilst to the eastward there is a well developed plane I or 2 metres higher. Along the coast westwards from Tangen, platforms of a strandflat occur at many places, forming often sharply marked incisions in the steep 1921. No. XT. THE STRANDFLAT AND ISOSTASY. 61 Fig. 29. Tangen on south side of Sogne Fjord. A. Seen from the sea. B. The platform of the strandflat at Tangen, 17.2 metres above sea-level. (Aug. rr, rorr). Fig. 30. The ness at Årdal, west side of entrance to Fuglset Fjord. (Aug. rr, rorr). 62 FRIDTJOF NANSEN. M.-N. Kl. Fig. 31. Strandflat at Holmen west of Fuglset Fjord. A. Eastern side. B. Western side. (Aug. rr, 1911). mountain slope, and the strandflat is perhaps still better developed on the opposite side of Sogne Fjord, westwards from Hoiang Fjord. The farms are lying on this plane on both sides of the fjord. Illustrations are here given of the ness or rocky point at Årdal, on the west side of the entrance to Fuglset Fjord (Fig. 30), of the point with sharply marked strandflat at Holmen, west of Fuglset Fjord (Fig. 31), and of the strandflat at Åkre (Fig. 32). The height of the level of the strandflat is at all these places very nearly the same as at Tangen. Further west there were similar platforms on each ness and point, and also at some places along the shore between the points, e. g. at Sorevik. At Matsnes, east of Eike Fjord on the south side of Sogne Fjord, there is a well developed strandflat, forming a sharp incision in the Fig. 32. Strandflat at Akre. (After photograph. Aug. 11, rorr). 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 63 Fig. 33. Strandflat at Matsnes, east of Eike Fjord on southern side of Sogne Fjord. A. The point seen from the west. B. Surface of strandflat, looking southeastward. (Aug. rr, IQII). nountain slope (Fig. 33). There are three low points with ridges parallel to one another. The two ridges have exactly the same level, measured to be 17.1 metres above the sea. At this height there is a distinct plane cut in the solid rock-surface. This plane lies a little lower on the western- most point. But here a ridge rises to about 25.5 metres above sea-level. A similar ridge rises to the same level on the middle point. The strandflat at Matsnes is relatively broad and extends a con- siderable distance westwards along the coast of the fjord. Its surface is scoured by glacial erosion (see Fig. 33 B). The projecting edges of the rocks are rounded on the thrust-side or eastern side, and are more angular on the lee side or western side (Fig. 33 D). But the surface has on the whole the appearance of having been originally formed by shore erosion by frost, and not by glacial erosion. Further west at Brekke, west side of Risne Fjord, there is a very conspicuous strandflat forming a distinct incision in the mountain side (Fig. 34). 64 FRIDTJOF NANSEN. M.-N. KI. "c yy di 5 Fig. 34. Risne Fjord with well / // if / Y \ À Hf, !F fl hil \ marked strandflat at Brekke on Lif A ” ^ A > WA) LAN Ho ag HELM d , west side (right hand side) of IM 1] MAL ME [ M : > : NN T INN, 1) ae: Z KS entrance to the fjord. (Sketch \ 71/4 / 1 - INN 11 M MI LAM 7 CL Pr / EN IN SW LL LEE AL Da July 27, 1911). Fig. 34. Fig. 35. Strandflat along the north side of Sogne Fjord from Vikholm and Mjelleli (to the right) and westwards past Torven towards Ra. (Sketch Aug. 10, 1911). (NN \ IN my EN IN Fig. 36. Strandflat at Brendings- dal and Bekken, where Sogne Fjord bends northeastwards to- = SN wards Lavik. (After photograph. <= EE D July 27, 1910): Fig. 37. Næsje Peninsula and Næs Holm, in Bø, on the north side of Sogne Fjord. (After photo- graph. July 27, 1911). Fig. 38. Rutletangene seen from the east. (After photograh. July 27, LOL 1): Fig.138: At Oppedal, between Eike Fjord and Risne Fjord, fluvial terraces have been deposited on the strandflat. On the north side of Sogne Fjord we find equally well developed coast platforms all along the shore, e. g. at Afsnes on the west side of Vadheim Fjord, at Torven (Fig. 35) where there are conspicuous platforms in many places along the shore from Vikholmen and Mijelleli westwards to Vareleite, Rà and farther west at Lavik and Brendingsdal (Fig. 36). The average height of these platforms seems to be the same (about 17 metres above sea-level) as at Matsnes and Âkre on the opposite side of Sogne Fjord. At Torven there is a conspicuous plateau, the height of which I esti- mated to be something like 200 metres above sea-level (see Fig. 35). At 1921. No. rr. THE STRANDFLAT AND ISOSTASY. 65 Ringereide further west, near Lavik, there is a hanging valley at about the same height, and a mountain ridge slightly higher. This plateau and hanging valley may possibly indicate the approxi- mate height of an initial Palæic valley of this region, which had been developed to great maturity before the excavation of the present Sogne Fjord began. Near the mouth of Sogne Fjord the platforms of the strandflat on both sides of the fjord become conspicuously wider and more developed than further in the fjord. The whole peninsula at N«sje in Bo, with the Nes Holm outside on the north side of Sogne Fjord, is low and flat, and belongs to the strand- flat (Fig. 37). At Rutletangene opposite this place, on the south side of the fjord, there is an exceptionally well developed and level strandflat, on the pen- insula as well as on the islets outside (see Figs. 38 and 39), and this plane is very distinctly marked as a formation different from the mountain slope inside. Fig. 39 illustrates well the evenness of the plane. The surface of this strandflat is seen in the panorama Fig. 39 taken trom a hill (28 metres above the sea) surmounting the plane. The surface is somewhat undulating with small hills or knolls. The tops of most of them are at the same level, measured to be 16 metres above the sea. Two hills farthest out reach an altitude of 20 metres. Another level at which the tops of some ridges are lying, is a little lower than the hill from which the panorama was taken; they are about 25 or 26 metres above sea-level. Only one ridge on the westernmost point reached an altitude of 32.5 metres. By far the greater part of this wide plane is, however, lying between 15 and 16 metres above sea-level. The whole surface of the strandflat at Rutletangene is well rounded by the erosion of the ice. At Dingenes south of the entrance to Sogne Fjord there is a well developed and unusually level strandflat (Fig. 41). Its average altitude was measured (on Aug. 12th, 1911) to be 11.28 metres above sea-level. A round knoll rises 3.38 metres above this plain to an altitude of 14.66 metres. The surface of the strandflat is scoured and rounded by glacial erosion as seen in Fig. 42. On the northern side of the entrance to Sogne Fjord indications of a strandflat, forming incisions in the steep mountain sides of sandstone, were observed in the sound between Inner Sulen island and Losneoi (Fig. 42 A), and well marked planes of the strandflat were observed on the two southern peninsulas of Inner Sulen and on the greater part of Næs Island (Fig. 21, no. 35) between them. A hill is rising above the levei of the strandflat in the northern part of the latter island. The rock is sandstone on these islands, with a border of phyllite along the south- eastern side of Inner Sulen and the southern side of Losntoi. Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. 171. 5 66 FRIDTJOF NANSEN. M.-N. Kl. Fig. 3c. Rutletangene. A. Seen from the west (Sketch Aug. 12/6 Fig. 40. The islands on the southern side of the Sogne Sea or entrance to Sogne Fjord. View t The Genetic Origin of the Strandflat in Sogne Fjord. Along the Norwegian west coast, north and south of the mouth of Sogne Fjord, numerous formations of the strandflat were observed, per- tectly similar to those which have been described above along the shores W of the fjord. All these formations must obviously have had the same i genetic origin, and before proceeding further in our description, let us examine what this origin might have been. Dr. Hans Reusch has described similar low rocky benches in front of the mountain slopes along the shores of Hardanger Fjord, especially in its inner part [1901, p. 189]; but strange to say he has not observed similar features in Sogne Fjord. He states that the height of these benches is often about 20 to 30 metres. I have not investigated these formations in the inner part of Hardanger Fjord, but in the outer part of the fjord I found their height to be about 19 metres above sea-level and even more (see later). They seem accordingly to be perhaps slightlv | higher there than in Sogne Fjord, although I have also observed a lower level there only some few metres above the sea. Reusch thinks that these rocky benches are remnants of the floor of the initial "Hardanger valley system” in which the deeper channel of the | I92I. No. 11. THE STRANDFLAT AND ISOSTASY. 67 hotographic view of Rutletangene and islands outside. (Aug. rr. IgII). ET TE Fake 3 are SEE Sie Pape ES kr UL ee mA. uS EE. nil - — P ae xe TS uc € ue Athe sea west of the coast between Rautingen and Kversoi, see Figs. 21, 52, & 46. (July 27, rorr). fjord has been excavated later. These benches should consequently be of preglacial origin. Reusch also points out that the strandflat along the coast outside the fjord may perhaps have been formed at the same time as this valley system. Reusch’s explanation of the origin of these benches seems to me im- probable for several reasons. Firstly it is hardly credible that these benches and flat rocky points on the sides of the fjord could possibly have survived the violent glacial erosion by which the fjord was excavated to its present depths, 600 or 800 metres deeper. Secondly if the strandflat along the coast outside the fjord was formed simultanuously with the initial Hardanger valley system, the floor in the inner part of that valley — in the inner part of the present fjord region, in Sorfjord — must certainly have been considerably higher than the sea-level indicated by the strandflat along the coast outside. But the level of the benches and rocky points along the sides of the inner Hard- anger Fjord is no higher than the strandflat of the outer coast, and the floor of the initial valley must obviously have been lower along its middle than now indicated by these benches along its sides. In Sogne Fjord ve found that the flat rocky points had even a somewhat lower height 68 „ FRIDTJOF NANSEN. M.-N. KL PSS Fig. 41. Dingenes. (After photo- graph Aug. 12, 1911). than the strandflat along the outer coast. If these points and bench:s were remnants of an initial valley floor, formed at the same time as the strandflat of the outer coast, we would therefore have to assume that the land in the inner part of the fjord is now standing comparatively a good deal lower than the land along the outer coast. Thirdly the flat platforms of these rocky points and benches often form very distinct incisions in-the steep mountain slopes on the sides of Fig. 42. View landwards from top of Dingenes. Surface of strandflat, rounded by glacial erosion. (Aug. 12, 1911). the fjords, indicating that these platforms and benches have been formed after the mountain slopes and not simultaneously with them. The com. paratively level surface of the platforms also prove that, after their final formation, they cannot have been exposed to any very effective glacial excavation like that which gave the fjords and their sides their present main features. There is no possibility that these low and flat points along the sides of Sogne Fjord can have been formed by glacial erosion, transforming BU "X a | Fig. 42 A. Southern entrance to the sound between Inner Sulen (to the left) and Losneoi. (Sketch Aue, Te rom): 1921. Norr THE STRANDFLAT AND ISOSTASY. 69 the projecting spurs on the sides of a valley in a manner similar to that suggested by Ahlmann [1919, p.73, Fig. 35]. The very nearly uniform height of the points must have been determined by the sea-level at the time of their formation, while the erosion of the glaciers that filled the Sogne Fjord could not be determined by the level of the sea to any similar extent. Without considering whether spurs may be eroded by glaciers in the manner suggested by Ahlmann, the distinct incisions frequently formed in the mountain slopes by the flat platforms of the rocky points along the sides of Sogne Fjord also prove that they cannot have been originated ın such a manner. There seems to me to be no other feasible explanation of the genetic origin of these flat rocky points and benches along the sides of Sogne Fjord, as well as Hardanger Fjord, but that they have been formed by shore erosion, chieflv by frost, and that they are formations identical with the strandflat of the outer coast. The fact that this strandflat in the fjords chiefly occurs on the rocky points and headlands, and much less along the shores between the points, is what might be expected, considering that the shore erosion by frost has a much greater surface for attack along the sides of a headland, than along the straight coast. Summary. We may summarize our researches in Sogne Fjord as follows: numerous indications of a strandflat occur along both sides of Sogne Fjord and in its side branches, chiefly on most of the points and promontories. The altitude above the sea of the horizontal level of this strandflat varies somewhat in the different regions of the fjord, it being about 10 metres in the inner part in Sogndal Fjord, Norum Fjord, and Leikanger, about 12 metres in Tjugum and Balestrand, and about 16 or 17 metres in the outer part of Sogne Fjord from Tangen and Hoiang Fjord to its mouth at Rutletangene. A higher level of the strandflat, about 25 metres above the sea, was observed in Tjugum (on Vegarnes and at Tjugum church), in Balestrand, on Vangsnes, at Matsnes, and perhaps on Rutletangene. This is the ap- proximate height of the inner boundary line of the strandflat at Matsnes, where it forms a distinct incision in the mountain slope. The Strandflat north and south of the Mouth of Sogne Fjord. North of the mouth of Sogne Fjord a strandflat was observed on the northern peninsula of Inner Sulen, and especially well developed on the islands Buskoi, Feroi, and Drevoi to the west. The strandflat is very conspicuous on Sakrisoi and Luten Island to the northeast of Inner Sulen, and also on the mainland at Skivenes, east of Sakrisoi (see Fig. 21). The rock is chiefly phyllitic schists in the whole of this region. 70 FRIDTJOF NANSEN. M.-N. Kl. qu : mpi À uch Fig. 43. On all the islands to the south of the entrance to Sogne Fjord the strandflat is well developed and its horizontal plane is very conspicuous. A well developed strandflat extends along the western side of Hisoi (His Island, Fig. 21, no. 42) continuing southwards on Store Vatsoi (Fig. 21, no. 43) and other small islands, and along the western side of Sandoi (Fig. 21, no.44). The rocks are here Archæan. A photographie panorama of the strandflat extending over the is- lands in this region, was taken from a small hill surmounting the plain on Pigenes, on the southwestern corner of His Island. The altitude of the hill was measured to be 42.05 metres above sea-level (Fig. 43). The altitude of the ridges of a good many islets seawards is some- what less than 28.0 metres above sea-level, while a great deal of the other ridges approach a level of about 36 metres. Many of the highest tops of the islands rise to nearly 42 metres above the sea, the altitude from which the panorama was taken. The strandflat cut in Archæan rocks along the western side of Sandoi (Fig. 44) forms a very conspicuous flat platform on which the farms are situated. I estimated its height to be about the same as that measured at Pigenes, 1. e. between 28 and 36 metres above sea-level, perhaps chiefly about 30 metres. The steep slope of the mountain inside ascends abruptly from the nearly horizontal platform. A great number of erratic blocks, partly very big, are scattered about on the surface of the strandflat on this island and on the other islands in this region. All the islands west of Hisoi and Sandoi form a very conspicuous strandflat, which is a continuation of the plane extending along the Panoramic view of the islands seen between E,S, W to N from a hill, 42 metres above sea-level upper ones a 1921. No. LI. THE STRANDFLAT AND ISOSTASY. yh! nes, Hisoi. (212, 1911). | | | E,S, W,N are East, South, West, and North. Lower pictures are a direct continuation of the western sides of those two islands, and over Store Vatsoi and the other islets between them. Fig.40 gives an impression of the flatnes of the strandflat in this region west of Hisoi and Sandoi. All the islands are very flat and low, and here are few higher hills. They consist of Archean rocks. On Mjomen Island (the island between Sandoi and Bjortnes Isl., Fig. 21, no. 44 and 45) there is a mountain in its northern part, while the southern part is quite flat. On the east side of Bjortnes Island (Fig. 21, no. 45) a mountainous hill rises above the strandflat, which is otherwise extended over the whole island. The whole of Kversoi and Grimen Island (Fig. 21, no. 46 and 47) form parts of the level strandflat, and so do the two Vats Islands, Store Hille Island, &c. north and northeast of Grimen Island and Kversoi. The Region of Lindas Peninsula. The strandflat continues over the many islands to the south, and is especially well developed and level on the southern side of Fens Fjord, where the rocks are chiefly crystalline schists (Ulriken gneiss) and a band of gabbro or labradorite rocks along the northeastern side of the Lindas Peninsula. On the northern side of the Lindås Peninsula the plain is extremely flat as seen from the sea (Fig. 46) with all the farms lying on it, very nearly at the same level between 16 and 18 metres above the sea. A panorama was taken from an isolated hill on Vardetangen, the northwestern end of Lindås Peninsula, 27.25 metres above sea-level. The first part of the panorama (Fig. 45 A) begins in the north-east, looking towards the flat Havarden Island (of labradorite rocks) in Fens Fjord 72 FRIDTJOF NANSEN. M.-N. Kl. Fig. 44. Strandflat along the western side of Sandoi. A. In northern part of island, seen from Undelandssund south of Skjergehavn. B. Middle part of island. C. View northward from Fens Fjord through sound along west coast of Sandoi. (Aug. 12, 1911). and the southern end of Sandoi ın the background on the northern side of the fjord. It goes southwards with the sun to east, south-east, &c., over land consisting of Ulriken gneiss, with labradorite rocks in the far distance. The second part of the panorama (Fig. 45 D) extends over is- lands (of Ulriken gneiss) from south-southeast and ends in north-north- west looking towards Store Stangen in Fens Fjord. Ärsoi and Bortnes Island are seen in the far distance. This panoramic view shows that the strandflat has a remarkably uni- form height in this region, which was measured to be on the average about IZ or 18 metres. The farms. are lying at this altitude. The pictures prove that the hill, 27.25 metres high, from which the photographs were taken, is higher than the plane of the strandflat on "Lindås Peninsula as well as on the islands to the west. Further south, on the Lindäs Peninsula and on the islands along its western side (Bakoi, N jotoi, &c.), the strandflat has very nearly the same height of about 18 metres. The rocks are Ulriken gneiss. At Kjelgaulen (Fig. 21, no. 53), on the southern end of the island between Bakoi (Fig. 21, no. 54) and the northern part of Lindås Peninsula, the height of the plain was measured to be between 17 and 22 metres above sea-level. Many of the ridges were lying at a level of 28 metres, but at this height one was above the general level of the strandflat on the islands to the south. But many ridges on the islands towards the west or seawards, on Bakei, N jotoi, and Fosenoi (Fig. 21, no. 54—56), rise to altitudes about 42 m. The ridges on the islands towards the south are on the average lower. ' and I looked down upon them from the height of 42 metres (see Fig. 47). E 1921. No. rr. THE STRANDFLAT AND ISOSTASY. 13 A level and well developed strandflat extends along the eastern side of Lygre Fjord over the many islands, Risoi, Lauoi, Dragoi, Bragoi. Spjotoi, &c. and along the whole of the Lindås Peninsula (Fig. 48). The rock is Ulriken gneiss in this region. There is also a well developed strandflat on the land on the western side of Lygre Fjord, on the Lygre Islands (Fig. 21, no. 57), and on the peninsula to the south of them (Fig. 49). The level plane is sharply de- fined against the steeplv ascending hills on the southern portion of Radoi behind. The general height of the extremely level strandflat in the whole of this region, on both sides of Lygre Fjord and northwards towards Kjel- gaulen, seems to be between 20 and 25 metres above the sea, but possibly rises slightly westwards towards the sea. The Region of Radgi. The conspicuously level strandflat of the northern Lindås peninsula is continued westwards over the islands Bakoi and Fosenoi (Fig. 21, no. 53— 56), and southwestwards over Radoi (Fig. 21, no. 58) which is on the whole very flat, especially in its northwestern part. Fig. 50 is a view of the northwestern end of Radoi with the many small islets outside and Fosenoi to the north, taken from the sea southeast of Feie Island (Fig. 21, no. 59). The height of this outer, verv flat land I estimate to be about 17 metres above the sea, or very much the same as that of northwestern Lindås Peninsula. Small hills rise here and there above the plane of the strandflat, but this is much more frequent in the southeastern part of Radoi. Seawards outside Hjelte Fjord and Fedje Fjord (Fig. 21, no. 65, 66) there is a series of low islands: Feie, Sulen, Staksoi, Hennoi, Lyngoi, Forhjelmen, Sæloi, Alvoi, &c., forming the so-called Oigaren. Seen at a distance the surface of this series of islands exhibits an almost uniform horizontal level or strandflat at about the same height as that of the land inside. The lighthouse of Helliso, at the southwestern end of Feie, is situated on a rock-surface 17 metres above the sea, which is very nearly level with the general surface of that island, to judge from what I saw from the sea. Here and there more or less isolated hills rise above the plane of this strandflat, e. g. Hesten and Feiebjornen on Feie, Sælstakken (59 metres), and Äsdolen (49 metres) on Sæloi. On the islands Bredviksoi and Blomoi to the south there are also a few hills rising to 51 and 52 metres above the sea, and one hill on Blomoi even to 70 metres. It is noteworthy that these outer series of islands have such a very sharply defined strandflat in very nearly the same level as Radoi inside of Fedje Fjord and Hjelte Fjord although they are built up of Archæan 7 4 FRIDTJOF NANSEN. Fig. 45. Panoramic views taken from Vardetuva, on Vardetangen, the north-western end of Lindås Peninsula and north-northwest rocks, while Radøi chiefly consists of younger crystalline schists (Ulriken gneiss) and in some parts of labradorite rocks. Ahlmann has visited Sæloi or Hjelmen, and says [1919, p. 102] that there is a general level between 20 and 25 metres above the sea. “In certain places along the western side we can also distinguish a lower level of denudation at 10—14 m.” In the Manger district, in the middle portion of Radoi, Ahlmann distinguishes “two levels: one at 12—16 m. above sea-level, and the other at 33—40 m. above sea-level. The first-named is considerably smaller in extent than the latter, but seems to be somewhat more level. It extends quite near the shore as an open plain, but also stretches in as bays into the higher level. Perhaps we may include in this level also the narrow ledges which in certain places occur along the valleys and hollows at the height of about 12 m. above sea-level” [1919, p. 99]. I know the Radoi and the Manger district very well, but have not been ashore there for many years, and not with the purpose of studying the strandflat. Ahl- mann’s description agrees, however, exactly with my recollection of it, 1921. Norr THE STRANDFLAT AND ISOSTASY. —] On \. View eastwards between north-east, Havarden Island, and south-southeast. B. Between south-southwest Aug. 12, 1911). and I think that these are just the characteristic features one might ex- pect to find along a coast where the shores have been cut back by frost erosion, forming broad benches or narrower ledges backed by steep cliffs, or shore-walls, along the outer coast as well as in the bavs. The débris formed by this erosion has been carried away to some extent by the wave action, but much more by the glaciers which have afterwards moved across the land. The steep sides of these bays and small valley channels on Radøi, which Ahlmann considers to have been formed by glacial erosion, and of which he has given a very good picture [1919, p. ror, Fig. 47], have just the characteristic features of shore-cliffs formed by frost erosion, and have not, as far as I can see, the typical surface of rock-walls originally formed by glaciers, although they are to some small extent scoured by the glaciers of the last glacial period. Ahlmann says that his higher level of between 33 and 40 metres, comprises the greater part of the Manger district, and he thinks that in the southern part of the island, at Sæbo, this same level may possibly be 45—50 metres above the sea, and he draws the conclusion that this “upper M.-N. NANSEN. FRIDTJOF "(11761 '£r:3ny) ‘pus 21847 jo you "9AAOQ9A[EM vou vas ay} LOI uses ‘poly a13ÆT JO opis u197s9 Suope pur[ureur pue spurjsı uo jeypueys "gt ‘A ‘(1161 ‘Er “8ny) "Bas au} 240q8 Saou ct ‘ugnesyjaly JO ysam my v uro.j Tøuasog pur 10JO[N ONU *SpieMOJ SPIEMISOM pur pzofg 21347 Sp.I£«0] spiemynos MOIA "Lt ‘Sr YET 20709 ‘(1161 'cr-Sny) cpiofg suaq wo. uses ejnsuluag sepury ay} jo puo UIOUJION "of “By > ‚purpumu oqj uo (AS 're sty) [oly o4exs 07 (19 ‘18 7814) løguÆT wos *v[nsuruo([ sepur[ pue rope»[ SSo.10% ayoag ‘1S "Zig In 07 0% 0€ 01 [7 $5222,5 7214222 SY00Y 271407990.1997 & iv eu oly 277214 RE ‘(1161 ‘Le Afnf) ‘npujoypurs avou vos oy} WO. MoIA 'oprsjno SJaIST 9t] JM løuasoq pur løpey JO puo u.9jsoAMqjrou oup ‘oS "Sig THE STRANDFLAT AND ISOSTASY. ‘(11671 ‘Er any) 'spue[s] 948A u19)99A4 pue ulojse;[ uo9Aj9q"punos ou} ur 'uo[pexsdo»siq Auıoys ou] vou vos 94} LOI} spaemignos MOIA "6b "Sig pr DE eaten ee VW 78 FRIDTJOF NANSEN. M.-N. Kl. Fig. 52. Strandflat at Salhus north of Bergen. (Aug. 14, 1911). denudation altitude slopes gently towards NW, or from 45—50 m. at Sæbofjell to 25—30 m." in the north-western part of the island. He furthermore considers it indisputable that the denudation surface at 20—25 m. above sea-level on Hjelmen (or Seloi, Fig. 21, no. 63) in Oigaren outside Radoi “corresponds to the upper level on Manger. The slope which this level proves to have at Manger thus continues as far out as Öigaren”. Although this denudation surface may have a slight slope, especially on extensive islands, I do not believe that this slope can be as great as assumed by Ahlmann. The reason why he finds the heights greater in the region of Sæbø is obviously because the labradorite rocks of this region are more resistant to the erosion than the gneiss in the other parts of the island. The strandflat has not therefore been developed to such a degree | of maturity, and more hills and ridges rise to higher altitudes. On Holsengi, at Gjernes (Fig. 21, no. 73), just opposite the Sæbo region, he says himself that inside a hill quite near the shore “there ex- tends a well-marked denudation plain at 25—30 m. above sea-level”. Hence, according to his own measurements, the height of this surface is | no higher here than in the Manger region, on the contrary it seems to be 8 or ro metres lower, or very much the same as the average altitude he found in his most north-western profile across Radoi, in the Bø region where it was between 24 and 30 metres above sea-level. On the other hand it may be noticed that, occording to my ob- servations, the general level of Feie, Fosenoi, and the north-western end of Radoi is probably somewhat less than 20 metres, or about 17 metres, Shore Sola Fig. 53. Strandflat on the southwestern end of Fane Peninsula and the island: 1921: No. rr. THE STRANDFLAT AND ISOSTASY. 79 and is obviously very nearly the same as that which I found in the north- western part of the Lindäs Peninsula. But this surface may correspond to Ahlmann's lower level which he found both at Manger and on Seloi (Hjelmen), where it was, however, 10—14 metres above the sea, and which he thinks, "does not show any inclination in any definite direction”. Fig. 51 is a profile across Radoi and the Lindås Peninsula from Lyngoi and Forhjelmen (Fig. 21, no. 61 and 62) in Oigaren (in 60° 40’ N. Lat.) to Skärefjell on the mainland (in 60° 42’ N. Lat.) east of Ost- fjord. This profile demonstrates the remarkably level plane of the very broad strandflat, above which the mountain sides rise abruptly. It also shows how the plane of the strandflat extends uninterupted and without any marked change in height across regions of different geological struc- ture. Some of the hills surmounting the plane of the strandflat are built up of comparatively resistant rocks, e. g. Kalsas consisting of mangerite. Region of Bergen. In the region round Bergen the land is more mountainous than along the coast farther north, and the strandflat is much less developed, and has not such great extent as in the region of Radoi and Lindas. But it is quite conspicuous along the sides of the sounds and fjords in some places. At Salhus, in the Salhus Fjord, north of Bergen, the strandflat forms, for instance, a well marked incision in the mountain slope (Fig. 52). Bergen is to some extent situated on a narrow strandflat, which extends more or less southwards through the valley to Fjosanger and Nordasvand. On the Fane Peninsula, between Nordasvand and Fane Fjord, south | of Bergen, the strandflat has a wide extension west of the steeply ascending mountains. Seen from the sea to the west (Fig. 53), it appears very flat and conspicuous. A great many of the islands to the west of Fane are also low and form parts of the strandflat. In the region of Os at the southern extremity of the whole peninsula between the Bergen By Fjord and Samnanger Fjord, the strandflat is well developed and sharply defined in the region of Rotingen (Fig. 54). Side. The low island right in front and to the left is Leroi. (July 26, tort). NANSEN FRIDTJOI D ye ouo Joddn ou) jo uogenunguoo yop v st o4njord. 19A 0[ OUI, CEE jnoqv jv (1101 jouivjr] JO doj ayy Wo uoye] iy 'uasng JO JS9M ‘puvjureu E ë FA - reg IN 109044 VTP Wie ry oO y x À e 'ony) ‘(1161 ‘os '3ny) pur ‘ojo 'r.]oG opp] ‘U10S 91076 "vas Ol 9404 S uosunow Je ‘pioljoutofg jo opis uloQjiou 94) uo je[put.3G ‘ spu jJ: I youl I u} jo PUM.IOURT URS 10405994 194573 2 imn ne JU GRE ge gene year wre CS 1921. No. TT. THE STRANDFLAT AND ISOSTASY. GI ny. f& Labs ¥/ é 2 Je 4 mn Fig. 56. Northward view from the summit (71 metres above the sea) of the peninsula at Ekerhovde on SI / Store Sotra. (Aug. 21, 1911.) Fig. 57. Strandflat at Hakensund, southern end of Store Sotra. (Aug. Fig. 58. The strandflat seen northwards from the hill (42 metres above the sea) north of Glesvær. (Aus. 2T, TOLL.) | Region of Sotra. The strandflat has a wide extension on the big island Store Sotra | and also on Lille Sotra (Fig. 21, no. 78 and 77) to the west of Bergen. | 3ut it is comparatively uneven on these islands with many ridges and | hills rising above the general level of the strandflat, to heights more than Go metres. The strandflat comprises the greater part of Lille Sotra, and the whole western and northwestern part of Store Sotra with the ex- ception of the many above-mentioned ridges and hills rising above its | general level. In the eastern and south-eastern part of Store Sotra the land is more mountainous, rising to heights of 341 metres at Litarnet (see Fig. 21, no. 79). Fig. 55 gives a panoramic view of the land towards h Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. rr. 6 A 82 FRIDTJOF NANSEN. M.-N. Store Soha DishjuA hof 5 fF Tof tot I 7 = h "À ae e weap € Fig. 59. Panoramic view between east and west-south the west, north, and east, taken from the top of this mountain. We here look down upon the extensive strandflat, which is especially flat and conspicuous towards the southwest and west. A part of the above- mentioned strandflat in the region south of Nordasvand i also seen to- wards the east, to the right. At Ekerhovde, on the east coast of Store Sotra, just west of the southern end of Lille Sotra, and under Litarnet, the height of the general level of the strandflat was found by levelling to be about 30 or 32 metres above the sea. At a height of 52 metres one was decidedly above the general level of the strandflat. [s The summit of the small peninsula at Ekerhovde, west of the southern extremity of Lille Sotra, was 71 metres above sea-level. Many ridges and hills on Lille Sotra and the islands northwards, rise approximately to this altitude (cf. Fig. 56), and the highest hill on Lille Sotra even higher. But the average height of these ridges is somewhat lower, per- haps about 50 and 60 metres above the sea. At Häkensund, at the southern end of Store Sotra, the strandflat has an unusually level surface at about 30 metres above the sea, and distinguishes itself sharply from the ascending mountain slopes to the north (Fig. 57). In the region of Glesvær, at the southwestern extremity of Store Sotra, the strandflat is well developed (Figs. 58 and 59). Its altitude was found by levelling to be 29.9 metres above the sea. In some places on the peninsula to the north of Glesvær (Kausland) it may be a little higher, but it does not reach 40 metres. The altitude of the highest hill just north of Glesvær is 42.5 metres above sea-level, but! this hill rises decidedly above the general level of the strandflat, as is shown by the view north- ward, taken from this hill, see Fig. 58). This picture gives an idea of the levelness of the strandflat in this region. In the background to the right is seen the mountain Litärnet from which the panorama Fig. 55 was taken. The altitude of the general level of the strandflat may be assumed to be between 30 and 33 metres above the sea in this region. | 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 03 It is interesting to note that the strandflat in this region just north of Glesvær and across the land westwards is cut in dioritic rocks, while the land both north and south, on Store Sotra and the other islands, is built up of Archæan gneiss and partly of granite [Reusch, 1901, p. 106]. This makes apparantly no difference in the height of the level strandflat. Islands between Kors Fjord and Hardanger Fjord. South of Kors Fjord (Fig. 21, no. 83) I observed a distinct strand- flat extending over the southern parts of Hundevagoi (granites), and over Horge Island (granites) along the eastern side of Hufteroi (granites), and on the small islands to the west of the latter: Mogster Island (schists and other rocks), the Äker Islands (where it is very conspicuous), Fugloi (gabbro), and the many surrounding islets. On the southern side of Hufteroi the strandflat is sharply incised in the mountain slope consisting of gabbro. Along the southern side of Selbjorn Fjord a well developed strand- flat, about 30 metres above sea-level, extends from Slotterei Lighthouse over all the islands eastwards as far as the western side of Fondoi. These islands consist of granites, while the eastern part of Fondøi consists of gabbro. On both sides of Langenuen Sound a strandflat is well marked, on the northern end of Stord Island (gabbro) as well as along the south- western side of Reksteren Island (granites) and along the west side of Tysnes Island (gabbro), see Fig. 60. Along the western side of Stord Island the strandflat is distinctly defined, but at an altitude perhaps somewhat higher than the usual level of the strandflat. The rocks are here granites, and in the southern part chlorite schists or similar schists, and also some conglomerate. Along the eastern side of Stord Island there is a-fairly distinct, but relatively high strandflat on many points, especially in the southern part near Leirvik (Fig. 61). The rocks are phyllite and in the northern part 84 FRIDTJOF NANSEN. M.-N. KL m [ZZ ——— Fig. 60. Strandlat in front of the high mountains on Reksteren Island and Tysnes Island (to the right). (Aug. 27, 1911). gabbro. There are indications of a kind of shore ledge at altitudes of between 45 and 55 metres above sea-level. A well developed shore-line was observed at about 60 metres (measured with the aneroid barometer), which is more or less continuous with the highest level of a fairly ex- tensive plane. There is, however, also a very low level of less than 20 m. above the sea, which is distinctly marked on the point north of Leirvik harbour (Fig. 62) and on the islands outside. The rock is here phyllite. A strandflat with about the same height is also found further eastwards 9 in Hardanger Fjord. Hardanger Fjord and Bemmel Fjord. In Hardanger Fjord the strandflat is developed in the same way as in Sogne Fjord, though at a perhaps slightly higher level. It is con- spicuous at the points of the promontories and peninsulas along both sides Ds Fig. 61. East coast of Stord Island, north of Leirvik. (Aug. 28, ror r.) sn did id Eg21: No. r1. THE STRANDFLAT AND ISOSTASY. 85 1 Fig. 62. View along the east coast of Stord Island towards Leirvik. Two levels are seen: the general higher level at 50 to 60 metres above the sea, and a lower one at less than 20 metres. (Aug. 28, 1911). 1 Fig. 63. Hamaren in Hardanger Fjord. (Aug. 30, ıgrr). East side of Varaldssi, near Haukanes, with the Sild Island (to the right), Hardanger Fjord. (Aug. 30, 1911). 86 FRIDTJOF NANSEN. M.-N. KL Fig. 65. Southern end of Varaldsgi. (Aug. 30, Ig11). Fig. 67. Ænes in Hardanger Fjord, at the entrance to Mauranger Fjord. (Aug. 29, rorr). of the fjord, e. g. at Hamaren (Fig. 63), on Varaldsoi (Figs. 64, 65, 66), Ænes (Fig. 67), and Ulvanes (Fig. 68). But it also occurs along the shores between the promontories. It is everywhere cut in solid rock, and forms often very conspicuous and sharply marked incisions in the mountain slopes (cf. Figs. 63, 64, 65, and 66). | The altitude of this strandflat was measured by levelling at Akre- havn on Varaldsoi. The rock is here phyllite. The ridge of the point (Fig. 65) is 19 metres above sea-level. The level of the strandflat was also observed on Sild Island and on other islets along the shore, though the latter are as a rule somewhat lower. The summit of the point at Ænes, opposite Varaldsoi, was found by levelling to be 33 metres above the sea, and belongs obviously to a higher level than that on Varaldsoi and Hamaren. The rock is here Archæan. On Snilstveitoi, Kvinherred, there is also a well-developed strandflat in Archæan rocks. I have not had an opportunity of investigating the occurrence of the strandflat in Hardanger Fjord inside Hamaren (Fig. 21, no. 100), but as mentioned on p.66, Dr. Reusch has pointed out the occurrence of what he calls a “mountain-foot” or a low rocky platform along the sides of the inner parts of Hardanger Fjord, and in the map Fig. 2ı I have 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 87 Fig. 68. Ulvanes, Hardanger Fjord. (Aug. 30, 1911). Fig. 69. Southward view along the eastern side of Hardanger Fjord, towards Husnes, where the strandflat begins to extend and the high mountains withdraw. (Aug. 30, 1911). marked the places with strandflat according to his map of the inner Hardanger Fjord [19o01, p.189]. Reusch states the heights of his plat- forms to be about 20 to 30 metres. I expect they are chiefly about 20 metres, which agrees with my measurements in the outer part of the fjord at Varaldsoi. As in Sogne Fjord so also in Hardanger Fjord the strandflat is con- spicuously wider and better developed along both sides of the fjord in its outer part, and in Bommel Fjord, than in the inner fjord. It is especially outside the region of Husnes and Huglo Island (Fig. 21, no. 1c9 and 110) that the strandflat begins to extend more widely over the islands as well as on the mainland, and the mountains retire from the shores of the fjord, leaving the strandflat as a wide level foreland (cf. Fig. 69) A distinctly developed strandflat extends along the northwestern side of Bommel Fjord cut in rocks varying much in their power of resistance. It extends over the southern end of Stord. Island (Fig. 70) consisting of sisting of chloritic schists and gabbro, along the eastern side of the southern peninsula of Bømlo Island, and over Espevær (Fig.75) con- sisting of schists and gabbro. Along the southeastern side of the outer Hardanger Fjord and Bommel Fjord, the strandflat is well developed along the whole coast from Husnes (Archean rocks, Fig. 69), on Hälsnoi, and Fjelbergoi (Archean rocks and phyllite on both islands), along Valestrand from Tittelsnes (phyllite, Fig.71), and southwestwards along the coast, consisting of Archean rocks, towards Ryvarden Lighthouse and Haugesund (Figs. 73, 88 FRIDTJOF NANSEN. M.-N. Kl. Bomdo Isl. ‘1 Moster Island Fig. 70. Strandflat on southern end of St Title la nes Mirass rite MestehA Island oS. lance. Panoramic view extending from Moster Island to the northwest across 74 and 77), and further southwards along Karmsund, where the rocks are chlorite schists or similar schists. I did not get an opportunity of measuring the height of the strandflat in this region of the fjord outside Stord Island. But on the whole it gave the impression of being higher than in the region further in the fjord, being as a rule perhaps about 30 metres above sea-level, and sometimes even higher. As mentioned above I found a fairly well developed plane at between 45 and 55 metres along the castern and southeastern side of Stord Island and especially at Leirvik. The distinct plane extending over the southern- most part of Stord Island (Fig. 62) has an average height approaching this level, or perhaps: more correctly between 40 and 50 metres. ; On Moster Island the average level of the strandflat 1s between 30 and 35 metres, but some few hills rise to 45 and 51 metres, and a hill in its northern part even to 55 metres. Whether the rocks are gabbro or weaker chloritic schists or similar schists makes no appreciable difference in the heights of the hills or the strandflat. The latter is lowest in the southeastern part of the island, near Mosterhavn, where it is less than 30 metres high. It is somewhat higher further west. 1921. No. Tr. THE STRANDFLAT AND ISOSTASY. 89 d and on Moster Island. (August, 1904). -westwards along the coast of Valestrand. (Aug. 30, rorr). langer Fjord to Valestrand and the coast towards the east. (Aug. 30, ıgrı). On the opposite, southeastern, side of Bommel Fjord the strandflat seemed to have a similar height of between 30 and 40 metres, or in some places perhaps slightly higher. The rocks are here Archæan, only at Tittelsnes they are phyllite. The islands out in the sea to the west, at Lyngsoi (Fig. 21, no. 123), also seem to have a fairly considerable height approaching this higher level. On Bomlo Island the strandflat has a wide extension along its western and over its whole northern part and on the islands outside. The height of the strandílat is on the average between 30 and 40 metres, perhaps nearer 30 metres, but many hills and ridges rise above its general level even to altitudes of more than Ioo metres. The Bomlo Island shows great variations in its geological structure. The whole northern part consists of granites, the middle portion of gabbro, while the southern peninsula is built up of schists, with spots of gabbro and also quartz porphyry. On the whole the strandflat in the region of Hardanger Fjord seems | perhaps to have a similar tendency towards rising slightly seawards from the inner regions as we found in Sogne Fjord. But it has to be noted | that there are obviously at least two different levels: a lower level less 90 FRIDTJOF NANSEN. M.-N. KI. Fig. 73. Strandflat along south-eastern side of Bømmel Fjord, south-westwards from Ekelandsnes, in continuation from right end of Fig. 71. (Aug. 30, 1911). ling, sign SE Ag Mr ta ti — en # Fig. 74. Strandflat along sonth-eastern side of Bommel Fjord, near Nesheim and Norbo. Aug. 30, 1971). £spe vær Islands Fig. 75. Northward view towards the fairly high southern peninsula of Bømlo Island, and the low islands of Espevær to the left, taken from the sea north of Ryvarden Light house. (Aug. 30, Ig11). than 20 metres high observed at Leirvik, Varaldsoi, Hamaren, &c., and a higher level of about 30 metres, or between 30 and 40 metres. The strandflat of the Hardanger and Bomlo region seems on the whole to have very nearly the same average height as in the Bergen region and the Sogne Fjord region, perhaps slightly higher in some places. On Stord Island the strandflat seems to be especially high. ED LA uu RN RIN en bid t ugar. No. rr: THE STRANDFLAT AND ISOSTASY. 9I VIII. THE STRANDFLAT OF THE SOUTHWESTERN AND SOUTHERN COAST OF NORWAY. The Region of Karmei. On Karmoi there is a well developed strandflat extending over nearly the whole island. But here and there hills rise above the level of its plane (cf. Figs. 77 B and 78), and this is especially the case in the middle and southern part of the island, mostly on its eastern side. The northern part of the island consists of chlorite schists, the middle and southeastern part of gabbro, and the southwestern part of granites or gneisses. The strandflat extends equally over these different formations without anv appreciable difference in height. But the highest hills occur chiefly in the gabbro region. The coast of the mainland along the eastern side of Karmsund consists of chlorite schists. According to levelling made north of the bay at Angvaldsnes, the general level of this strandflat is about 29 metres above the sea. But a great part of the plain, on which many farms are situated, is between 16 and 20 metres, and this is also the general level of the strandflat on the mainland along the eastern side of Karmsund. The town of Haugesund is situated on this plane at the same height about 17 metres above sea-level. The heights were measured by levelling with a theodolite from a hill at 30.5 metres above sea-level, north of Angvaldsnes Bay. Fig. 78 gives a panoramic view taken from this hill. By careful levelling with the theodolite it was ascertained that the ridges of the undulating plain of Karmoi were very nearly at the same level as this hill, or a metre or two lower. E. g. the height of the platform on which the Angvaldsnes church is lying, was found to be 29.5 metres above sea-level. The bases of several houses in Haugesund were measured to be at about 16 metres above sea-level. To the north Bjorjene Hills on Karmoi are seen rising above the plane of the strandflat. On the mainland hills are also seen rising above this plane, but e. g. east of Haugesund they distinguish themselves sharply from the level of the strandflat. A sharply defined and widely developed strandflat extends south- wards along Karmsund on the mainland (Fig. 80) as well as on Karmoi 5? west from Kristiania Kilomettes [7] 30 /00 Fig. 76. Map of the Norwegian coast between Haugesund and The Naze (Lindesnes). r Haugesund. 2 Karmoi. 3 Angvaldsnes Bay. 4 Karmsund. 5 Hoie Varde. 6 Eastern Bokken. 7 Western Bokken. $8 Rennesoi. 9 Fjoloi. ro Mosteroi. rr. Kvitingsoi. r2. Stav- anger Peninsula. 13 Stavanger. 14 Tananger. 15 Hastein. 16 Roth Islands. 17 Hellesto (Håland). 18 Feisten Lighthouse. 19-19 Region of Klep. 20 Region of Nerbo. 2r Ogne. 22 Egersund. 23 Egeroi. 24 Presteskjær Lighthouse. 25 Josing Fjord. 26 Sogndal. 27 Hitteroi. 28 Lister Fjord. 29 Lister. 30 Farsund. 31 Southeastern part of Lister. 32 The Naze (Lindesnes). 1921. No nt. THE STRANDFLAT AND ISOSTASY. 93 Fig. 77. Strandflat north of Haugesund. (Aug. 30, rorr). (Fig. 79) but, as mentioned above, a good many hills rise more or less abruptly above its plane. The geological structure differs much on the two sides of the sound, the rocks being gabbro on Karmøi and chlorite schists on the mainland; but there is no appreciable difference in the appearance or height of the strandflat. A well marked strandflat, with a height approaching 30 metres, and forming a sharply defined incision in the mountain slope extends along the western and southern side of Eastern Bokn island consisting partly of phyllite partly of Archæan rocks (Figs. 81 and 82). On the southern side of the island another level was noticed at about double that height or a little more (Fig. 82). On the southern part of Western Bokn island (chiefly Archæan rocks and some phyllite), there is also a distinct strandflat. The Stavanger Region. The northwestern end of Rennesoi, north of Stavanger, forms a very flat and low strandflat (cut in granite), with a height of less than 20 metres (Fig. 83). Ahlmann in his attempt to prove that the strandflat has not been formed by marine denudation, points out that the occurrence of the strand- flat or rocky bench with a steep cliff behind it, on the southern side of Rennesoi, coincides with the tectonic difference in the geological structure of the island where igneous rocks, forming the cliff, rest on a base of weaker sedimentary rock (phyllite), forming the strandflat. He thinks that in such a case the formation of the bench “can be well explained as a result of subaérial and glacial erosion, but not by marine abrasion". But what is the explanation in the many thousands of other cases of similar shore-benches or strandflat formations where there is no such tectonic difference? And why have the horizontal strandflat and the shore-benches so very similar heights, or to a great extent practically identical heights, in the different regions so widely separated, although the rocks may differ much in their power of resistance to erosion? It seems that Ahlmann, in his anxiety not to admit the effect of the marine abrasion, has been compelled to seek for different explanations of the same formations in the different cases. FRIDTJOF NANSEN. M.-N. Kl. Fig. 78. Panoramic view of Karmøi and the mainland, taken from a hill north of the bay at Angvaldsr | of the u Fig. 79. Karmoi south of Hoge Varde lighthouse, with hills rising above the plane of the standfla (Aug. 31, 1911) On the islands south of Rennesoi (Ulfstein Island and Fjolloi), there is a well-developed strandflat. The sketch Fig. 84 demonstrates how the almost horizontal plane of the strandflat extends to the foot of the moun- tains Byrefjell and Kneberg, which rise abruptly above this plane. The rock is granite on both islands. The strandflat has a wide extent over most islands in this region north of Stavanger and out in the sea to the west where all islands are low and very flat. Kvitingsoi with its hundreds of surrounding islets and skerries has a very conspicuous low flat level cut in chlorite schists (Fig. 85). In the eastern part of these islands where the view Fig. 86 was taken, the average height of the plane was measured by levelling to be about 9.5 metres above the sea. But the level at which the farms are lying farther westwards (see 1921. No: rx: THE STRANDFLAT AND ISOSTASY. 9 ht of camera 32 metres above sea-sevel. (Aug. 31, 2911.) The lower pictures are a direct continuation Bat a. Fig. 80. The mainland along the eastern side of Karm-sund, seen from the sea south of Hoge Varde lighthouse. Fig. 86 right side) is higher. I estimated it to be about 20 metres or per- haps a little more.! The general level of the very flat Rott Islands further south, west of Tananger on the Stavanger Peninsula (see Fig. 89), was found by levelling to be about 17.7 metres above the sea, or perhaps between 16 and 18 metres, but the western and southern part of the islands is somewhat lower. They consist of phyllite. The many islets between Kvitingsoi and Rott are mostly low and flat, marking a low plane (largely less than 10 metres high) above which | After this was written I learn from kind information I have received from the Super- intendant of Lighthouses, that the base of the lighthouse of Kvitingsoi is 22 metres above sea-level, which agrees well with my estimate, as this base is level with the plane mentioned above. 96 FRIDTJOF NANSEN. M.-N. Kl. Fig. 81. Points at Ovrebs on north-western side of Eastern Bokn island. (Sept. 1, 1911). Håsteinen (phyllite) rises abruptly to a height of 45 metres (according to "Topografisk Kart Blad 6 D, Stavanger”). The island Storkjør, south- west of Rott, has a height of 18 metres. The land on the Stavanger Peninsula forms on the whole an un- usually level and well-developed strandflat, cut in solid rock, mostly phyl- lite, but in some places, at Tananger and round Hafs Fjord, also granite. The difference in the rocks causes, however, no appreciable difference in the plane or the height of the strandflat, though a difference in the rough- ness of the surface is easily perceptible. Hills, like Randeberg (Fig. 87) rise more or less abruptly to heights of 79 metres above this almost per- fectly horizontal plane, extending to the foot of the hills. North of Stavanger, at Finnestad near Dusevik, I found by levelling the height of the plane to be 29.5 metres above the sea. This plain is to a great extent covered by moraine material, but the solid rock (phyllite) protrudes at the surface of the plain in many places. On the northwestern side of the peninsula, south of Tungenes Light- house, the strandflat is conspicuously level and low, less than 10 metres above the sea (Fig. 87), and is cut in solid rcck (phyllite) forming the shore. The base of Tungenes Lighthouse is about 8 metres above sea-level. At Tananger the general level of the very even plane of the strandflat, extending landwards and cut in granite, was found by levelling to be about 14 metres above the sea. Near the shore it was somewhat lower. The hill with a cairn, north of Tananger harbour, rises to about 22 metres above sea-level. The panoramic view Fig. 89 was taken from this hill. It shows that the level of the plane 1s much below that height. The height of the small Tananger Lighthouse seen in the middle of the picture is 15 metres above the sea, and that of its base about r1 metres. The height of Fladho!m Fig. 82. Eastern Bokn island, seen from the south, with strandflat extending along the whole coast from the point to the north-west, which is the same as in Fig. 81. (Sept. r, rorr). hel STRANDFLAT AND ISOSTASY. THE No. 11. 1921. 'spuv[st. JO duois ‘(toGi TOR ‘ I “any dag) Us u J I}: » 5) "ud. opp] 2 geo. A o0 ØDIS UL] SUO-1[].1O1 (DOOD. ST "WUTOASO| IE A asnoypybı 7 our sj ur (so.pour OST CuZyVO veu ngon a; BERT Qro pst (1161 adog) ju oun BOs { uo ou I dog) TOPOS, uo [I vs v 'jsvo oy) O1] "BOS WOOS UIPAVASO] I) SI" ot} oAOqu 'idaodqouw sanou wo. pur JUSI ou] I IL UVIOUIEO JO JUS] SOM LOI} uoos OSNOYNLIIT DU) Lolo jo Jul put UM IOSSUIJIAST UM 19)S0P] Ul ST] »1] nos SP-IEMO] ‘IOSSUIPIAN J fy ? ^g LI ul IOSOUU o JO o Jo pur[st MOIA ot} DHUUUIOUR,] pue topo MM 19757/] puo UI9JSOM-UJIOU Je OUT "98 on GVA "Hur Wow 07 Kl. 1921. No. 11. Skrifter. I. M.-N i K. .-Selsk Vid 98 FRIDTJOF NANSEN. M.-N. Kl. Fig. 87. The low strandflat cut in solid rock (phyllite) southwards from Tungenes Lighthouse, nørthern of Stavanger Peninsula. The Randeberg rising abruptly above the level strandflat. (Sept. ı, 1g1r). 3ay and the islands outside, taken Fig. 89. Panoramic view of Tananger Lighthouse is 15 metres above the sea, and its base about 8 metres. The picture demonstrates the remarkable flatness of all the islands out- side the coast. These islands consist of phyllite. The picture also shows the roughness of the granite surface of this strandflat north of Tananger. The ridge on the peninsula south of Tananger Bay (to the left in the picture) has a fairly rough contour, although it is built up of phyllite. Further south, at Hellestø (Håland) at the northern end of Jæderen, we find the same strandflat cut in solid rock at the foot of steep mountain slopes, rising to heights of go metres above sea-level (Fig. 90). According to Reusch's geological map [1913] the rocks in this region are argilaceous schists (phyllite). The height of the rock of Feisten, in the sea southwest of this place, is about 12 metres above sea-level. Relation between the Geological Structure of the Coast and the Occurrence of the Strandflat. | In the preceding description of the strandflat along the Norwegian west coast, occasional remarks have been made on the geological structure of the coast and its relation to the occurrence and extension of the strand- flat. The geological dates are taken from the geological maps of the coast and from Reusch’s description with map of the geology of Sondhordland and Ryfylke [1913]. As has been pointed out on several occasions, it is striking how the strandflat often extends equally over regions with very heterogeneous ia geological structure, without showing any appreciable differences in its altitude or in its whole appearance. The plane of the strandflat is, for in- 1921. No. 11. THE STRANDELAT AND ISOSTASY. 99 Fig. 88. The strandílat cut in granite north of Tananger. (Sept. 1, Ig11). Tamanger Lighth il (22 metres above sea-level) north of Tananger harbour. (Sept. 1, 1911). stance, very often continued horizontally without a break from regions built up of very resistant rocks, like granites and gabbro, into regions with weak schists (chlorite schists, phyllite, &c.). This is the case in the regions of Bomlo Island, Karmoi, and Stavanger Peninsula. A difference may be that in the regions of the more resistant rocks there are often more and higher hills and mountains surmounting the plane of the strandflat, and the latter may not have as wide an extension there as in the regions of weaker rocks. But even this is not always the case, e. g. on Bomlo Is- land, and the height of the real plane of the strandflat does not as a rule differ. The only simple explanation of this striking feature seems to me to be that although the principal processes for the lowering and sculpturing of this coast have been the subaérial denudation and the glacial erosion, the final levelling of the plane of the strandflat has been accomplished by the marine denudation, 1. e. chiefly shore erosion by frost. After this plane had been thus formed, there cannot have been any great amount of sub- aérial denudation nor glacial erosion within the outer regions of the strandflat, for otherwise greater differences in the heights of the plane of the strandflat would necessarily have been created, especially where the power of resistance of the rocks differ much. On the other hand the strandflat has been exposed to some glacial erosion, which has to some extent broken the level surface of the strandflat and made it less even than it was originally. The effect of this glacial erosion has naturally differed somewhat with the structure of the rocks and their power of resistance. It has, however, to be considered that the power of resistance to shore erosion and also to glacial erosion depends less on the hardness of the rocks, 100 FRIDTJOF NANSEN. M.-N. KI. than on their tendency to be split by the frost or to form a rough surface to be attacked by the moving ice. It is for instance striking that the granites have in some regions been quite as much eroded as the much softer schists, probably because they have as a rule a rougher surface. Jæderen. Jæderen or Jæren is the low land extending along the coast between the Stavanger Peninsula to the north and the Egersund region to the south. It is 11 to 13 kilometres broad and bounded along its eastern side by a mountainous land (of Archæan rocks) rising more or less abruptlv above the plain, with comparatively steep mountain slopes, to altitudes of 1901020007 even 250 metres, The plain of Jæderen is formed to a great extent by quaternary, chiefly glacial, accumulations which have filled up the depressions and hollows of the rocky ground, often to great thickness. In numerous spots here and there the bare rock appears, however, in the surface of the plain, and in the northern and southern part of the plain this is even the case near the outer coast line [cf. the map by Grimnes, 1910]. The plane indicated by these exposures of bare rock has a height above the sea of about 15 to 25 metres. near the coast, in the region of Sele and Byberg and eastwards to Hegre in the northern part of Jaderen, south and southeast of Hellesto (Håland). According to Bjorlykke [1913, p. 16] the protruding rocks southeast of Sele are hornblende- and mica- schists. According to Grimnes’s map the protruding rocks rise to higher levels, above 50 metres, in the region further inland towards east-south- east, at Svensvoll, Lea, and Skjæveland, where the rocks consist of a grey gneiss [Bjorlykke, 1913]. Further east towards the foot of the mountains forming the eastern boundary of the plain, the level of the rocks is again lower, about 25 metres or even less, and at Ase, north of Hoiland railway-station, Bjorlykke ob- served hornblende-schists and lavers of brown granular limestone (marble). Further south, between Bore and Klep, there are rocks of mica-schists and gneiss rising to 50 and even 75 metres above the sea, at a distance of only 3 to 6 kilometres from the coast. Rocks of hornblende-schist, gneiss, and amphibolite rise to similar heights of between 50 and 75 metres in the region south of Klep towards Tu, where the hill Tua or Tinghaug (hornblende-schist and amphibolite) is even higher. An almost continuous region with numerous exposures of Archean rocks, chiefly gneiss, and hornblende-schists [Bjorlykke, 1913, p. 15], ex- tends from Nærbo towards east-northeast. The rocks (gneiss) in the western part of this region, at Bjärland north of Nærbo, 4 kilometres from 1921. Nos rr. THE STRANDFLAT AND ISOSTASY. IOI Fig. 9o. Rocky coast with strandflat at Hellesto at the northern end of Jæderen. (Sept. 2, 1911). the coast, have heights of less than 20 metres, or about 17 metres above sea-level. But further east the heights rise towards 50 metres and more. Further east and northeast, in the region of Tuneim, Mossige, Lende, Folland, and Hoiland near the foot of the high eastern mountains, the protruding rocks, observed by Bjorlykke, consist of phyllite, and their heights rise to 75 and 100 metres above sea-level. In the southern part of Jederen, north of Ogne, the level of the distinct plane of the low protruding rocks, of granite and labradorite, in iront of the higher hills and mountains (of labradorite rocks) is between 15 and 25 metres. It is of course impossible to study in detail the topography of the rocky ground where it is covered to such an extent by quaternary accu- mulations as is the case on Jæderen. It seems, however, probable that if these accumulations were removed, we would have a low somewhat uneven rocky surface to some extent perhaps broken up into peninsulas and is- lands separated bv shallow fjords and sounds. But this rocky surface would probably to a considerable extent have low heights of about 10 or I5 to 25 metres above sea-level, as indicated by the rocks especially in the northern and southern parts of the plain. I see no reason why this low rocky foreland should not be a strand- flat of the same kind as the strandflat on the Stavanger Peninsula (forming its direct, northern continuation) and along the coast further north. The striking topographical difference between the plain of Jæderen and the higher mountainous land to the east may to some extent be due to the difference in geological structure, the rocks of Jæderen being largely crystalline schists and partly phyllite which may have been more easily eroded to low levels than the Archzan and igneous rocks of the higher land to the east and south, although we have seen that fairly resistant Archæan rocks (gneiss, amphibolite, &c.) also occur on the low land of Jæderen. But howsoever this may be, it seems to me obvious that the low and nearly horizontal level, or perhaps levels, marked by the rocks protruding in the surface of the plain of Jz deren, cannot have been formed solely by subaérial denudation, and still less by glacial erosion. The simplest ex- planation is here as elsewhere, that these low horizontal levels of the coast-land have been finally created by shore-erosion levelling the hills 102 FRIDTJOF NANSEN. M.-N. Kl. The land north-westward along the coast, seen from a hill (135 metres) on the peninsula north of Presteskjær Lighthouse. (Sept. 3, 1911). of the low coast, which had already beforehand been much lowered to- wards sea-level by the other agencies. It is also a striking feature here on Jæderen, that the plane of the strandflat extends with almost uniform heights along the coast over regions with rocks differing very much in their power of resistance, a feature which is characteristic of the result of the shore-erosion. Ahlmann suggests that the erosion of the inland-ice in a previously flat region, like Jæderen and the Stavanger Peninsula, would result "in soft and still more levelled forms than before” [1919, p.48]. Although the glacial erosion may grind the forms rounder and softer, I do not con- sider it possible that it can make any extensive rocky ground more level than it was before. On the contrary I think it will always make it less level, and it is, in my opinion, probable that it is just the glacial erosion to which Jæderen has been exposed after its strandflat was finally levelled, that has made its rocky ground so uneven in height as it now seems to be. There is no reason why the inland-ice should have had any special tendency to form such nearly horizontal planes just above sea-level. As pointed out before, the erosion of the inland-ice and the big glaciers is not limited in any way by the sea-level, but goes on equally well at all levels down to the depths below the sea reached by the moving ice. Why then are these planes always limited to the coasts? Why has not the inland-ice formed similar levels and horizontal rocky plains under the water, and also far inland, away from the coasts? The high, steep Coast between Jæderen and Lister. Everybody travelling southwards along the coast of Jæderen must be struck by the sudden change in the whole character of the coastland in the region of Ogne, about 17 kilometres north of Egersund, where the mountainous land suddenly approaches the coast, leaving onlv a com- * Fig. 92. I92I. No. rr. THEFSTRANDELATFANDFISOSTASY:: 103 View south-westwards towards Sogndal and the mouth of Jøsing Fjord, from a hill (135 metres) on the peninsula north of Presteskjær Lighthouse. (Sept. 30, rorr). paratively narrow, but low and well marked strandflat, cut in solid rock, between the shore and the fairly steeply rising hills. This strandflat may be a couple of kilometres broad, with a level perhaps about 20 metres or less above the sea. It extends along the coast southeastwards as far as Egerøi, on the western peninsula of which it is fairly well developed. But further southeastwards from this island the coast becomes high and often precipitous as far as Lister, and there are only few indications of a very narrow strandflat in front of the steep mountain slop2 along this coast. The sudden change in the character of the coast is obviously due to the difference in geological structure, the coast in this region being built up of resistant igneous rocks, the so-called Egersund labradorite rocks [Kolderup, 1914]. This high coastland is dissected by narrow valleys, but its general surface is fairly level or undulating, rising gently inland from a fairly equal height of about 130 to 150 metres, above the sea, near the coast. It is probably the same kind of formation as the fairly level coast- land of southern Norway, about 100 metres high or somewhat mare, which Ahlmann calls the base-levelled plain of southern Norway. I think it represents more or less the Palæic mountain surface of this region which has not been substantially lowered by glacial erosion because the inland-ice has had very slow movements over these mountain plateaus, although the rocks have everywhere been rounded by the moving ice (see Fig. 91). In the region northwest of Presteskiær Lighthouse I found, by baro- metric reading, the fairly level mountain surface (Fig. 91) to be between 140 and 180 metres above the sea, and to the southeast, in the region of Sogndal and Josing Fjord (Fig. 92), it was perhaps about 170 to 200 metres high, with a steep declivity down to the shore, where in several places, under the headlands and elsewhere, there are ledges cut in the 104 FRIDTJOF NANSEN. M.-N. KI. M, 366 400 IT 212 >. N S SIN S SY Q A^ Sad N Dybland Varde à en gg u In Biren gta ON 3 RN N Kilometres a Ne pef Pe rh re re ee ee re eS 772. © / 2 3 4 ER 6 7 8 9 /0 Fig. 93. Profile of the coast and the islets outside, at Dybland and Trætodden, the promontory south of Josing Fjord (see Fig. 16, 25). solid rock (see Figs. 91 and 92). Along the coast northwest of Preste- skjær, as well as outside Sogndal, josing Fjord, and some other places, there are a number of low rocky islets and skerries (Fig. 92) consisting of the same kind of rock (labradorite) as the mainland. In connection with the ledges along the shores inside, they form a low and distinctly marked strandflat in front of this high and steep coast (see the profile Fig. 93). The many islets and skerries along the steep coast west and southwest of Hitteroi, west of Lister Fjord, form a similar strandflat. It can hardly be doubted that these shore-ledges and the low islands outside, have been cut by marine denudation (shore-erosion). They are in appearance perfectlv identical with those we have found in Sogne Fjord and Hardanger Fjord. Here along this outer coast I suppose all ideas have to be given up that these formations could be due to base-levelling by subaërial denudation, or that thev might be remnants of the floors of some preglacial valley-generation. From Lister to the Naze (Lindesnes). Like Jæderen the low plain of Lister is to a great extent formed by quaternary (glacial) accumulations, but especially in its southeastern part much rock rises to the surface of the plain, indicating a low and fairly horizontal level, or probably two levels, the lower one being also marked by the many low rocky islands and skerries outside the coast in this region south of Farsund (Fig. 94). The rocks of the low land and the islands outside are chiefly Archæan gneiss and granite, partly also diorite and gabbro [Reusch, 1901, p. 92]. The higher mountains behind the low foreland consist chiefly of Archean gabbro or labradorite rocks further inland. Though there is a marked difference between the low foreland, and the higher land behind, the mountain-slopes do not on the whole rise so abruptly from the plain as for instance in some regions of Jæderen, but 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 105 Fig. 94. South-eastern part of the Lister Land, from Einarsnes north-westwards towards the valley of Fram- waren, inside Helvig Fjord. View taken from the sea near Asegrund west of Svaneflu. (July 25, rorr). , 5 J 5 ar) D? nevertheless I see no reason why the low rocky levels should not be parts of a strandflat of the same nature as the one we have found extending all along the coast to the northwest and north. The mountainous land inside the low land of Lister has a fairly level surface at about 200 metres or more above the sea, rising in Ravneheien to 350 and 366 metres (see Fig. 94). Between Lister and The Naze (Lindesnes) and along the coast further eastwards where the rocks are partly gabbro or labradorite (between Far- Y sund and The Naze) and partly Archæan, there are a great many low rocky islands and skerries indicating distinctly the lower level of a strandflat, and to some extent perhaps two levels. The promontory of the Naze itself (consisting of Archæan rocks) belongs to the strandflat and exhibits two marked levels, a general higher level at about r6 to 18 metres above the sea, and another very low leve! at the outer point, only a few metres above the sea (Fig.95). The level of about 16 to 20 metres was also observed further east, e. g. at Kje- holmen and Kalvehaue on Imsa Island at Spangereid (Fig. 96). The Southern and South-eastern Coast of Norway. Along the southern coast of Norwav, between Mandal and Christiania Fjord, there is a border of numerous islets, skerries, and rocks, but there are comparatively few perfectly certain indications of a strandflat. Ahl- mann goes, however, decidedly too far when he asserts [1919, p. 36] that "there is no sign whatever of marine abrasion or the presence of any marine coastal plain”. Where the general land surface is low and slopes gradually towards the coast, as it does in this region, it 1s very often difficult to decide where there is a coastal plain or strandflat cut bv shore-erosion, and where it is only the general low level of the land surface that slopes gently into the sea. It seems to me, however, that a plane so nearly perfectly horizontal as is exhibited by many series of islands along this coast (see for instance Fig. 97 and especially Fig. 98) cannot have been formed solely by subaérial denudation and glacial erosion, but it must have been finally levelled by shore-erosion, in the manner I have previously described. Sometimes one may observe a distinct break between the horizontal level of this narrow strandflat and the slope of the higher land inside. The 106 FRIDTJOF NANSEN. M.-N. Kl. r, 95. The Naze (Lindesnes). The light of the lighthouse is 50.1 metres above sea-level. (July 25, tort). Fig. 97. Land northward from Ulvoisund, east of Christiansand. (Sept. 4, 1911). islets and skerries in some places show indications of two levels of shore- erosion. Some observations in the region of Langesund may be of interest to prove the existance of the strandflat along this coast. The low islands in the mouth of Langesund Fjord, when seen from the sea (Fig.99), exhibit a low level distinctly different from the much higher surface of the mainland on both sides of the fjord. The Langesund Peninsula shows a higher level. Fig. 100 represents the southern point of the peninsula on which Langesund is situated. There can be no doubt that the flat points and ledges, a few metres above present sea-level, with the steep cliffs behind, have been cut by shore-erosion. They have obviously the same level as the islets outside, seen in the picture. It is hardly probable that these ledges and islets have been formed in postglacial time. We may be con- vinced of this by looking at the coast on the western side of the peninsula, a view of which is given in Fig. ror. The level of these low flat islands with rounded, ice-worn surfaces is approximately the same as that of the flat points and islets of Fig. 100, and it is also the same as the low, flat points forming distinct horizontal incisions in the slopes of the two pro- montories seen behind the low islands in Fig. 101. These formations can- not be due to postglacial erosion. Hence, we have here a low level or strandflat along the coast, due to shore-erosion, and distinctly different from the higher general level of the land behind, which is seen as a fairly even surface on the peninsulas in Fig. ror and also in Fig. 99 on the left hand side. The peninsula of Langesund (Fig. 100) is built of sedimentary rocks (phyllite) and so are the low islands and the nearest promontory in Fig. 101, but the distant promontory in this picture, which has an especially distinct low point or strandflat under the steep shore cliff, is built of Archzean rocks. Whatever the genetic origin of the higher, fairly level surface of this land may be, there can, in my opinion, be no doubt that the lower level 1921. INO DE. THE STRANDFLAT AND ISOSTASY. 107 Fig. 96. Indications of a strandflat outside Spangereid, east of Lindesnes. Kjeholm in the foreground. To the right the point Kalvehaue on Imsa Island, with a well-marked strandflat. (July 25, 1911). Fig. 98. Islands north of the entrance to Kragerø. (Sept. 4, 1911). of the small islands and the points in this region is a regular strandflat of the same nature and origin as the strandflat of the Norwegian west coast where it has, however, a much wider extent. It may be that this low level of the strandflat along the southeastern coast of Norway corresponds to the lowest level (12—17 metres high) of the strandflat of the west coast. The reason why it is here so much lower might be, in that case, that this southeastern coast has been less elevated than the west coast after the last development of the strandflat, because the denudation of this low land, and the amount of waste carried away from it after that time, have been considerably less than what was removed from the much higher and steeper west coast. The Inner End of Christiania Fjord. As Prof. W. C. Brogger’s well known investigations have proved, the Christiania Fjord is a fault trough, in the inner part of which the Silurian or Ordovician clay-slates have sunk down to levels below those of the Archæan region to the east and of the igneous rocks forming the hills to the north and west of the fjord. It is to a great extent by the subaërial and glacial erosion of these clay-slates, much less resistant than the Archæan and igneous rocks on the sides, that the depression of the fjord has been formed. If one looks down upon the Christiania valley and the fjord from one of the heights round this valley, it must strike one that the surface of the many islands in the inner part of the fjord, inside Lagoi, Lang- ären, and Steilene, and also the peninsulas, Bygdoi, Fornebo, Snaroi, and Konglungen, forms a remarkably level plane, where the ridges generally rise to between 20 and 30 metres above sea-level, and very seldom above HE metres (ci. Mic. 102), The land of Archean rocks to the east, i. e. the Nesodd Land and the land east of Bunde Fjord, rises abruptlv, with a sharply marked fault 108 FRIDTJOF NANSEN. M.-N. Kl. Fig. 99. Entrance to Langesund Fjord. (Sept. 4, 1911). escarpment, above this plane, to 150 and 200 metres above sea-level, while the land in Aker, Bærum, and Asker, rises more gently in ridges to the foot of the higher hills to the north and west of the fjord. But even here there is often a distinct difference between the undulating slopes of these valley sides and the lower plane of the islands and peninsulas of the fjord, as is demonstrated by the profile Fig. 103. Fig. 100. Cliffs with low points on the southern end of the Langesund Peninsula. (July, 1904). Fig. 104 gives a photographic view of Fornebo Peninsula and the islands and hills towards the south-southwest and west-southwest taken from the top of the writer's house on the hill marked X in Fig. 102 in the northeastern part of Fornebo Peninsula. The peninsula as well as the ıs- lands and the low land to the right in the picture, form a nearly horizontal plane, distinguishing itself sharply from the steeply ascending hills be- hind: Skogumsäs, Vardeäs, &c. As the land is covered with pine wood, the plane appears in the picture higher than it actually is. The Nesodd Land to the left in the picture, rises very steeply from the fjord, with Fig. ror. Indications of a strandflat on the eastern side of Langesund Peninsula. (July, 1904). Cc OC UBY} JOMOL SJ Il TULYIPDY J-Dp IL “VIUBIYSTAIY jo puo Jouur ou] "Sol OU YUM jeppuv.s oy} sojvor 4 oF AM Pl x a y / } UMD) Vv = 7 IND IY TLS SU ping, To rai jus e å ) ? ; 244007 POD 109 uooysoly y MIC 266 ; uabumbuoy vusabunsumg bisp? Ait Af | iN 3 7 ' er | uopmánlq y "ww po OQ AUS CUN: abo" | 147° & ? y vj wr 5 Tuae Y | É AL År ug.alobun T e Yobrmsmumlg UDD à 6 PN C] ) uzosmme) & men EL P Wie. | 9 sige iM Sg | ylasay) A "2^ d DE va dr be (747 2077 ^ , : da ge _ 5 2 ) Z2 our x | 4 pa \ ET wobuqposayy "pA 19001 a x up uoppubis nest = sc i 150A Ge SE EE L2 - um P NS De $ 4j SK ce NAQUIVNS yen] an ; : >> ZU N RA N bat] Lis die M wr am: mh “SNINAd 3 x j ; OHINYOT EET CEE ET i asino SAS UN V- op ni ates ‘Rion =e AS (|, RSR Iud THE STRANDFLAT AND ISOSTASY. CN ES dk iy" JE SN a IIO FRIDTJOF NANSEN. M.-N. KI. A 2 3449607490 822772777772 LAPTOP es 2 oo oss] Pee Devonian Sandstone 244224 Silurian Schists with LILLIA Fig. 103. Profile across the inner end of Christiania Fj i J indications of a strandflat formed by the islands of Ildjernet (seen in the picture) and Steilene at the foot of the steep mountain side (cf. Fig. 102). This plane cannot, in my opinion, have been finally formed by sub- acrıal denudation, and still less by glacial erosion. These processes would have made the general surface of this land more sloping or more bowl- shaped. The plane must have been finally levelled by marine denudation, 1. e. shore-erosion by frost, in a similar manner as we have seen (p. 37) that shore-ledges have been formed at present sea-level in postglacial time in this same region. The shore-erosion has found very favourable conditions for work in this region of easily crumbling argilaceous schist, dissected by glacial erosion into numerous islands, peninsulas, and points with a very long shore-line for attack. It is therefore not surprising that, although the inner part of Christiania Fjord was probablv filled by glaciers during the greater part of the various glacial epochs, there has still been time enough for the shore-erosion to cut this plane, extended over so wide an area, in a low dissected land where there was ‘only a comparatively small quantity of easily crumbling rock to remove in order to level the surface down to sea-level. The plane thus formed has afterwards been eroded by the glaciers of the last glacial period which have denuded more or less the weaker parts of the rocky surface, while the more resistant parts have been less affected and form ridges largely going in the direction of the strike of the folded schists. The fairly flat summits of these ridges have to a great extent nearly uniform heights of between 20 and 30 metres above sea- level. In some places, especially on Snaroi, Ostøi, Brønnøi, and Nesøi (see the white spots in Fig. 102) they rise above 30 metres, and only in a few cases they rise to 40 and 50 metres. 1921. No. Tr: THE STRANDFLAT AND ISOSTASY. III 400 Kilomettes Gasungene » Xr As à Kolsas to Nesodd Land, from A to B in Fig. 102. It is difficult to decide what the exact height of this plane may originallv have been, because after its final planing, it has been denuded by glacial erosion. Most of the land on the Fornebo Peninsula, for in- stance, is lower than 20 metres, and a great deal of its area is even lower than 10 metres, but this chiefly consists of fields formed of loose material. The many long rocky ridges running in the direction of the strike (about WSW to ENE) [cf. Werenskiold, 1911] between the flat fields are mostly between ro and 20 metres high, with their fairly flat summits slightly above 20 metres. They show, however, distinct traces of glacial erosion. Their summits are rounded and the dykes of diabase rise above the argilaceous schist with rounded, polished, and striated surfaces (cf. Fig. 17). These rocky ridges have, therefore, obviously been somewhat lowered by the glacial erosion, but it is difficult to say exactly how much. I think, however, that the general plane may be assumed to have been about 25 metres above present sea-level, or perhaps a few metres more. The sides of the rocky ridges are frequently so steep and abrupt that they look like shore formations or shore cliffs somewhat modified by later glacial erosion. Fig. 104. The plane of Fornebo Peninsula and the islands and land to the south-west, seen against the surroundung higher hills. View from south to west-southwest from the top of the writer’s house near Fornebo. (April, 1922). 112 FRIDTJOF NANSEN. M.-N. Kl. According to what has been said above, the low level region at the inner end of Christiania Fjord, may be considered to be a regular strand- flat formed in a manner similar to that of the west coast. Whether there are two different levels, or even more, in this region, is difficult to decide, because the original plane or planes have been more disturbed by the late glacial erosion than those of the strandflat of the Norwegian west coast. Another difficulty hampering the investigations is also that the strandflat in the Christiania region is almost everywhere wooded. Although it may look as if there are indications of at least two levels in several places, I dare not express a definite opinion without having made more careful investigations. | y | { 1921. No. LT. THE STRANDFLAT AND ISOSTASY. 113 EX THE SIRANDELAT ALONG. THE- COAST FROM SOGNE FJORD TO VIKTEN. The Region of Sendfjord, Nordfjord, and Stad. The Norwegian west coast in the region of Askevoll and Floro north of Sogne Fjord has a distinctly developed strandflat in the shape of numerous low islets, skerries and sunken rocks, and in many places there is a low foreland in front of the mountainous coasts of the higher islands and the mainland. The rocks are here Silurian schists and later (upper Silurian and Devonian) sandstones and conglomerates; and in some few places (near Askevoll and on the southern side of Bremanger Land) granite. I have not had an opportunity of investigating the strandtlat in this region. By a study of the charts of the coast one will notice that in many places the submerged platform with shoals and rocks is more widely developed in this region than outside the coast farther south. Dr. Reusch gives [19or, p. 189] an illustrative drawing of the narrow strandflat (10 metres above sea-level) at the foot of the steep mountain side on the outer coast of Askroven Island in Sondfjord. Small cirques with nearly flat floors have there been carved by the shore-erosion into the mountain sides. North of Bremanger Land the coast is built up of Archæan rocks, and the strandflat is less conspicuous. Neither on nor outside the high Stad Promontory are there indi- cations of a strandílat, excepting perhaps a few sunken rocks. In this respect the Stad Land forms an exception from almost the whole rest of the west and northwest coast of Norway. Along the coast northeast of Stad Land there is again a strandflat consisting of a submerged platform with numerous skerries and rocks, and often a low foreland on the islands. The rocks are presumably Archæan. The Region of Ålesund. The high islands Godoi and Valderoi, outside Ålesund, have the typical shape of a hat swimming on the water, the low strandflat forming the flat brim above sea-level {Fig. 105). This shape, which was already Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. 11. 8 114 FRIDTJOF NANSEN. M.-N. Kl. ADD AN: Wi 7, HR en — i. OSS Godör Havstein Siskót Fig. 105. Islanc described by Dr. Reusch as characteristic of the strandflat, is often seen even on small islets and holms. [ measured the heights of the strandflat on the southern and south- western side of Harei to be between 17 and 25 metres above the sea, on the west coast of Mien Island 28 metres, and on the small Dronen Is- land, with the mountain Dronehatten in the middle, 18 metres. These islands are northeast of Alesund, and the heights were measured with sextant from off the coast of Fjørtoft Island, where I was lying at anchor on August 22nd, 1909. Owing to the distance the measurements cannot be expected to be very accurate. The Borgund Fjord, just south of Ålesund, is narrow and fairly well sheltered against the open sea outside. There is none the less a well developed strandflat along the northern coast of Suloi, and on the islands in the fjord (Fig: 106). The mainland as well as the islands in the region of Alesund are formed of fairly resistant rocks, generally supposed to be Archæan, but lately by J. Schetelig [1913] maintained to be vounger eruptive gneisses of the great Caledonian "folding-ditch" of Northern Norway. The low parts of the row of islands north of Ålesund — including Giskoi, Valderøi, Vigra, Lepsoi, Haramsei, Flemsoi, Fjortoft, and Harei — are to some extent built up of quaternary (glacial) material. But the strandflat de- scribed above, is largely cut in solid rock. From the seaward coast of these islands submerged platforms, with Å hundreds of rocks and shoals in or slightly below sea-level, extend 7 to | 10 kilometres out into the sea. It is a noteworthy fact that the submerged platforms with sunken rocks and shoals are much broader in these northern regions than any- where along the Norwegian coast further south. Advancing along the coast northeastwards and northwards we will find the submerged strand- flat increasing still more in width. This striking difference in the development of the submerged strand- flat cannot be explained by a difference in the geological structure of the ccast, because in this region the coast is built up of very much the same kind of what is supposed to be Archæan rocks, as in many places Eu 1921. No. Tr. THE STRANDFLAT AND ISOSTASY. 12105 Aycholin Valderoat outside Alesund. further south; the rocks of this region are at anv rate not less resistant to erosion than those further south. The natural explanation of the increasing development northwards of the submerged platforms of the strandflat is in my opinion that in these northern regions the marine erosion, and especially the shore erosion by frost, has been much more favoured by severe climates than further south. Hence, the quantity of rock cut away by shore erosion during past ages much increases northwards with increasing latitude. There is also the likelihood that in these northern regions the climates have, probably always, been more stormy than farther south. As I have pointed out before, the transporting and erosive capacity of the waves increases with something beween the third and sixth power of the velocity of the wind. Along a coast like this, exposed to the full power of the sea, this may also be of much importance for the marine denudation. The severer climates of the northern regions may also increase the subaërial denudation, but not sufficiently to explain the striking difference in the development of the strandflat and its submerged platforms. It is a striking fact that in these northern regions the submerged parts of the strandflat have considerable areas as compared with those of its emerged parts. In the region of Hustad there is a conspicuous level strandflat ex- tending over the low skerries outside the coast, as well as over the outer border of the mainland, where the steep, often precipitous mountain sides Fig. 106. Strandflat in Borgund Fjord, inside Alesund. à West from Christiania 30 M ap showing the Sttandflat of Smölen (D Hiltezen (II) feéiallP and Feoan [standsiV) ES Land lower than 30 melees above sea-level ES Land belwen 30and GO meltes above sea-level. SK Pair on Hillesen higher Lan 60 melkes. ( land higher than 60meltes above sea-level. E {Suserged Plalfesms less than 25 melses below sta-level. Fig. 107. Map showing the strandflat in the Region ol $ h A, Te 7 ng & SR is WE p. d eM uf s M / LM ^ m 7 Li 77 *olen (I), Hitteren (II), Froia (III), and Froan Islands (IV). 118 FRIDTJOF NANSEN. er — Inveien Hummesdt Hvalpöi LLL SIDI FESD U^ Ye J(u gg Z Yj Pressed Igneous Rocks ze Kilomclses M.-N. Kl. Rambet glid va Rosvolléi Kıdı Island Torshaug 20 er a 10 Fig. 108. Profile across Smolen and Tusteren jslands, from } joint A to south of point B in Fig. 108. T gives the natural relati rise abruptly above the plane to heights of 600 and 700 metres above the sea. This coast gives a convincing impression of how the plane of the strandflat must have been cut horizontally into the oversteepened mountain sides [cf. Nansen, 1904, PI. V, Fig. 5]. The high mountain Stemshesten is conspicuous, rising as a “stack” above the lev el plane which, however, is to a great extent formed of quaternary loose material on both sides of the mountain. The mainland as well as the islands of this region is built up of rocks, supposed to be Archean, but Schetelig [1913] considers them to be younger eruptive gneisses and igneous rocks. The strandflat extends as submerged platforms with innumerable shoals and rocks 9 to 15 kilometres out to sea, 4 region much feared by all seafarers. The surfaces of these submerged platform s are fairly uneven and are dissected by numerous depressions making the depths vary. As will be mentioned later, this is generally the case where the submerged plat- forms are built up of resistant rocks like grani te or gneiss, &c. There are many scattered shoals and rocks near sea-level, or about 5 to IO metres below it, some rocks and skerries also rise above the sea. It is difficult to decide exactly at what level the plane of these submerged platforms stands. There is no sharply defined edge of the plane, as the surfaces of the platforms slope towards the deeper sea on the sides, as a rule without any sharp break. If, however, the tops of the many shoals and sunken rocks may be taken to indicate approximately a plane, this stands very near present sea-level, or perhaps five to ten metres below it. Outside the coast in the region of Christian sund, there is a series of submerged platforms with shoals and rocks and small islands, situated, as it were, on a submarine ridge running parallel to the average direction of the coast, and forming a continuation of a ridge on which are situated: 1921. No. 11. THE. STRANDFLAT AND ISOSTASY. 119 Jöggars vä gsalen 907m. Tustesnaksla 675m. NN tical scale is 5 times exaggerated in relation to the horizontal scale. The profile in black on the land height to length. Orskjærene north of Hustad, Ona (with Ona Lighthouse), and sur- rounding submerged platforms, Sandoi, and the before mentioned series of islands, Haroi, Fjortoft, Flemsoi, Haramsoi, Lepsoi, and Vigra. The high islands of Smolen, Hitteren, &c. are situated on the same ridge to the northeast (see later). This ridge was probably formed during the great Caledonian mountain folding of this part of Norway. It is separated from the coast of the mainland, and the mountainous islands near it, by a channel (the fairway ar? Fig. 109. The surface of the strandflat on Smolen. Northward view from the Nelvikberg (67 metres above sea-level) towards Roksvag. (Photograph by P. Schei. July, 1904). 120 FRIDTJOF NANSEN. M.-N. KL Fig. 110. Strandflat along the west coast of Hitteren, with the Skär Fjell behind, seer or ‘leden’), often more than 200 metres deep. The distance from the coast to the outer edge of these submerged platforms is in the region of Christiansund about 12 or 13 kilometres. The submerged plateau of Grip with numerous islets and skerries, outside Christiansund, may be especially mentioned. These submerged platforms have uneven surfaces similar to those of the platforms, just described, to the southwest. The Grip Plateau seems, however, to have in parts somewhat more level surfaces with more distinctly defined edges. It may probably be built up of somewhat less resistant rocks, like those of the Smolen Plateau to the northeast. The Region of Smglen, Hitteren, and Froia. The region of Smolen, Hitteren, and Froia is interesting because of the complexity of the geological structure, and the unusually well developed strandflat which cuts horizontally through the various geological forma- tions, frequently without any appreciable break in its level plane (cf. Figs. 108 and T TD). Especially on Smølen and its neighbouring islands (see the map Fig. 107) we find the most perfectly developed plane of the emerged strandflat which occurs along the coast of Norway. Smolen island is 16 kilometres from south to north and 20.7 kilo- metres from west to east. The whole of the island is one unbroken plain, which is especially even in its northern part where only two small hillocks (Dyrnestuva and Mäbergtuva) rise slightly above the plane. The height of this almost perfect plane is 15 to 20 metres above sea-level. In the southern part of the island the plain is somewhat more undulating and a few isolated hillocks rise above it to 26 metres (Storsetberg), 33 metres (Hoaäsen), 35 metres (Torshaug); 39 metres (Rambergtuva), and one even to 45 and 67 metres (Nelvikberg) in the southeastern corner. The northern part of Smolen consists of diorite with a belt of pressed igneous rocks along the northwestern coast [cf. Schetelig, 1913]. In the southern part there are various rocks, probably of Silurian age [Reusch, 1914, Schetelig, 1913] with enclosures of a limestone probably of Ordo- vician age [Holtedahl, 1914]. On the islands to the south of Smølen, on Kuli Island, Edoi, &c. there are conglomerate and sandstone, probably Silurian. The profile Fig. 108 from the mainland (Saksen), across Tusteren Island, Kuli Island, Smolen, and the small islets to the north, gives the 7 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 121 WSs from the eastern side of Smolen. (After photographs by P. Schei, July 11, 1904). various rocks according to Schetelig’s map [1913]. The strandflat is here about 36 to 39 kilometres broad, from the foot of the Tusteren mountains to the edge of the outer platform with skerries (see the map Fig. 107). This profile demonstrates the remarkable evenness of this strandflat, its plane cutting horizontally through the geological formations, southwards to the foot of the steep mountains. The depressions between the islands north of Smolen, at Hvalpoi, Hammerei, Inveien, &c., are drawn much too deep in the profile (Fig. 108). These depressions are not deeper than 10 to 20 metres below sea-level, generally less. The same is also the case south of Smolen, at Rosvolloi and Kuli Island. On the islands south of Smolen, built up of conglomerate-sandstone, there are a few small hills rising above the plane: two hills to 44 and 78 metres (on Kuli), two hills to 39 and 47 metres on Edei, and one hill to 40 metres on each of the small islands Orten and Glasoi. Fig. 109 is a photograph taken by Mr. P. Schei in Juli 1904 from Nelvikberg (67 metres high) on southeastern Smolen. It gives an illustra- tive picture of the even surface of the strandflat on Smolen. The rocks are here diorite and are rounded by glacial erosion. The flat plain of northern Smolen is to a very great extent covered with peat-bogs. As our map Fig. 107 shows, Smelen is surrounded by a submerged strandflat which is about ı2 kilometres broad at its broadest on the southwestern and the northwestern sides of the island. The area of this submerged strandflat is considerably greater than that of the whole island. Our map gives the submerged strandflat at levels less than 25 metres below sea-level. Unfortunately lack of time has not allowed the writer to draw more detailed maps showing its surface topography. It is dissected by channels and depressions but not as much as the sub- merged platforms to the southwest which were described above. Its surface is more level than the surfaces of those, and in great parts it forms extremely level horizontal planes, near present sea-level. Hundreds of islands and rocks, rising above the sea, are scattered almost over its whole area, also near its outer edges. If in a detailed chart the isobaths be drawn for 10, 20, and 50 metres of depth, it will be seen that the isobath for 20 metres has very compli- cated shapes, it comes almost everywhere close to the isobath for 50 metres near the outer edges of the platform, and even the isobath for 10 metres comes very near them to a great extent. This indicates that the edge of the submerged strandflat is fairly sharply defined, and is in most places 122 FRIDTJOF NANSEN. M.-N. Kl. Kilometres ag BST a Si = 20 Dr RO! KVALÓI FROIA E a Diorite and Quartz Dose WV teh Granite izf- SWAN - TAKRBUSSKJK R^N SKOGSO/ REZ N Archaan 0% younges Jgneous Rocks Fig. 111. Profile across Froia and Hitteren from point C to point D in Fig. 108. The vertical scale is 5 times between height | less than 10 metres below sea-level, i. e. the edge of the horizontal plane indicated by the summits of the many shoals and sunken rocks, where it is bounded by the steeper sideslopes of the platform. The topography of the large island Hitteren shows a considerably greater variation than that of Smolen, but there is a well developed strand- flat, especially in its western (Fig. 110) and northern part (cf. Fig 102% The strandflat is, however, not so perfectly level as on Smolen, and is on the whole somewhat higher, to a great extent above 30 metres. It cuts through a variety of geological structures. The northern and northeastern part of the island is according to Schetelig [1913] built up chiefly of pressed igneous rocks, gneisses and gneiss-granites, with a belt of diorite passing across this region from west to east. The middle and southeastern part of the island consists of diorite, with a border of conglomerate and sandstone (probably of Silurian or early Devonian age) along the eastern half of the south coast. The western part of Hitteren is built up of comparatively young granite [cf. Schetelig, 1913, Reusch, 1914]. In the profile (Fig. 111), across Hitteren and Froia, the occurrence of the various rocks is indicated according to Schetelig’s map. The strand- flat is seen cutting through the various geological formations to some extent, but in the southern half of Hitteren the land is higher (cf. Fig. 107). This region consists to a great extent of diorite. There are a good many hills rising to 160 metres above sea-level or more, some even to 220 and 227 metres, and Els Fjell to 319 metres. The strandflat extends al- most horizontally to the foot of the higher hills (cf. Jamt Fjell in Fig. Tia )e In the western granite region of Hitteren there is also a small sharply defined mountainous area, rising abruptly above the plane of the strandflat to heights of 150 and 200 metres, Skar Fjell even to 306-metres ( Morvolls- tuva) and 369 metres (Morkdalstuva). Otherwise the strandflat is well developed in the coastal region of this western part of the island and on the many smaller islands outside the coast to the west and southwest, likewise consisting of granite, as well as on the small islands to the north- west (Sæbuøi, Stromsoi, Gjedsoi, Skårøi, &c.) consisting of diorite. Although as was said above, the strandflat of Hitteren is not on the whole as remarkably level as that of Smolen, still it is extremely even in 1921. No: Tr THE STRANDFLAT AND ISOSTASY. 123 Els Fjell 39 m Stau E227. HF 220m Jan heil 178m AK gut 220m exaggerated in relation to the horizontal scale. The proäle in black on the mainland g:ves the natural relation and length. many places, for instance in the region of Kvenvær, as Schetelig has | pointed out to me. Fig. 112 is a photograph or the mountain Tonningen (231 metres above sea-level) in the western granite region of Hitteren, taken by Prof. J. Schetelig. It demonstrates the abruptness with which the mountains rise with their steep sides above the denudation plane of the strandflat. This plane as well as the mountain is formed of the same granite and there is no difference in the geological structure to account for the configuration. Forms like these cannot therefore be formed solely by subaérial denudation, which would necessarily give to the mountains bounding the plane less abruptly ascending sides. They might be formed by glacial erosion, and the ridges of the surface of this strandflat have obviously been rounded by glacial erosion, as Fig. 112 shows. But if this glacial erosion had lasted long enough to produce mountain forms like Tonningen, the strandflat would necessarily have been deeply dissected into a much more uneven surface than we now find. The onlv natural explanation is that before the last glacial erosion (of the last glacial epoch) the marine denudation finally planed the surface of the strandflat which rises gently from the shore to the foot of the mountain slope probably at about 30 metres above sea-level. Between the western granitic mountain area and the more extensive dioritic mountainous region to the east, a broad and flat plain extends across the island from the south coast to the northwest coast, forming a continuation of the strandflat, rising gentlv to somewhat more than 60 metres above the sea, but its greater part, especially in its northern and | northwestern area is less than 50 metres high. According to kind in- formation from Schetelig, this low region is built up of crystalline schists, mica-schists, and hornblende-schists which have been more easily denuded than the granite to the west and the more resistant diorite to the east. The strandflat continues along the northern coast of Hitteren, formed | of pressed igneous rocks, gneisses, and some granite and amphibolite, &c. The plane is well developed at heights of between 20 and 35 metres above the sea with some few hills rising to about 50 metres. The long Dolm | Island to the north is also a continuation of the low strandflat with two isolated hills rising to 46 metres (Storvarden) and 70 metres (Hjertäs) above the sea. 124 FRIDTJOF NANSEN. M.-N. Kl. Froia is chiefly built up of granite which in some places is pressed. Along its southern coast there is dioritic gneiss. Froia is very low and most of its area belongs to the strandflat, with some hills and ridges rising above its plane, especially in the southern or southeastern part of the is- land (see Fig. 107), to heights of about 50 to 70 metres. The height of the strandflat of Froia is 20 to 30 metres above the sea in its western part and along the northern and eastern coast. In its inner and southern parts the land is mostly more than 30 metres high. The surface is considerably less even than the surface of Smølen, and has many ridges and depressions. This is obviously due to its geological structure, the granite giving often a rough and broken surface. As Schetelig has pointed out to me, the unevenness in this case may especially have been caused by alternations of regions with more resistant porphyric granite and regions with pressed granite or gneisses, less resistant to erosion. Along most parts of the coast of Hitteren and also along the south and west (or northwest) coast of Froia the submerged strandflat is com- paratively narrow and is much dissected and uneven. This is also the case along the coast of the mainland (see Fig. 107). But to the north of Froia a submerged strandflat with hundreds of islands and skerries extends 20 kilometres into the sea, and continues 50 kilometres towards the north- east, comprising the extensive region of the many low and flat Froan Is- lands (see Fig. 107). The surface of this submerged platform is much dissected as the map may give the impression. But in some parts, e. g. in the region of Sillen, Bu Skjær, and Gjeit Skjær northwest of Froia (see map Fig. 107), the surface is extremely level over considerable areas, forming horizontal plains near sea-level or only a few metres below it, and having well defined edges at depths of less than 10 metres. The width of the strandflat from the edge of this partly submerged platform to the foot of the higher land on Hitteren is 43 kilometres. But if we reckon it to extend across the Hitteren to the foot of the mountains on the mainland the width will be 58 kilometres. The width of the strand- flat from the edge of the outermost submerged platform outside Smolen to the foot of the mountains on Tustern is 40 kilometres. The distance from the outer edge of the submerged platform of the Froan Islands to the foot of the high mountains on the mainland is about 46 kilometres. The strandflat is here conspicuously much wider than in any region along the Norwegian coast to the south, and is partly developed to fuller maturity. The reasons may be several. On the one hand the geological structure has favoured the formation of a strandflat. By the Caledonian mountain folding a fairly low land was made to emerge along the top of one or two folding ridges far out in a stormy sea, where it was exposed to the full fury of the marine denudation. This low land was to a great extent built up of rocks, dioritic 1921. Nor Lr. THE STRANDFLAT AND ISOSTASY. 125 Fig. 112. The mountain Tonningen, seen from the north-western shore of Laugen Lake, which is seen in the foreground. (Photograph by J. Schetelig, 1909). schists and pressed schistose igneous rocks, which were fairly liable to erosion by subaërial denudation as well as by marine denudation. On the other hand the erosion, the subaërial as well as the marine erosion, has been much more favoured by a severer climate in this northerly latitude than it was along the coast further south. The severe and frequent frosts of a beginning glacial period would commence much earlier here and last much longer than along the southern coast of Norway. The subaërial denudation would be much increased by the disintegrating effect of the frosts, and the shore erosion (by frost), assisted by the stormy sea, would become very vigorous, planing down the low land, which was already dissected into numerous small islands during previous glacial periods. Finally the probability is that these islands out in the sea, were covered much later by the inland ice than the coast of the mainland, and they were therefore exposed to the destructive forces of a glacial climate, combined with the attack of the sea, during a much longer period than other parts of the coast. It seems to me that these are reasons giving a satisfactory explanation of the occurrence of a very wide and fully developed strandflat in this region, as well as along the coast of Nordland to the north, as we shall see later. It has been maintained, by Ahlmann and others, that the glacial erosion might have helped to plane the strandflat. Such a view seems contradictory to what may now be considered as an established fact, namely that it is greatly the glacial erosion which has dissected the coast into its thousands of islands and skerries. If, for instance, we look at the map Fig. 107, it would indeed be difficult to understand why the glacial erosion should have helped to plane the surface of Smolen and Froia while it has dissected the surrounding land into those swarms of islets, often with 126 FRIDTJOF NANSEN. M.-N. Kl. deep sounds between them. It would seem absurd to think that the same agency could have had such entirely opposite effects in the same region, where moreover there would be no apparent differences in the geological structure to account for it. The fact is obviously that the geological erosion has generally and everywhere a pronounced tendency to dissect the land surface and not to plane it. It might be asked why the strandflat of Smølen is somewhat lower and much more even than that of Hitteren and also to some extent than that of Froia. The reason may chiefly be differences in the geological structure, the rocks of Smølen having been more easily and more evenly eroded. The situation of the islands may also have been of some ima portance. Although in my opinion, the shore erosion by frost has been the most vigorous factor for the marine denudation, the work of the waves (the surf) has also been very important especially for the transport of the waste, and it is obvious that Smølen and to some extent Frøia has always been exposed to a more effective wave action than the more pro- tected Hitteren, as in this region the prevailing winds were probably always southwesterly, as long as the Norwegian Sea was not ice-covered. I have pointed out before that the wave action on a coast exposed to the full fury of the open sea, may also have a tendency to wear down the strandflat cut by the shore erosion by frost to a level somewhat lower than the initial one. I do not believe, however, that this would be a feasible explanation of the comparatively low flat level of Smølen, be- cause in that case its plane would naturally be expected to slope somewhat seawards, and could not be so almost perfectly horizontal as it actually is, differing only some few metres in height from north to south. It is, however, a question whether there are not two levels of the emerged strandflat in this region as in other regions of the Norwegian coast. In that case we may expect the plane of Smolen to belong to the lower level, it having almost exactly the same height as the lower level of the strandflat at the mouth of Sogne Fjord. From Trondhjem Fjord to Vikten. Along the coast between Trondhjem Fjord and Folla Fjord there is a distinctly developed strandflat in front of the steeply ascending moun- tains, and there are many submerged platforms with swarms of islets and skerries outside the coast. The width of the strandflat from the foot of the mountains to the edge of the submerged platforms, at less than 20 metres below sea-level, is not very considerable in this region, and decreases northwards from about 17 kilometres in the region of Melstein and Lovoi (63° 56’ N. Lat.) to a few kilometres in Folla Fjord. The coast of this region is built up of pressed igneous rocks generally considered to be of the Archean age, but which Schetelig [1913] holds to be vounger. 1921. No. 11 THE STRANDFLAT AND ISOSTASY. 12 —| To the north of Folla Fjord a group of numerous islands, with a submerged platform outside, extend far seawards from the coast of the mainland. It is Vikten with its innumerable islets and skerries built up of granite. These islands and platform are probably situated on a con- tinuation of the large folding ridge or anticline on which the Froan Islands are situated to the southwest [cf. Nansen, 1904, Pl. XI]. A strandflat with heights less than 30 metres above sea-level, extends over a great part of Inner Vikten island. But many small hills rise above the level of the strandflat to altitudes of 40 and 50 metres and more, and several greater hills or ridges even to between 100 and 150 metres. On the whole the strandflat has not been developed to any high degree of maturity on this island and that is still less the case on Outer Vikten, but the islands to the north: Kalvoi, Borgan, Rodoi, &c., are very flat with a conspicuous strandflat, and only some few isolated hills rise above 30 metres. It is obvious that the general level of the strandflat in this region, wherever it has been developed, has a height of less than 30 metres or perhaps nearer 20 metres above sea-level. The area with heights between 30 and 60 metres ıs only a verv small part of the low land, and the foot of the hills, surmounting the plane of the strandflat, may as a rule be considered to be below 30 metres above the sea. This is still more marked further north along the coast of Helgeland. In this respect there is a difference between the strandtlat of these northern regions, and the strandflat of the Norwegian west coast further south. For instance, in the regions of Radoi, Store Sotra, Bømlo Island and Stord Island, &c. the greater part of the low land forming the strand- flat is somewhat higher than 30 metres above sea-level, on Stord Island even higher than 40 metres. In the regions of Karmoi and Stavanger a considerable part of the strandflat is higher than 30 metres, although a great part of it is about 20 metres high or even less. On Smolen the whole strandflat is less than 30 metres high, to a great extent about 20 metres or less. On Froia a great part of the strandflat is less than 30 metres high, but about an equal area is between 30 and 60 metres or largely between 30 and 40 metres. On Hitteren Island the strandflat is largely somewhat higher than 30 metres, though along the northwestern coast of the island a considerable part of it is lower. The many islands north of Froia are lower than 30 metres and largely about or lower than 20 metres, and so are the Froan Islands, where only three or four solitary hills on Væroi, Risoi, and Kunna rise to 31, 35, and 49 metres above the sea. On the whole the emerged strandflat seems consequently to be some- what lower along the northern part of the Norwegian coast, north of the Romsdal region, than we have found it to be south of the Sogne Fjord region. 128 FRIDTJOF NANSEN. Outside the Vikten islands, to the south, west, and northwest, there is a submerged platform, 10 to 17 kilometres broad, with a perfectly bewildering number of low islets, skerries, and shoals. The great majority of the thousands of shoals and sunken rocks on this platform is very nearly at sea-level or only a few metres below it. By far the greater part of this submerged platform has depths of less than 15 metres below sea-level, and its general level is less than 10 metres below the water. It forms a fairly even and horizontal plane extending over many kilometres. It is traversed by many narrow chan- nels, sometimes 50 to 100 metres deep, and at its outer border the sea- bottom falls abruptly towards depths of 150 to 200 metres of the sea outside. The edges of the platform along the traversing channels as well as along its outer border are as a rule very sharply defined at depths of less than 10 metres. It is the same kind of platform as those extending northwest of Smolen, and north of Froia, with a general horizontal level at only some few metres below sea-level and sharply defined edges along the outer borders as well as along the many traversing channels. It seems obvious that after these channels and depressions had first been formed, the initial projecting peninsulas and islands have been truncated at a level some few metres below present sea-level, to form these very even horizontal planes, which may have been still more even at first before they had been exposed to the subsequent erosion of glaciers. Along the coast of Helgeland to the north, similar platforms have a still wider extent, and when describing that coast we shall return to the question of their formation. 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 129 he PE STRANDFLAT OF NORTHERN NORWAY. Helgeland. The strandflat is very conspicuous and extremely well-developed along the coast of Helgeiand between Vikten and Vest Fjord. It consists partly of an as a rule sharply marked plane or planes extending over the hundreds of low islands and peninsulas, and to a still greater extent of very flat submerged platforms with thousands of skerries, rocks, and shoals. It has an average breadth of 40 to 45 kilometres as stated by J. H. L. Vogt [1900]. In some places it may even be 50 kilometres wide, or more, from the steep mountain sides on the mainland to the cuter edg: of the submerged platform out to sea at less than 20 metres below sea- level. The strandflat of Helgeland has been described by J. H. L. Vogt [in 1900 and in 1907], and after him by several authors, especially Hog- bom [1913], Oxaal [1914], Sahlstrom [1914], and Rekstad [1915]. In the two latter papers there are given some most illustrative pictures of the strandflat and the isolated mountains rising abruptly like ‘stacks’ above its plane. The present writer has also previously [1904] described the strandflat along the coast of Helgeland. This coast has a very complex geological structure, and is built up of a great variety of rocks. They are chiefly mica-schists, granites, young gneisses, limestone, gabbro, some syenite, and some serpentine. Th s2 rocks vary much in their power of resistance to erosion, the granites and gabbros and also the serpentine (on Leka) and the gneisses are as a rule Fig. 113. Map of the coast of Helgeland from Bindal Fjord to Donna Island. Scale r : 350,000. Black areas on land are lower than 30 metres above sea-level. The dark hatching on land indicates areas between 30 and 50 metres above sea-level. The light hatching in the sea indicate submerged plateaus with depths less than 25 metres below sea-level. /sobaths are drawn for every 50 metres of depth. 7. e. for 50, roo, 150, 200, 250, &c. The black spots Indicate rocks and skerries above sea-level. The small crosses indicate sunken rocks and shoals. crosses with spots indicate rocks near sea-level, and dotted areas shoals near sea- level. The figures on the land and in the sea give the heights and depths in metres. I Vega Island. II Sola Island. III Ulvingen Island. IV Hamnoi. V Tjøtta Island. VI Alsten Island. VII The mountains ,Syv Søstre" (Seven Sisters). VIII Herei. IX Donna Island. Vid.-Selsk. Skrifter, I. M.-N. Kl. 1921. No. rr. 9 g - - LAIT 27 y 8% TE | yy WE, Res 7 Gr all ty ” "e * A r TIL 5 777 9 j Wy, Noe IL, y My 4 " / N IM. f Vy, Ps >T Y hy Å ") 7 I a Wire SEE / ÆN Z JU MW) PIN) Za" hy, m Le ; A — — oe t7 L ee Uu S, - - Xi 2 K.. M.-N. NANSEN. FRIDTJOF MEME c i er 1921. No. 11. THE STRANDELAT AND ISOSTASY 133 Fig. 114. Map of coast of Northern Helgeland, northward Continuation of the map Fig. 114. Besides the Isobaths for every 52 metres of depth, the Isobath for 25 metres is drawn with dotted line. I Vandved Island. II Donna Island. III Lokta Island. IV Lifjell on the mainland. V Hugla Island. VI Handnesoi. VII Tomma Island. VIII Hestmannoi. IX Nesoi. X Sornesoi and Lyngvær. more resistant than the limestone and the mica-schists. None the less the strandflat often cuts horizontally through the various rocks, without any appreciable difference in height, straight to the foot of the mountains and hills rising abruptly and steeply above its plane. The region of Solver and Lovunden (see Fig.114) may be mentioned as an illustrative example. The many islands of Solver consist of mica. schist and limestone on the southeastern islands, gabbro on the south- western islands, granite on the northern, and mica-schist, limestome, gabbro, and granite on the northeastern islands. Lovunden mountain, as well as the low islets to the east, south, and west of it, are built up of gneiss, while the low islands of Lovundver to the north and northeast consist of granite, gneiss, mica-schist, and limestone. All these many islands, built up of rocks varying so widely in their power of resistance, are cut down to an almost perfectly horizontal plane at about 10 metres above sea-level, and the plane extends at the same level to the foot of Lovunden, which rises abruptly as an isolated ‘stack’ to 619 metres above mie sea |cf. Nansen, 1904, Pl: V, Fig. 1]. This is a convincing piece of evidence that the plane of the strandflat has been cut by an agency working horizontally, 1. e. by the shore erosion. and cannot have been formed by the vertically working subaërial denu- dation, nor by glacial erosion, which would necessarily have produced a marked difference in height between the regions of more and of less resistant rocks. The plane cuts in many cases so evenly across areas of entirely different rocks that it can only be explained as an effect of the shore erosion by frost. The wave erosion cannot have had very great direct effect, because it would produce greater difference in the level of the rocks with different power of resistance. In other cases there is such a difference, which may be accounted for by the wave erosion. The mountains rising as ‘stacks’ above the strandflat consist very often of granite, e. g. on Vega and Sola islands, but in some cases, e. g. on Lovunden and Hestmannen (Hestmannoi), they are built up ‘of gneiss, although the gneiss in other regions has been much denuded, and forms parts of the very low and level plane of the strandflat. The reason why the strandflat is so well-developed along the coast of Helgeland may be especially two fold: On the one hand the severe climate of this northern region has been especially favourable for the subaérial denudation as well as for the shore erosion. It is for this latter reason that in postglacial time the now raised shore-ledges have been 134 FRIATJOF NANSEN. M.-N. Kl. so well-developed in this northern region, and still better further north in Tromsø Fylke and Finmark, while they are hardly seen along the coasts of southern Norway. On the other hand the rocks forming the outermost coast of Helgeland are on the whole less resistant to erosion than the rocks of the Romsdal and Sondmore region and also on the whole less resistant than the igneous rocks of Lofoten and Vesterälen. It is furthermore probable that the initial outer coast land 'of the Helgeland region was comparatively low, and that no great quantity of rock had to be planed down for the formation of the strandflat, after this land, consisting of the low outer folding ridges of the great Caledonian mountain folding of Northern Norway, had been dissected into thousands of islands by the glacial erosion. The stage of development of the strandflat varies somewhat in the different parts of the coast. In some regions, c. g. in Heroi, Donna, and Solvær, the emerged surface is quite unusually level, whilst in other regions, e. g. on the Vikten islands, in the region of Torghatten, &c., the surface is undulating with more hills and ridges rising to different heights above the plane of thé strandflat. This depends naturally on the degree of maturity to which the strandflat has been developed. In regions with less resistant rocks, or where the land was more dissected into smaller islands, and where there was much less rock to be planed down, the strandflat was sooner developed to full maturity than in regions where the conditions were less favourable. Along a coast where the conditions differ much in this respect we may therefore expect to find the strandflat in all stages of maturity. It has to be admitted that if one considers the strandflat to have been formed solely by wave erosion, it might be difficult to understand how any strandflat at all could have been formed in regions where numerous hills and ridges are still rising above the plane of the strandflat, with no great distance between them. One would expect that the waves would have had to wear down the hills on the seaward side first before they could obtain the necessary force to erode a strandflat further inland. But in a severe climate the effective shore erosion by frost works simultaneously along all shore-lines, on the outer as well as the inner sides of the islands and peninsulas, and in all small creeks and bays. The islands will thus be attacked from al! sides, and by the joint action of subaerial denudation, the shore erosion by frost, and the waves carrying away the débris, the strandflat may gradually be developed to different stages of maturity in the whole indented and dissected coastal region at the same time. Fig. 113 gives a map of the strandfiat along the coast of Helgeland from Bindal Fjord to Donna Island. As material for the drawing of this map, I have used the excellent detailed charts in the scale of 1: 50,000, and the maps ("Gradavdelingskarter") in the scale of 1:100,000, published 1921. No. r1- THE STRANDFLAT AND ISOSTASY p by the Norwegian Geographical Survey ("Norges Geografiske Opmäling”). The black areas on the land have heights lower than 30 metres (100 feet) above sea-level, the dark hatching on the land indicates areas with heights between 30 and 50 metres above sea-leve!, and the light hatching in the sea indicate submerged plateaus with depths less than 25 metres below sea-level. The black spots in the sea indicate islets and skerries rising above sea-level, and the small crosses mark sunken rocks and shoals. Isobaths are drawn for every 50 metres below sea-level. The figures on the land and in the sea give the heights and depths in metres. Maps ot the same coast have been published by J. H. L. Vogt (1900, pp. 36—37] giving the emerged and submerged strandflat in less detail, and by J. Rekstad [1915] giving the isobaths of the sea. Our map Fig.113 shows that the greatest part of the emerged strand- flat has heights less than 30 metres, and the areas with heights between 30 and 50 metres are comparatively so very small that it may seem doubt- ful whether they can be considered as actually belonging to the strandflat, the base of the steeply and abruptly ascending hill-sides being as a rule lower than 30 metres above sea-level. it has already been (p.127) pointed out that the general level of the emerged strandflat is on the whole lower in this northern region than along the coast of Norway further south. I have not had an opportunity of actually measuring the height of the strandflat along the coast of Helgeland, but as far as I can make out from the maps, from my photo- graps, and from the most accurate measurements made bv previous in- vestigators, especially Sahlstrom, the general level of the emerged strand- flat of Helgeland seems to be between ro and 20 metres above sea-level, and in some places even somewhat lower [cf. Sahlstrom, 1914. I shall return to this subject later, but wish first to draw attention to another striking feature in the formation of the strandflat of this region brought out very clearly by our map. It is the wide extent of the very flat submerged plateaus of the strandflat. In this respect the strandflat of Helgeland differs entirely from that of Southern Norway. Along the coast south of Sogne Fjord, the submerged strandílat 1s insignificant as compared with the extent of the emerged strandflat. Along the coast northwards the submerged strandflat increases in extent. In the region of Smolen and Froia the area of the submerged part of the strandflat at least equals that of the emerged part (cf. Fig. 107) and in Helgeland the area of the emerged strandílat is very small as compared. with that of the submerged strandflat. The depth below sea-level of these submerged plateaus, indicated bv the light hatching, is less than 25 metres, and by far the greater part of them have depths less than 10 metres, as is demonstrated by the detailed map Fig. 115 of the Hysvær Plateau to the northwest of Vega and Sola islands. This map is based upon a small part of No. 54 of the Norwegian » SEC M x den À al i | | NY N N N | AY eee =, a eS et em ee ae LO OO war NA) en ee = ZA zi ZZ SSS SSS >> = ——<_ — — NS — a EL SL OO Ze I SE a a a a TT ME A M A PS LEE OO A e IIIT a = LE 122222 = = az - Jae | ae 39% 2 BE ica -schist Geanite Fig. 115. Explanation 36° 0 METRES Ze i Ls am p = = | LM = m pi = — a (ur er a a o o = | À ee run 2272272 na a ts — : SESS rm oo ass Sa wee ee OF een h next page. 138 FRIDTJOF NANSEN. M.-N. Kl. Fig. 115. Chart of the Hysvær Plateau, northwest of Vega and Søla islands, based upon the Chart No. 54 published by ,Norges geografiske Opmáling". The figures in the sea indicate the depths in metres below low-water level, which is about 1.5 metres below mean water-level. detailed charts of the coast of Norway. It is given here as a characteristic illustration of the detailed surface relief of these submerged plateaus. The figures give the depths in metres below lowest water-level, which is about 1.5 metre below mean water-level: Isobaths are drawn with dotted lines for 5 metres, with broken lines for 10 metres, with thin lines for 20 metres, and with thick lines for 50, 100, and 150 metres of depth below lowest water-level. The isobath for 10 metres follows as a rule very closely and at a very short distance the isobath for 20 metres, so that the area bounded by the latter contour line is not substantially larger than that bounded by the 10 metres line. The isobath for 5 metres demonstrates that the greater part of the surface of the plateau is even less than 5 metres below lowest water-level, and over great areas the depths are between 0.5 and 3 metres. The general horizontal level of this plateau may be said to be between 2 and 7 metres below mean sea-level, and in its northeastern part near the islands of Hysvær, it is almost in the sea-surface. Fig. 116 gives a profile across this plateau along the broken line in Fig. 115, passing across Søla Island northwestwards to Skjærvær and thence seawards. This profile demonstrates the remarkably horizontal evenness of the plane of this plateau, in which the channels and hollows form sharply defined depressions with well marked edges, mostly at 3 to 4 metres below mean sea-level. The even surface of this submerged plateau has obviously much resemblance to the even planes of the emerged strandflat, e. g. on Dønna and Herøi, described by Sahlstrøm and mentioned later. The other submerged plateaus shown in Fig. 113, have a similar surface relief, but their outer parts in the northern and southern regions of this map are somewhat more broken and irregular. The Hvsvær Plateau has a width of about 15 kilometres, and the other submerged plateaus have a similar extent. Several writers, the present one included, have stated that the edge of the submerged strandflat of Helgeland is at 20, 30 or 40 metres below sea-level. This is hardly correct and is apt to give an entirely wrong impression that the plane of the strandflat slopes to such a low level. As we have just seen the almost perfectly horizontal plane of the sub- merged strandflat lies very near present sea-level, and, as Fig.115 demon- strates, the edge of this plane is sharply defined at guo of less than 10 metres below the water suríace. I92I. No. r1. THE STRANDFLAT AND ISOSTASY. 139 It may be asked whether these extensive horizontal plains have actually been cut in solid rock. The many hundreds of islets and skerries, scattered over their surface and rising above sea-level, prove, however, that they must be rocky plateaus, although this does not make it impos- sible that their surface may to some extent be levelled bv loose material. The sharplv defined channels traversing them, with well markel edges and the sharply marked edges on their outer seaward borders where thev are exposed to the full fury of the ocean, creating a violent surf, se>m, however, to prove that the horizontal plane of these plateaus is actuallv to a very considerable extent cut in solid rock. It 1s obvious that horizontal, rockv plateaus, with wide dimensions such as these, cannot have been formed in postglacial time, nor can thev be cut by wave erosion. Thev must have been finally planed by shore erosion by frost at some period or periods before the last glacial epoch. As they have so much wider an extent than the plains of the emerged strandflat on the islands and the mainland thev may possiblv have needed a longer time for their formation than the latter, although we have to consider that the previous strandflat over these now submerged plateaus was probablv low, and that it was much dissected. In the region of Donna and Heroi Sahlstrom [1915] has studied the emerged strandflat, and has by very accurate levelling constructed some in- structive profiles across the northern flat part of Donna, across Southern Heroi, and across Blomsoi (Fig. 113). The strandflat forms here quite remarkably flat and extensive planes. On the northern part of Donna (see Fig.114, II) the plane is 9 to 10 metres above sea-level, and in some places (Rolvag) 11 metres. There are numerous small depressions and small vallevs, but they are as a rule only some few metres below the uniform level of the solid bare rocks projecting in the surface of the ground, and are often not so large that in my opinion a great many of them may not more or less have been formed originally when this strandflat was planed by the frost in the shore and by the waves, and have only been slightly modified later by subaérial denudation and by glacial erosion. As mentioned before, there is a great resemblarce between these planes and the level surface of the submerged plateaus in the sea outside. Some few isolated hills rise above this plane to heights of 21 to 35 metres above sea-level, and near the east coast of the island to 42 and 50, or a few even higher. The plane extends horizontally to the foot of these hills and there is as a rule a quite sharp demarkation line, almost like a shore-line, which, however, is often covered by shore gravel, and talus débris. The region of the strandflat of the northern part of Donna is built up of mica-schist, gneiss, and to some smaller extent of crvstalline limestone. I 4.0 FRIDTJOF NANSEN. A N WS N SER RN NIS ANY x WY; N. za Tuff ZH Mica- schist Fig. 116. Profile along the broken line in the map Fig. 115 north-westwards from Sela Islands "m N ! the horizontal scale. The profile in black on The northern part of Southern Heroi, south of Donna (see Fig. 113), consists of gneiss-granite, mica-schist, and limestone. This region also forms a strandflat with a very level suríace 8 metres above the sea. The same level plane with the same height of 8 metres also occurs on Northern Heroi (Fig. 113, VIII) to the east and, as Sahlstrom points out, it is note- worthy that the small rock in the sound beween the two islands has a flat surface at just the same level. This is convincing evidence that the plane has been formed by marine denudation (7. e. shore erosion by frost) after the sound had been deepened approximately to its present shape by glacia! erosion. The relief of this level surface cannot have been much modified by glacial erosion after this small rock had been truncated, for otherwise its flat top surface would certainly have been rounded and worn down to a lower level. Across the middle part of Southern Heroi the strandflat forms a very level plane between 6 and 7 metres above the sea. The ground is composed of gneiss and limestones which are planed to exactly the same level. In the southern part of Southern Heroi the plane of the strandflat is between 4 and 5 metres above the sea, but not quite so level as further north, ridges of gneiss-granite often rising slightly above the crystalline limestone which forms the greater part of the surface. As Sahlstrom points out, it is noteworthy that on the remarkably even strandflat described above two kinds of rock so very different as to their power of resistance as granite and limestone, are in some places planed to exactly the same level, and in other places the difference of denudation is only a couple of metres. According to Sahlstrom's measurements, as mentioned above, the plane of the strandflat slopes slightly southwards, from about ro metres above the sea in the northern part of Donna to 4 or 5 metres in the southern part of Southern Heroi. Sahlstrom considers it possible that 1921. No. 11. THE STRANDFLAT AND ISOSTASY. TAI — LD LL 72777 WIE? “SOK AASSKJAERAN Cl GE ? Svær Plateau to Skjærvær and thence seawards. The vertical scale is 5 times exaggerated in relation to E gives the natural relation of height to length. | this might be due to the fact that the limestone of Southern Heroi is less € resistant to erosion than the harder rocks in the north. | It is of much interest that real shore formations, striated by later glaciers, were actually observed by Sahlstrom on the surface of this level strandflat. The lines of demarkation along the foot of the hills rising above the plane of the strandflat are in some places so sharply defined, that they might be called. shore-lines. ——— ee The surface of the many hundreds of very low and flat islands and skerries in the region of Solver and Lovunden, north of Donna (see Fig. 114), is obviously at the same low level which was measured by Sahlstrom on Donna and Heroi. Pictures iilustrating the even flatness of the islands of Solver and the islands surrounding the solitary mountain of Lovunden are given by Rekstad [1912, PI. I, Fig. 1], Sahlstrom [1915, Fig. 14], and the present writer [1904, PL V, Fig. 1]. Rekstad [1915, PI. II, Fig. 1] gives a most illustrative view of the many islands in the region of Heroi, Husver, and Skalver (cf. Fig. 113), west of Alsten Is- land with De Syv Sostre (Seven Sisters). It demonstrates the extreme flatness and low altitudes cf the many islands in this region. There is a striking difference between the low altitudes of these level planes of the emerged strandflat of Helgeland and the heights, generally stated to be between 30 and 40 metres, of the inner boundary or upper limit of this strandflat. Sahlstrom could find no traces of this higher level in the region studied by him. He found the plane with a height of about 8 to 10 metres extending to the foot of the mountains. J. H. L. Vogt [1907, pp. 20 f.] says that, according to his investi- gations along the coasts of Helgeland and the Lofoten Islands, the upper limit of the strandflat, or the demarkation-line ("Knickpunkt") between its nearly horizontal plane and the steeply ascending mountain-sides stands everywhere at almost exactly the same level. In numerous profiles taken -— 142 FRIDTJOF NANSEN. N.-N. Kl. he found it slightly higher than 30 metres above the sea, and he thinks that it may be put approximately at 40 metres above sea-level. From occasional observations during short visits to the coast further north (Andøi, Bjarkoi, &c. in 69° N. Lat.) as well as further south (in the Romsdal region, Karmoi, Haugesund, Bømlo Island, &c.) Vogt draws the con- clusion that the upper limit of the strandflat is fairly exactly at the same level along the whole of the Norwegian coast. He adds, however, that it is impossible to determine the height of the upper limit of the strandflat within an accuracy of some metres, and that the estimate will to a certain degree depend on the observer. But he thinks "that greater errors than 15 to 20 metres are excluded”. As he does not say that his estimate of the heights of the strandflat is based on accurate measurements by level- ling, we may conclude that his figures are not meant to be very accurate, and with possible errors of 15 to 20 metres they give us a broad margin. Though the emerged strandflat of Helgeland mav possibly to some extent, like the strandflat of southern Norway, have two levels, a widely extended lower one, like that described by Sahlstrom, and a much less extended higher one, still I think we ought to receive these statements of the higher levels of between 30 and 40 metres with some caution as long as thev are not based on actual measurements by levelling on the spot. There has obviously been a tendency towards establishing general rules for the heights of the strandflat along the entire coast of Norway, and the limits of these heights have been put at 30 to 40 metres above the sea, and 30 to 40 metres below sea-level. We have seen that along the coast of Helgeland as well as in the region of Smolen, Hitteren, and Froia, where there are well-developed submerged plateaus, this estimate of the lower limit is not correct, the outer edge of the submerged strand- flat being there rather less than 10 metres below sea-level. We have not yet obtained sufficiently accurate measurement to establish the height of the inner edge, or the upper limit, of the emerged strandflat of Helgeland. It seems at any rate to be somewhat lower thcre than along the west coast of southern Norway. ! In Fig. 118 from northern Helgeland the demarkation-line between the low flat strandflat and the very steep mountain-sides is seen. The inner part of the strandflat is to a great extent covered by the scree or talus heaps, formed in postglacial time by stones tumbling down from the mountain-sides, but it is obvious that the plane of the strandflat, hardly 15 metres above the sea, continues under the scree to the foot of the rocky walls at about the same height. J. H. L. Vogt’s description [1907, p. 14] of the strandflat, as a plain sloping gently seawards from its inner higher parts 30 to 40 metres above sea-level to its outer sub- merged edge 30 to 40 metres below sea-level, is also in my opinion some- what misleading. The strandflat is not really one sloping plane, but con- sists rather of several more or less horizontal planes. As we have seen, 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 143 there is in Helgeland one almost perfectly horizontal plane of the sub- merged platform at a level of some few metres below the present sea surface — and there is at least one plane above the sea, measured by Sahlstrom on Heroi and Donna at a level of about 8 to 10 metres Whether there are more planes in this region is not quite certain. Træna. Far out to sea, northwest of Lovund and Lovundvær, separated from their plateau by a deep sea, the Træn Fjord, up to 438 metres deep and 12 kilometres broad, is a submerged plateau with the island-group of Træna (see Fig. 114). We may call this plateau the Træna Plateau. It is 31 kilometres long from SSW to NNE, and about 9 to 12 kilometres broad. Its islands are much scattered, and subdivided into several smaller groups: the Træna Islands proper, in the southwestern part of the plateau, with the biggest islands Sanda (with the high peak Trænstaven, 338 m.) and Husoi, built up of pressed granite, gneiss-granite, Sandavær just north of this group and built up of the same kind of rock, Sandøi (Sandøy, of gneiss-granite) and to the north of it Tørvær (young gneiss) in the middle of the plateau, Dørvær to the northeast, built up of not pressed granite, Arvær and Bäsan or Rosoian (young gneiss) to the northwest of Tørvær and Dørvær, and finally Selvær in the northeastern part of the plateau, built up, in its southern part of mica-schist with layers of crystalline limestone, and in its northern part of gneiss [cf. Rekstad, 1912, geological map). The geology of the islands of the Træna Plateau has been described by J. Rekstad [1912]. John Oxaal [1915] has given an interesting general description of the island-group and its strandflat. There are on these islands many evidences of the vigorous marine érosion, or shore erosion, to which the land has been exposed. As such evidence may be mentioned the precipitous sides of the mountains rising abruptly above the strandflat, the many big caves, the trequently cirque- like valleys (‘botten’ vallevs) with almost vertical sides. The erosion by frost, especially along the shores, has obviously been of the very greatest importance for the development of these formations. When the shore-erosion by frost is greatly intensified during periods with a severe climate, and ıs assisted by the violent wave action of a stormy sea on an exposed coast, as in this region, this erosion will become extremely effective, and will have a great ability to cut away the land. Thus the shapes of the mountains of Træna are simplv explained: the shore-erosion has cut away the land, but on the higher and more resistant islands it has not been able to plane down the whole islands, and the high mountainous parts with their precipitous sides, or shore walls, especially on Sanda Island (pressed granite) and Buøi in Dørvær 144 FRIDTJOF NANSEN. M.-N. Kl. ERTL RE LS SE ee DSR SEER (granite), remain, indicating the initial height of the land, and having on their top often the old surface, or Palæic land surface, extending almost unaltered to the edges of the precipitous mountain sides, which is a con. vincing proof that, during the time when the strandflat was formed, the effect of the subaérial denudation was of but little importance as com- pared with that of the shore-erosion, where the latter was as effective as in this region. Other convincing evidence of the efficacy of the shore-erosion are the many big caves on the islands of Træna. As the floors of these caves are at levels between 29 and 56, and some even at about 70 metres, above the sea [cf. Oxaal, 1915, p. 72], and consequently above the level of the strandflat, they must have been formed during comparatively short periods when the land was temporarily submerged to these levels. The fact that caves such as these formed in granite or gneiss, only occur near the coast and especially on the most exposed parts of it, indi- cates that they have been formed by shore erosion. In my opinion, the chief agency which has helped to form them i; the frost. This is already indicated by the fact that such caves are especially numerous in the northern parts of the Norwegian coast, and the great majority of them do not occur near present sea-level, but at levels to which the land was submerged during the glacial periods, and when there were cold climates. In more arctic latitudes, e. g. on Bear Island and Spitsbergen the caves occur mostly at the present sea-level. As has been pointed out by Rekstad and Oxaal and previous writers, the caves are formed along fracture lines, or lines of weakness, in the rock. Here the frost had easy work by breaking loose blocks along the many fissures of the rock. Where the water in the rock was permanently frozen, its temperature would be near melting point where the rock sur- face was near the sea water, and frequent daily changes in temperature above and below freezing point would be caused by the temporary con- tacts with the warmer sea water, especially due to the tide, but also occasionally to storms. The stones thus loosened by the active frost will tumble down from the roof and the walls of the caves. They will also easily be broken away by the waves, especially during storms, and where the caves have the required shape for it, the alternate compression and expansion of the air ın the caves by the waves, may have a considerable effect in breaking loose the stones, as was pointed out by Rekstad [1912, pp. 59 f., cf. also Oxaal, 1915, pp. 74 f.]. The stones thus broken loose, will accumulate on the floor of the caves, where they will be exposed to a vigorous dis- integration by frost when the floor is alternately submerged and left dry by the tide. Especially during winter, ice is also formed on the floor, and when shifted and broken loose in summer, it may help to carry awav material. That the wave action generally is of little direct importance for 1921. Norr THE STRANDFLAT AND ISOSTASY. 145 the disintegration of the stones is proved by the fact that as a rule little rolled material, pebbles or boulders, are found in the caves. The often cirque-like valleys with precipitous sides on the Træna Islands have also, in my opinion, been formed by the shore-erosion to a very great extent. Oxaal [1915, p. 79] thinks they have been formed by the wave erosion, but I consider it probable that in their formation also the frost has been the chief causal agent, although it has been effectively assisted by the wave action. It may be doubtful whether it is justifiable to make such an absolute difference between these kind of formations and the ordinary cirque valleys. I think the first commencement of these valleys may often have been small regular cirques eroded by small local glaciers or accumulations of snow and ice, in the manner I have discussed before (cf. p. 27, and Fig. 8). This erosion has then been continued by the frost erosion in the shore, of the kind described in Chap. V (pp. 28 ff.), which is to some extent of the same nature as the erosion of the small cirque glaciers. The shore-erosion by frost has at times been vigorously aided by the violent wave action, breaking and carrying away all loosened material. In this manner the combined erosion of frost and waves ad- vances comparatively rapidly along the lines of fracture and weakness of the rock, and forms small cirque valleys which may develop into narrow passes breaking through the mountain ridges. Considering the vigorous marine denudation, to which the Trana Plateau-has been exposed, it was to be expected that it would have a well- developed strandflat, although it is to a great extent built up of compara- tively resistant rocks. It would have been of much interest to know exactly the height of the emerged strandflat and especially its upper limit in this region, as we might expect to find it fairly sharply defined at the foot of the steep mountain sides. Oxaal mentions this strandflat, but unfortunately he does not seem to have actually measured its heights, and neither his description nor his illustrations give any clear indication of the actual altitude of its level plane or of its upper limit at the foot of the mountains. According to the maps ('"Gradavdelingskarter", in scale 1 : 100000) marked "Trænen” and "Lurøy”, the many islands are in general less than 30 metres above sea-level, and only on some few of them does the low land rise to heights of between 40 and 45 metres. The probability seems to me to be that on the many low islands there is, to a great extent, a low level similar to that measured by Sahlstrom on Donna and Heroi. Whether there is also a somewhat higher level approaching 30 or 40 metres is doubtful, but may be possible. The method employed by Oxaal, consisting in measuring with a planimeter the areas between the contours for each thirty metres of height above the sea, and for each ten metres of depth below sea-level, and then drawing a profile of the heights and depths of the plateau accordingly Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. rr. 10 146 FRIDTJOF NANSEN. M.-N. Kl. will give an idea of which heights and depths predominate on the strand- flat, but cannot as a rule be of much value for finding the indications of its original, nearly horizontal levels or planes. In exceptional cases where the contours run more or less concentrically and parallel to each other, it may give fairly satisfactory results. But where, as in most cases, the planes of the strandflat are dissected by numerous channels and depres- sions of varying depths, and where only a part, and perhaps even a comparatively small part, of the area of the strandflat actually indicates its plane or planes, although these may be extended over ridges approaching the outer edge (cf. the Træna Plateau, Fig. 114), there Oxaal's methød will give results entirely misleading for the determination of these planes and their heights. The probability is that it will generally give a more or less graduallv sloping profile of the strandflat with no distinct breaks, and where the planes disappear more or less. From his computations of the kind mentioned above, Oxaal draws the conclusion that the outer edge of the submerged strandflat of the Træna Plateau is at 30 to 32 metres below sea-level. This is hardly correct, and the actual edge of the original plane of the submerged strand- flat is probably nearer the water surface (cf. Fig. 114). But its depth is difficult to determine with accuracv along the outer side of this plateau, as there is no sharply marked break between the plane of the submerged strandflat and the slope of the sea bottom outside, which slopes gently towards the surface of the continental shelf. In this respect there is a striking difference between the outer edge of the strandflat in this region, and the sharply defined edge of the almost perfectly horizontal plane of the submerged strandflat to the south, in the region of Vega (see Fig. 113). We have seen that in the latter region the extremely level surface of the extensive submerged plateau stands only some few metres below the sea surface (see Fig. 115) and extends very nearly to the isobath of 50 metres, which is often quite close to the isobath of 100 metres, there being a sharply marked edge at less than 10 metres (or near 5 metres) below mean sea-level, and a distinct break between the horizontal plane and the slope of the sea bottom outside.. But the surface of the submerged Træna Plateau is much more irregular, with greater and more varying depths, and especially on its outer side there is often a considerable distance between the very irregular isobath of 25 metres and that of 50 metres, and the latter is largely more distant from the isobath of 100 metres than from the islands (see Fig. 114). Along the eastern or northeastern side of the Træna Plateau, at Selvær and northeast of Dørvær, it is different. The isobaths of 25, 50, 100, 150, 200, and 250 metres are there closer together (see Fig. 114), and the surface of the submerged strandflat is more level and nearer the sea surface, with a sharply defined edge at depths of about 10 to 20 metres. 1927. No. rr. THE STRANDFLAT AND ISOSTASY. 147 Oxaal [1915, p. 87] thinks the probable explanation of this fact to be that the eastern, lower part of the submerged strandflat has been cut away by the deep channel, excavated along the inner side of the Træna Plateau, and this channel should then to some extent be younger than the strand. flat. The probability of this explanation might seem to be supported by the fact that the channel 1s deepest, with depths of 420 metres, just east of Selvær, where the submerged strandflat is especially level and high, with a sharply marked edge at about ro metres below sea-level, while further south, southeast of Dorvær, where the channel is less deep (288 metres), the edge of the strandflat is at depths of about 30 metres, and still further south or southwest, south of Dorvar and east of the Trana Islands (Husov), where there is no deep channel, the submerged strandflat has no sharply defined edge. Along the south-eastern side of the Træna Plateau there is also a very deep channel with depths more than 300 metres (and even 438 metres), but the submerged strandflat has no sharply defined edge in this region. Relation between the Differences in the Surface Topography of the Submerged Plateaus and Differences in the Nature of their Rocks. When we come to look at it, however, it is striking that the dif- ferences in the surface relief and the depths of the edge of the submerged strandflat of the Træna Plateau coincide to some extent with differences in its geological structure. Selvær and the northern part of the Træna Plateau, where the eastern edge is so sharply defined at about ro metres below sea-level, are built up of mica-schist and young gneiss, while Dor- vær is built up of granite and the islands of Sandoi and Træna to the south- west of pressed granite, and here the surface of the submerged strandflat is deeper and it has a less distinctly defined edge. There is a similar difference in the slope of the sea bottom outside the western side of the plateau. It is much steeper off its northern part built up of young gneiss than west of the southern part built up of pressed granite. It may be difficult to find a satisfactory explanation of these features. It might seem probable that the greater depths and the more sloping surface of the submerged strandflat of the Trana Plateau, as compared with that of Lovundvær and Solvær region inside and the regions of Gâsvær, Lyngvær, Flovær, Skjærvær, Fuglvær, &c., to the south (see Fig. 113), may, to some extent, be due to the effect of a violent wave erosion, which has been especially effective on the much exposed Træna Plateau, and which has eroded the strandflat after its first planing by the joint effect of the shore-erosion by frost and the wave action. It might be objected that the plateaus, for instance at Lyngvær, Flovær, Skjærvær, &c., have been almost equally much exposed to the fury of 148 FRIDTJOF NANSEN. M.-N. Kl: the waves, and still there 1s a striking difference in the depths and even ness of the surfaces of the submerged plateaus and their outer edges, which are so very sharply marked in the latter regions. There is this difference in the situation that between Lyngvær in 66? 47 N. Lat. and the Engelsbo Skerries (Engelsboskjæran) in 65°31’ N. Lat. the outer coast or edge of the now submerged plateau has been almost continuous (see Fig. 113), while the isolated Træna Plateau has been exposed to the full fury of the sea almost on all sides, but least on the northeastern side where the edge of the plateau is sharpest. It might therefore be expected that the effect of the wave erosion has been greater on this plateau and that especially all loose material has been more completely swept away, while it may to some extent have accumulated in the hollows and de- pressions of the extensive plateau to the south. It is noteworthy that the more isolated submerged plateaus in the northeastern part of the map Fig. 113, at Slaggrunnen and still more at Floholman, have less horizontal and more irregular surfaces than the plateaus to the south and their depths are greater. They resemble the surface on the outer side of the Trama Plateau. The surface of the platform north of Skibatsveer in 66°10’ N. Lat. (see map Fig. 113) and at Jonsgrunnan in 66? 12’ N. Lat. (see map Fig. 114) is still more irregular. Outside Slaggrunnen the sea is less deep and the bottom is also sloping less steeply seawards than along the edge of the submerged plateau to the south (see Fig.113). This is also the case outside Jonsgrunnan (see Fig. 114), but not outside Floholman where there is a fairly steep slope (see Fig. 113). It is, however, a striking fact that just the last mentioned regions at Lyngver, Slaggrunnen, and Floholman, where the submerged surface has so great a resemblance to that of the southern part of Træna Plateau, are also built up of granite, and so are Skibatsver and Jonsgrunnan [Rekstad, 1915, pp. 19 f.]. It is noteworthy that the submerged plateau west and southwest of Lovund and Lovundver has an irregular surface like that of the western side of the Træna Plateau. It is built up of comparatively resistant gneiss and partly of granite. The much dissected plateaus of Nesgi, Sornesei, Lyngver, and Maver, east of Træna (Fig. 114, IX and X) are built up of granite. On the other hand, the most level submerged plateaus with the most sharply defined outer edges, like those of Flover and Lanan — and Sor- ver to the east-southeast of them as well as the plateaus at Ytre Flesan to the north —- are built up of limestone, and so are the northern parts of Vega and the plateau to the north of it (at Kilver). The extremely level plateaus at Husver and Sandver, and at Hysver are built up of mica-schist, and at Skjærvær of a kind of metamorphic tuff (see Fig.115). The plateaus to the south of the latter region, at Fuglvær and westwards to Sjola and southwards to Steinan and Engelsbo Skerries (see Fig.113), are largely built up of granite, and so are Sola, the southern part of Vega, I92I. No. 11. THE STRANDFLAT AND ISOSTASY. 149 and the group of islands called Mudvær to the south of the latter. At Alflesa north of Engelsbo Skerries there is granite and limestone. Although the inner parts of the submerged plateaus of this granite region, e. g. south of Fuglvær, may be almost as level as the plateaus of mica-schist and limestone to the north, their outer parts, towards west and southwest, are less regular, as the map Fig.113 shows, and their outer edge, e. g. at Sjøla, Steinan, and Engelsbo Skerries, is less sharply defined than in the regions of mica-schist and tuff, at Skjærvær, and of limestone, at Flovær and Ytre Flesan to the north. The outer parts of the submerged plateaus of the granite regions have thus a resemblance to the Træna Plateau built up of granite. On the whole as regards their surface relief there seems to be a typical difference between the submerged plateaus built up of granite, or similarly resistant rocks, and those built up of limestone, mica-schist or other less resistant rocks. But irrespective of the differences in geological structure it is natural that the surface of more or less isolated submerged plateaus far out to sea and exposed to the full effect of the breakers, should be somewhat lower and more outward sloping, with a less sharply marked edge. We may also find this in the region of the mica-schist and limestone, e. g. on Skjærværgrunnan outside Skjærvær (see Fig. 113) where the smallest depth is 17 metres and there is no sharply defined edge. At the outer- most edge the plateau southwest of Skjærvær (and west of Hysvær at Flesa, Langtaran, Einarfall, &c., see Fig. 115) also exhibits similar fea- tures. We do not know, however, whether the rock may not be granite in this region, although the island Flesa consists of highly metamorph- osed tuff. We find granite quite near to the south at Sjøla which is obviously situated on the same ridge as Skjærværgrunnan (see Fig. 113). The plateaus at Onsteinen, Ertenbraken, and Storbraken (northeast of Ryggefallan, see Fig. 113) are built up chiefly of mica-schist and to some extent of limestone (e. g. Storbraken). They have the very level and horizontal surfaces near sea-level, with sharply defined edges and very steep side slopes, which are typical of plateaus cut in these rocks. At Horsver to the south the rock is to some extent gneiss, and the islands are more scattered, and the surface is less regular (see Fig. 113). West of Horsver and south of Ryggefallan the submerged surface is very irregular and resembling that of a granite region, and some rocks rising above the sea actually consist of granite. The banks at Hogbraken (southwestern corner of map Fig. 113) may possibly also consist of granite, although they have perhaps more the features of plateaus of mica-schist, with fairly level surfaces, well-marked edges bounded by steep side slopes. 150 FRIDTJOF NANSEN. M.-N. Kl. South of Hogbraken, and far out to sea, in about 65° 12’ N. Lat. and 11° E. Long., is an isolated plateau with the small island-group Sklinna which is built up of granite. The islands are somewhat scattered as is generally the case on granite plateaus, but on the outer southwestern, western, and northwestern side of the islands the surface of the plateau is very level, forming a horizontal plane some few metres below the sea- surface with a sharply defined outer edge and very steep outer side slopes descending abruptly to depths of more than 300 metres. This is more like the typical features of plateaus of mica-schist or limestone. But on the inner side of the islands, towards northeast, east, southeast, and south, the plateau has a more typical sloping granite surface, with greater depths and with no definite horizontal plane, and no sharply marked edge. The plateau of Horta, east of Sklinna, in about 65° 12’ N. Lat. and 11° 25’ E. Long., is built up of gabbro containing a great deal of carbo- nate of lime. Its submerged surface is extremely level forming a hori- zontal plane a few metres below the sea-surface with a very sharply defined edge at the same depth, and with a great number of low small islands, skerries, and rocks scattered over its whole area. As was mentioned on p. 128, the island-group of Vikten built up of granite, and extending far into the open sea, is surrounded on its outer sides by broad submerged platform, exhibiting an almost horizontal plane only a few metres below the sea-surface, with no appreciable seaward slope, and with a sharply defined outer edge at about the same depth, or at least at depths less than 10 metres. The surface of this plateau is, however, less level and more dissected by channels and depres- sions than the very level surface of e. g. the Hysvær Plateau built up of mica-schist. As a result of the above cursory investigation of the relation between the surface topography of the submerged plateaus and their geological structure we may establish the following general rules: The typical plateaus built up of granite (and also of gneiss) have an uneven surface, the islands on them are lying scattered, their surfaces are much dissected by channels and depressions, and their depths vary much and are often comparatively great. Their surfaces slope outwards, with no well-marked edge, and often the sea outside is not very deep and has an outward sloping bottom, with no very deep channels or hollows, and there is no very sharp difference between the sloping bottom of the shallow parts of this sea and the submerged plateaus of the strandflat. The typical plateaus built up of mica-schist or limestone (or similar less resistant rocks) have a very different surface topography. The is- lands on them are flat and lying close together, only separated by narrow and shallow sounds. The submerged surface is very level with small depths, forming a horizontal plane near present sea-level or only some few metres below it, and the outer edges are sharply defined at about 1921. No. II: THE STRANDFLAT AND ISOSTASY. IS the same depth. The side slopes are generally very steep and there are often channels and hollows with considerable depths just outside or on the sides of these plateaus. It may seem difficult to find a satisfactory explanation of this difference between the two kinds of plateaus. One might have expected that the plateaus of less resistant rocks should have been more attacked by recent erosion, and more denuded, and consequently lower, than the granite plateaus. The only explanation I can find, is that the plateaus of rocks with little power of resistance have formerly had a greater extent, and have formed fairly compact land masses rising above the sea. After the land had been more or less worn down, the outer part of these plateaus have been much cut back, also during the last glacial period, by the glaciers excavating the deep channels and hollows outside them, where the weak rocks offered especially favourable conditions for the glacial erosion. This is the reason why there are often such deep channels and hollows with verv steep side slopes outside these plateaus. It is probable that the erosion of glaciers in rocks with comparatively little power of resistance to frost erosion, produces a very different sculp- turing above and below the water surface. Above the sea the mountain slopes on the sides of the glaciers are much attacked by the frost erosion, and the result is comparatively broad vallevs with sloping sides. Below the sea this is entirelv different, the rocks are protected by the sea against the frost erosion, and there will only be erosion on the under side of the moving glaciers. They will therefore cut narrower channels with steeper side slopes, and sharply defined edges bounding the flat plateaus which will not in interglacial time be attacked and rounded off by frost erosion or subaerial denudation against which they are protected by the sea. The still remaining middle parts of the plateaus were truncated by the shore erosion comparatively recently. They are, therefore, very level, standing near present sea-level, as there has been but little time for the wave erosion or for glacial erosion to wear them down to greater depths. It might be asked where are the older plateaus cut in this kind of rock? and why do we not find them at lower levels? The answer may be that where the older plateaus were cut in weaker rocks, they have been more or less cut back by the glaciers during the subsequent glacial periods, and they no longer exist as parts of the submerged strandflats. The map Fig. 113 also shows that the outer edges of the plateaus of mica-schist and limestone, e. g. at Flovær and Skjærvær, are cut back more than the edges of the granite plateaus at Lyngvær, Slaggrunnen, and Floholman to the north, and at Sjøla and Steinan to the south. The plateaus at Ertenbraken and Storbraken are also cut back with deep channels and hollows round them. 152 FRIDTJOF NANSEN. M.-N. KI. Fig. 117. Southward view from Melsivær towards Amoi. Strandflat cut in granite. (Sept. 9, 1912). The plateaus built up of granite, or hard gneiss or similar resistant rocks, have not been cut back by the glaciers like the plateaus of weaker rocks. Their surfaces are therefore to a great extent older, and the sea outside them less deep and with more gradual slopes, as the glaciers had more resistant rock to work in. The surfaces of the plateaus are more uneven because, during the length of time after they were first formed, they have been exposed to much glacial erosion, dissecting them and making them more irregular and sloping. The channels between the islands have also been widened, producing the appearance of more scattered is- lands. The wave erosion must also have had some appreciable effect upon the surfaces, especially of the outer parts of these plateaus, during the long time they have existed; and may have lowered them. Smaller and more isolated plateaus outside the greater ones, may have been lowered to varıous depths by glacial erosion, as well as by wave erosion, and owing to the resistance of their rock they have not been cut away by the glaciers like those of weaker rocks. Coast of Northern Helgeland and the East Coast of West Fjord. The outer coast of northern Helgeland, north of Solvær and Lovund, and the coast farther north along the eastern side of Vest Fjord is chiefly built up of granite and to some small extent of gneiss, i. e. rocks with much power of resistance to erosion. It is therefore in accordance with what might be expected, that neither the emerged nor the submerged strandflat are developed to any great width in this region. But the emerged strandflat is seen almost everywhere along the shores, forming a flat, low foreland in front of the steep mountains (cf. Fig. 118) on the peninsulas of the mainland and on the high islands, and its low .plane extending seawards over the various groups of small low islands (see Figs. 3, 117, and 119). Being largely cut in granite the surface of these islands is often somewhat uneven, with small rounded knolls (see Fig. 117). Rekstad gives [1913, Pl. I, Fig. 11 a most interesting illustration of the uneven surface of the strandflat cut in granite on Briksvær Island, in 67? 16" N. Lat. and 14? E. Long. It consists of a great many rounded 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 153 ee ele Pa D De So. EEE Fig. 118. Strandflat cut in granite at the foot of steep granite mountains near Kunna south of Salt Fjord. (Sept. 9, 1912). knolls with steep sides and fairly deep depressions between them. But the summits of the knolls are to a great extent at the same level of about 30 metres or somewhat more above the sea. I have had no opportunity of measuring the heights of the strandflat along this coast, but judging from the impression made when seen from the sea (cf. Figs. 117, 118, 120, and 121), I believe that there is, at least to some extent, a low level similar to that measured by Sahlstrom on Donna and Heroi. There is possibly also a higher level as, for instance, indicated by the summits of the many rounded knolls on Briksvær Island, mentioned above. Ahlmann says [1919, p. 205! that on the seaward side of the fairway between Sandnessjoen and Bodo "there occur continuous level suríaces at 5—10 metres and at 20—30 metres altitude above sea-level”. The picture Fig. 119 of the island Landegode, north of Bodo, shows two levels, the low level of the south-westernmost point of Landegode and of the islets to the west, and a higher level on the southwestern part of the island in front of the steeply ascending mountain side (partly covered by a fog in the picture). As pointed out by Rekstad [1913, p. 15] this plateau is about roo metres above sea-level, and cannot therefore belong to the strandflat we are discussing in this paper. But it has ob- viously been cut by shore erosion. It is noteworthy that it has very nearly the same height as a similar plateau (or "shore-line") at Torghatten which is about 109 metres above the sea [cf. Rekstad, 1915, p. 45 -and PI. VII, Fig. 2]. I consider it probable that these plateaus may be remnants of an earlier strandílat, perhaps formed at the beginning of the first Great Ice Age. They are in both these cases cut in granite and have thus been able to survive later erosion. Remnants of an old strandflat at a similar level may perhaps also be found at other places, e. g. on the Viker Mountain (granite) northwest of Torghatten where there is a fairly ex- tended plateau, on the coast of the mainland inside on the southern side of Sonnesviken, on the southwestern corner of Vega (granite), &c. 154 FRIDTJOF NANSEN. M.-N. Kl, Fig. 119. Low land on south-western end of Landegode Island, with strandflat øn small islands outside. (Sept. 9, 1912). The submerged strandflat round the islands has no great extent along northern Helgeland and the coast to the north, and it rapidly dimishes in width northwards towards Vest Fjord, forming only a nar- row strip along the coast of the mainland, and small platforms round the island-groups out in the sea. Its surface is on the whole uneven and irregular and has much the same type as that of the southern part of the Træna Plateau. There may, however, be some difference: All the submerged plateaus with small island-groups built up of granite have very uneven surfaces, dissected by numerous channels and depressions, and especially far out to sea their surfaces are sloping outward towards the deeper sea on the sides without any sharply defined edge, and the depths of the plateaus vary much, so that it is difficult to find anv special depth which might be said to indicate the levels of their initial planes. Outside these plateaus of granite there are also as a rule a great manv isolated small shoals standing at various depths and indicating no definite plane. As examples of sub- merged granite plateaus of the above kind may be mentioned the plateaus of Myken, Valvar, and Skjerver, northwest of Træna, with numerous isolated shoals, and the plateaus of Rorstapvær and Gronna far out to sea in about 66° 54° to 67° 3’ N. Lat. and 13° 3’ to 13°18" E. Long. with 1e typical surfaces. Some parts of the submerged surface of these plateaus stand very near present sea-level with numerous shoals and rocks almost in the water surface or only some metres below it. One might get the impression that a plane has been cut approximately at this level, but then the ground slopes outward on all sides without any marked edge, and this makes it extremely difficult to decide what the depth of the level actually is. In many cases the surfaces of the plateaus slope more gradually outwards on their outer, seaward side than on their inner, landward side, where there may even sometimes be more of a well marked edge. This might seem to indicate that the surfaces of these granite plateaus have been eroded to some extent by the wave action, which has lowered their initial levels and made them more sloping. It is very characteristic that the submerged plateau of Fugloiver (consisting of granite), in 67° 3’ N. Lat. and 13° 36’ E. Long. hasse typical outward sloping surface of a granite plateau, while Fleinver only 6 kilometres to the northeast which is built up chiefly of crystalline lime- 1921. No. rz. THE STRANDFLAT AND ISOSTASY. I on On! Fig. 120. Engeloi with the strandflat on Lundøi in front, cut in granite. (Sept. 8, 1912). stone [Rekstad, 1913, p. 4], has a comparatively horizontal surface, with a great number of low islands, and a fairly well marked edge with steep slopes outside not far from the outer border of the islands. The plateau of Helligver, in about 67?24' N.Lat. and 13°54’ E. Long., east of Landegode, has a quite similar surface with a sharply defined outer edge near present sea-level'and steep side slopes. It is built up of mica schists [Rekstad, 1913, p.13]. But the plateau of Lyngver just inside and separated from Helligvær, only bv a narrow channel consists of granite and has the tvpical outward sloping surface of granite plateaus. The small plateaus of Kj«rv«r (chiefly granite) and Steinsvær (granite), between Fleinver and Helligver, have the typical surfaces of granite plateaus. It is also a quite common feature with the granite plateaus that their islands are more scattered, while on the plateaus of less resistant rocks, like limestone and mica-schist, the islands lie as a rule closer together with narrower sounds between them, cf. for instance the striking difference between Lyngver and Helligver lying close together. The small plateau of Terra is built up of a kind of schistose horn- blende rock. Its surface is most like the granite surface. The plateau of Giver far out to sea north of Fleinver is built up chiefly of a coarse mica-schist. It has a fairly horizontal submerged plane with well-marked outer edges some metres below sea-level. The plateau of Karlsoiver, in about 67°33’ N.Lat. and 14°38’ E.Long., on the southern side of the entrance to Folla Fjord, is built up of mica- schist [Rekstad, 1917a, p. 16 and map], and has the typical surface of a plateau of rocks of little resistance, with the numerous islands close together and a sharply defined outer edge some metres below sea-level, and comparatively steep side slopes, while Slovær consisting of gneiss, and situated just to the northeast and separated from Karlsoiver only by a narrow channel, has more the surface of a granite plateau with more scattered islands and less sharply defined outer edges. Still more characteristic in this respect is the plateau of Husver (with Husoi), in about 67° 43’ N. Lat. and 14° 23—44' E. Long., north D"? 156 FRIDTJOF NANSEN. M.-N. KL Fig. 121. Strandflat cut in granite and syenite at Tranøi Lighthouse on Hamargi, near the inner end of Vest Fjord. (Sept. 8, 1912). of Folla Fjord. It is chiefly built up of gneiss [Rekstad, 1919, p. 27 and map]. It has a great many scattered islands, skerries, and sunken rocks, and its submerged surface slopes outwards with no sharply marked edge. Lofoten and Vesterålen. The islands of Lofoten and Vesterålen are to a great extent built up of very resistant igneous rocks: gabbro-monzonites, granites, &c. And as the initial land was high the development of the strandfiat must have been a very slow process in this region in spite of the severe northern climate and the exposed situation of the coasts out to sea. The strandflat is therefore naturally narrow along the coasts of Lofoten and Vesterålen, but in many places it is very conspicuous and sharply marked at the foot of the high steep mountains (cf. Figs. I and 2), frequently forming deep horizonta! incisions in the mountain sides, with precipitous rock wal!s or cliffs behind them. Descriptions of the strandflat of this region have been given by J. H. L. Vogt [1907] and Th. Vogt [1912] and also by Ahlmann [1919] who, however, holds the view that whilst in some places like Værøi its plane is, at least partly, formed by wave erosion, it is along the rest of the coast, what he calls the “distal base-levelled plain”. Th. Vogt gives [1910, PI. IT and III] some very illustrative photo- graphs of the strandflat at Gaukveroi and Hasseloi in Vesterålen, which seem to me to demonstrate clearly how utterly impossible it is that these planes extending horizontally to the foot of the steep mountains can have been formed solely by subaérial denudation (see also Fig. 1 of this treatise). The previous writers have given no accurate heights of the emerged strandflat of Lofoten and Vesteralen, based upon actual measurements by levelling, nor has the present writer had an opportunity of measuring its height. J. H. L. Vogt [1907, p. 20], obviously basing his estimate on the official maps ('"Gradavdelingskarter" in scale I : 100,000), says that the inner edge of the strandflat in Lofoten lies in numerous profiles 1921. Norr THE STRANDFLAT AND ISOSTASY. T5 (probably made from the maps) just a little higher than 30 metres above sea-level. Judging from the impression which the emerged strandflat gave, when seen from the sea in various regions of Lofoten and Vesterålen, and also judging from the many photographs taken, I estimate the height of a great part of it to be about 20 metres or less above sea-level. It is possible that the height of its inner margin, at the foot of the mountains, may be somewhat higher and frequently approach 30 metres above the sea, but its actual height will generally be difficult to determine, as it is to a great extent covered by the scree. In his excellent description of the topographv of the south-western part of Lofoten Th. Vogt expresses himself in a very similar manner. He says [1912, p. 15] that at the foot of some headiands of Vzroi, there are low points the inner boundarv of which at the foot of the almost vertical ciiffs 1s about 35 to 4o metres above sea-level, but he did not directly measure them. "As a rule the demarkation line between the pre- cipitous cliffs and the strandflat is much lower both on Væroi and on the Rost islands, in some places nearly at sea-level, but 1t is frequently hidden by the heaps of stones and gravel fallen from the cliffs." The submerged strandflat of the Lofoten and Vesterålen Islands has a remarkablv small extent, considering the exposed situation of the is- lands. Its surface topography is on the whole most similar to that which we have found to be typical for submerged plateaus built up of granite or other resistant rocks. It has in general fairly great depths, is sloping more or less outwards from the islands, and its outer edge 1s less sharply defined than that of the submerged strandflat of southern Helgeland. The submerged strandflat of Lofoten is most perfectly developed on the two small submerged plateaus farthest out to sea towards the south- west. On the one are situated the two islands «roi and Mosken and some scattered skerries, and on the other the islands of Rost. These is- lands are built up of gneiss and other crystalline schists. Only the rocky island Mosken near the north-eastern end of the Vzeroi Plateau is built up of gabbro and granite. Th. Vogt [1912] has given a most interesting description, with a sketch-map and illustrations, of the emerged as well as the submerged strandflat of these plateaus. Their submerged topography may be studied in much detail in the charts Nos. 70 and 71 (in the scale 1: 50,000) of "Norges geografiske Opmäling”. Both plateaus are oblong with their longitudinal axes in the direction SW to NE. They are much alike as to shape and size. If we take the isobath for 25 metres as boundary the Rost Plateau is about 25 kilometres long, from SW to NE, and about 11 kilometres broad at its broadest. The Væroi Plateau is about 19 kilometres long (from SW to NE) and about 11 kilometres broad. 158 FRIDTJOF NANSEN. M.-N. Kl. Their submerged surfaces are comparatively even, and considerably more so than that of the Træna Plateau, to which they otherwise have resemblances in several respects. Along their middle parts the surface is near sea-level or only some few metres below it forming horizontal planes which on both plateaus extend towards the north-western side, where they come near the outer slopes with fairly sharply defined edges at depths of about 5 or 6 metres below mean sea-level. Towards the opposite, 1. e. the south-eastern, sides of the plateaus their surfaces are more sloping, with less sharply defined edges, perhaps at about 20 metres or more below sea-level. Towards the south-west the surfaces of both plateaus slope more or less gently, and in most places with no well marked edges at any special depth. In their north-eastern parts they have, how- ever, more sharply defined edges at some few metres below sea-level. Rostoi, the biggest island of the Røst Plateau, is situated near its north-eastern end and is quite flat, its highest part being only 11 metres above sea-level. Most of the many other islands on this plateau are also quite low and flat, but some of them form isolated ‘stacks’ with steep sides rising abruptly above the plane of the strandflat to heights of about 100 to 167 metres above the sea [cf. J. El. L. Vogt, 1907, p. 12, The Vea 1912]. They are obviously the last remnants of the old land, which the shore erosion has not managed to plane down to sea-level. On the fairly flat tops of most of these ‘stacks’ {called ‘nyker’) the old, Palæic, land- surface still remains, almost intact, extending with its rounded undulating forms to the abrupt edges of the precipitous side walls [cf. Th. Vogt, 1972, pp: re |. This is still more striking on the island Væroi, where this old land- surface is of a greater extent with sharply marked edges above the precipitous side cliffs [cf. Th. Vogt's illustrative drawing, 1912, Fig. 8]. Here again we have thus convincing proof that, during the last period when the strandflat of this region was planed to its present shape, the effect of the subaerial denudation has been insignificant as compared with that of the shore erosion. As was already pointed out by Th. Vogt, it is striking that on the Rost Plateau as well as the Veroi Plateau, the high islands, being the remnants of the initial land, are all of them situated along the eastern or south-eastern sides of the plateaus, with the greater part of the submerged strandflat on the outer side towards the west and north-west. The natural explanation might seem to be that this is due to the marine denudation which has attacked the plateaus most vigorously on their outer sides. But the above mentioned fact that the surfaces of the plateaus are most level, and nearest the sea-surface in their north-western parts and have the most sharply defined edges along their north-western sides might seem contradictory to this explanation. 1921. No. rr. THE STRANDFLAT AND ISOSTASY. 159 Another feature is also of interest in this connection. Both plateaus are dissected by shallow submerged bays and channels along their south- eastern sides, while there are hardly any such formations along their outer north-western sides. These channels generally indenting the plateaus ir northerly or north-westerly directions may be r5 to r7 metres deep and in some places even deeper than 20 metres. The emerged land is to some extent indented in the same manner. The island Rostoi has several similar narrow bays on its southern and south-eastern side. But it is especially conspicuous on Væroi. The north-western coast of this island is high and steep and is not indented while its whole south-eastern coast is in- dented by two or three cirque-like bays, which Th. Vogt assumes to be formed chiefly by marine erosion. I think he is right, but it is the shore erosion by frost and not the wave erosion which has been of chief im- portance, the same as on Træna (see p. 145). I also consider it to be probable that these bavs may originally have been more or less cirques formed by local glacial erosion. But if the marine ersosion (i. e. the shore erosion) has formed these bays and channels along the south-eastern sides of the plateaus, why has it not produced similar formations along their north-western sides and why is not, for instance, the north-western coast of Væroi indented? It might be answered that on the latter side the marine erosion has been so vigorous that it has cut back the coast sufficiently te obliterate these formations, but this answer would hardly be satisfactory, first, because an increased marine erosion might rather be expected to increase the bays if they are partly formed by it, and secondly, because it might at any rate be expected that traces of these bays and channels should occur on the submerged strandflat outside the coast. This strandflat is, however, very level especially on the north-western sides of the plateaus, and stands nearer sea-level there than on their south-eastern sides. It might be assumed that these channels and bays have to some extent been sculptured by local glaciers on these plateaus, at an earlier time before the land was so much cut back by marine denudation, and the level submerged strandflat, especially on the north-western sides of the plateaus, may then be expected to have been formed by shore erosion during later periods, and to have become so perfectly even because the land was not previously as much dissected in those inner areas. In that case we might, however, expect to find traces of similar submerged channels along the outer north-western slope of the plateaus, but this is not the case, and the edges are well defined near the side slopes of the plateaus in these regions, and are near sea-level. Even if we could assume that because of the meteorological con- ditions, the glaciers especially occurred on the south-eastern sides of the plateaus, this could hardly give a satisfactory explanation. 160 FRIDTJOF NANSEN. M.-N. Kl. To me it seems most probable that these features in the topography of the submerged strandflat of these two plateaus are due to the special structure of the gneiss forming them. The fact that at least some of the submerged channels have more or less parallel directions may also indicate their dependence on the structure of the rock. It may be pointed out that on Moskenesoi to the north-east, there is a similar difference between the coasts, the inner, eastern coast of the island being indented by fjords and dissected by valleys, while along the outer, western coast there are no fjords, and the coast is very steep with an almost continuous mountain-ridge along this side of the island [cf. Th. Vogt, 1912, Fig. 11]. The fjords and valleys of this island are cirques or cirque valleys sculptured by local cirque glaciers. The explanation that the absence of fjords along the outer coast of Moskenesoi is due to the fact that this coast has been cut back by the marine denudation is hardly satisfactory, because we might then at least expect to find traces of the deep fjords on the submerged platform outside the coast. If the difference in the topography of the two coasts cannot be ex- plained by differences in the structure of the rocks, I think it probable that the meteorological conditions may have been more favourable for the formation of cirque glaciers and for the cirque erosion on the south- eastern and eastern side of the initial land than on its outer, western and north-western side. The strandflat of Moskenesoi is entirely different from that of the Veroi and Rost Plateaus. This may to some considerable extent be due to the difference in the rocks, which are very resistant, consisting of monzonite (augite-syenite), gabbro, and labradorite rocks. As pointed out by Th. Vogt, a narrow but well marked emerged strandflat occurs in several places along the inner, eastern coast of the island, e. g. at A, Sor- vag, and Reine, and on its northern side, at Mevold and Valle. But alorg the outer, western coast there are hardly any indications of an emerged strandflat, the mountains falling steeply into the sea. In the case of the submerged strandflat it is quite different; there are hardly any indications of it along the inner coast of the island, the sea bottom sloping without any appreciable break from the coast towards the deep hollow of the Vest Fjord. Outside the outer coast there is, however, a submerged platform, which at least in some places has a fairly well- marked edge. But the depths of this platform and of its outer edge are as a rule much greater than those of the submerged strandflat of Helge- land. In some places there are somewhat higher banks on the platform, with depths of about 20 to 28 metres below sea-level, but to a great extent its depths are about 35 to 40 metres or even more. In some places the surface of the platform slopes gradually from the coast to the depths of the continental shelf without any noticeable edge. Eger SNO! FT. THE STRANDFLAT AND ISOSTASY. 161 If the isobath for 40 metres of depth be assumed to form the boundary of the platform its width varies between 7 and less than 2 kilometres. As pointed out by Th. Vogt the submerged strandflat is most distinctly developed outside the coast at Refsvik (near the southern end of the island) where the land is built up of labradorite rock. He thinks this might be due to the fact that this rock is somewhat less resistant to erosion than the other gabbros of Lofoten. There is here a platform nearly 2 kilometres broad, with numerous shoals and rocks near sea-level and some emerging above it, and the outer edge of the platform is sharply defined. It seems doubtful whether the greater part of the submerged plat- form outside Moskenesoi with its surface at depths between 30 and 4o metres and even between 40 and 50 metres, can actually, in its present shape, be considered as a submerged strandflat. It seems hardly probable that it can have been formed at a level so deep below present sea-level. Th. Vogt may be right in thinking that the reason why there is less of a strandflat round Moskenesoi than on the Værøi and Rost Plateaus, may be that there has been a more vigorous glacial erosion under the high mountains of this island. It seems to me probable that it is the glacial erosion which has lowered the level of the submerged platform along the outer coast of Moskenesoi, although the surface of this platform is more even and less deeply dissected by channels or hollows than is generally the case where there has been an effective erosion by glaciers. It seems also difficult to understand why there is no submerged strandflat along the inner coast of Moskenesoi. The less effective marine erosion on the inner, less exposed coast is not sufficient to account for this fact, for we would at any rate expect some indications of a submerged platform, even though narrow, especially as there actually is an emerged strandflat, and there are parts of a submerged one along the coast further to the north-east in Vest Fjord, and a well developed submerged strandflat often occurs along more sheltered coasts. Is it perhaps possibile that the big glacier which deepened the Vest Fjord, has cut away the submerged strandflat? It is, however, also obvious that the nature of the rocks has some connection with these differences in the development of the submerged strandflat, for here again we find the same feature, that the submerged platforms cut in more resistant rocks have greater depths and more sloping surfaces than those cut in weaker rocks. The gneiss of the Væroi and Rost Plateaus is certainly considerably less resistant to glacial erosion as well as to shore erosion than the rocks of Moskenesoi. It seems probable that these platforms cut in very resistant rocks where the initial land was comparatively high, have required a very long time for their formation. They are therefore comparatively old, and have been exposed to much glacial erosion during several glacial periods. The Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. r1. 11 162 FRIDTJOF NANSEN. M.-N. Kl. result is that they have been more or less lowered, so that their depths have been much increased, their surfaces have become more or less outward-sloping, and their outer edge has been rounded off and is less sharply marked. As was pointed out above, it is, however, strange that the glacial erosion has not sculptured deeper valleys and channels on this platform, similar to those that occur on land. As has been pointed out by Th. Vogt, some mountains and mountain ridges on Moskenesøi have flat tops formed by the initial, Palæic surface of the land, which still exists more or less intact, extending with its undulating level surface to the very sharply defined edges over the pre- cipitous side walls of the many cirque valleys. This proves that in this region during the period when these valleys were finally formed, the effect of the subaërial denudation has been very insignificant as compared to that of the erosion of the cirque glaciers, which works to some extent in a manner similar to the shore erosion by frost, cutting back the sides of the cirque valleys into the mountain block with the initial fairly flat surface on top. The sharp edges between this surface and the mountain walls have thus arisen. Along the south-eastern coasts of Vest-Vägoi and Óst-Vágoi (north- east of Moskenesoi) and the south coast of /Tinnoi, bounding Vest Fjord to the north-west, there is a distinctly developed, although narrow strand- flat, consisting to a large extent of a platform with numerous small is- lands and skerries at the foot of the steep mountains (see Figs. 1 and 2). The surface of the submerged platform between the emerged islands and skerries is uneven and irregular with depths varying between 10 and 50 metres or even more, as they might be expected to be where the platform has been much exposed to glacial erosion. The rocks of this region are gabbros and granites. Along the outer, north-western coast of Flagstadoi, Vest-V agoi, Grimsoi, and Öst-Vägoi there is a narrow submerged platform. In some places, e. g. north of Flagstadoi, it is flat and fairly even, at depths of about 12 to 16 metres below sea-level, having a fairly well marked edge at this level up to 7 kilometres from the coast. In other places it is more irregular. North of Grimsoi there is a 5 kilometres broad and very even platform with depths less than 10 metres, to a large extent between I and 6 metres below sea-level. To what extent these plateaus are levelled by recent sediment cannot be decided. Along the outer coast of Vesteralen, further north, there is an ir- regular submerged platform similar to that along the outer coast of Lofoten. The islands of this region are likewise built up of gabbros, mon- zonites, and granites. There is also a well-marked emerged strandflat along the coasts of the islands [cf. Th. Vogt; 1910, photographs Pls. II and III]. 1921. NO. Et. THE STRANDFLAT AND ISOSTASY. 163 Fig. 122. Strandflat west of Komag Fjord on the southern side of Sørøi, view towards Kobbe Fjord and Öi Fjord. July 6, 1912. Senjen to Ringvasgi. As there are few detailed charts of the coast north of Vesterålen, it is difficult to study the submerged strandflat in this region, but on the whole it seems to have very much the same character as along the outer coast of Lofoten and Vesterälen. Outside the great island of Senjen (where there is a detailed chart, No. 87) the submerged platform is in places as much as 9 kilometres broad, but has a very irregular much dissected surface, with varying depth. The outer coast of this island is also dissected by long, deep fjords. The rocks are to a great extent granites. A submerged strandflat of very much the same character as the one just described to the south-west, extends along the outer coast north- eastwards as far as Rebbenesoi, Grotoi, and northern Kvaloi (70° 16’ N.Lat.). In some places, e. g. outside southern Kvalgi, it attains a width of 18 kilometres (in about 69°55’ N. Lat.). It is much dissected, and carries a great number of scattered islets, skerries, and shoals. The coast is supposed to be built up of igneous rocks similar to those of the coast to the south-west. Finmarken. There are only few indications of a strandflat, above or below present sea-level, along the coasts east of the region of Ringvasoi, northern Kvaloi, and Vannoi. This sudden disappearance of a fairly well developed strandflat coincides in a striking manner with the sudden change in the geological structure of the coast, as I have already mentioned on pp. 50 f., where this fact has been discussed at some length. The lack of detailed charts of this coast with sufficiently numerous soundings prevents us from studying the detailed topography of its sea-bottom, and of possible submerged platforms at deeper levels. In some places, e. g. on Soroi (Fig.122) where there are igneous rocks (gabbro) I have observed indications of what may be considered 164 FRIDTJOF NANSEN. M.-N. Kl. to be an emerged strandflat. But on the whole there are very few such formations along the coasts of Finmarken, which as a rule is extremely steep on the outer, seaward side. It is, however, possible that the low land extending along the coast from Vardø to Vadso and along the north side of Varanger Fjord may be considered as a strandflat, as Reusch has indicated on his map [1894]. As I have pointed out [1904, p. 119] it is also possible that there are indications of an emerged strandflat in the inner parts of the Finmark Fjords, e. g. in the inner end of Porsanger Fjord. 1921. No: T4. THE STRANDFLAT AND ISOSTASY. 165 Fig. 123. Norwegian Harbour (Norske-havn) and Mount Misery, seen from the south. July rr, 1912. [From Nansen 1920]. XI. THE STRANDFLAT OF BEAR ISLAND. The northern part of Bear Island, comprising nearlv two thirds of its whole surface, forms a very flat and low plain (cf. Fig. 124, "Lavt, flatt slettelann"), cutting horizontally through the various geological formation and rocks, and through several faults (cf. Fig. 125), without any appreciable difference in height. Its flat surface is composed of sandstones, shales, limestones, and conglomerates of the Carboniferous and Devonian svstems [cf. J. G. Andersson, 1900 a, and Olaf Holtedahl, 1919]. This plain is about 13 kilometres broad, and about 9 kilometres wide from the north coast to the foot of the mountains which rise steeply from the plain in the southern part of the island (cf. Figs. 124 and 125). Seen from the sea, this plain gives the impression of being perfectly level (cf. Fig. 127). It is bounded along the shore on all sides by a vertical cliff (Figs. 11 and 128), which, according to Joh. Gunnar Andersson, is be- tween 25 and 30 metres high above the sea. Only at some few isolated places is there a gentler slope from the plain down to the shore. Professor Holtedahl informs me that according to his observations the height of the shore cliff may exceed 30 metres and even approach 40 metres on the north-west coast of the island, while it may be but little more than 20 metres above sea-level on the north-east coast in Coal Bay ("Kulbukten") near the Norwegian coal station (see Fig. 124). Perso- nally I have not been ashore in this northern part of the island. Joh. Gunnar Andersson [1900 a, p. 248) says that “from the said height of the cliff (25—30 m.) at the shore the plain rises uniformly by almost imperceptible degrees landwards to the region between the 166 FRIDTJOF NANSEN. M.-N. Kl. * Engelske Slauren Kull-budelen 5 na (skibmirgs- dh 20 reg dant. | flatt (Elisabeth É t Russe-havn = 16 =f, 3 20Norske- ha vr ey Dr = ioHyalross-havrn K.Niülssor Fig. 124. Map of Bear Island, according to the survey of C. J. O. Kjellstrom and A. Ham- berg in 1898, with additions by J. Kessler 1890, and O. Holtedahl 1918. ı Ella Lake. 2 Alfred Mountain. 3 Ymer Valley. 4 Antarctic Mountain. 5 Hamberg Mountain (424 metres). 6 Fugle Fjell (Bird Mountain). 7, 8 and 9 Three peaks Urd (539 metres), Verdandi (465 metres) and Skuld (464 metres) on Mount Misery. Lavt flatt Slettelann is the low, flat plain of the northern part of the island. [From Nansen 1920]. I92I. No. II. THE STRANDFLAT AND ISOSTASY. GN c o Ájells from Herwig H ^ T Kepep { = (TT Fors bery L/ J Ostorvdag(Skibninsros- g d Ream) ¢ Norske kudl-grub | il! TI (li (| U. Ilısery v Trias Eu He) te OU'te Kull-Liol Spirifer kalkdler) dare pvteXuu-lud EEE kalksten) Gul samsten mea konglo- | j "meraber, sansyrl mitre Kul, Muse Que cel mest kalkoten l.rekke Sa le 2 td de age ar Tehradi ks EEE ICH Yrrose dolcrilt À Ladere Ote op CU Hekla -Jezzk j Skifer-kvalsilt zekke (8 ys Lei E N * 9 Fo as "A p 1 * cf EHER nm Fig. r25. Geological map of Bear Island by O. Holtedahl, based on his investigations in 1918, and those of J. G. Andersson in 1898. [Holtedahl 1919). Translation of explanation, to the left: 1 Trias. 2 Younger Upper Carboniferous (Spirifer- 3 Older Upper Carboniferous (Fusulina limestone, &c.). sandstone with conglomerates, probably Middle Carboniferous. Cora-coral limestone). Yellowish 4 5 & 6 Middle Carboniferous. 5 Upper part chiefly limestones with limestone conglomerate at the top. 6 Lower part chiefly red sandstone and conglomerate. 7 & 8 Lower Carboniferous and Upper Devonian 7 Chiefly sandstone. 8 Sandstone often interbedded with shale. 9 Tetradium limestone, Middle Ordovician. sandstone series with coal seams. Io Younger dolomite series, Lower Ordo- vician. II Slate-quartzite series. 12 Older dolomite series, presumably Ozarkian. 9— ı2 Heclahook System. Explanation to the right: 1 Faults, probably older than the Spirifer limestone. 2 Probable faults of the same age. 3 Faults younger than the Spirifer limestone. 168 FRIDTJOF NANSEN. M.-N. KL northernmost part of Oswald Promontory (Oswald's Forberg, Fig. 124) and the western corner of Mount Misery, where its altitude may amount to about 100 metres”. Judging from my observations made from the sea, I understand that it is only in the southern central part of the plain that its surface attains altitudes as high as this estimate. On the south-eastern side of the island, south and south-west of Mount Misery, inside Russian Harbour and Nor- wegian Harbour (“Russe-havn” and "Norske-havn" Fig. 124, see also Fig. 125, D) there is a low land rising gently inland with somewhat similar heights (cf. Fig. 123). During the Isachsen Expedition to Spitsbergen in 1910, Adolf Hoel visited the northern plain on June 24th and kindly gives me the following extract of his diary: “24/6, 1910. Together with Koller, Hävimb, and Malme I went out to take the levels of the plane of abrasion north of Mount Misery. A pro- file southwards from the north point of Bear Island looks like this: Aout /50 m. apove 4 About 50 m. 6 * above Stor Plane of Abrasion Fig. 126. The plane of abrasion extends (from the coast) to a point a good distance north of Mount Misery. South of that point a low, but more broken land begins, which is not a plane of abrasion at all.” Hoel adds that unfortunately the time was too short for carrying out the intended measurements by levelling, the heights given in the above profile Fig. 126 are, therefore, based on aneroid readings, and are not accurate. The altitudes 50 metres and especially 150 metres may be too high. Holtedahl also informs me that in its central southern parts the plain is somewhat less even than further north, and that it rises gently in low ridges towards the higher mountain slopes to the south (cf. Fig. 129). The general level of the very flat northern part of the plain, and of its marginal parts east and west, is between 30 and 50 metres above the sea. On the north side of Mount Misery there is at this level a sharply defined boundary between the level plain and the steeply ascending mountain side (see Fig. 127). I estimate the height above the sea of this demarkation line at the foot of the mountain slope, to be about 30 or 35 metres on the east coast near Cape Levin, and it rises gently with the plain inland. 169 THE STRANDFLAT AND ISOSTASY. No. rr. 1921. '[oz61 ussueN O1 q] ‘SB9-UJIOU 9} won MOIA 'ute[d uioyylou MOT ou} Jo 31ed ve pue ‘Aıssıy juno ‘ed uszayynos SI — puv[s 1804 ‘Ler "314 ss —— SS 170 FRIDTJOF NANSEN. M.-N. Kl. Fig. 128. West coast of Bear Island, showing the horizontal plane of the strandflat, and the hills rising steeply above it. (Photograph by O. Holtedahl 1918). J. G. Andersson says that in its western part the plain is perfectly level. The surface consists there of Carboniferous limestone and sand- stone which by weathering form a boggy argilaceous soil. The region of Spirifer limestone east of North Harbour (Nord-havn) is somewhat undulating, and so is also the extensive area of Devonian sandstones. Over the whole plain there are numerous shallow depressions, with hundreds of small lakes, but no indications of any vallevs. Most part of the plain is covered by débris, big, and small stones, obviously formed in situ by frost disintegration, but in some places. especially in its inner higher part, low flat ridges of bare rock are seen (Fig. 129), as is mentioned by Holtedahl. Andersson considers this remarkable plain to have been formed in preglacial, and posttriassic, time by marine abrasion (1. e. wave erosion), in the manner suggested by Richthofen. “In the weak and easily dis- integrated Devonian and Carboniferous layers which build up this low land, the abrasion has advanced relatively rapidly, while the Heclahook- massive to the south has offered much greater resistance” [1900 a, p. 278]. I think there can be no doubt that Andersson is right in assuming that this is actually a plane of marine denudation, at any rate the lower and flattest part of it, as there is no other process that can cut an extensive level surface like this in solid rock with no valleys and no actual drainage system, only numerous shallow lakes with accidental outlets. According to my view, however, it is not the wave erosion, but the shore erosion by frost that has been the chief agent for the development of this plane as well as that of the Norwegian strandflat. The wave action has been of 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 17% Fig. 129. From the sandstone area in the central part of Bear Island. To the right where the ground is darker is seen a part of a small isolated ridge of Spirifer limestone north of Alfred Mountain. (Photograph by O. Holtedahl 1918). great importance mainly by washing away the débris of the shore erosion, and also by wearing down the outer parts of the plain. We can at present observe this denudation process going on along the shores of Bear Island, where it has formed the vertical shore cliffs, with many small accumulations of ice and snow lying on the beach at their foot during a great part of the summer (see Fig. 11). That the wave erosion also has much direct effect along this weather- beaten coast is demonstrated by the many caves formed in the present-day shore-line [see Nansen, 1920, Pl. IIT]. I have observed such caves in South Harbour (“Sorhavn”, Fig. 124), in Walrus Harbour (“Hvalross- havn”, Fig. 124), and in Norwegian Harbour ("Norske-havn", Fig. 124). Holtedahl has found deep caves penetrating far inland on the south-west coast of the island. The caves are generally formed along lines of frac- ture in the rock. As I have pointed out before (p. 144) the disintegration by frost is, in my Opinion, of much importance also for the formation of caves in this cold climate. Where the average temperature of the rock is below freezing point of water, there will easily be alternate thaw and frost according as the rock surface be washed by the sea or left dry. As far as I have seen, it is on the whole striking to what a small extent the walls of these caves exhibit traces of direct wave erosion, i. e. forms rounded by the waves. The surfaces are generally rough like that of rock exposed to disinte- gration by frost, and the edges are only to some small extent water-worn. Where there are limestones or dolomites, or where there are fractures in the rock filled with limestone, the lime may be dissolved by the sea- water, or also by fresh water, provided that the low temperature of the rock does not prevent liquid water from percolating through the fractures 172 FRIDTJOF NANSEN. M.-N. Kl. Fig. 130. The vertical cliff and the older, undulating mountain surface, on the west side of South Harbour (,Sorhavn"). July ro, 1912. [From Nansen 1920|. The efficacy of the shore erosion on Bear Island is clearly demon- strated by the vertical cliffs, often some hundred metres high, along the southern coast. In most places they bound the older undulating mountain surface of the island with sharply defined edges (Fig. 130). This mountain surface has probably been developed partly by the subaërial denudation in the length of time and partly by glacial erosion. Although the sub- aerial denudation is obviousiv very effective in this region where the rocks have so little power of resistance, and where the disintegration by frost is so very active, it has not been able to keep pace with the shore erosion and round off the edges of the cliff to any appreciable degree, along the exposed parts of the coast. Traces of a strandflat at the same height as the outer parts of the northern plain of the island may also be found along its southern coast where it forms parts of a horizontal platform at the foot of the steep mountain slope (see Fig. 131). Along this part of the coast it has, how- ever, to a great extent been cut away by the effective marine denudation of more modern time. It is a striking fact that there are very few traces to be found of a submerged part of the strandflat near present sea-level round the coasts of Bear Island. In some few places there are narrow submerged ledges, with depths less than 20 metres and with some few rocks emerging above water here and there, but they are hardly more than a few hundred metres broad, and as a rule the sea-bottom near the shore sinks steeply down to depths of 30 and 40 metres. At about this level there is, however, a 1921. No. 11. THE STRANDFLAT AND ISOSTASY. E73 ; " b iN M 7 PE SAN l * ^ M abi CIN Fig. 131. Fugle Fjell (Bird Mountain) on the south side of Bear Island. After a photograph by A. Hamberg 1898. [From Nansen 1920]. submarine platform 9 to 20 kilometres broad, surrounding Bear Island. A similar submarine platform evidently surrounds Hope Island to the north-east, and on the submarine ridge connecting these two islands the soundings indicate three flat banks at the same level, with depths about 30 to 40 metres below the sea surface. The question is whether these platforms ought not to be considered as parts of the strandflat which during times of emergence have been cut down to somewhat lower levels than the Norwegian strandflat. The probability is that they are built up of rocks with relatively little power of resistance to erosion, like those of Bear Island and Hope Island, and they have, therefore, easily been planed off during periods of emergence, even though these may have been relatively short. In my opinion it is impossible that the emerged strandflat of Bear Island (the northern plain) can have been developed to its present shape during preglacial time, neither by marine denudation nor by subaërial denudation. In the latter case a drainage system would have been developed on the emerged, gently sloping plain. It might be objected that all traces of the broad, shallow vallevs of this system have been obliterated by later glacial erosion. But if so, this glacial erosion would naturally have dissected the plain and made it more uneven. By whatever process this strandflat was formed, it 1s obvious that no preglacial plain, as level as this and cut in rocks with so little power of resistance, could have survived the destructive erosion of the glaciers of the great Ice Age. It seems to me probable that this emerged strandflat was planed off to its present level surface by the shore erosion, as I have previously described, during periods when the island was standing somewhat lower (at least 30 to 50 metres) than now. Before that time the island had been 174 FRIDTJOF NANSEN. M.-N. Kl. much denuded by subaérial erosion, intensified by the frost in a climate for the most part severe, and during milder climatic periods by fluvial erosion which developed a drainage system of broad flat valleys, which, however, have been obliterated by the subsequent glacial erosion and shore erosion. During the Ice Ages the land has probably been much denuded by glacial erosion, which, however, has not cut very deep valleys and fjords in this region of soft rocks. Another process which has been of importance for the surface forms and the planing of the land in this region, is the flowing soil (“soli- fluction") [cf. G. Holmsen, 1915), which J.G.Andersson [1900] has studied on Bear Island. By the disintegration of the frost the soft rocks are in many places transformed into an argilaceous mud which, when soaked with water by the melting of snow and ice in the spring and summer, becomes semifluid and slowly flows down the slopes even though they be very gentle. The freezing of the water in this boggy soil and the melting of it again, greatly helps this movement. In this manner the moving soil has a tendency to flow down into the small valleys and depressions and to some extent protect them against the frost erosion, while the higher sloping parts are more or less deprived of their coating of soil and their solid rock is more exposed to the disintegration by frost. This process may have some effect towards planing the land surface, and may help to obliterate the valleys [cf. Nansen, 1920 & 1921, Chap. II]. The northern plain is, however, to a very great extent covered by stones formed by the disintegration of the sandstone, and the above process cannot have been of so much importance in those regions. After its final formation the strandflat has been covered by a local glacier during the last glacial period of the island. This glacier has not, however, eroded the surface of the strandflat to any appreciable extent, but on the surface of the rocks in some places, striæ still occur, radiating from the central part of the island towards the coast, as was first dis- covered by Nathorst [cf. Jj. G. Andersson, 1900, p.438]. It is possible that the very shallow depressions now forming the many lakes, are due to this glacial erosion. After the last glacial covering the bare rock-surface has been much disintegrated by frost, but as there has been very little transport on this flat plane the débris has to a great extent remained in situ. It might be more difficult to decide the age of the now submerged strandflat of Bear Island — and between that island and Hope Island — now standing at a level of about 30 to 40 metres below the sea-surface. The probability seems to me to be that this part of the strandflat has been developed during the glacial periods. It is a striking fact that no traces of a postglacial elevation of the land have been discovered on Bear Island, as has been mentioned by 1921. No. rt. THE STRANDFLAT AND ISOSTASY. BAS Nathorst and J. G. Andersson [1900, p.439]. As the latter points out it is possible that such marks might have been obliterated along these shores where the rocks have but little power of resistance and the postglacial erosion, especially by frost, has been considerable. But if there had been shore-lines or shore-cliffs on the strandflat further inland, it seems none the less probable that some traces of them might have been found some- where. As long as there is no evidence to the contrary we may therefore assume as most probable that this island has had no postglacial elevation, as seems also to be the case on other small island plateaus like that of the Feroes, Shetland, and possibly Jan Mayen. It might be more probable that there has been a positive movement of the shore-line in postglacial time, otherwise it may, for instance, be difficult to explain why there is not a broader submerged shore bench near present sea-level round the island, 1f the present-day shore was ex- posed during the whole of postglacial time to the very effective shore- erosion now going on. In the few places where a quite narrow shore bench with shallow water has been developed, e. g. Walrus Harbour, Norwegian Harbour, Herwig Harbour, North Harbour, and west of that region, the shore is built up of rocks, with very little power of resistance to erosion, and where it cannot have taken a long time to erode the existing sub- merged shore benches. In spite of the considerable postglacial elevation of the land that has taken place in Scandinavia to the south and on Spitsbergen to the north, and also on Franz Joseph Land, the disappearance of the ice cap has probably caused no appreciable postglacial elevation of the crust in this region, for during the last glacial period the island was probably covered by a small local glacier only, the weight of which depressed the crust less than the sea-level was temporarily lowered by the reduction of the volume of the Ocean owing to the accumulation of frozen water on land. But of more importance in this respect is probably the considerable displacement of the semi-plastic ‘magma’ underlying the rigid Earth’s crust, which must have taken place when by the weight of the ice caps Scandinavia to the south was depressed 300 metres, or more, in its central parts and Spitsbergen some hundred metres to the north. By the displacement of the ‘magma’, the intervening region of Bear Island has probably been raised, and when, after the disappearance of the ice- caps, the displaced ‘magma’ again ‘flowed’ slowly back to its former position more or less, and the previous equilibrium was restored, there would be a slow subsidence of the crust in the region of Bear Island. If in this manner, the shore-line in the Bear Island region stood during the glacial time about 30 or 40 metres lower than now, the plat- forms may have been formed which now are submerged about 30 and 40 metres below present-day sea-level. 176 FRIDTJOF NANSEN. M.-N. Kl. The vertical range between the uppermost level above the sea and the lowest submerged level of the apparent strandflat is thus considerably greater on Bear Island than is generally the case along the Norwegian coast (with the exception of Finmark perhaps). This may be due to the fact that the rocks of the Bear Island region have so little power of resistance that the vigorous shore erosion may have managed to plane down fairly broad platforms during relatively short periods. The planes cut at temporary high or low levels at which the shore-line may have stood during vertical movements of the land crust or of the sea-level, may therefore in this region appear as though they belonged to the strandflat. In Norway, however, a much longer time has generally been required for the development of broad shore benches. The Norwegian strandflat was therefore formed during long periods when the land crust stood at its normal level of equilibrium (cf. p. 42), while the higher shore levels lasting for shorter periods have left few conspicuous marks only in the shape of old raised beaches and shore-lines. While there can hardly be any doubt that the outer flattest parts of the plain of Bear Island have been levelled by shore erosion, it is very difficult to decide how its inner part, higher than 50 metres and rising to 100 or, according to Hoel, even to 150 metres above the sea, has been formed. We have seen that Hoel does not consider. it to be a plane of marine abrasion because it is more uneven than the outer very level plain. On the other hand there is as a rule a fairly well marked boundary between this higher plain and the more steeply ascending mountain sides along its southern margin, especially at Mount Misery. Although there may be some difference in the power of resistance of the rocks of the mountains and of the plain, it is hardly sufficient to account for the difference in slope, and it seems to me to be possible that also the inner, higher part of the plain may have been formed by shore erosion, but during a more remote period than the lower flatter part, and by exposure to later erosion it has become more uneven. On the other hand it is difficult to believe that, during some comparatively recent period, the land has been sub- merged up to these higher levels for sufficiently long time to have an extensive plain like this cut by shore erosion. This higher plain of Bear Island has a certain resemblance to the plain across Hitteren in Norway, previously described (p.123), rising gradually above 60 metres in the middle of the island (cf. map Fig. 107). It has likewise a width of 13 kilometres. On Alsten Island at the foot of the "Seven Sisters” there is a similar plain (about 8 kilometres across) rising above 60 metres in the middle of the island. It is probably cut in mica-schist although to a great extent it is covered by quaternary marine deposits and moraines. If it were not for the small areas of these islands one might be tempted to assume that these plains have been graduallv raised by iso- 1921. No. rr. THE STRANDFLAT AND ISOSTASY. 17 -] static movements during and after the formation of the strandflat. We do not know yet within how small areas the isostacy may produce more or less local uplifts; but the gradient of lateglacial and postglacial upheaval sometimes seem to vary appreciably within comparatively short distances. Besides the rigidity of the crust has not prevented the formation bv mountain folding of ridges no broader than these islands. On Bear Island as well as on Hitteren, and probably also on Alsten, considerable quantities of rock have been removed, which originally covered the areas of the plains. The mountains on the sides of the plains may give some indication of the initial height of the land. Where the rocks are so extremely weak as those forming the top of Mount Misery (539 metres above the sea) it 1s also obvious that a great thickness of rock has been removed from the top of the mountains during the long time that has elapsed since the development of the present strandflat commenced. The removal of the weight of hundreds of metres of rock from above the present plains has caused a slow elevation of the crust in the region of the islands. During this continuous elevation of the original strandflat its outer parts have been gradually lowered by the shore erosion, and thus a gentle outward slope from the inner parts of the plains has been formed. As the elevation was much slower during its latest stage, the outer part of the plain became most horizontal. It might be objected that, if this explanation be correct, the extremely level plain of Smølen (cf. pp. 120 f.) ought to have been elevated in a similar manner. The probabilitv 1s, however, that the initial land of Smolen was much lower, the isostatic elevation was therefore much smaller and much slower, and while the shore erosion was still most vigorous. it had time to plane down the whole plain, and make it almost horizontal. This might seem a rather bold hypothesis, and it has to be admitted that weighty objections may be raised. If the isostatic compensation can assert itself, to some extent, within such small areas, it might be difficult to understand why the strandflat now stands at levels which are very similar over extensive regions although the quantities of rock re- moved may differ greatlv. These problems will be discussed in a later chapter. Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. 171. 12 178 FRIDTJOF NANSEN. M.-N. Kl. by ai ON N ANAS OST À A MA SE Fig. 132. Vogel Hook, the northern point of Prince Charles Foreland, seen from the north (July 27th, 1912). The difference between the steeper west side of the island, and the more sloping east side with a broad strandflat is noteworthy [from Nansen 1920). XII. THE STRANDFLAT OF SPITSBERGEN. The emerged strandflat 1s a very conspicuous feature in the land- scape along the coasts of Spitsbergen. It is very different from the Norwegian strandflat as it forms more or less continuous low plains in front of the often oversteepened mountain sides, and it is not split up into numerous islands and skerries. Literature. Adolf Hoel [1909, 1914] has subjected it to special investigations. He says [1914, pp. 25 ff.] that "along the whole of the Spitsbergen coast which he had an opportunity of examining, from Ice Fjord to Wood Bay, the coast, between the sea and the mountains, is surrounded bv a border of low land from which the mountains rise abruptly and partly vertically forming a rather conspicuous precipice”. "The boundary between the plain and the mountain 1s often covered by quaternary marine terraces, or by a talus (scree). But it also often appears very sharply marked, and at a certain distance one always gets the impression of a well defined line of demarkation." “These coastal plains are missing only in the inner parts of the fjords, €. g. in the inner part of Cross Bay. They are especially well developed along straits, thus along Foreland Sound ro to 20 kilometres wide, thev attain a considerable width on both sides of this sound. They reach their maximum development at prominent points, c. g. at the north-east corner of Prince Charles Foreland, at Quade Hook, at Cape Guissez, and Cape Mitre." "Under otherwise equal conditions, they are wider where the rocks are less resistant, e. g. Carboniferous limestones and schists of the Hecla Hook system, and are narrower where more resistant rocks predominate.” I92I. No. rz. THE STRANDFLAT AND ISOSTASY. 179 Hoel states that, in the region between the southern end of Prince Charles Foreland and Cross Bay, the inner margin of the strandflat, at the foot of the steep mountain-slopes, is about 25 and 30 metres above sea-level. He thinks that this strandflat is a plane of marine abrasion, formed by wave erosion in the manner suggested by Richthofen. It is a plane of perfect regularity, much more level than the Norwegian strandflat is generally. He agrees with my views [1904] as to the age and formation of similar strandflats, and does not consider it possible that this strandflat can be of preglacial age, but assumes it to be "more recent than the time of maximum development of the ice covering: it seems impossible that a plain could preserve so perfect an evenness as it has here, if it had been traversed by inland-ice”. He also considers it to have been formed after the excavation of the fjords by the glaciers; and gives several convincing pieces of evidence [1914, p. 27] to prove that such has been the case. On the other hand, he thinks that, “after the development of the strandflat there has been a period when the glaciation was more con- siderable than at present. At that time erratic blocks and moraines were left in several places, e. g. on the south-east extremity of Danes Island.”’ “The geological conditions as regards this coastal plain prove that the glacial covering has varied considerably on Spitsbergen, and that the plain has been formed by marine abrasion at a time when the glaciation was relatively less considerable.” Adolf Hoel maintains that the sea must have remained at its present level for.a long time along the coast of Spitsbergen, for the wave erosion has had time to form typical shore cliffs in numerous places along the open coast and in the great fjords. At the foot of these cliffs there is generally a sandy beach, dry at low water. This beach is often continued in a narrow submerged platform sloping gently seawards, till the bottom suddenly descends by a steep escarpment to depths of 200 and 300 metres: This submerged platform must be a plane of marine abrasion, which he has especially observed in Cross Bay. Gerard de Geer has also discussed the strandflat of Spits- bergen, but tries to explain its formation by his theory of dislocations (faults), and considers it to be thus preserved remnants of a peneplain, an explanation which, according to my view, is especially improbable on Spitsbergen, for several weighty reasons. First there are strandflats backed by steep mountain sides in many places where there are no traces whatever of any faults or dislocations, as proved by the investigations of Hoel and Holtedahl. Secondly the surface of the strandflat of Spitsbergen is decidedly not that of a regular peneplain. As Hoel has pointed out, it is often 15? 90, Verleegen Hook £ Moffen I. Aldert DER B = ak Valley, Quade Hook tz; " e > TI TT ANT mar i = = CF d, © ST RE] : Fig. 133. 30 Land lower than 50 metres above sea-level. == Submerged Sttandflat less than === 30 meties below sea-level. Glacier lt! niit VUE Hit Glacier ICT the SE Suandflat Map showing the Emexged and Submetged | Sttandflal of West Spitsbergen Based chiefly on the Sueveys by the Norwegian Spitsbe ıgen-Expedit ions/906-/921 The Contous of the Submerged Stiandflat beimeen Vogel Hook, Peince Charles Foreland, and South Cape is based on the Soundings made by the Hoel-Expedilions 19/3792]. Fig. 134. igs. 133 & 134. Map of the North and West coast of Spitsbergen, showing the distribution of the Strandflat. Fig. 134 is a direct continuation of Fig. 133. 182 FRIDTJOF NANSEN. M.-N. Kl. perfectly even, and it shows no indications of any drainage system, which must be the typical feature of a peneplain. There may be a good many shallow lakes on this surface, draining through mcre or less accidental channels of postglacial origin, but there are no indications of older valleys on the flat planes. Bertil Hogbom has not studied the strandflat of Spitsbergen, but like Hoel he points out [1914, p. 294] that shore-cliffs are charac- teristic of the Spitsbergen fjords, and are well developed even in places where the wave action can only have been quite insignificant. He maintains that the surf and the ice drift are essential for the transport of the waste, and are therefore necessary for the formation of a cliff-shore, but their direct power of erosion may be of minor im- portance. The destruction of the rocks by the frost must be much more effective. The fact that accumulations of snow (“‘snow-foot’’) frequently remain on the beach at the base of the small cliffs during a great part of the summer without being washed away by the breakers, also dis- proves the direct importance of the waves for the development of the cliff. He thinks that by keeping the cliffs always wet, the freezing sea- water must have much disintegrating power, especially as even open crevices are kept full of water. The sea-water will furthermore thaw the frozen rock, and by alternate high- and low-tide a regular "regelation" may thus be produced. Where the coast is relatively much exposed, and the surf can assist the frost in breaking loose the material and carrying it quickly awav, a considerable abrasion may be produced, and he assumes that the sub- merged flat platforms, 1 kilometre broad, outside more exposed coasts in Ice Fjord — e. g. between Cole Bay and Advent Bay and at Cape Thordsen — have been thus formed. As may be seen, the views of the present writer coincide in several respects with those of B. Hogbom. He justly points out that, although a great dislocation may probably have occurred along Ice Fjord, as sug- gested by Gerard de Geer, this cannot explain the formation of the sub- merged platform, intervening between the deep channel of the fjord and the steep mountain side. B. Hogbom does not think it is possible to decide finally at present whether or to what extent, these platforms with their shore-cliffs have been formed in postglacial time. His view obviously is [cf. 1914, p. 295] that the Norwegian strand- flat has been formed in a similar manner. Angus MEwen Peach [1916] describes the strandflat (which he calls the Preglacial Platform) of Prince Charles Foreland, and also along various parts of the coast of the mainland of Spitsbergen. He VESLEMOYS RUTTE MED STASJONER 1912 SPITSBERGENS GEOLOGISKE BYGNING 5 efter A.G.NATHORSTS) ~~ sammenstilling av À svenske, russiske skot | ske, og norske unnersö ih + a + Å Ht LT FRINS KAR fon: | | E | LS ^ 1— —»— 2 = 52 IM 2 BELLSUN S Diabas ex N Jura og VE RS ne Reteiote = | N Ariil(Mocom) \ HEN ee IM] | oc ER \ SY ; Ar “ = Fer 1 | Björn Ordovicisk eller Unner- Süur(BekLa-huk Formasjon) Cranilt og C ncis- granit, ' Sansynlig Fra Si lur(dler Hod) 550 À \ \ 50 100 kim V nn 10° Geological Map of Spitsbergen, chiefly after A. G. Nathorst, based on the Swedish, Rus- IE 135. The broken and the dotted lines indicate sian, Scottish, and Norwegian researches before roro. the course of the "Veslemoy" in 1912, with the oceanographic stations. 2 Diabase. 3 Jurassic und [From Nansen 1920]. Translation of the explanation in the lower left corner. 1 Tertiary. 4 Trias. 5 Carboniferous and Permian. 6 Devonian. 7 Ordovician Cretaceous (Neocomian). 5 or Under-Silurian (Hecla-Hook Formation). 8 Granite and gneiss-granite, probably Post-Tertiary (according to Hoel). 184. FRIDTJOF NANSEN. M.-N. Kl. states that “this shelf (on Prince Charles Foreland) has in general a rocky surface, planed or carved partly out of nearly vertical members of the Heckla Hook series. It rises gently from near sea-level towards the slopes of the central hills, terminating inland at an altitude of about 150 feet (46 metres). The constancy of level maintained by this inner margin and the fact that it is often marked by lofty cliffs or at least precipitous slopes, indicate very clearly that the platform is the result of marine erosion." ... "Beach deposits occur here and there on the plat- form, but it is clear that they have no genetic connection with it. They are obviously of postglacial age, while the rock platform itself is ob- viously preglacial.” His reasons for the latter conclusion are 1) that the surface of the platform "has been shown to be striated in several places”, 2) "it is frequently strewn with iceborne erratics from the mainland of Spits- bergen, while patches of drift containing foreign boulders have been found here and there covering its surface.” The probability that these striæ, erratics, &c. may be due to the last advance of the glacial covering is, however, not considered, nor is it explained how this remarkably level platform might have been able to preserve its evenness if it had been exposed to the erosion of the big glaciers of the Great Ice Age. The platform is in several places on Prince Charles Foreland and on the mainland of Spitsbergen described as rising from the shore to a general level of between 100 and 150 feet (30 and 46 metres); while it is said to rise to about 200 feet (61 metres) at the base of the over- steepened hills, in several places on the mainland of Spitsbergen, e. g. at Quade Hook, at the mouth of St. John’s Bay in Foreland Sound, in Lowe Sound (Van Mijen’s Bay), in Recherche Bay, on the south-west side of Advent Bay near Advent Point, south of Sassen Bay. Peach considers it to be beyond a doubt that the cutting of this plat- form was a later event than the partial submergence of the old river- valley system, by which according to his view the fjords originated, consequently in preglacial time. His view is that "the Spitsbergen rock-platform is clearly the same as that of the coast of Norway”, and a platform of similar type “is found also on the west coast of Scotland, at a height of 100 to 140 feet (30 to 43 metres) above sea-level. There is also a platform of marine erosion of preglacial age a short distance above sea-level in England and in the south of Ireland.” 1921. No. rr. THE STRANDFLAT AND ISOSTASY. 185 Fig. 136. The Saddle Mountain, with the strandflat on both sides, on the southern end of Prince Charles Foreland, seen from Foreland Sound on July 16th, 1912. [From Nansen 1920]. Relation between the Development of the Strandflat and the Geological Structure of the Land. The strandflat of Spitsbergen is to a great extent cut in rocks with relatively little power of resistance to the frost erosion. It has therefore easily been levelled to a fairly regular plane in most places, rising gently inland from the shore. Where, however, the rock is more resistant, the strandflat is much narrower, or is poorly developed, with a more uneven surface. This is, for instance, the case in the region of the north-west corner of Spitsbergen, where there are gneiss-granites and granites (see Fig. 145). The strandflat is here poorly developed, and its surface is un- even like that of the Norwegian strandflat cut in resistant rocks. On the east side of Wijde Bay the land is built up of gneiss-granites, and in its northern parts of mica-schists and other crystalline schists. There the strandflat is well developed, with a flatter, more regular sur- face, obviously because the rocks are less resistant. A comparison between the geological map Fig.135 and the map Fig. 133 and 134 may give some idea of the relation between the distri- bution of the strandflat and the geological structure of the land. Prince Charles Foreland. The emerged strandflat is well developed on Prince Charles Fore- land, and it is a noteworthy fact that in the northern part of the island it is wider along the relatively sheltered east coast than along the west coast exposed to the violent wave action of the open ocean, and where we might expect to find it especially well developed. The explanation may to some extent be that the strandflat has chiefly been finally planed by the shore erosion by frost after the land had been much denuded especially by the local glacial cirque erosion, while the main importance of the wave action has been to carry away the débris formed by the shore erosion. For this purpose there has been sufficient wave action in the Foreland Sound, now 10 to 20 kilometres broad, and 186 FRIDTJOF NANSEN. M.-N. Kl. Fig. 137. East coast of Prince Charles Foreland northwards from the Foreland Plain formerly, when the shore-line stood higher during the planing of the strandflat, even broader It is, however, striking that the highest mountain ridge of the nor- thern part of the island is much nearer its west coast than its east coast and is steeper and less dissected by vallevs along its west side than along its east side (cf. Fig. 132), where there is also a greater accumulation of glaciers. These are features somewhat similar to those previously men- tioned on Moskenesoi, and also on Værøi and Rost, in Lofoten (see p. 160). This similarity may be accidental, and may be more or less due to the geological structure of the land. But it is also possible that the greater accumulation of glaciers on the eastern side of Prince Charles Foreland is due to the meteorological conditions, and that, therefore, there has been a more active local erosion by glaciers (cirque glaciers) on the eastern side of the island than on the western side, cutting back the mountain slope. It might seem most natural to explain the difference in steepness between the eastern and western sides of the mountains as an effect of a more vigorous marine erosion along the more exposed west coast. But in that case there should be a broader strandflat along the west coast. As will be mentioned later, there is a submerged platform along this coast, but not very broad, and the width of the submerged and emerged strandflat is not broader along the west coast than along the east coast of the island. In its southern part the strandflat extends across the island, forming the Foreland Plain (or Foreland Laich), 4.5 to 9 kilometres broad from coast to coast, and 15 kilometres long between the slopes of Mcunt Methuen tomthe merth=(Big. 137) and of Persis Crest (Fig. 140) of the Saddle Mountain to the south (Fig. 136). According to Hoel [1914, pp. 25 f.] Mr. Koller of the Isachsen Ex- pedition took the levels of this plain in 1909. It rises very gently land- wards from both shores, but the highest point along his line of levelling, 16.3 metres above the sea, was 4.6 kilometres from the west coast and only 1.95 kilometres from the east coast, which may indicate that the western part of this plain has been slightly more denuded by the wave erosion. The width of the strandflat may otherwise vary between I and 1921. No: Tr: THE STRANDFLAT AND ISOSTASY. 187 N N ; and Mount Methuen, seen from Poole Point on July 23rd, 1912 [from Nansen 1920|. 5 kilometres along the east coast, while along the west coast it is as a rule less than 2 kilometres and often less than 1 kilometre. | The strandflat of Prince Charles Foreland is cut in shales and lime- | stones of the Hecla Hook system, which are easily disintegrated by the | frost. In some places there are lenses and lavers of quartzites forming quite low ridges, as pointed out by Hoel. The bare rock is seen everywhere in the surface of this strandflat, or is covered by a thin layer of débris evidently disintegrated by frost, ‘and in many places transformed into an argilaceous or muddy soil, with the characteristic network of stone-rings, which, according to my view, is due to the effect of the frost and thaw causing expansion and con- traction of the water in the wet soil and in the patches of snow when freezing and melting [cf. Nansen, 1920 and 1921, Chap. VIII]. Wherever the rock is bare near the shore, there is a vertical shore cliff 4 to 8 metres high. At many places there is, however, a flat shore | of sand, gravel, or pebbles, evidently to some extent consisting of water- worn moraine material (Fig. 138). In some places in the shore I noticed | that this drift was stratified. It lies nearly at the same height as the real strandflat cut in solid rock, and rises to a few metres above high water | level. | The wave-action, and perhaps also the sea-ice, have built up ridges which may often extend considerable distances along the shore, forming lagoons, which are common along the east coast of this island. | On July 25th, 1912, I observed that on the north side of Poole Point | the storm of the previous day and night had entirely filled up and ob- literated the entrance to the lagoon. Only two days earlier this entrance had been so deep that I could not easily wade across it. The strandflat rises gently from the shore, or the shore cliff, to a general level, the altitude of which I estimated to be about 6 to 10 metres in the region of "Sandbukta”, near the northern part of Saddle Mountain, | south of the Foreland Plain. Further inland there are a good many ridges rising to a higher and fairly uniform level extending to the foot of the mountain, which rises | abruptly from the plane (cf. Figs. 139 and 140). I estimated the height 188 FRIDTJOF NANSEN. M.-N. Kl. of this level to be 20 to 30 metres above the sea, but I had no oportunity of measuring it by levelling. My estimate agrees, however, with Hoel's statement that the inner margin of the plain is 25 to 30 metres above sea-level. Peach’s estimate of the height of the inner margin of the strandflat of the Foreland, 150 feet (or 46 metres), appears to be too high. At the foot of the mountain, Persis Crest, there is a conspicuous ledge, to a great extent built up of loose stones. I observed indications of similar ledges at the foot of the mountain, on the south-eastern side of Saddle Mountain, and also on the south-east side of Mount Methuen (cf. Fig. 137). I found a similar conspicuous ledge in Lake Valley on the west side of Wijde Bay (see later). Fig. 138. The Sand Bay ('"Sandbukta") with the southern part of Saddle Mountain and the strandflat on Prince Charles Foreland. July 22nd, 1912 [from Nansen 1920]. Hoel assumes that these stone-ledges have been formed by stones that have fallen down from above on to the surface of small glaciers along the mountain sides, and have gathered at the foot of these glaciers. But considering the evenness of their upper surface, situated very nearly in the same level as far as I could see from the distance, — I think that they indicate a raised shore-line, and they may have been formed to a great extent by stones that, owing to the regular shore-erosion, described pp. 30 ff., have continually been falling down from the mountain side above on to the accumulations of snow on the shore ledges, and have gathered on the beach and on the relatively steeply sloping sea-bottom outside the foot of these shore-accumulations of snow and ice. The stones that remained above water were soon disintegrated by the frost, while those below water were more protected. The fact that the stones on these ledges are sharp-edged as*a rule, and show no traces of having been worn by the surf, may be accounted 1921. No: Ir. THE STRANDFLAT AND ISOSTASY. 189 Fig. 139. Surface of the strandflat with ‘stone-rings’, on the east side of Saddle Mountain. July 22nd, 1912 [from Nansen 1920|]. Fig. 140. The strandflat at the foot of Persis Crest, on the north-eastern side of Saddle Mountain. July 2nd, 1912 [from Nansen 1920]. 190 FRIDTJOF NANSEN. M.-N. KL for as an effect of the frost action, in a similar way as the fact that the rocks of the shore-ledges cut in solid rock are also sharp-edged, with very few traces of wave-erosion. Some stones have obviously also fallen down on these ledges after they were raised above sea-level. It is striking that these ledges, wherever I have observed them, always occurred at the foot of very steep mountain sides, where stones may he expected to have been perpetually falling, especially when the shore erosion worked at the foot of the mountain. The probability is, however, that the inner part of these ledges are more or less cut in solid rock, but this is often difficult to examine, as their inner margin is generally covered by a talus (scree). I had no opportunity of measuring the height of these stone-ledges on Prince Charles Foreland, but estimate it to be about 50 metres above sea-level. At the foot of the ledges accumulations of snow are now eroding small cirques in their steep slope, oversteepening them (cf. Fig. 140). Along a part of the east coast of Prince Charles Foreland, from J. Murray Point southwards, the strandflat is now covered by flat gla- ciers, Murray Glacier and Buchanan Glaciers (Fig. 9 and ro). The rocks of the strandflat project in several places along the outer edge of the glacier. I agree with Hoel, that the strandflat was obviously formed during periods when the glaciers had less extent than at present. They have afterwards extended over this flat plane, and form a nearly hori- zontal ice-sheet, to some small extent fed by the small glaciers of the mountain slopes behind. The glaciers to the south, Geikie Glaciers, form thin sheets extending from the mountain slopes over the undulating lower land (Fig. 137). The strandflat of Prince Charles Foreland is continued outside the shore in a submerged strandflat (see Fig. 133) the contours of which may be approximately traced along the east coast by the soundings of the Isachsen Expeditions of 1909—-1910 in the Foreland Sound [cf. Isachsen, 1912, chart}, and along the west coast by the soundings taken by the Hoel Expeditions in the years 1913 to 1921. By Hoel’s kind permission I have been able to study the detailed charts with these soundings. In the map Figs. 133 & 134 is drawn the isobath for 30 metres below sea-level. The edge of the submerged strandflat seems to be very near this isobath at depths between 20 and 30 metres or often near 20 metres. In some places the edge seems to be quite sharply defined, whilst in other places the side slope of the submerged plateau is more gentle, making the edge less distinctly marked. Along the northern part of the west coast of the island, north of Cape Cold, the submerged strandflat is mostly about 2 kilometres broad, the width decreasing north of Cape Cold to about 1 kilometre. Off Cape 1921. Norr THE STRANDFLAT AND ISOSTASY. IQI Cold it is broader, nearly 5 kilometres, and along the coast to the south it is between 2 and 3 and 4 kilometres broad. Along the east coast of the island the width of the submerged strand- flat varies much, being mostly between 1 and 2 kilometres, but off the north-east coast it has a wide extent, 7 to 8 kilometres. The surface of this broad platform slopes gently from a depth of 10 metres near the shore, to about 27 to 30 metres near the edge, which seems to be very sharply defined towards the east and north-east, where the depths suddenly increase to 126 and 178 metres, while towards the north and north-west of Vogel Hook the sea-bottom slopes more gently outwards. It is a striking contrast between this wide submerged plateau and the total absence of a submerged strandflat along the west coast of Brogger Peninsula on the opposite side of Foreland Sound. As the north- east coast of Prince Charles Foreland is to some extent built up of Tertiary sandstone and conglomerate, the probability is that the wide submerged strandflat, being a continuation of the very broad emerged strandflat, has, to some extent at least, been cut in rocks of this system which have offered relatively little resistance to the shore erosion. On the opposite side of Foreland Sound the strandflat may, to some extent, have been cut away by the glacier formerly extending far towards the north-west from Comfortless Glacier. At the north-western end of Brogger Peninsula, off Quade Hook, however, there is a submerged platform, which has not been cut away by the glaciers of Foreland Sound or King Bay. Further south there is a Barrier ("Revet") across Foreland Sound, from John Murray Point to Michael Sars Point, which, however, seems to be built up of loose material, mostly sand, like the sand spit of Michael Sars. Point. Between this region and St. John Bay there is a submerged strandflat 2 to 3 kilometres broad. The rock of the shore is here Tertiary and it is the same on the opposite side of the sound on both sides of Ferrier Haven and at Poole Point where the submerged strandflat is also fairly broad. Considering that the emerged strandflat is cut in solid rock, it seems probable that the rock surface continues more or less in the platforms under the sea surface. It is a striking fact that these platforms are especially broad where the shore is built up of Tertiary rocks, viz. off the north-east coast of Prince Charles Foreland, north and south of Michael Sars Point, at Ferrier Harbour, and at Poole Point. This seems to indicate that the platforms are not built up of loose material to any great extent. The Tertiary rocks have obviously been less resistant to the shore erosion than the rocks of the Hecla Hook system. 192 FRIDTJOF NANSEN. M.-N. Kl. Fig. 141. Axel Island. August 31, 1912. West Coast of Spitsbergen south of Ice Fjord. Along the west coast between Ice Fjord and Bell Sound, there is a well developed emerged strandflat cut in rocks of the Hecla Hook system. The submerged strandflat is also broad in this region, as much as 11 kilometres, with depths between 10 and 20 metres and the sharply defined edge not much deeper than 20 metres. The breadth of the emerged and submerged strandflat together is about 14 kilometres. 16 to 25 kilometres outside this coast is the Sentinelle Bank, the highest part of which has depths less than 30 metres. Axel Island in Bell Sound has a sharply defined level surface, less than 20 metres high, cut in rocks of the Carboniferous system (Fig. 141). On the north side of Lowe Sound there is an extensive low plain which to some extent is a real strandflat cut in solid rock, but a part of it is the floor of the wide Ondiepe Valley which has been filled up with sediment. Along the coast southwards from Cape Lyell, in Bell Sound, there is a well developed emerged as well as a submerged strandflat. The latter is 3 to 5 kilometres broad, and off Torell Glacier even 9 kilometres brcad. It is mostly less than 20 metres below sea-level. On the north side of the entrance to Horn Sound there is practically no emerged strandflat because, as W. Werenskiold tells me, the coast is here built up of gabbro. South of Horn Sound there is a well developed emerged strandflat which has been surveyed by A. Hoel and W. Werenskiold during their expeditions of recent years. This strandflat is especially extensive at the southern end of the land. As the soundings taken by the Hoel Expeditions during the last years have shown, there is also a broad flat submerged strandflat outside the coast in this region. It is near sea-level with depths to a great extent less than 12 and 15 metres and carries many shoals and rocks. It is 9 to 10 kilometres broad, and at South Cape and east of it even 12 kilometres broad. The sea outside is not very deep and the sea-bottom slopes fairly gently, especially on the south-western side, to depths of 70 to 120 metres without any very distinct edge. On the south-eastern side the slope is somewhat steeper. I92I. NOTE. THE STRANDELAT AND ISOSTASY. 193 Fig. 142. Shore cliff and strandflat at Cape Guissez, with Mount Grimaldi. August 28, 1912. Cape Guissez in Cross Bay. Along the shore east of Mount Grimaldi, on the east side of the entrance to Cross Bay, northwards from Cape Guissez, there is a vertical cliff of solid rock (see Fig. 142) which, according to Hoel's statement [1914, p. 26], is about 20 metres high. The plain rises gently inland from the edge of this cliff to the foot of the mountain where, according to Hoel, it attains an altitude of about 35 metres above the sea. It is here covered by more recent terraces of gravel, and the surface of the strand- flat, cut in solid rock, is lower. Hoel estimates it to be about 25 metres above the sea. Outside this shore, north and south of Cape Guissez, there is a submerged platform, half a kilometre to one kilometre broad, or even more, with depths less than 20 metres [cf. Hoel, 1914, p. 40, Pl. XXV, 1]. Cape Mitre Peninsula and the North-western Part of Spitsbergen. On the south and west side of Cape Mitre Peninsula, west of Cross Bay, there is a very flat and well developed emerged strandflat, the Dieset Plain ("Dieset Sletten”, map Fig. 143), as has already been pointed out by Hoel. It is 2 to 4 kilometres broad, and rises very gently from the low shore to the base of the abruptly and steeply ascending mountains (Fig. 144), at about 25 to 30 metres above sea-level. There are a good many shallow lakes on this strandflat. Towards the south it is continued as a submerged platform, 3 to 4 kilometres broad and with depths less than 20 metres. As regards the occurrence of the emerged strandflat there is a striking difference between this peninsula and Prince Charles Foreland. Here the strandflat is well developed along the west coast, while there is no strandflat along the east coast of the peninsula, in Cross Bay, except near Ebeltoft Harbour (“Ebeltoft Havn”, Fig. 143). The reason why there is no strandflat along the coast north of Ebeltoft Harbour is obviously that after the development of the strandflat, Lilliehöök Fjord Vid.-Selsk Skrifter. I. M.-N. Kl. 1921. No. 11. 13 194 FRIDTJOF NANSEN. M.-N. Kl. gs X /#0 : = 7S 7 as = AR. eg P FSR st" Sy 77 SR WS CSS EBELTOFT // VA p / e / N KAPP /MITRA Rud 2 { Words tcin apo | Fig. 143. Cross Bay and the Cape Mitre Peninsula, based on the maps by Gunnar Isachsen. The horizontal hatching indicates the strandflat. /sobaths are drawn for 50, 100, 200, and 300 metres of depth. The contours on land for every 50 metres. [From Nansen 1929]. and Cross Bay (“Kross Fjord”) have been much deepened and excavated by glacial erosion, which has cut away the strandflat and steepened the mountain sides. It is, however, noteworthy that here too there may b» observed a certain tendency towards formation of cirque glaciers on the eastern side of the mountain ridges which is especially conspicuous on King Häkon Peninsula ("Kong Hakon’s Halvo", Fig. 143). The strandflat of the Cape Mitre Peninsula is cut in schists of the Hecla Hook system, which are fairly easily disintegrated by frost. But to the north of this peninsula the coast is built up of very resistant granites 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 195 Fig. 144. Strandflat on the west side of the Cape Mitre Peninsula. The Dieset Plain (Dieset Sletten) and Dieset Lake (Dieset Sjø). [From Nansen 1920]. and gneiss-granites which fact causes an abrupt and striking change in the development of the strandflat, as has been pointed out by Hoel. In this granite region the emerged strandflat is, as a rule, hardly more than a hundred or a few hundred metres broad. On both sides of Ham- burg Bay, south of Magdalena Bay, it is 300 to 400 metres broad. In some places in this region the emerged strandflat is missing altogether. The submerged strandflat also seems to be poorly developed along a great part of this coast, but there are too few soundings to trace its extent. On Danes Island and Amsterdam Island, built up of granite, the emerged strandflat is also narrow or missing. Fig. 145 shows the strand- flat along the north-east coast of Danes Island. It is in this region less even than in the region of the Hecla Hook rocks to the south, and it is more like the strandflat in the granite regions of Norway. The low level plain, the Hollaender Ness, on the east side of Amster- dam Island (Fig. 146) is chiefly formed of loose material (sand and moraine material), but in its inner part near the foot of the mountain there is obviously rocky ground near the surface (Fig. 147). Off these islands and also north of the islands Vogelsang, Cloven Cliff, and Norway Islands, there is a submerged strandflat with skerries and rocks and with depths of less than 30 metres. Its extent cannot be traced, as the soundings are too few. North of Norway Islands it seems Fig. 145. The coast east of Virgo Harbour on north-eastern side of Danes Island. : t5 August 223 Or IOI2. 196 FRIDTJOF NANSEN. M.-N. Kl, Fig. 146. The east side of Amsterdam Island, with the low Hollaender Ness. August 1, 1912. [From Nansen 1920]. to have a width of 9 kilometres. On the whole the sea-bottom seems to be uneven in this region, as we have generally found it in regions of granite and resistant igneous rocks. Reindeer Land. Almost the whole of Reindeer Land forms a very level strandflat which is about 18 kilometres across (Fig. 148). I have onlv been ashore on its east coast 5 or 6 kilometres north of its south-eastern corner. There were in some places low vertical shore cliffs, with a flat beach in front, while in other places the rocks sloped more gently down to the shore (see Fig. 149). The general level of the flat gently undulating surface of the land (Figs. 150 and 151) is between 15 and 20 metres above the sea. Low ıidges rise above this level to about 26 metres. The highest ridge inside our anchorage on the east coast, was 27.5 metres above sea-level. Most ridges seen inland had about the same height, but some ridges further in to the north of us, were higher, and may have attained altitudes of about 50 metres. Bare rock was seen in the surface in many places especially on the ridges. Near the northern point of the peninsula, near Welcome Point, there is a solitary hill rising to 98 metres above the sea, as determined by the Isachsen Expedition 1909—1910. The whole peninsula is built up of Devonian schists. In its south- western part there are higher mountains consisting of the same kind of rocks. According to what I was told by Hoel, the plain extends almost horizontally to the foot of these mountains, which rise abruptly, with a sharply defined line of demarkation between the plain and the mountain sides. 1921. No. rr. THE STRANDFLAT AND ISOSTASY. 197 Fig. 147. The Hollaender Ness on the south-eastern side of Amsterdam Island. August 22, 1912. [From Nansen 1920]. The Peninsula between Liefde Bay and Wijde Bay. On the east side of Liefde Bay, where I was ashore, perhaps 12 kilo- metres south of Grey Hook, there is a sloping platform cut in solid rock (see Fig. 152), but its upper level is very much higher than the strandflat of Reindeer Land. From a vertical shore-cliff, about 10 or 11 metres high, backing a flat beach, there is a relatively steep ascent to a sharply marked shore-line cut in solid rock 41 metres above sea-level. It is marked by a horizontal series of small accumulations of snow (see Fig. 152) and is backed by a vertical shore-cliff about 6 metres high. From the edge of this cliff, 47.25 metres above sea-level, there is again an ascent to 62.25 metres above the sea, where a relatively broad plateau extends southwards along the foot of the steep mountain side (see Fig. 153). The foot of the steep scree along the inner margin of this plateau stands about 4 to 8 metres higher, i. e. 66 to 70 metres above sea-level. On the plateau there were indications of a shore-line marked by a series of snow- accumulations (see Fig. 153, along the middle of the plain, towards the mountain slope). The surface of this plain consisted of loose material. The highest level at which solid rock was observed was that of the shore-cliff at about 47 metres above the sea. This may be the actual height of the rock plateau, which may, however, rise gently to a few feet more under the layer of loose material at the foot of the mountain side. To the north of this place, where we made our measurements, there was a lake (see Fig. 154) Iying at a lower level. On the north side of 198 FRIDTJOF NANSEN. M.-N. Kl. € ——— —— 0€ 1 Fig. 148. Panorami iew of the cast coast of Reindeer J this lake and its outlet, the plain under the steep mountain-side, ascended to a higher level than that of our plateau, perhaps 30 metres higher, giving an altitude of about 90 metres above sea-level (see Fig. 154 to the right). The river running out of the lake has formed a canyon through the broad moraine terrace which has dammed up the lake (see Fig. 154). This moraine has a considerable thickness as is proved by this canyon, and is built up of coarse material, with numerous boulders embedded in its mass, as is seen in the sides of the canyon. The surface of the moraine is levelled by the sea to form a horizontal terrace at about 16 metres above sea-level. The well-marked coast-ledge of this region extends along the coast northwards to Grey Hook where there is a well-developed strandflat in front of the very steep mountain side (see Fig.150). The coast-ledge continues from Grey Hook south-eastwards along the west coast of Wijde Bay. I was ashore in Lake Valley, on the west side of Wiide Bay. The lake in this valley is a big lagoon to which a narrow channel leads from the sea through the shore terrace built up of drift material. The channel leads first into a smaller lagoon, and then a longer distance into the big lagoon. Strong tidal currents run through this narrow channel like a river. I took the height of the strandflat by levelling. The ground rises from the plain near the shore (see Fig. 155) inland to a height of 46.8 metres where there is a well-marked shore-line partly cut in solid rock. Its exact level was difficult to determine as it was covered by too much gravel and loose material. This shore-line forms a conspicuous horizontal line, marked by accumulations of snow, along the coast southwards. From this shore-line an extensive plain rises gently inland towards a terrace built up of stones at the foot of the much oversteepened mountain side (see Fig. 156). The base of the terrace is about 55.8 metres above the sea, and its upper level surface about 64.8 metres (Fig.157). This stone ledge is obviously a formation similar to those observed on Prince Charles Foreland, and has been formed in the same manner. Similar terraces were seen northwards along the coast towards Grey Hook, ap- proximately at the same height at the foot of the mountains, along the inner margin of the coast platform. On the north side of the big lagoon of Lake Valley, the platform appeared to lie, to a great extent, at about the same level as the well- 1921. Nosti. THE STRANDFLAT AND ISOSTASY. 199 > | from our anchorage in Liefde Bay. August 8, 1912. marked shore-line described above, at about 47 metres above the sea. It rises gently inland towards the foot of the mountain. Hence we may assume that the upper level of the platform cut in solid rock lies about 47 metres above the sea in the region of Lake Valley, and is probably a few metres higher at the foot of the mountain-side This is exactly the height of the coast platform, which we found on the west side of this peninsula, on the east coast of Liefde Bay. But it is considerably higher than the observed heights of the strandflat on Reindeer Land, and on Prince Charles Foreland. The question is then whether this coast platform may be considered as actually belonging to the strandflat, or whether it is rather a shore- ledge similar to the raised beaches and shore-lines, formed during some more temporary depression of the land. On the one hand it seems to be too high to be a part of the regular strandflat, on the other hand it seems difficult to assume that a platform as broad as this has been formed during temporary depressions of the land. Lately Hoel [1922] and Werenskiold [1920], however, have found some most remarkable bread ledges or plateaus, cut in solid rock, on the west coast near the = Fig. 149. East coast of Reindeer Land. August 8, ıgı2. [From Nansen, 1920]. 200 FRIDTJOF NANSEN. M.-N. KL Fig. 150. On the plain near the east coast of Reindeer Land, with the "Veslemøy” at anchor. The crows nest of the latter is 13 metres above the water. As it is very nearly level with the horizon, the plain at this place is about that height above sea-level. The land at Grey Hook with the strandflat outside is seen in the back ground. August 8, 1912. southern end of Spitsbergen. They must have been formed during periods of temporary submergence of the land, for they are at various heights, the highest plateau being as much as 340 metres above sea-level. They are as much as some hundred metres broad, and must have been formed after the land was covered by glaciers at that place, for there were many pebbles and round shore boulders on the highest plateau. This seems to prove that, owing to the vigorous shore-erosion in this region, fairly broad shore benches or shelves may be cut in relatively short time where the rock is not very resistant. There is thus a possibility that these high platforms on the west and east coast of the peninsula between Liefde Bay and Wijde Bay, are raised coast platforms of the same nature as the raised beaches, and are not a part of the regular strandflat. If this be correct, we may assume that the real strandflat on both sides of this peninsula has been more or less cut away by the big glaciers which filled Wijde Bay and Liefde Bav (and Wood Bay) and have deepened and excavated these fjords after the strandflat had been developed. East Coast of Wijde Bay, and Verleegen Hook. There is a well developed strandflat along the east coast of Wijde Bay, which was observed from the region of Aldert Dirkse’s Bay and northward to Verleegen Hook (Figs. 158 and 160). I did not land on this coast, but as far as I could see from the sea, the strandflat is cut in 1921. Norr THE STRANDFLAT AND ISOSTASY. 201 solid rock, and is to no considerable extent covered by drift or moraines. In many places the surface of the bare rock slopes gently down to the shore, while in other places there is a low shore-cliff, with accumulations of snow on the beach at its foot. The rock consists here chiefly of erystalline schists (mica-schists, hornblende-schists, gneisses) and granites, and the strandflat once formed, has been relatively well preserved. The land on the west side of Wijde Bay is built up of sedimentary rocks of the Devonian system which have Fig. 152. Platform on the east side of Liefde Bay. August 9, 1912. [From Nansen, 1920]. 202 FRIDTJOF NANSEN Fig. 153. The level upper surface of the platform of the east coast of Liefde Bay. August 9, I9I2. obviously less power of resistance to the frost erosion than the crystalline rocks of the east side of the fjord. The only manner in which I can explain why, in spite of this, the strandflat is so much broader and lower on the east side, is that the glaciers have cut away the Devonian rocks more easily than the crystalline schists and granites, and that during the deepening of the fjord during late glacial periods, after the strandflat was formed more or less, the western side of the fjord has been more excavated than its eastern side. I did not land at Grey Hook, but, seen from the sea, it looked as if the strandflat is wide and fairly low in that region, which has been less exposed to the erosion of the glaciers of Wijde Bay as well as of Liefde Bay. On Verleegen Hook I was ashore. The strandflat is very wide and low, cut in mica-schist and hornblende-schist, its surface being to a great extent formed of bare rock which is in many places scoured and rounded by glacial erosion (Fig. 159). At the outer edge of this plane a cliff much disintegrated by frost was observed inside a flat somewhat raised beach, near the present shore (see Fig. 15). Fig. 154. Panoramic view of the great terraces of moraine material outside the 1921. No. Er. THE STRANDELAT AND ISOSTASY. 203 The low rocky ridges of this flat plain attained an altitude of 16 metres above sea-level. Further inland there was a slightly lower plain covered with gravel and pebbles. Near the shore, at an altitude of about 9 metres, was a broad flat plane in the rock, a raised shore-line several hundred metres long. Small shore ridges of wave-washed pebbles were seen in several places up to the highest level of 16 metres. The strandflat extended inland, rising slightly, to the foot of the oversteepened mountain sides (Fig. 160). About 3 kilometres north of Verleegen Hook I found the depth to be only 30 metres, indicating that the strandflat continues as a sub- merged platform some distance seawards. About 5 kilometres north of the Hook I found a depth of 48 metres, but then it suddenly dropped to 152 metres and deeper further north. North-west Coast of North East Land. Great Stone Island, and Low Island outside, on the north-west side of North East Land, are low and seem to form a well-developed strand- flat cut in rocks of the Hecla Hook system. I have not, however, landed in this region. From this coast a wide submerged platform extends about 27 kilometres (15 naut. miles) north-westwards, with depths chiefly about 15 to 25 metres. The outer edge may possibly be at a depth of about 25 or 30 metres, where the bottom begins to slope more steeply towards depths greater than 100 metres. In about 80° 25’ N. Lat., at a distance of about 35 kilometres from North East Land, I sounded 30 metres. This wide platform may probably be considered as a part of the strandflat. The Fjords. In the inner parts of the fjords of Spitsbergen, the strandflat is not so well developed as along the outer coasts, but there are nevertheless traces of a strandflat in many places, indicating that the shore erosion le east coast of Liefde Bay. The lake is seen to the right. August 9, 1912. 204 FRIDTJOF NANSEN. M.-N. Kl. Fig. 155. Strandflat in Lake Valley, view southwards along the west coast of Wijde Bay. August Io, 1912. has been at work there too, although not so effectively and perhaps during a shorter time than along the outer and more exposed coast. On the north side of Lowe Sound (Van Mijen’s Bay) there is an ex- tensive flat plain corresponding to the strandflat as was mentioned above (p. 192). In Ice Fjord there are obvious strandflats in a good many places, e. g. Cape Erdmann, Cape Boheman, Cape Woern, Cape Thordsen, Bjona Haven in Sassen Bay (according to Peach), Advent Point west of Advent Bay, &c. As was pointed out by Bertil Hogbom [1914] there are also narrow submarine platforms outside the shore in several places in Ice Fjord, and they seem to be best developed where the coast is most exposed, e. g. west of Advent Bay, and off Cape Thordsen. West of Cape Boheman there is also a submarine platform with several rocks, the Twin Rocks &c. The Age and Genesis of the Strandflat of Spitsbergen. The strandflat of Spitsbergen is obviously a relatively young form- ation. As was previously mentioned (p. 179), and was already pointed out by Hoel [1914, p. 27], its present very level surface has not been exposed to the erosion of the glaciers of the Great Ice Age, or Ages, which covered the whole land and have deepened and excavated the fjords, and have sculptured the land surface. The present plane or planes of the strandflat have, therefore, been developed after that time. On the other hand there has been a considerable advancz of the glaciers after their formation, as is proved by the erratic blocks, mentioned by Hoel and Peach, and by the moraine material found on the surface 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 205 Le 77 Fig. 156. The level surface of the platform in Lake Valley, with a terrace of big stones at the foot of the steep mountain. August ro, 1912. [From Nansen, 1920|]. of the strandflat. Its rocks are also scoured and rounded, e. g. at Ver- leegen Hook, and striæ have been observed, as mentioned by Peach. This strandflat must, therefore, have been planed to its present levels after the Great Ice Age, or Ages, and before the last great advance of the glaciers of Spitsbergen. In Chapt. VI (pp.47 f.) I have pointed out that the strandflat of Norway has obviously been developed during periods when the land crust had attained its natural level of equilibrium, and the shore-line remained stable during a long time, 7. e. during periods when the land was not depressed bv the weight of any ice-caps. At the same time there must have been a severe climate favouring the shore erosion by frost. I there- fore consider it probable that the Norwegian strandflat has to a great extent been formed during periods with a severe climate preceding each glacial pericd, and before the land had been depressed by the inland ice. In Spitsbergen the conditions are different. The land is still covered with glaciers to a very great extent, and we cannot say what the natural level of equilibrium of the crust may actually be. At the same time the climate of that region is so severe that probably, even during warmer interglacial periods, it was sufficiently cold for an active shore erosion by frost. Nevertheless it is a striking fact that the emerged as well as the submerged strandflat of Spitsbergen have levels that are very similar to those of the Norwegian strandflat, and we may assume that thev indicate levels of an approximate natural equilibrium of the crust in this region. I imagine that the Spitsbergen strandflat was planed to its present levels during interglacial periods when the shores were not covered by glaciers and the ice covering of the land was similar to what it is now. 206 FRIDTJOF NANSEN. M.-N. Kl. "e — Tem - nee M y IIE Fig. 158. Panoramic view of the strandflat along the coast south ot Mossel Be During some part of the time when the strandflat was formed the glaciers had less extent than at present. As pointed out by Hoel [1914, p. 27] this is especially proved by the Buchanan Glaciers and the Murray Glacier now extending over the strandflat on the east coast of Prince Charles Foreland. It has been already mentioned, that two levels of the strandflat were probably observed on Prince Charles Foreland, one at about 6 to Io metres and one at about 20 to 30 metres above the sea. The lower level is probably the same as that of the low strandflat at Verleegen Hook, where it was between 10 and 16 metres above the sea. The higher level of 20 to 30 metres is generally found on the strand- flat along the whole west coast of Spitsbergen, and also predominates on Reindeer Land. It was pointed out before (p. 200) that the higher shelves, at about 47 metres or more above the sea, observed on the west and east side of the peninsula between Liefde Bay and Wijde Bay cannot really belong to the strandflat, but must have been formed during some more temporary submergence of the coast. According to Peach the altitude of the rocky surface of the strandflat at the base of the mountains should be 150 feet (46 metres) above the sea, and he states it to be even 200 feet (61 metres) in some places (see above p. 184). His statements seem, however, to be rough estimates, and not based upon very accurate investigations. D o | 1921. No. 11. THE STRANDFLAT AND ISOSTASY. sé Pig. 156) at the foot of the mountain side in Lake Valley. August ro, 1912. je land near Verleegen Hook is seen to the left. August Io, 1912. Raised Shore-lines. Raised shore-lines and beaches frequently occur along the coasts of Spitsbergen, and have been described especially by A. Hoel [1914, pp. 28 ff.| and Peach [1916, pp. 297 ff.]. They have obviously been formed after the strandflat and are relatively recent formations. At the place where I landed on the east side of the entrance to Biefde Fjord (see above p. 197) I fi und shore-lines cut in solid rock at the follewing heights above sea-level: Fig. 159. Strandflat cut in hornblende-schist and mica-schist on Verleegen Hook. August I2, IQI2. 208 FRIDTJOF NANSEN. M.-N. Kl. — m eae —— — we, f steriet la E E: pompe e pro? pq 7f age zl. t P PE E GE m EI il i M mu RUE TN ga I, Il { — ; LI i Mi — Fig. 160. The land north of Mossel Bay to Verleegen Hook, with the strandflat along the shore and =. : 5 > : : : > | Fig. 161. The north side of Brøgger Peninsula, with the conspicuous flat platform (about 200 metre right, with the mountain on Prince Charles Forelanw I 11 metres. This shore-line continued northwards along the slope of the big moraine terrace in front of the lake mentioned p. 198. 27 metres. A fairly distinct shore-line in solid rock. 41 metres. A sharply defined shore-line marked by a horizontal row of small accumulations of snow, and backed by a vertical cliff. 47.25 metres. The upper horizontal edge of the above mentioned cliff. In Lake Valley, on the west side of Wijde Bay, shore-lines were ob- served at the following heights: | II metres — quite distinct. 24 metres — less distinct. 30.8 metres — sharply marked. 46.8 metres — partly in solid rock, very conspicuous along the coast as a horizontal line marked by accumulations of snow. At Verleegen Hook a shore-line was observed at about 10 metres above sea-level. Platforms at high Levels. | In several places along the coasts of Spitsbergen one may observe É traces of horizontal planes at relatively high levels. Especially conspicuous is the remarkable, broad plane on the Brøgger Peninsula south-east of Quade Hook (Fig.161). It extends north-westwards from Mount Schetelig, 1921. No: Ex: THE STRANDFLAT AND ISOSTASY. 209 ———<———S — MÀ = SS === — Te = — = Sn ATT RL e 4 ; es 5 = cA Ni il Ii! ill | UT Inh, (, ! ui N == the old flat surface (peneplain) at the top of the mountains. August ro, 1912. [From Nansen, 1920]. above sea-level) in front of Schetelig Mountain. The low strandflat at Quade Hook is seen to the behind. July 31, 1912. [From Nansen 1920|]. is nearly 2 kilometres wide and is bounded along its outer edge by a vertical cliff more than 150 metres high. According to Hoel's statements and the measurements of the Isachsen Expedition 1909—1910, this remarkably flat plane rises gently inland from the top of the cliff, at a height of about 200 metres above the sea, or somewhat less, and the plane attains a height of about 240 or 250 metres at the foot of the mountain, where the boundary between the plane and the steep mountain slope is to a great extent covered by a glacier. As proved by O. Holtedahl’s and A. Hoel’s investigations this plane cuts the strata of the Carboniferous system of which the land is composed, and, as Hoel maintains, it is obviously a plane of marine denudation. It has been formed in a similar manner as the strandflat at lower levels, chiefly by shore-erosion by frost, assisted by the wave-action. It is hardly conceivable that this very level plane, giving the impression of being a quite recent formation, can have been exposed to any considerable glacial erosion, for in that case it could not have preserved its level surface. The probability is, therefore, that it has been formed at some period after the time when this region was covered by the inland-ice of the Great Ice Age. It has, however, been formed before the lower strandflat of between 10 and 30 metres above the sea. This younger strandflat has a fairly great width at Quade Hook and has obviously been cut in under the older and Vid.-Selsk. Skrifter. I. M.-N, Kl. 1921. No. zr. 14 210 FRINTJOF NANSEN. M.-N. Kl. higher platform. Thus the high vertical cliff at the edge of the latter was formed. Traces of a similar plain of marine denudation have also been ob- served by Hoel north of Ebeltoft Harbour in Cross Bay, but it was there lying at a lower level of about 150 metres above the sea. On the east side of Amsterdam Island I observed indications of what may be an ancient platform which I estimated to lie at a level somewhat higher than 150 metres (Fig. 146). On the southern Norway Island there is also a plateau in a similar height (see Fig. 8). But as these platforms are cut in more resistant rocks (granite and gneiss-granite) thev may be older. Inside the low and level strandflat at Verleegen Hook the mountain rises to a very flat plane with a similar altitude. As, however, the inner margin of this plane is not marked by any declivity, and as there is a quite gradual transition from this plane to the general mountain plateau inland, without any marked difference, it may here most probably be a part of the raised ancient level mountain surface, that extends southward over all the land east of Wijde Bay. As was mentioned above (p. 199) A. Hoel [1922] and W. Werenskiold [1920] have found several horizontal shelves or plateaus at various high levels along the coast in southern Spitsbergen near South Cape. There is one shelf at about 40 metres above sea-level, another at about 80 to 100 metres. This platform is especially well developed. It is in some places several hundred metres broad, and is widely extended along the south coast of the land, inside the low plain of the strandflat, which is there very broad (see Fig. 134). Farther north towards Horn Sound this platform is per- haps somewhat lower, about 70 metres. There is one shelf, somewhat uneven, at 220 metres, and then a fairly broad and conspicuous one at 340 metres above the sea, on which Hoel observed many pebbles and shore boulders. It is indeed strange that shore formation of so recent date, that the pebbles have not even been removed by glaciers, occur at such high alti- tudes so near the southern end of the land. It shows on the one hand that there has been very great vertical movements of the crust in this region relatively recently, and on the other hand that the shore erosion must be so effective in this region, that in the rocks of little resistance broad shore platforms can be cut in relatively short time during temporary depressions of the land. 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 211 XIII. THE STRANDFLAT ALONG COASTS INSIDE AND OUTSIDE THE ARCTIC REGIONS. The Coasts of Siberia, Greenland, and Alaska. Along the north coast of Siberia there is a well-developed emerged strandflat, which I have previously described [1904, pp. 20 ff., Pl. III]. On the Eastern Taimur Peninsula and the Chelyuskin Peninsula, between the mouth of Taimur River and Chatanga Bay, it forms a very conspicuous level foreland backed by mountains rising abruptly above its plane [see 1904, PI. III, Figs. 1—4]. Its height, near the coast, was estimated to be less than 30 metres above the sea, it has a considerable width, and forms a continuous level plain along most part of the coast, extending hori- zontally to the foot of the mountains. It is cut in solid rock, but is to a great extent covered with drift material, which may in some places attain considerable thickness. The coast between Taimur Bay (the Norden- skidld Archipelago) and the mouth of Yenisei River is low, and as there are few mountains or hills near the sea, it is difficult to say whether the whole of this low land is actually a strandflat which has been cut horizontally by shore erosion. We must in that case assume that most initial hills surmounting the plane of this strandflat have been planed down. As this coast land and the islands outside are so very flat [cf. 1904, PI. III, Figs. 7—10, PI. IV, Fig. 1], and considering that there is a quite similar low coastland with low islands to the north forming a foreland or regular strandflat in front of the steep mountain sides, it seems to me to be probable that this land too has been levelled by shore erosion, and that it is actually a strandflat. The sea along the north coast of Siberia is very shallow; often 30 or 40 kilometres or more from the coast, it has depths less than 40 and 50 metres. The soundings taken in this region are, however, much too few to make any study of the topography of the sea-bottom possible. It has to be considered that there is an exceptionally broad continental shelf, with depths less than 100 metres, extending a great distance north from the Siberian coast, in the region of the New Siberian Islands even as much as 600 or 700 kilometres, and that the whole of this sea is therefore very shallow. As it is especially shallow outside the mouths of the great rivers, 212 FRIDTJOF NANSEN. M.-N. Kl. Yenisei, Lena, &c., it seems probable that it is to some great extent filled up with river sediment. But on the other hand, as small rocky skerries rise above the sea in many places along the coast, and as I also observed sunken rocks near or in the water-surface, it is obvious that the sea- bottom consists of solid rock to a great extent, and it seems probable that there is a submerged rocky strandflat which is very widely extended in some places, and the plane of which lies at levels less than 30 metres helow the sea-surface. In the region of Yugor Strait and Vaigach the land is low and flat. The plain is to a great extent cut in solid rock as is especially clearly seen along the shores of the strait and on Vaigach [cf. Nansen, 1904, p. 22]. Along the coasts of Novaya Zemlya there is in many places an un- usually well-developed strandflat forming a flat foreland in front of the steep mountain sides ascending abruptly above its plane. The low and flat Goose Land seems, for instance, to be a broad strandflat. On the Holtedahl Expedition to Novaya Zemlya in 1921 the emerged strandflat was studied and its levels taken in several places, and we may look for- ward to an interesting report on these investigations. The soundings taken along the coasts of Novaya Zemlya indicate that there is a submerged strandflat, but they are too few to tell much about its topography and extent. On the whole it is striking that along all these Arctic coasts, we find a well developed strandflat, which often, especially along the north coast of Siberia, forms extensive plains. It indicates that in these regions there has been a very vigorous shore erosion, obviously due to the cold climate in these northern latitudes, which has caused an active dis- integration by frost of the rocks of the shores even during the warm interglacial periods. Well developed strandflats obviously also occur along other coasts of the Arctic region. Along the west coast of Greenland there is a strandflat very similar to the Norwegian one, with a belt outside the coast of numerous low islands and skerries [cf. Nansen, 1904, pp. 90 f.]. It does not seem, however, to be as well developed as along the coast of Norway. | Along the east coast of Greenland I have found no certain evidence of the existence of a strandflat near present sea-level. This is what might be expected, as Greenland is still covered by an ice-cap which extends to the outer coast along most part of the east coast south of 68° N. Lat. The probability is, therefore, that this coast is still much submerged by the weight of this ice-cap. If there is a strandflat it may be at some depth below sea-level. Along the west coast of Greenland south of 68? N. Lat. the conditions are different. The margin of the inland ice is a great distance from the outer coast, and there is a broad coast land which is not covered by the 1921. No. II. THE STRANDFLAT AND ISOSTASY. 213 ice-cap. It is therefore possible that the outer part of this coast land may have risen towards its natural level of equilibrium, and even that, by the pressure of the ice-cap over the inner land, the outer coast may have been upheaved above its natural isostatic level, although this is hardly probable. These are interesting questions which have to be settled by special investigations on the spot. On the islands of the Arctic Archipelago north of Canada, there is obviously also a strandflat. On the islands along the coast of Alaska, there is a strandflat forming a flat foreland between the base of the steep mountains and the descent to deep water. Gilbert [1904, pp. 130 ff. and 179] mentions this low foreland in several places and gives some very illustrative pictures of it (see his Figs. 64, 65, 85, and his Pl. XVII) showing that it is obviously of the same type as the Norwegian strandflat. Gilbert, however, explains it as a preglacial peneplain, or base-levelled plain, in the same manner as Ahlmann has lately adopted. This peneplain formed originally a more continuous foreland, which has afterwards been dissected by erosion, forming deep channels now separating the islands. These channels have to a great extent been formed even by fluvial erosion “at least 500 feet (150 metres), and probably 1,000 feet (300 metres) or more, below the present sea-surface" [1904, p. 136]. It seems to me difficult to under- stand how a plain of this kind could possibly have survived a fluvial and glacial erosion which has cut channels through it, now 1,500 to 1,700 feet (450 to 520 metres) deep. Gilbert has also to assume that "the glacial degradation must have been locally quite moderate, or the general plain character would not have survived" [1904, p. 131). In my opinion there can be little doubt but that this low foreland in Alaska is a formation of the same nature as the Norwegian strandflat, and has been formed in the same manner by shore erosion, during cold interglacial periods, and during the beginning of glacial periods, before the land began to sink, and before the coasts were covered by glaciers. The heights of the Alaskan strandflat seem to be similar to those of the Norwegian one. (Gilbert states that on the islands along the coast of Kadiak "the height ranges from about roo feet (30 metres) to sea- level" [1904, p.179]. On the Annette Island, in the Alexander Archi- pelago, he says, however, that "there is a general and gradual ascent from the sea front to the mountain base, where the altitude may be three or four hundred feet" (90 or 120 metres). This description does not, however, agree with the impression given by his illustrations, which show a low fairly level plane, and I think, therefore, that this high alti- tude of the mountain base is not the general one. 214. FRIDTJOF NANSEN. M.-N. Kl. Fig. 162. Low land along the east coast of the southern portion of Mainland. I The coast northwards from Sumburgh Head, seen from the north-weast. I Southward view along the coast from the sea off Mousa. III View northwards along the coast from the sea off Mousa. IV View southwards along the coast from the sea off Helli Ness. V View northwards through Bressay Sound from Lerwick. August 23, 1911. Shetland Islands. As I considered it to be of interest to study the strandflat on an ex- posed island group far out in the ocean, I sailed across to Shetland for a few days in August 1911. The stay was, however, too short for a real survey, and I could only expect to get a general impression of the topo- graphy of the coast. I sailed along the whole east coast of Mainland and nearly to its north end, and I landed at several places. I also crossed the island from Lerwick to Weisdale Voe on the west coast. The Shetland Islands have a very complicated geological structure. In the southern portion of Mainland the clay-slate series, with associated limestones and quartzites, prevails. Its eastern sea-board from Lerwick southwards is skirted by the lower Old Red Sandstone (Devonian). The north-western half of Mainland, as well as the islands Whalsey, Yell, and I92I. No. II. THE STRANDFLAT AND ISOSTASY. 215 Fig. 163. The Nab south of Lerwick, the west side of Bressay in the background. the western sea-board of Unst consist chiefly of micaceous and horn- blendic gneiss with limestones and quartzites. In Unst and Fetlar, the north-eastern islands, there are large masses of serpentine and gabbro. In Delting and Northmavine, in the north-western portion of Mainland a large area is occupied by diorite. The islands Foula, far out to sea toward the south-west, and Bressay, east of Lerwick, are built up of the lower Old Red Sandstone, and so is the greater part of Walls, in the western portion of Mainland. As these rocks, building up the islands, have to a great extent con- siderably less power of resistance to erosion than the rocks of the west coast of Norway in the same latitude, it is natural that the islands have an aspect very different from the Norwegian coast. They are on the whole low with rounded forms, while the shores are cut back by recent marine erosion, forming cliffs and many isolated vertical rocks, the so-called "drongs", in the sea outside. But in spite of these conspicuous marks of a recent shore erosion, no quite convincing evidence of the existence of a real emerged strandflat could be discovered along the shores. Many low islands occur, and low flat plains extend inland from the shore in many places in Mainland. But nowhere did I observe a sharply defined boundary between the coastal plains and the hills rising above them. It seems to me, however, to be probable that the low land, about 20 to 30 metres above sea-level, extending along the southern east coast of Mainland, northwards from Sumburgh Head (see Fig. 162, I—IV) is actually an old strandflat. Inside this low land the hills rise more steeply, but as a rule not abruptly with a sharply marked boundary. In some places especially on the points, there may be a more marked difference between the flat shore land and the rising hill side (cf. Fig. 161, V, the distant low point on the west side of the sound north of Lerwick, see also 216 FRIDTJOF NANSEN. M.-N. Kl. Fig. 164. I Lunna Holm and the Islands west of Lunna Ness. II Out Skerries with the Lighthouse. The height of the highest islands is 52 metres above the sea. August 26, 1911. Fig. 163, the west side of Bressay in the background). On some of the islands similar formations are. noticeable, a low outer border and higher ridges inside (see Fig. 164). In Yell Sound at Ollaberry Bay, on the east coast of Northmavine (in the northernmost portion of Mainland), I found, by levelling, the plane of the supposed strandflat to be about 33 metres above the sea. The is- lands Bigga and Samphrey in the middle of the sound are 33 metres and 30 metres above sea-level. If this low land may actually be considered to be a regular strandflat of the same kind as the Norwegian strandflat, it seems probable that the slopes of the hills inside have been much changed by subaërial denudation and perhaps by glacial erosion after the formation of the strandflat. During the periods when the strandflat was developed, the shore erosion by frost was probably not very effective in this region, so near the warm Atlantic Current, where the climate was probably not very cold. Hence the strandflat was not cut very broad, and as its formation took a long time, the surface of the land was at the same time to a comparatively large extent affected by the subaërial denudation. There is no well-developed submerged strandflat along the shores of the Shetland Islands. Along a great part of the coast the sea-bottom slopes gradually from the shore down to depths of 100 metres and more, without any distinct break or well marked edge. At many places there are, however, indications of a submerged narrow platform, less than 15 or 20 metres below sea-level. They may be as much as ı kilometre broad and are bounded by a somewhat steeper slope outside. Considering the exposed situation of these islands to a stormy sea, and the comparatively small power of resistance of their rocks to erosion, it may seem remarkable that there is not a better developed emerged or submerged strandflat along their coasts. It proves: — on the one hand, that the wave action alone has not much power to form a strandflat, and on the other hand, that there cannot have been much shore erosion by frost for its formation in this region. I92I. No. 11. THE STRANDFLAT AND ISOSTASY. 217 EDCCOTEHE LEVELS OF THE STRANDFLAT AND THEIR DEVELOPEMENT. We now propose to discuss the possible changes in the level of the shore-line and the relation between the two similar formations, the strand- flat standing at levels near or slightly above present sea-level, and the much broader continental shelf standing at levels one or two hundred metres below present sea-level. Let us first, however, summarize the conclusions on the nature of the strandflat to which our investigations have led us. Summary of the Results of our Investigations of the Strandflat. We have found: On the one hand that, during the long periods required for the form- ation of the strandflat, the shore-line has maintained very uniform levels along the extensive coasts where a strandflat occurs, 1. e. especially in Arctic and Subarctic regions. On the other hand that after the formation of the now emerged strandflat began, there has been a negative shift of the shore-line caused either by an upheaval of the coasts or by a lowering of the sea-level. These changes of level have been very uniform over extensive areas. On the whole, the strandflat creates the impression of having been formed during long periods when the earth’s crust in those regions stood at its natural level of equilibrium; and since then there has been no ap- preciable tilting of this level on the whole, although there may have been small local changes in the course of time. Our investigations show that there are probably several levels of the strandflat: the emerged strandflat has probably in most places two levels, and the submerged strandflat represents at least one level. The results of our investigations as regards these levels may be sum- marized as follows: The emerged Strandflat. Along the west coast of southern Norway, in the regions of Stav- anger, Karmoi, Hardanger Fjord, Sotra, Radoi, Lindås, and Sogne Fjord, the emerged strandflat seems to have two levels: An upper level at be- 218 FRIDTJOF NANSEN. M.-N. Kl. tween 30 and 40 metres, or in some places perhaps between 26 and 35 and a lower level at about 15 to 18 metres above metres above the sea the sea. In most places in these regions the upper level comprises the greater part of the area of the strandflat. The lower level extends near the shore, is more even, and is obviously of younger age than the upper level. In the region of Stavanger, this lower level is of comparatively wide extent, especially where the rocks are phyllite and chlorite schists, &c. which have comparatively little power of resistance to erosion. In the region of Smølen, Hitteren, and Frøia (Fig. 107) the emerged strandflat has probably also two levels: an upper level about or higher than 30 metres above the sea, and a lower level lower than 20 metres above the sea. The lower level is here of a comparatively greater extent than in the above mentioned region of the west coast. It comprises the most part of Smølen, and a great part of Frøia, and is also widely extended along the north coast of Hitteren. Along the coast of Helgeland the lower level of the emerged strand- flat comprises the greater part of its area, especially in regions where rocks with comparatively little power of resistance to erosion prevail. On Donna and Heroi it forms very even planes at altitudes of 8 to ro meters above the sea, and in some parts of the islands even lower. This low plane of about 10 metres seems to be of very wide extent on the many islands of Helgeland. The upper level at about 30 metres, or between 30 and 40 if it exists, is at any rate of very small extent in the region of Helgeland (cf. the maps Figs. 113 and r14). On Lofoten and Vesterälen the emerged strandflat has probably also two levels, and the upper level, perhaps at about 30 metres, seems to be of a greater extent, e. g. on Hasseloi, than in Helgeland. The lower level is well marked on the small islands along the coast (see Figs. ı and 2). The submerged Strandflat of Norway. Along the west coast of southern Norway south of Sogne Fjord there is not much of a submerged strandflat. There are numerous shoals sunken rocks here and there, at somewhat varving depth, but there are no well defined platforms with horizontal planes. Along the coast between Sogne Fjord and Stat, there are more indi- cations of a submerged strandflat in the shape of small submerged plat- forms and groups of shoals and sunken rocks often far out to sea. The soundings given in the charts of this coast are not sufficiently numerous for a study of the shape and topography of these platforms. Their depths seem to vary somewhat, but are to a great extent less than 10 metres below sea-level. 1921. No. 11. THE STRANDFLAT AND ISOSTASY. — 219 Along the Sondmor and Romsdal coast the submerged strandflat is considerably wider and more developed, forming platforms extending far out to sea. Outside the islands Fjertoft and Haroi, north-east of Âle- sund, these plattorms extend as much as 8 or 10 kilometres seawards from the outer coast of the islands, and have depths to a great extent less than 10 metres below sea-level. Their surface is somewhat uneven and dis- sected by channels and depressions, and their edges do not seem to be very sharply defined. The submerged strandílat is similar outside the coast at Hustad. It is especially well developed in the region of Smolen, Froia, and the Froan Islands where it extends 12 to 20 kilometres, or more, seawards from the outer coast of the big islands, and has a level suríace, less than IO metres below sea-level, and well defined edges. It is, however, dis- sected by numerous channels. This strandílat is cut in pressed igneous rocks and granites, which, however, seem to have no very great power of resistance to erosion by frost. The submerged strandílat of this region has, on the whole, a greater area than the emerged strandflat. Along the coast to the north-east the submerged strandílat is well developed, and its surface topography is largelv similar to the one just described. Along the coast of Helgeland the submerged strandflat is of ex- ceptionally wide extent. The area of the emerged strandílat is quite small in comparison. The suríace of this submerged strandílat is, as a rule, very level, almost perfectly horizontal, and less than 10 metres below the sea-surface, largelv in fact between 2 and 6 metres. Its edges are to a great extent sharply defined with steeper side slopes. Where the rocks are mica-schist, limestone, and weak gneiss the surface of this submerged Strandflat is more level and the edges more sharply defined, than where the rocks are granite or other fairly resistant igneous rocks. In Lofoten and Vesterålen the submerged strandflat is not broad, obviously owing to the great power of resistance of the rocks to erosion, and also owing to the considerable initial height of the land. The sub- merged strandflat of this region has, however, as a rule a much greater width than the emerged strandflat. Its depth is as a rule greater than those of the submerged strandflat of Helgeland, its surface is less hori- zontal, and the edges less marked. Along the coast to the north-east there is also a well developed sub- merged strandflat at about the same depth, as far as Ringvasoi and Kvaloi. The three Levels of the Strandflat. We may thus assume that the strandflat of Norway has at least three different levels: An upper level which in southern Norway is mostly be- tween 30 and 40 metres above the sea (in some regions, as for instance 220 FRIDTJOF NANSEN. M.-N. Kl. on Stord, perhaps somewhat higher than in other regions). In northern Norway, especially in Helgeland, this level is perhaps somewhat lower, and is less conspicuous. A lower level which in southern Norway is about 15 to 18 metres above the sea (in the inner part of Sogne Fjord about 10 and 12 metres) and in Helgeland in northern Norway is somewhat lower, about 8 to 10 metres (or even 5 metres), and is there of wide extent. A submerged level which is not much developed along the coast of southern Norway, is much more developed along the coast of Søndmør, Romsdal, and Nordmør coast, and is of a very wide extent along the coast of Helgeland. Wherever this level is well developed it has a depth of only some few metres, and less than 10 metres, below present sea-level. These different levels of the strandflat obviously indicate that the shore-line has stood at different levels during the long, periods when the strandflat was developed. We must assume either that the land has risen or that the sea-level has been lowered. The inner part of the emerged strandflat (at the upper level) has obviously been formed at some earlier period than the lower part of the strandflat (at the lower level). When the submerged level was formed is more difficult to decide. We have seen that in Helgeland where this level is especially well developed and is of very wide extent, it is only some few metres below the lower level of the emerged strandflat, and it might almost seem doubtful whether, in this region, it has not been formed more or less during the same long period as the latter. In Spitsbergen we have found a well developed emerged strandflat with heights above sea-level very similar to those of the Norwegian strand- flat, and there is also a distinct submerged strandflat with a depth of less than 20 metres. On Bear Island there seems to be a wider range between the upper limit of the emerged strandflat and the level of the submerged strandflat, but this may be due to special reasons as has been previously mentioned. In other regions, especially Arctic, where there is a well developed strand- flat, the investigations are not sufficiently detailed to give definite in- formation about the heights of the levels, but they seem to be somewhat similar to the heights we have found in Norway and in Spitsbergen. Causes of the Changes in the Level of the Strandflat. It is, in my opinion, probable that the different levels of the strand- flat in Norway indicate different interglacial periods of its formation, and mark the levels of equilibrium of the land crust during each of these periods. Owing to the great quantities of rock and the débris of the inter- glacial erosion carried away from the land-surface into the sea by the big 1921. No. rr. THE STRANDFLAT AND ISOSTASY. 221 glaciers, the land has been somewhat raised by isostatic movement to the new level of equilibrium after the disappearance of the ice cap of each glacial period. It is not known how many Pleistocene glacial periods there may have been in Norway. But considering that at least four different glacial periods are now established for Central Europe, it seems hardly probable that there should have been less in Scandinavia. If the strandflat has two distinct levels it seems to indicate that there have been at least three glacial periods in Norway as was already assumed by Oxaal [1914, pp. 42 f., cf. above p. 48]. If there are actually three different levels, it may indicate four glacial periods. If we assume that the changes of level are solely due to isostatic movements of the earth's crust, and in no degree to changes in the sea- level (caused by changes in the volume of the Ocean), it may seem diffi- cult to understand why the heights of the raised strandflat are so verv similar along the Norwegian coast and even on Spitsbergen, although the quantities of rock removed may probably have varied much in the divers regions of the coast. If we assume that the upper limit of the strandflat is universally at some height between 30 and 40 metres above the sea, we would then have to assume that the quantity of rock material removed from the surface of the coast land corresponds to a continuous layer of rock with an aver- age thickness of at least 36 to 48 inetres, which has been removed after the upper level of the strandflat was first developed. This seems a great deal. Although much thicker layers of rock have obviously been excavated from the deepened valleys and fjords during this long period, the thickness of rock removed from the high land surface, between the deep valleys and fjords, has probably not been very considerable. It is also striking that the level surface of the strandflat itself cannot have been much denuded. On the other hand, if there have been at least two glacial periods, and probably three, after the upper level of the emerged strandflat was developed, it is not inconceivable that the weight of the rock material removed by the glacial erosion of the coast land during these periods may go some way towards explaining the elevation of the strandflat above present sea-level. The submerged strandflat offers, however, another difficulty to this assumption. If, during some period before the last glacial epoch, this part of the strandflat was cut at a level actually lower, though slightly lower, than the present sea-level, the level of the land cannot have been permanently raised after that time, unless the general sea-level has also been raised. To me it seems probable that, in addition to the isostatic upheaval of the land, there have been changes in the level of the sea. D D D FRIDTJOF NANSEN. M.-N. Kl. There are several processes continually at work causing changes in the volume of the Ocean. The continual emission of water vapour from the volcanos adds new water to the Ocean, while on the other hand water is substracted from it by the alteration of rocks which binds water chemi- cally. These processes are slow, however, and the one more or less checks the other. It is, therefore, hardly probable that, during the periods we are here considering, they have produced changes of sufficient importance to account for the observed shifts of the shore-line after the formation of the strandflat. The displacement of sea-water caused by a volcanic eruption on the sea-floor would probably only cause a temporary rise of the general sea- level, as the effect would probably be more or less readjusted by the isostatic movements of the crust under the Ocean. Crustal movements changing the size or depth of the Ocean basin would naturally also cause changes in the general sea-level, but as these movements would be finally controled by isostasy, it is hardly probable that they can have produced appreciable changes during the periods we are discussing. The deposition of sediment on the sea-floor may gradually raise the general sea-level, as will be mentioned later; but this is also a slow process and is partly checked by crustal sinking. Changes in the position of the poles would cause changes in sea-level. But if the lowering of sea-level since the first formation of the strandflat should be thus explained, we would have to assume, that the pole has come nearer to the regions of the strandflat, which would involve the probability that the climate has become more arctic since that time, which is exactly contrary to what might be expected. Changes in the earth’s centre of gravity might also change the sea-level, but is probably so slow a process that it would not help much to explain the changes under consideration. The same is also the case with possible changes in the earth’s rotation. The subtraction of water from, and the addition of water to, the Ocean caused by the formation and melting of the great present and Pleistocene ice-caps have probably produced the most considerable changes in sea-level during comparatively short periods. Much water is now accumulated in the extensive ice-caps of the Antarctic and of Greenland. According to Hess, the area of the Antarctic ice-cap is about 13 mil- lions square kilometres and that of Greenland 1.9 million sq.km. If we add to this the glaciers of the rest of the world, we get an ice-covered area of about 15,156,000 sq.km. altogether. We do not know what the average thickness of these ice-caps may be. The ice-caps of Greenland and the Antarctic with their general level surfaces standing at altitudes of 2,000 and 3,000 metres and more above the sea, must obviously have quite considerable thicknesses. If we assume the average thickness of the ice- caps to be 600 metres, the melting of them would increase the average 1921. No. r1. THE STRANDFLAT AND ISOSTASY. 223 5.156 depth of the Ocean by an amount of > 361.1 the area of the Ocean being about 361,100,000 sq. km. and the specific gravity of the glacial ice about 0.9. x 600 X 0.9 = 22.7 metres, If the average thickness of the ice-caps be 1,000 metres, the increase of the Ocean depth caused by their melting would be 37.8 metres. The final rise of the general sea-level caused by this increase of the average depth of the Ocean, would be somewhat reduced by the gradual crustal sinking of the sea-floor under the increased weight of the oceanic water masses. If the specific gravity of the plastic rock or magma underlying the crust be 3, the depression (u) of the sea-floor will be where d is the increase of the average depth of the Ocean. Hence, if the increase of the Ocean depth be 22.7 metres, the rise of sea-level will be 15.1 metres. It will be 25.2 metres if the increase of the Ocean depth be 37.8 metres. This is provided that the crustal sinking of the sea-floor is entirely compensated for by the upheaval of the areas which were covered by the ice-caps. If not, as will generally be the case, the sinking of the sea- floor will be somewhat reduced, as it will then have to be compensated for by the upheaval of the continents surrounding the Ocean (cf. pp. 235 ff.). We see that the probable changes in the general sea-level caused by the reduction of the existing ice-caps would be quite sufficient to explain the negative shift of the shore-line after the first formation of the strand- flat, if we add the probable isostatic upheaval of the land caused by the removal from its surface of glacial and interglacial waste. The question is, however, whether we can assume that all ice-caps had disappeared when the strandflat was formed. The probability is that during long preglacial periods, there have been no ice-caps of significance, and that during those periods the Ocean had what we might call its normal average depth, which was somewhat greater than the present one. During the warm interglacial periods it is also probable that the ice- caps of the earth may have been essentially smaller than they are now. The difficulty is, however, that the strandflat has obviously not been developed during these warm interglacial periods, but during periods with a cold climate favouring a vigorous shore erosion by frost. And these periods may have preceded the glacial periods, or have formed their be- ginning, before the crust was pressed down by the weight of the accu- mulating ice. The development may also have continued some time after this sub- sidence of the land began, as the sea-level sank simultaneously because of the subtraction of water from the Ocean by the increasing accumulation of water in the ice-caps on land. But it should be noticed that this sub- 224 FRIDTJOF NANSEN. M.-N. Kl. sidence was not uniform, it being greater inland than nearer the coast, and in the outer coastal region there may probably have been an upheaval of the land during the first part of the subsidence of the inner land. Hence it is not probable that the strandflat was developed to any large extent during this period when the land surface was warped, a characteristic feature of the strandflat being that its levels are practically horizontal. However this may be, it seems probable that the general sea-level has sunk somewhat since the strandflat began to be developed, and it is possible that changes in the thickness and extent of existing ice-caps may at least to a large extent have caused these changes in the sea-level. As long as there are ice-caps which during some periods increase and during others decrease, the average depth of the Ocean and the general sea-level will not remain quite stable. It might then be possible that the present submerged strandflat was planed during some long period when the ice-caps of the earth were a good deal greater than now, and that although there has been an isostatic upheaval of the land since that time, the level of this lowest part of the strandflat has not been raised above the present level of the sea surface. As will be mentioned in the next chapter there is, however, weighty evidence to show that the lower level of the emerged strandflat was formed just before the last glacial period. If therefore the plane of the submerged strandflat represents a different stage, we would in that case have to assume that it was formed before the lower level of the emerged strand- flat, although this would be somewhat difficult to understand. Bv the assumption that, during the long time which has elapsed since the strandflat began to be formed, the shore-line has been shifted partlv by isostatic upheaval of the land and partly by changes in the general level of the sea, we obtain a simple explanation of the reason for there not being greater differences in the heights of the strandflat in the divers regions. The explanation of the fact that the lower level of the emerged strandflat seems to stand somewhat lower along the coast of Helgeland and in the inner part of Sogne Fjord than along the outer west coast of southern Norway, in the region of Sogne Fjord and south of it, may then be, either that a smaller quantity of rock have been removed from the land surface in these regions after the formation of this level, — or that the isostatic upheaval of the land has not yet been quite completed in these regions. The former explanation seems hardly probable, considering that the rocks of Helgeland are not on the whole very resistant. It seems less improbable that the upheaval of the land after the last glacial period is not yet finished in these regions which were considerably depressed during the last glacial epoch. The inner region of Sogne Fjord was de- 1921. Norr THE STRANDFLAT AND ISOSTASY. 225 pressed more than 100 metres and was probably covered by big glaciers comparatively recently, and the extensive Justedal glacier still remains, weighing down the land to some extent. In the region of Helgeland where the outer coast was depressed more than 75 metres, there may also have been a glacial covering comparatively recently, remnants of which still exist in the big "Svartisen" glacier. Another fact which may also have retarded the upheaval of the crust in this region, is that the extensive submerged strandflat was covered during the depression by a layer of water as much as 75 metres deep or even more near its inner margin, and the weight of this water made the upheaval of the land slower. It may, therefore, not seem improbable that in Helgeland, as well as in inner Sogne Fjord, the upheaval of the land may still be a few metres short of its full complétion, while it is long ago completed along the outer west coast-si”southern Norway as well as in Lofoten and Vesterälen where the late-glacial depression was very small or nothing at all, and where there was no extensive area of submerged sea-floor outside that should be elevated. The Nature of the Rocks and the Topography of the Strandflat and the Continental Shelf. Our investigations have shown that the shape and development of the strandflat vary to some extent with the nature of the rocks. This is especially conspicuous in the topography of the submerged strandflat of Norway. Where the rocks possess comparatively less power of resistance to erosion, the submerged strandflat has a very level surface forming a nearly horizontal plane only some few metres below present sea-level, and its edges are sharply defined at about the same depth. Its side slopes are often steep descending to considerable depths on the continental shelf outside. Where the rocks possess a comparatively great power of resistance to erosion, the surface of the submerged strandflat is considerably more uneven and irregular. It is generally sloping seawards, its edges are less sharply defined, and its depth may vary a great deal. Its outer side slopes are as a rule not steep, and the depth of the continental shelf outside not considerable. If this be compared with the surface of the continental shelf of Norway outside the strandflat, we find a striking difference. In regions of weaker rocks the continental shelf is broad, but is comparatively uneven and its surface is to a great extent lving at a con- siderable depth below present sea-level, while, as we have seen, the sub- merged strandflat is extremely level in those regions, and is standing comparatively high, being near present sea-level. Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. 11. 15 226 FRIDTJOF NANSEN. M.-N. Kl. In the regions of more resistant rocks, e. g. outside the coasts of Søndmør, Romsdal, Nordmør, Lofoten, Vesterålen, Senjen, &c., the con- tinental shelf is comparatively narrow, its surface fairly level, and its depth below present sea-level to a great extent less than 150 metres, and in some regions even less than 100 metres, while the submerged strand- flat, as we have seen, is also narrow, but is comparatively uneven and irregular, sloping seawards, and lying deeper below present sea-level than in the regions of weaker rocks. There is often no very sharply defined boundary between the low strandflat and the high inner part of the con- tinental shelf. Although the submerged strandflat is very broad outside Helgeland, its outer side slopes seem to have been cut back more and to have been made steeper in the regions of weaker rocks than in those of more resistant ones. Its very level surface in the former regions seems there- fore largely to be of a younger age than the more uneven surface of the latter regions. Let us now leave the strandflat for a while and consider the form- ation of the continental shelf. 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 227 SV ThE CONTINENTAL SHELF AND-TES FORMATION. In a previous treatise on the bathymetrical features of the northern seas [1904] I have described the continental shelf of Norway and of other northern regions and discussed its formation. There is this resemblance between the continental shelf and the strandflat, that both of them form fairly horizontal planes, in front of the coast which in Norway and several other countries is steep and ascends abruptly from the inner margin of the planes. Both formations as far as they are cut in solid rock, may most naturally be assumed to have been planed largely by marine de- nudation of some kind. There is, however, this striking difference be- tween them, that the typical strandflat is largely confined to cold regions, where there has been severe climates favouring shore erosion by frost, and it is only exceptional that strandflats occur outside such regions, in places where there have been special climatic conditions, as for instance along the south-east coast of India — while the continental shelf has a universal distribution along most old coasts in all latitudes. The continental shelf 1s obviously to a large extent built up of waste from the land carried into the sea during long geological periods and deposited outside the coasts. But as I previously pointed out [1904] it is also to some extent cut in solid rock. It would, for instance, be extremely difficult to explain in any other way the striking fact that outside the Norwegian coast its shape and the height of its level is ob- viously to some extent dependent on the nature of the rocks of the coast. It is especially narrow and high where the rocks possess a comparatively great power of resistance to erosion, as along the Romsdal, Sondmor coast and the coast of Lofoten, Vesteralen and Senjen, while it is very broad and lies comparatively deep below sea-level outside Helgeland where the rocks on the whole possess much less power of resistance to erosion. The submerged fjords on the continental shelf, e. g. outside Sondmor, and outside Helgeland, and the coast north of Trondhjem, also indicate the rocky nature of the shelf. These fjords, which to a large extent follow the same direction as the valleys of the great Caledonian mountain folding on land, are obviously sculptured in solid rock [cf. Nansen, 1904, p. 151]. 228 FRIDTJOF NANSEN. M.-N. Kl: As a whole the continental shelf is obviously a very old formation developed during long geological periods, to a great extent preglacial, while the strandflat has been developed after the first Great Ice Age. A few points may be specially mentioned. Our investigations of the Norwegian strandflat and the late-glacial submergence of the land (see next chapter) prove the almost perfect isostacy of the crust. It seems then improbable that the initial land in the region of tke continental shelf can on the average have been very high. Outside Helgeland this shelf has a width of 250 kilometres, very nearlv equal to the distance from the coast eastwards to the central region of Fenno-Scandia where the land had its greatest late-glacial submergence of 300 metres or more. This shelf is consequently so broad that the crust in that region must stand very nearly at its level of equilibrium. If the average specific gravity at the eroded surface rocks be 2.6, that of the underlying plastic rock or magma, displacing the upheaval (i) of the crust, be 3, the thickness of rock eroded be h, and the permanent lowering by erosion of the level of the land surface be I, we have: ux3 = hX<2.6 /=h—u Sey JE. E dE Hence in order to lower the average level of the land surface roo metres it would be necessary to remove a laver of rock having an average thickness of 750 metres. If the specific gravity of the underlying magma be higher, the thickness of the laver of rock which had to be removed would be smaller, e. g. with a specific gravity of the magma of 3.5, it would be only 389 metres. As the planing of a shelf in solid rock by the joint action of subaërial denudation and marine denudation is obviously a very slow process, especially if it is not vigorously assisted bv frost disintegration, and as the continental shelf of Norway cannot be assumed to be of sufficiently old age to make a vertical denudation of very great dimensions probable, we may assume that the initial land in the region of the present continental shelf was fairly low. It may, however, have been much more uneven, and there may have been isolated parts or mountains rising to greater heights. The sub- merged lower parts, the depressions and vallevs, of this initial land, may then in the course of time have been filled up with waste from the land, and the crust may thus have been depressed to a certain degree. There is also the possibility that in the outer part of the shelf there is only a small amount of rocky ground, and that this part is chiefly IQ2I. No: Tr. THE STRANDFLAT AND ISOSTASY. 229 built up of waste. This accumulation of waste will have pressed the crust down to some great extent. On the deeper sea-floor outside there may probably also have been formed thick layers of deposits, weighing down the crust. But why is there such a comparatively steep and sudden descent from the outer edge of the shelf on to the flatter sea-floor if the shelf and the sea-floor are built up of the same kind of material? There is also another difficulty with which we are faced. The level surface of the continental shelf, whether cut in solid rock or built up of loose material, indicates an earlier sea-level or rather sea-levels, when either the land stood so much higher than now or the sea-level so much lower. In Norway there is furthermore this difficulty that the height of the level of the shelf varıes a great deal as was previously mentioned. Outside Romsdal and Sondmor as well as outside Lofoten the level of the continental shelf stands at a depth of 100 to 150 metres below sea-level, and outside Vesterälen and Senjen the depth below sea-level of the very flat shelf is even less than 100 metres. Outside Helgeland the surface of the continental shelf sinks down to 300 and 400 metres below sea-level. Considering the nearly perfect isostasy of the earth’s crust, which the crustal movements of Fenno-Scandia indicate, it seems extremely difficult to understand that, during the long period when the shelf was formed, the land as a whole can have stood so much higher as the depth below sea-level of the continental shelf; and when we consider that the other coasts of the globe must in that case also have been similarly elevated, the idea becomes quite impossible. If the continental shelves of the world actually indicate one or more earlier sea-levels we would therefore be bound to assume that there have been considerable fluctuations in the level of the Ocean, and that during the periods when the continental shelves were developed it stood perhaps 100 to 150 metres lower than now [cf. Nansen, 1904, pp. 200, 211 f.]. Fluctuations in Sea-Level caused by the Formation of Ice-Caps. During the Ice Ages great quantities of water were accumulated in the extensive ice-caps of the northern and southern hemispheres. Penck (1881, p. 76, 1894, II pp. 528, 660] estimated that the abstraction of water from the Ocean caused by the glaciation of the northern hemisphere alone sank the general sea surface 67 to 71 metres. Assuming that the glaciations of the northern and southern hemispheres were simultaneous, Drygalski (1887, p. 274] calculated that the lowering of the general sea-level thus caused was about 150 metres. The present writer pointed out [1904. pp. 211 f.] that the ice-caps of the northern hemisphere may probably during their widest extent have had a considerably greater area than 230 FRIDTJOF NANSEN. M.-N. Kl. assumed by Penck and the general sea-level may possibly have been sunk as much as 100 metres by their formation. If it be assumed that simultaneously there was a great extension of ice-caps in the southern hemisphere, and the antarctic ice-cap had a greater thickness, I thought it "conceivable that the level of the Ocean was at times lowered as much as 200 metres or even more”. Reginald A. Daly [1910, 1915, p. 173] has estimated that by the melting of the Pleistocene ice-caps since their maximum development "the general sea-level has been raised by an amount ranging between 23 and 129 metres”. He thinks that this minimum estimate is likely to be too small, while the maximum estimate is too large. He thinks a rise of sea-level of the order of 50 to 60 metres to be most probable. I think Daly’s estimate is too low. It seems to me to be probable that during their maximum development the Pleistocene ice-caps had a greater average thickness and a greater extent than assumed even by Drygalski and Penck. The Thickness of the Ice-caps. During the last glacial epoch Fenno-Scandia was depressed by the weight of the ice-cap probably about 350 metres in its central region about Bottenviken (the Gulf of Bothnia). If the specific gravitv of the plastic magma underlying the rigid crust be 3, the specific gravity of the ice 0.9, and the thickness of the ice-cap H, we have: Hx<0.9 = 350x3 + M where M is a certain quantity due to the pressure counteracting the de- pression created by the upheaval of the peripheral areas surrounding the ice-caps, as will be mentioned below. If for the moment we leave this quantity out of consideration we have: FH ÈS 1167 metres. 0.9 This is, however, a minimum value. First, it is improbable that the land had been depressed to the full extent corresponding to the weight of the ice-cap before the latter began to decrease. Secondly, there is considerable evidence to prove that the depression of the areas covered by the ice-caps caused an upheaval of the regions surrounding the ice-caps. This upheaval will gradually spread outwards from the ice-caps over wider and wider areas, and the elevation will thus be reduced again very slowly. It is, however, obvious that as long as it lasts, the weight of the elevated magma under these upheaved regions will counteract to some extent the depression of the ice-caps, and will reduce accordingly the depth to which the underlying crust can be de pressed by their weight. The wave of upheaval surrounding a depressed area will as it were temporarily raise the level of equilibrium of this area 1921. Noy rr: THE STRANDFLAT AND ISOSTASY. 231 by the height of the wave. It is, however, extremely difficult to determine what the height of this upheaval may have been at the time when the ice- caps began to decrease, or, more correctly, when the sinking of the de- pressed areas ceased. A great part of these surrounding areas are now under water. The probability is, however, that owing to the upheaval of these areas we have to add a considerable amount to the thickness of the ice-cap computed from the late-glacial submergence of the land below its present level. If the volume of the underlying magma be not altered by any chemical changes, it is obvicus that the total volume of upheaval must be equal to the total volume of depression, without taking into consideration the elastic compression which in this connection is insignificant. If we assume that the area of the depressed land under an ice-cap is equal to one fourth of the area of the upheaved region surrounding the ic2-cap, the average height (uw) of upheaval must therefore be equal to one fourth of the average height (h) of depression. As, in the case of equilibrium inside these regions, the pressure should be uniform at a certain level below the earth’s surface, this means that ux3 = dxo.g — hx3 where d is the average thickness of the ice-cap, 3 the specific gravity of the magma displaced by the depression, and 0.9 the specific gravity of Her ice: As u = 0.25> Helliss#Eishthouser rer cree. 2 » 17 » The measured altitudes of the upper level of the emerged strandflat may indicate a similar rise of altitude from the inner parts of Sogne Fjord towards the outer coast. We found it to be about 25 metres on Vegarnes, 26 metres on Vangsnes, on Matsnes, and possibly on Rutletangene, 33 to 40 metres on Radøi (according to Ahlmann), &c. Provided that these observations be correct, and that the difference be not due to glacial erosion, the strandflat has consequently been some- what more raised near the outer coast than further inland, as was previously mentioned. The upper limit of the lateglacial and postglacial submergence (or upper marine limit) in the region of Sogne Fjord can only be traced by the highest raised terraces. J. Rekstad [1905, 1906, 1907, 1910] has found the following heights: : 2 Height above sea-level of Distance from the outer = x Locality es Utvær upper limit of lateglacial . submergence N N — Wad Clr te A ernennt 72 kilometres 77 metres Ortne vik yout ex seer eee sre) ates ole 88 » 87 » VER EEE oo 112 > IIS » Hovland, Årdal Polo eee EE I70 » 137 » 0 Let us assume that the isobase (1. e. line of equal postglacial upheaval) for 17 metres (i. e. the height above sea-level of the lower level of the emerged strandflat near the outer coast) passes across the middle of 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 247 Yttre Sulen, across the outer part of Atleoi to Rugsund near the mouth of Nord Fjord. Let us furthermore assume that the isobases for greater elevations further inland follow directions parallel. to this line. In the following table are given: 1) the direct distance of each locality mentioned from the isobase for 17 metres, 2) the height of the upper limit of lateglacial submergence above the lower level of the emerged strandflat (as given in the table on p. 246), 3) the gradient of the postglacial elevation (minus the height of the strandilat) a) between the isobase for 17 metres and the locality, and b) between each locality. DEERE from Height of upper Gradient of Elevation : : A marine limit above Locality the isobase for - . , x : lower level of from isobase for between the 17 metres "e strandflat I7 metres localities Wadheim >. 2... 52 kilometres 60 metres 1.15 per mille ) 0.53 per mille Gifnevik 2-2 te y: » 70 > 0.99 » » } Meme Mia... 95 » 103 » 1.08 » » Efoviandis--- e I43 » 128 > 0.89 » » ) 952 i The gradients between Vadheim and Ortnevik and between Ortnevik and Vik differ much from each other and from the gradient between Vad- heim and the isobase for 17 metres. If we assume that the terrace measured at Ortnevik does not actually give the upper limit of sub- mergence, and if we take the gradient between Vadheim and Vik, we find it to be 1.00 per mille, which is slightly lower than the gradient 1.15 per mille between Vadheim and the isobase for 17 metres. The gradient in the inner part of the fjord, between Vik and Hov- land in Ärdals Fjord, is very low, 0.52 per mille. The difference between this gradient and the gradient in the outer part of the fjord is much too great to be explained by the regular decrease of the gradient of elevation inland towards the central region of the depressed area. Rekstad is ob- viously right in assuming that the highest terraces at Hovland do not mark the upper limit of submergence, because the inner part of the fjord was filled with glaciers during the time of greatest submergence, and when the glaciers retreated and the terraces could be deposited, the land had already begun to rise. The probability of this explanation is confirmed by Rekstad’s measurements of the upper marine limit in the inner part of Hardanger Fjord and by H. Kaldhol’s measurements of the raised terraces in Nord Fjord. The observations made in Nord Fjord are of special interest to us here in another respect. 248 FRIDTJOF NANSEN. M.-N. Kl. The Lateglacial and Postglacial Upheaval in the Region of Nord Fjord. Rekstad found [1905] that the gradient of postglacial upheaval is much smaller in the outermost part of Nord Fjord than farther in. Kaldhol’s numerous measurements (by levelling) of the upper heights of the raised terraces in this region, at about hundred different places, have shown this still more clearly [Kaldhol, 1g12al. At twenty different places in the outer coast zone, between the north coast of the Stat Peninsula and the south coast of Bremanger Land (and Froien Island), Kaldhol’s measurements of the upper limit of submergence give heights between 15.2 and 17.7 metres above present sea-level (see map Fig. 165). In most cases it is between 16 and 17 metres. At two places, Revik on Vagsoi and Forde on Bremanger Land, he found the height to be 14.9 and 13.8 metres, but these values seem to be too low, for at Vedvik, 2 kilometres north of Revik, the height was found to be 15.8 metres, and at Tysketveit close by, also on Vagsoi, it was 16 metres (cf. Fig. 165). At Kalvag on Froien Island, 10 kilometres south-west of Forde and more seawards, the height was 16.6 metres, and at Steinset on the outer side of the same island it was 17.3 metres. These heights about 16 and 17 metres and less than 17.7 metres are found inland as far as Rugsund, inside the mouth of Nord Fjord, and about 23 kilometres from the outer coast-line (cf. Fig. 165)?. Kaldhol points out that the gradient of elevation is very gentle in this outer region. Even if the height of 13.8 metres at Forde (Bremanger- pollen) be used, and heights found farther seawards be considered too high, the gradient will be no more than 0.26 per mille. It seems to me, however, to be much more probable, that the exceptional heights found at Forde and Revik are a little too low. Kaldhol’s observations give then practically no gradient of elevation in this coastal zone. The land has here been elevated about 16 or 17 metres, keeping its horizontal level, or at least without any appreciable tilting. It is striking what a perfect accordance there is between the height of this horizontal upheaval and the height of the strandflat in the outer part of Sogne Fjord and in the coastal region outside, which I also found to be about 16 and 17 metres. It is hardly probable that such a coincidence is merely accidental. This seems in an unexpected manner to prove the correctness of our assumption that this level of the strandflat represents the level which the shore-line had in this region before the last glacial period and before the last submergence of the land. 1 If the observations of 28.9 and 23.9 m. at Sandvik and Hammersvik, in the inner portion of the Stat Peninsula, be correct, the border with the upper shore-line at heights less than 17.7 m. may be somewhat narrower in that region. 249 THE STRANDFLAT AND ISOSTASY. No. xr. I92I. 524)39M1 X 0h 0% 0 pnis) 04] 35M 4G \ Ne d uabynugng orf] ow) Burmoys $257 GOS) — X '2u1T- sad» 24} J0 Op OG 5:01 '20u3P12ung Jo 2417 vddy 74] JO 'sajoy UA ‘sy bry PAIS) 8-91 | "Saul po3op ay} Suo[p uM 1p aq 0} oAvy Arur syjeqost ou {991109 918 ISIM-UNOS ay} 0j sorjulo[w 9 jnoge (6'325) JUS pur (6'£&) xm s1ourum]T[ jv pue (‘ul 6'ge) v[nsuru -9I WIS uo ylapurg ye punoj 22uo23.I9urqns Jo mu aoddn oy} 10] SONIA oy} j[ '92uo8 -Iourqnc [|erov[3o3v7T jo ywı aoddn 943 jo syystoy SIOUPIEM SUIMOUS paol,] PION Jo j18d 153no pue 'ro3uvut -91q IS JO uorsoy « ou) jo de “Cor ‘sl; n IN LT 250 FRIDTJOF NANSEN. M.-N. Kl. The land has consequently not been depressed during the last glacial period in this coastal zone, 25 kilometres broad, in the region of Nord Fjord, Bremanger, and Stat, although there has been a postglacial change of 16 to 17 metres in the level of the shore-line. The depression has only occurred in the region inside Rugsund, whence the upper limit of sub- mergence suddenly begins to rise inland, as is clearly demonstrated by Kaldhol's profile. The gradient of elevation is 1.20 per mille between Rugsund (Strøm- men, height — 18.2 metres) and Eikenes in Hyen Fjord (height — 61.2 metres), a distance of about 35.7 kilometres if measured at right angles to the direction of the isobases (if we take Strømmen in Hyen Fjord, height 59 metres, the distance”is 33 kilometres and the gradient 1.24, cf. Fig. 165) — while it is on the average 2.00 per mille in the inner 32 kilometres of the fjord, between Hyen Fjord (Eikenes) and Indvik in Indvik Fjord (height — 125.3 metres), provided that Kaldhol’s deter- minations of the upper limit are correct in this region. They give gradients which vary much in value. Between Lote (71.7 metres, see Fig. 165) and Henne (95.7 metres, see Fig. 165), a distance of 6.7 kilometres, his values give a gradient even of 3.6 per mille. It seems to me to be probable that the highest terraces, found by Kaldhol in this region of the fjord, are not marine. We may, however, expect some irregularities here, as the region of Nord Fjord is perhaps the most prominent centre of seismic activity along the Norwegian coast [cf. Kolderup, 1914, map p.111]. In the innermost region of Nord Fjord, inside Indvik, in Stryn, Olden, and Loen, Kaldhol’s measurements of the heights of the highest terraces give suddenly much lower values than in the region west of Ind- vik. The explanation may be either that the formation of terraces was prevented by glaciers filling the vallevs and innermost parts of the fjords during the time of the deepest submergence of the land, or, as suggested by Kaldhol, that a later advance of the glaciers has destroyed the highest terraces in that region. Kaldhol’s detailed investigations of the lateglacial and postglacial terraces in the region of Nord Fjord give most valuable information about the submergence and emergence of the land during this period, and his height measurements support, as we have seen above, the correctness of my view of the relation between the horizontal level of the strandflat — indicating the level of the shore-line before the last great submergence — and the tilted planes of the raised terraces and beaches — indicating the submergence and the upheaval of the land. There is unfortunately no other region of our coast, which has been subjected to similarly detailed investigations, as far as I am aware, at least not in the outer coastal region. Put several scattered observations in various localities indicate that along those parts of the outer coast, 1921. No. Er: THE STRANDFLAT AND ISOSTASY. 251 where the upper limit of submergence lies no higher than the strandflat, more detailed investigations would probably demonstrate a horizontal upheaval of the outer coastal region, and a tilted upheaval of the land inside, in quite a similar manner as we have found in the region of Nord Fjord. Gradient of the Lateglacial and Postglaciel Upheaval of the West and North Coast of Fenno-Scandia. A general impression of the postglacial upheaval of the land may be obtained by comparing the gradients of this upheaval in the different regions of the coast of Norway and of the Kola Peninsula as given in the following table. The values of the gradients are computed from the heights of the highest terraces and raised beaches which are supposed to indicate the upper limit of lateglacial submergence. The heights were measured by the authors given in the last column. The heights of the lower level of the strandflat have not been deducted from the figures used for the computation of these values. In several regions it is difficult to decide which raised terraces and beaches actually indicate the upper limit of lateglacial submergence. In the outer coastal regions of Finmark Tanner [1906, 1907] has found raised shore-lines and terraces situated considerably higher than those which have been used for the computation of the gradients in our table. Similar higher shore-lines have also been found at several levels by Gronlie [1914] in the Tromsø distrikt and by W. Ramsay [1898] on the Kola Peninsula. These shore-lines, however, are less distinct than the lower shore-lines and have a much older appearance. They do not seem to correspond to the shore-lines which are supposed to mark the upper marine limit (the upper limit of lateglacial submergence) further south in Norway, and it is difficult to understand that they can have been formed during the last glacial period. They may more probably be sur- vivals from a previous period of submergence, as is assumed by Ramsay and Gronlie. For my computations I have therefore used the heights of the shore- lines and terraces belonging to the level which Tanner calls Je, as this level seems to correspond to the upper level of the two conspicuous raised shore-lines of the Tromso—Hammerfest region and Vesterålen, and to the generally accepted upper limit of the lateglacial submergence farther south in Norway. These gradients given in the table differ so much locally that one might doubt their correctness; but on the whole there seems to be a certain system in their variations. If they be introduced in a map of the Nor- wegian coast where the submerged continental shelf is also outlined [cf. 252 FRIDTJOF NANSEN. M.-N. Kl. Gradient of Locality Elevation in Observer per mille NoztheruqOstesdal s qe e E EE G. Holmsen [1917] ChrsiüaniasWbOLdP cue IE TT LE ca. 0.7 Øyen Coast between Larvik and Christiansand ....... 0.68 Danielsen [1912] Hardanser Mord, outer! pant ul E ca. 0.78 Rekstad [1906] — — "centrali pant: < ee Cotes 0.68 — — — — Halsenéi to Rosendal ........ 0.04 — — Sogne Fjord, between Vik and Vadheim ....... 1.0 — [1910] SENG ge jORG outer partes ee ET TS I.O — [1906] = INHER MDAT EM Ne se bois ete Ca CICR 0.9 - — Nord) Rjord,zcoastalezone as mes. ee 0.0 Kaldhol [1912] — middler36.kllometres n...c 199 9 1.2 -- — — inner 32 NL En TE 2.0 (?) — —. sondmerssblardeirdland mer 95 9 39 eee Rekstad [1905] Coastal region northeast of Ålesund ........... I.T — [1906] Nordmor, Reinsvik (Christiansund) to Tingvoll .. 1.48 Kaldhol [1913] — Reinsvik—Vägbe (Halsa Fjord) ...... 2.00 — — = Reinsvik—Bruset (Todal)............ 1.32 — — — dine voll Bruset er 1225 — — x Henden (Arisvik Fjord)— Valsoibotten. . 1.87 — — Southern. Helgeland, average. e e eio OU 0:73 Rekstad [Vogt 1900] -- — region ot Donna... seen ee 0.67 — [1904] Diünderland Valley sto Trana os. 0.91 = [Vogt 1907] Mainlandetog Bofoten er ern 0.76 J. H. L. Vogt [1907] Ofoten ktorkvælEj ode Autos etd ote ee ee ates 0.71 Vogt [Rekstad 1905] Region between Andoi and Senjen ............ 0.90 Helland [1900] ! Re SION (eji Sle er Re DOO Qo ODDO 1.22 — E — between Senjen and Ringvasgi......... 0.85 = = E -— Ringvasoi and Skjervei ....... 0.90 — = kKiondesouth “of Mammertest’ ann: 0.67 R. Chambers [1850] FA OES ANCE GEN oe re 0.60 Tanner [1907] EKS SÆF Onde RE ERNE st SOR t Tw DO arden Blab 0.48 — 2 TER TITI SP ee er 0.58 — [1906] VAN ens MERE oo bles ETT 0.51 — = Resionssouth of Varanger HE jord ..........+... 0.60 — — 2 Region of Ribachi (Fisker) Peninsula .......... 0.53 Ramsay [1898] — RAT ER Eee eke Gad TERI CO AEG 0.65 — = — » Woronye River, Kola Penins. ........ 0.72 = — Southeastern coast of Kola’ Penins. ...........: 0.32 == — ! O. T. Gronlie gives in his text [1914, p. 224] values (between 1.35 and 1.77 per mille) of these gradients for the region between Andoi and Skjervoi, which are much higher than those computed from Helland's observations; but as far as I can see Gronlie must have made some strange mistakes in his distances. His map of the isobases gives much the same gradients as Helland's observations. ? As will be mentioned later (p. 263) it seems to me that Tanner has probably mistaken his level /e in this region, and I have used his highest terraces for the computation of the gradient. 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 253 Nansen, 1904, Pl. XI], it is seen that, as a rule, the steepest gradients occur in those regions where the edge of the continental shelf is nearest to the outer coast of the land, e. g. in the region of Senjen and along the coast from Nordmor to Nord Fjord (cf. Fig. 166). In Sond Fjord it is also steep (1.0 per mille) although this region is farther away from the edge of the continental shelf. But here the deep outer part of the sub- meged Norwegian channel is very near the outer coast, while this channel is shallower outside the region of Hardanger Fjord where the gradient is less steep (0.7—0.8 per mille). The lowest gradients occur along the south-east coast of Norway (0.68 per mille), in Helgeland (0.67—0.73 per mille), in the region from Hammerfest to the Varanger Peninsula (0.48—0.60 per mille), and on the Kola Peninsula. These regions are farthest away from the outer edge of the submerged continental shelf. It is also noteworthy that the gradient seems to increase somewhat towards regions where there are deep submerged fjords on the continental shelf outside the coast, e. g. outside Træna [cf. Nansen, 1904, PI. XI], where the gradient was found to be 0.9 per mille, while it was 0.67 and 0.73 per mille! in the region of Donna and Vega to the south, where the shelf outside is broader and less dissected. As À. G. Hogbom has pointed out to me in a letter, the investigations of several geologists obviously show that there may be appreciable local variations in the upheaval of the land. By careful levelling of a very distinct raised beach (from the Tapes period), formed of boulders, along the coast of Lake Venern in Sweden, R. Sandegren [1916] has found that along a distance of about 11 kilo- metres, from the region of Kleven (height 65.2 metres above the sea) to the region north of Otterbacken (70 metres above the sea), the gradient of upheaval is 0.44 per mille, and along the next 19.5 kilometres to the NNE, between the region north of Otterbacken to the region east of Vall in Visnum (height 92.1 metres above the sea), the gradient is 1.13 per mille. Hence, in the latter region, the land has been elevated about 13.5 metres more than it would have been, if the gradient of upheaval had been uniformly 0.44 per mille along the whole distance of 30.5 kilometres. By his measurements of the levels of the ancient beaches left by the ice-dammed lakes in Northern Osterdal, Gunnar Holmsen [1915, 1916, 1917] has found that the gabbro mountains may have had an influence upon the postglacial upheaval of the land which has taken place in this region. The isobases are deflected by, and go round, the intrusive masses of gabbro, and it looks as if the latter have risen somewhat more than the surrounding regions, and the gradient in these regions may thus locally be increased from 0.70 per mille to between 0.85 and 1.63 per mille. I J. H. L. Vogt [1907, p. 30], however, remarks that according to later investigations by A. Hoel, these values are probable somewhat too low. 4 FRIDTJOF NANSEN. M.-N. Kl. un Gunnar Holmsen points out that A. Helland’s measurements of the raised shore-lines [1900] in the Tromso district indicate a similar local difference in the postglacial upheaval near intrusive masses of gabbro, especially conspicuous in the region of the Lyngen Peninsula. Gronlie [1918] also maintains that there has been appreciable local differences in the upheaval of the land in the Tromso district. It was previously mentioned that Kaldhol’s measurements of the heights of the “upper marine limit” in the region of Nord Fjord seem to indicate considerable local variations in the upheaval of the land, the gradient varying even as much as from 1.2 to 3.6 per mille. His in- vestigations in Nordmør [1916] give similar results. As was previously pointed out, however, the difficulty with these determinations of the “upper marine limit” is first, that to a great extent they are based on terraces of loose material which do not give the exact level of the shore- line; secondly, they are made in fjords, where ice-dammed lakes may easily have been formed during lateglacial time, and the terraces may thus have been formed at levels much higher than the sea. It is therefore of im- portance to have it proved that the terraces actually are marine. As the same terrace cannot be continuously followed from one fjord to another, it is often difficult to decide the identity of the terraces. Although these numerous observations by Kaldhol and others in the fjords may, therefore, have to be carefully sifted, before conclusions of wide bearing are drawn from them, still it 1s hardly doubtful that, on the whole, they prove the probability of appreciable local differences in the upheaval of the land, and that the gradient of upheaval may change ap- preciably inside distances of no more than 10 to 20 kilometres. The investigations of the Swedish geologists also indicate similar local differences in the upheaval of the land in Sweden. Munthe’s and Sundelin’s map [Sundelin 1919, Pl. X] of the raised shore-line of the Ancylus Lake along the east coast of Sweden, in Oster- götland and Småland, shows that the gradient of the upheaval of this shore-line varies a great deal inside the region of the map. Inside a distance of about 90 kilometres the gradient may increase from 0.24 per mille in the region of Vastervik and Oscarshamn, to about 0.50 per mille in the region of Söderköping, Norrköping, and Linköping. The gradient of the upheaval of the Littorina shore-line seems to differ even still more locally in this region. Similar local variations of the gradient of upheaval have been found at a good many places in Sweden, by the measurements of the heights of the "upper marine limit”, as well as of the shore-lines of ice-dammed lakes. The isobases drawn in Fig.166 are not intended to show the possible local variations in the gradient of upheaval of the Norwegian coast. It was rather attempted to give a general idea of the upheaval according to the most trustworthy observations. THE STRANDFLAT AND ISOSTASY. 255 Isobatıh for 200 meltes " " 400 ” Isobases showing the Lateglacial Submergence accotding lo (he latest sources chiefly VTANWEZ foe Finmask R.CHAMBERS fot Allen-Hammetfest, A.HELLAND fot [ht Romsó District, VOGT & REKSTAD fot Nosdland, H-KALDHOL fot Noutmtót „Nosd Fjord JREKSTAD foe Söndmöt Sogn Hardang, D.DANIELSEN foe Southern Not wey, PA. DYEN fot the Trondhjem and Chusliania Region The Isobaths for 400 and 600 Metres imdicale the citer edge of the Continental Shelf 256 FRIDTJOF NANSEN. M.-N. Kl. Relation between the Inclinations of the two Conspicuous Raised Shore-Lines of Northern Norway and the Kola Peninsula. In northern Norway there are two especially conspicuous raised shore-lines, to a great extent cut in solid rock. Amund Helland [1900] pointed out the fact that the planes of inclination of these two levels do not intersect the sea-level along the same line, zero isobase, outside the coast; but in the Tromsø region (Troms Fylke) the hypothetical zero isobase of the lower shore-line lies 8 to 17 kilometres further seawards than that of the upper one. The two planes of inclination "intersect one another along a line in the air a.few metres (on the average 5 metres) above the surface øf the sea”. This line lies just over the outermost islands and skerries in the Tromsø distrikt. J. Rekstad states [1 905, p. 21] that there is a similar relation between the sloping planes of the corresponding two levels of raised beaches and terraces in Helgeland, and also on the Norwegian west coast (between 60 Rand 629 NA) Thinking that this peculiar relation between the two shore-lines proves that the postglacial upheaval did not extend so far seawards during its first period, before the time of the lower shore-line, as it did during its later period, Rekstad assumed this to be evidence against the probability of the isostatic nature of the postglacial upheaval of the land, for, he argued, as the load of the ice-sheet was first removed from the border regions of the depressed area, one might expect an isostatic up- heaval of the crust to begin in those outer regions and gradually extend landwards, and not the other way. The inference from our studies of the strandflat and the raised beaches — that there may be distinguished between two movements in the lateglacial and postglacial upheaval, a vertical change of the hori- zontal level of the shore-line as indicated by the strandflat, and a tilted elevation of the land as indicated by the raised beaches — gives a simple explanation of the above mentioned relation between the tilted planes of the two shore-lines. Let us here, in order to simplify matters, assume for a moment that the former movement be due to a postglacial sinking of the sea-level, while the latter tilting movement is due to an upheaval of the depressed land. Let us then take as an example a special case, e. g. Helland’s measurements of the heights of the two raised shore-lines at Helgoi (70° 7’ N. Lat.) and at Havnnes (69° 47’ N. Lat.) in Lyngen Fjord in the northern Tromsø district. The heights of the two shore-lines were found to be 17 and 8 metres on Helgoi and 60.9 and 22.8 metres at Havnnes. Let us assume that 17 metres is the height of the lower level of the strandflat in this region, 1921. Ne: if. THE STRANDEEAT AND! ISOSTASY. 257 Y /0 " /0 20 30 40kilomelses 50. (a 1. e. is the height of the lateglacial and postglacial relative sinking of the sea-level. At Mikkelvik on Ringvasoi, about 15 kilometres south-west of Helgoi, or very nearly in the direction of the isobases in this region, Helland found a raised shore-line at 10.7 metres above sea-level, which is obviously the same as his lower shore-line on Helgoi, 8 metres above sea-level. Let us therefore take the mean between the two and make the height of the lower shore-line in this region 9.3 metres. Let us further- more assume that the distance between the isobases drawn through Helgoi and Havnnes is about 54 kilometres. According to our assumption there has been no postglacial tilted upheaval of the land on Helgoi (Fig. 167, O), the upper raised shore-line standing at the level of the strandflat; there has only been a sinking of the sea-level. During the first period of upheaval, before the time when the lower shore-line was formed, the upper shore-line rose to the line Be. The sea-level had then sunk 7.7 metres to the line DEf, along which the lower shore-line was eroded. During the last period of upheaval the upper shore-line rose to the line BC, the lower shore-line to EF, and the sea sank to its present-day level HH. The result of these movements is that we now find the upper raised beach along ABC, the lower raised beach along DEF, and the present sea-level at HH. If we continue the tilted lines BC and EF, they intersect one another at x, 6 metres above present sea-level. The plane of the upper shore-line will intersect the present sea-level at y, about 13 kilometres inside that of the lower shore-line (2). Fig. 167 is naturally a simplified diagram. In reality there will probably be a more gradual transition from the horizontal outer parts AB and DE to the rising planes inside, BC and: EF. These results are in perfect accordance with Helland’s computations mentioned above, and the explanation of the facts here given may be considered to be fully satisfactory. On the other hand, the facts described above seem to support the probability that we are right in assuming that the lower level of the strandflat (about 15 to 17 metres above the sea) actually marks the level Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. 11. 17 Diagram illustrating the upheaval of the shore-lines between Helgoi (O) and Havnnes (6). 258 FRIDTJOF NANSEN. M.-N. Kl. of the shore-line before the subsidence of the land during the last glacial period. Tanner’s investigations [1906, 1907] of the raised shore-lines in Fin- mark show a relation between inclinations of the planes of the two shore- lines which he calls Je and //A, quite similar to what Helland has found in the Tromso district. As will be mentioned later, Tanner’s shore-lines Ie and JIA correspond probably to the two well known shore-lines of the Tromso district and Alten. Tanner found [1906, p. 130] that the planes of the two shore-lines intersect one another about 50 kilometres north of Kvitnes (in the mouth of Tana Fjord) and 80 kilometres north of Havningberg (25 kilometres north-west of Vardo), at heights of 8 and 7 metres above sea-level. The explanation is obviously the same as before. Besides the tilted upheaval of the land, there has also been an elevation of the land in its horizontal position, or a sinking of the sea-level, which has the same effect. And this change of level has probably been of about the same magnitude as in the Tromso district and in the region of Nord Fjord and Sogne Fjord, or perhaps a trifle higher if we may judge from the height of intersection of the two planes. In the region, however, of the Varanger Peninsula the plane of the upper shore-line (7e) will intersect the horizontal plane of elevation (the plane of the lower level of the strandflat) far outside the coast. If we assume the height of the latter plane to be 18 metres the distance will be about 25 kilometres north of Kvitnes (in the mouth of Tana Fjord) and 54 kilometres north-north-east of Havningberg. This might seem to indicate that the inland-ice, which pressed the land down, extended far seawards outside the coast in this region. Ramsay's measurements show a similar relation between the in- clinations of the two planes of shore-lines on the Ribachi Peninsula, on Kildin Island, and along the Murmanski Coast, as well as along the south coast of the Kola Peninsula. Along the east coast of this peninsula, how- ever, in the region of the mouth of Ponoi River, there seems to have been no postglacial upheaval of the land. Fig. 168 gives a profile of the heights of the two shore-lines along a line at right angles to the approximate direction of the isobases in this region according to Ramsay’s map [1898, p.132]. The gradients of both shore-lines decrease outwards in a similar manner as the gradient of Kaldhol’s upper limit of submergence decreases seawards in the region of Nord Fjord. According to recent statements by Ramsay [cf. A. G. Hogbom, 1921, p. 137], however, the land at the entrance to the White Sea, should have been so much higher than now during the lateglacial period when the ice- sheet retreated from that region, that the White Sea may have been cut off from the Ocean, and transformed into a fresh-water lake, similar to 1921. No. xi. THE STRANDFLAT AND ISOSTASY. 259 the Ancylus Sea of the Baltic region. Hence the heights found for the upper limit of submergence along the south coast of the Kola Peninsula may possibly have to be somewhat corrected. Relation between the Altitudes of the two conspicuous Raised Shore-lines in the Tromse—Hammerfest Districts. Let us now study the relation between the heights of the two levels represented bv the two conspicuous raised shore-lines in the different regions of northern Norway. Tanner [1906, 1907] and Gronlie [1914] are probably right in as- suming that the upper raised shore-line (of Helland) in the Tromso and Hammerfest districts corresponds to the level of the Finmark shore-lines which Tanner has called Je. It seems to me to be probable that this shore-line marks the upper limit of lateglacial submergence in these northern regions. If so, it probably also corresponds to the level of the upper limit of submergence (the upper marine limit) observed in the different parts of southern Norway. It was previously mentioned (p.251) that the old raised shore-lines and terraces, found by Ramsay, Tanner, and Gronlie above the level corresponding to Tanner's /e, may probably be survivals from a previous submergence. The lower raised shore-line in the Tromsø and Hammerfest districts obviously represents the same level as Tanner’s line //A in Finmark. There seems to be good reason for accepting Gronlie's and Tanner's assumption that this shore-line corresponds to the so-called Tapes-level in southern Norway. Gronlie therefore calls this shore-line the Tapes-line. Probably owing to the mildness of the Tapes climate, which has not favoured the shore erosion by frost, this level is not marked by shore- lines cut in solid rock south of the Tromso district (68th parallel), but as a rule merely by marine terraces and wave-built shore ridges, which are less reliable marks of the actual level of the shore-line existing at the time of their formation. The surface of a terrace may have been somewhat lower than the sea-level, and a wave-built ridge may have been thrown up above high-tide level during storms. According to the figures given above, the height of the lower raised shore-line (the Tapes level) is 37.4 per cent of the height of the upper raised shore-line (the upper limit of submergence) at Havnnes, while this percentage is 54.7 on Helgoi if the height of the Tapes-line be 9.3 metres. According to what has been said above, it is obvious that this percentage should decrease with increasing height of the upper limit of submergence, and it is therefore useless to try to find a fixed figure of percentage which would suit all cases. 260 FRIDTJOF NANSEN. M.-N. KL Provided that the upheaval of the land has increased regularly in- land, and provided that the relation between the inclinations of the two planes of the shore-lines has been similar to what is represented in Fig. 167, then we should be able to compute the probable height of the Tapes level at any place where we know the upper limit of submergence. Between Helgoi and Havnnes (Fig. 167) the upper limit of sub- mergence rose 43.9 metres (from 17 metres to 60.9 metres), while the Tapes-line rose 13.5 metres (from 9.3 metres to 22.8 metres). Hence, for every metre which the upper limit of submergence rises landwards the Tapes-line will rise 0.308 metre. If x be the height above the sea of the point, where the planes of the upper limit of submergence and of the Tapes-line intersect one another, and H be the height of the upper limit of submergence above sea-level, the height h of the Tapes-line will.be: h = (H — x)x0.308 + x According to the above values of H and h on Helgoi and at Havnnes HAS e pr metres Hence: h = (H — 5.87)X0.308 + 5.87 h=Hxo3 + 4 (1) By taking the mean of Helland’s measurements of both shore-lines at six places where the height of the upper shore-line was between 57 and 62.7 metres and at seven places where it was between 28.7 and 38.4 metres we find the formula to: be: h= HoesX5 + 3.4 (2) The values computed by this formula does not differ much from those computed by the former formula. In order to test the correctness of our formula let us take some reliable observations of the upper marine limit and the Tapes-level in a region as far away from the Tromsø district as the Christiania valley. | At Skädalen Station, on the Holmenkollen tramway, near Christiania, P. A. Öyen has found the upper limit of submergence at a height of 220.8 metres above sea-level. At Ullern, west of Christiania, he found the Tapes-level at a height of 69.5 metres. The distance between Skädalen and Ullern is about 4 kilometres at right angles to the probable direction of the isobases in this region. If we assume the gradient of elevation to be about 0.7 per mille, the height of the upper limit of submergence at Ullern should consequently be 218 metres. Hence the height of the Tapes-level at Ullern should be: h = 218X0.3 + 4 = 69.4 metres er h = 2187«0.315 + 3.4 = 71.3 metres. This agrees well with Öyen’s value, 69.5 metres, especially con- sidering that our formula is based only on some few observations by Helland in the Tromsø district. 7921. No. 11. THE STRANDFLAT AND ISOSTASY 261 Height in Metres of: Locality N. Lat. Upper Lower Shore-line Shore-line | observed | computed Difference Molstrand ......... K : 13.3 13.6 — 0.3 Hammerfest Island | Sjaholmens-- ern. South of Hammer. Kyalsunde ee, Kvænklubben ...... 70° 28 46.0 17.4 18.2 — 0.8 Vargsund south of Ma; : Es fest Mainland opposite Storbekk Fjord ... | 70° 20' 49.1 19.5 18.9 — 0.6 Helgoi— Mikkelvik... | 70° 6’ 17.0 9.3 8.8 0.5 Kvitnes, Vannei .... | 70° 6 28.7 II.O I2.4 mit Lanesoren, Vannoi .. 70° 3’ 29.4 XE Dor] — 1.6 Region outside Karla ass qo. 1° 32.1 15.0 13.5 SETA Lyngen Fjord and noli T 60° «8' 2 ne ARE EN Fjord Reinsvoll, Reingi ... 95 33-5 15:5 13.9 p SEJERVOl - DONE 70 3° 41.7 18.0 16.5 LES Finkroken, Reingi... | 69° 51’ 38.1 14.5 15.4 — 0.9 Glimma, Ringvargi .. | 69° 49' 97.2 14.4 15.1 — 0:7 3 a JMovie es ER 69. 43' 42.6 17.8 | 16.8 + 1.0 "IE D ard | Kalsletta, Bals Fjord..|69 37 41.6 19.3 | 16.5 132.8 ze Havnnes nen sense 69° 47 60.9 22.8 22.6 +0.2 nn. \Rotsund S ere Erato E 69 46° 59.7 23.4 22.2 ar lige Ulfs Bjord UISnes ams oma acc 69° 42’ 57-0 19.6 21.4 — 1.8 å fGreipstad .......... 69 31" 38.4 14.5 I5*5 — 1.0 od Ll Ansnes Dem, A 69° 30' 42.8 17.2 16.9 +o Inside Senjen Bukskind, Gi-sund | 69° 22’ 48.6 18.8 18.7 HOT Bjornera, Grytoi .... | 68° 33’ 43.8 16.8 17-2 — 0.4 Lundesnes » 5291168253, 44-4 18.3 17-4 + 0.9 SITES Kjeoi, Vägsfjord .... | 68° 51’ 46.5 17.1 18.0 — 0.9 zus Nine as as er 69° 1° 60.8 21.6 22.6 — 1.0 Andervag, Andorja .. | 68° 33’ 61.4 22.2 22.7 — 0.5 Anstad, Andorja .... | 68° 49" 62 22.7 23.2 — 0.5 0.0 1 Shore terrace of loose material. The table above gives the measurements of the altitudes of the upper and lower raised shore-lines measured by Chambers in the region between Hammerfest and Alten (the five first stations), by A. Helland at eighteen places in the Tromsø district (Troms Fylke), and by K. Pettersen at four places (Movik, Greipstad, Ansnes, and Bukskind) near Tromsø. The values of the height of the lower shore-line (the Tapes-line) computed by the formula (2) above from the altitude of the upper shore-line, are given in the sixth column of the table. The differences between the computed values and the observed ones are in most cases less than a metre, and no greater than what might be expected to be within the limits of observational error. Even in the case 262 FRIDTJOF NANSEN. M.-N. Kl. of shore-ledges cut in solid rock as here, it may often be difficult to decide where exactly the actual level is. If, however, the differences be marked on a map, it looks as 1f there may be certain areas where the heights of the Tapes-line are slightly lower than the computed values, e. g. between Kvitnes and Glimma, and in the region of Vinje, Änstad, Bjornerä, while especially in the region inside a line Skjervoi, Karlsoi, Reinsvoll, Movik, and Kalsletta the heights are 0.2 to 1.6 metres higher than the computed. values, and in one case, Kalsletta, as much as 2.8 metres (if this measurement be correct). This may indicate that there has been some irregular warping of the land during the first period of upheaval before the Tapes period, by which the areas with too low heights of the Tapes-line were elevated relatively more than those with too high values. According to what was previously said about the local variations of the gradient of upheaval it seems probable that there should be such irregularities in the relation between the heights of the upper limit of submergence and those of the Tapes-line. It might rather seem surprising that the departures are not greater. Ole F. Gronlie has measured the heights of shore-lines and terraces in the Tromso district and further south, but unfortunately he only gives [1914, p. 226] the heights of the Tapes-line, and its percentage of the height of the upper shore-line (his M-line). If we compute the heights of the upper shore-line from his figures, we obtain, however, values which show great irregularity in their relation to the height of the Tapes-line, and differ in this respect very strikingly from Helland’s values. It seems probable that this is due to inaccuracy of some kind, either in Gronlie’s measurements or in the figures given in his paper. Relation between the Altitudes of Tanner’s Shore-lines /: and //A in Finmark. In Finmark Tanner [1906, 1907] has found a great many raised beaches. It was mentioned before that his shore-line Je probably corre- sponds to Helland’s upper shore-line in the Tromsø district and in the Hammerfest— Alten region, while Tanner’s line //A corresponds to the lower shore-line or Tapes-line in the Tromsø and Hammerfest region. It is not always easy, however, to decide which is his line Je among the different shore-lines observed at the various places. On the other hand it has to be considered that, to a large extent, Tanner’s shore-lines are not cut in solid rock, but are marked by wave- eroded terraces of loose material, or by wave-built shore-ridges of pebbles and boulders. The one may easily give too low values, and the other too high, as compared with the heights of shore-iedges cut by frost in 1921. No. 11. THE STRANDFLAT AND ISOSTASY 263 solid rock. We cannot therefore expect such a degree of regularity in the relation between the two levels of shore-lines as we found in the Tromso and Hammerfest—Alten region. If, however, we compute the probable height of the Tapes-line, from the heights which Tanner himself gives for his line Je, we find on the whole fairly good agreement with his heights for his line 774, except in the region south of the Varanger Fjord. As far as I can see, however, Tanner has mistaken his line Je in the region east of Bugofjord. He has there observed three levels of shore- lines, and he has assumed the middle one to be Je and the lower to be 77.4, but I consider it probable that the uppermost level is his line Je. This would give good agreement with our formula for the relation between Te and //A. It would also give the isobases a more natural shape in this region, without the sudden turn southward which Tanner had to give them on his map [1906, PI. 5]. Furthermore it would give a gradual incline of the plane of this shore-line from the region south of Varanger Fjord and northwards across the Varanger Peninsula, without any break, as Tanner has on his diagram [1907, Pl. 4, Fig. 1]. Hence there will be no necessity to assume that there has been a postglacial dislocation along Varanger Fjord, as Tanner suggests in order to explain the break in the inclination of the line. It might be objected that Tanner has also found three conspicuous levels of shore-lines at several places in the inner part of Varanger Fjord, e. g. at Nyelv, Veinesbukt, Adelsberg, and Nesseby, and there the middle shore-line is obviously Je. It has, however, to be noticed that at most of these places, more than three shore-lines have been observed, and there is one below Je which might well correspond to the middle shore-line in the region to the south-east. Although it may be a mere accident, I may just mention that these three shore-lines in the region south of Varanger Fjord have a certain similarity to the three shore-lines Kaldhol has observed in Nord Fjord, which he calls the upper marine limit, the epiglacial shore-line, and the Tapes-line. | With the corrections mentioned above, Tanner’s heights (in metres) of his shore-lines Je and 774, have been introduced in the following table. The probable heights of the Tapes-line computed by our formula (2) from the heights of his line Je, are given in the fourth column, and the difference between these and the observed heights are given in the fifth column. (s,s) added to the name of the place in the first column indi- cates that both shore-lines are marked by shore-ledges cut in solid rock, and (t, f) that they are marked by terraces of loose material or are ledges cut in moraine material. (t,s) or (s, t) indicate that the upper shore-line is marked by terraces of loose material, and the lower line by shore-ledges cut in solid rock or vice versa. (f) indicates that they are marked by 264. FRIDTJOF NANSEN. M.-N. Kl. Tanner's Shore-lines le and ITA. Height in Metres of Locality See Tine Share ine d Difference or Tapes-line 2 observed computed Porsanger Fjord. Teeildası (Ei) ER CEE 65.3 (/) 24 (0) 2 0.0 Banines (ED) en ee ca. 65 < 25 23.8 <+ 1.2 Annika 427.2), sen create secret 63 (I) 23.5 (I) 23.2 + 0.3 Anopset (Fy p).................. 62.3 (I) < 23.6 (I) 23 c GB 3ille Fjord (49$) ............... 58 (/) 23.3— 21 (I) 21.7 STEHIVELOI le Die eeepc 55.5 (I) 22 (I) 20.9 - T.I Yttre Veinesbukt (#,p) .......... ss (2) 22.3—21 (J) 20.7 Russ mark (Carll Go. gaol ee 49 (0) 19.5 (0) 18.8 + 0.7 Treviknes, Kistrand (s, 2) ........ 47 (0) 19 (/) 18.2 + 0.8 Sauberget (s,s) ...- s. eere eet ee 45 (À) 16.5 (/) 17.6 -— mn Brenner SEE e cites sas) tee) t eat: 42 (/) ca. 15 (/) 16.6 — mut Sirarvbergete(s» S) ers -. 0-0 41.2 (J) 16.5 (/) 16.4 + o.I Inre Sortvik (SS) wu. E EC ees 38 (0) 15 (/) 15.4 104 Irvinyarga (S, S) 2... cece en. an 35 T4 14.4 to Molvik (SES) FEER Re certe 33.5 (2) 14.8 (/) 14.0 + 0.8 Repvàg (s, 2) 22.2... EGE 33.5 (1) 16.2— 14.2 (/) 14.0 " (SS) DERE PT coo DEO. Sa CIS 30.5 (/) 14 (2) 13.0 EO Honningsvåg, Mageroi (7,7)....... 24 (/) rr (J) II 0.0 CL Lakse Fjord. Landersfjord (427) .............. 50 (/) 20.5 (/) 19.2 + 1.3 Hammervik (Eikvik) (5,0 ........ 47 18.5 18.2 +03 ebesbyala Serre See ee ca. 45 18 (/) 17.6 + 0.4 Weise S)) oo 5 odo 5 Bios noch HUC 38 (1 15.2 (/) 15-4 02 Kjellefjord (s,p)................ ca. 25 (/) 15.2— 11.6 (/) Tes ver axo lu (Glos sono ESKE 26.5 (J) II.5— 12 (/) 11.8 0.0 Miehavn (FI were. CT sels 19.1 (/) ro (/) 9.4 29:6 , (ER) aaa o arbres Dn Sona iG ODS 2I IO IO 0.0 +-0.3 Tana Fjord. Sinvalliorel (Kiso ocloaaaacawou dus 55 18 20.7 — 2.7 Benjaminbukt (6,72)! ESS eee 50 16—19 19.2 — 1.7 CAVISIUONAIP AE OCT ORDEI ERO soc 51.5 17 19.6 — 2.6 avvomiansan(s SSeS oss bom oo 49 (/) 16.2 (/) 18.8 — 2.6 Vase (SEEN) Nr M 51.5— 48.5 16— 19 19.2 — 1.7 Between Vagge and Stangenes (s, ?) 48.9 (/) 18 (/) 18.8 -— 0.8 ELEANOR REEKS 2 15.5 16.6 pis x 4 (GHG) re S sexe SER ss 40 I4 16.0 — 2.0 Store MOMIE (Svp) ESC SES 33 14.5 13.8 0.7 Kyiines ls wäre 28 12.5 12.2 03 — 1.4 1 Tanner assumes a terrace he found at 32.1 metres above sea-level to be his line Je, but it seems to me more probable that the broader terrace found at 38 metres is his Ie, as it agrees better with his Tapes line (//A). 2921. No. rir. Locality North coast of the Varanger Peninsula. MAR URSS) nie cits Res ENT CE Syiteklubben (s & 4 2)...2......... Swiheijeiral UAI sooo EDO d Nordfjord, Syltefjord (4 #)........ Élaynimgberpe(s SJ... 0. South coast of the Varanger S Peninsula. SUS OA SNA D) SES nero Balketlauset (Z,D)-= 22. ers Reale Ss (ons) eee. re Sales (GAYA Beara RENTREE Kampenes (S S) «1: ent enr, Sitore dE kero (25'S) irate: et cree MERS TIMES RE Er ee ac. Ra AS) EE re BSItbDenq(2 S) - sec ecmecere.seec Ber-Parsavikı (SKS) ahs cus 9 eevee ose MOovtensnesr (SS) 21e... Nessciyy (a5) Same codecs dels eios sels REISE (IJ) oto ODIO TO QOO MSS ice val (4392) ee een tee Southern side of Varanger Fjord. Rérlbotten (2.51. 2-4. 2e Uses Repeat (Caras mu ee en e NEMESDURKE (ZIZ) ner eee. Sian la ARR SORTE Sopnes, Bugofjord 77) ......2.. Stanga, Neidenfjord.(s, 7) ........ Munkvaselv, , CAC carey oe Ran TUS No RERO CE TENE QE ETE BEISHEINT SZ) See a gs 2) Den Bn Eeness(s he see ele rors Sandnes (4,7) .. iiauetjordsBotn' (2,8). - - -.2:...... asfiord Wake (Z2) cese THE STRANDFLAT AND ISOSTASY. 265 Tanner's Shore-lines Ie and ITA. Height in Metres of Shore-line //4 erence Skate tie i | Difference or Tapes-line Te observed computed 35-5 15 14.6 icr: 38—39 16— 16.5 15.5 mn O7 43—47 I7.5— 18 (/) 17.6 120.2 41 18 16.3 ZT 41 17.5 16.3 2722 +1 0.3 48 E85 05 18.5 12.0:5 50 18.5 19.2 — 0.7 46 17-19 17-9 = Os 58.5 20 21.4 — 1.4 60 (2) 23 (/) 22:9 xis 37] 6o (?) 22.5 no +- 0.2 67.5 23.5 24.7 — I. 70 24.5 25.4 — 0.9 70 26 25.4 + 0.6 68.5 27 25.0 + 2,0 70.5 20.5 25.6 70 24.5 25.4 — 0.9 71 227] 25.8 xS ig? 69 ca. 27 25.I dO T 9.2 69—73:5 26 2g 3205 One 74.5 25.5 26.7 — 0.8 74-5 27-5 26.7 2.0.8 74-5— 79 28 2617-2833 2p ON 86.8 (7) 31.4 () 30.8 si OO 89 30.5 31 — 0.5 QI 33 32 ir 2:0 80 27-5 28.5 — 1.0 82 (/) 31.1() 29.2 =I ES) 85 (2) 30 30 0.0 90.2 (/) 34.2 (2) 31.8 T 2-4 90.5 34 31.9 ap PET 92 (1) 32.5 32.4 ag LONE 266 FRIDTJOF NANSEN. M.-N. Kl. shore-ridges of pebbles. (Il) after the figures in the second and third columns indicate that the heights are taken by levelling. Otherwise the heights are measured by the aneroid-barometer. According to this table Tanner's observed heights of the Tapes-line TIA in the inner end of Tana F jord are 0.8 to 2.7 metres lower than the computed heights, while at Store Molvik and Kvitnes, near the mouth of the fjord, the observed heights of the Tapes-line (//A) are slightly higher (+ 0.3 to + 0.7 metre) than the computed heights. Along the north coast of the Varanger Peninsula the observed heights of the Tapes-line are also comparatively high, and along the north and south side of Varanger Fjord they are partly higher partly lower than the computed values, but on the average slightly higher. In Lakse Fjord and Porsanger Fjord to the west of Tana Fjord the observed heights of the Tapes-line are also on the whole higher than the computed ones, but there is no distinct regularity in the differences. Provided that the observed heights of the two shore-lines are fairly correct, the distribution of the negative and positive differences in eastern Finmark, as given by Tanner's observations, may indicate — either that, in the region of the inner end of Tana Fjord, the land has risen com- parativelv less during the later period of emergence, after the Tapes time, than in the region to the east, and also less than in the region of Hammer- fest Varanger Peninsula and also along the southern side of Varanger Fjord Alten and Tromsø, while especially along the north coast of the this upheaval may have been comparatively greater — or that the upheaval during the first period of emergence, before the Tapes period, has been comparatively great in the inner part of Tana Fjord, and comparatively small along the north coast of Varanger Peninsula, &c. As long as we have no reliable investigation and measurements of the strandflat and its levels in this region, it is hardly possible to decide which of these alternatives are most probable. If we could assume that the upheaval of the land is not vet quite completed in the region of inner Tana Fjord, and that there is still left about 2 metres, this might give a simple explanation, although it would not explain that the Tapes-line seems to stand nearly 1 metre too high along the north coast of the land. The Upper Limit of Lateglacial Submergence and the Tapes Level on the Kola Peninsula. On the Ribachi Peninsula (Fisker Halvøen), Kildin Island, and the coasts of the Kola Peninsula Wilhelm Ramsay has investigated and measured the heights of several levels of raised beaches [1808]. The highest of these are higher than the shore-line which seems to correspond to the upper shore-line in northern Norway, generally assumed to represent the upper limit of submergence. 2921, No, ET. THE STRANDFLAT AND ISOSTASY. 267 Ramsay assumes these higher shore-lines to be of interglacial age, as they have a much older appearance than the lower ones. The heights of Ramsay's two lower shore-lines corresponding to the Norwegian shore-lines of the upper limit of submergence and the Tapes- level, are given in the following table (in metres). (/) added to the figures indicates measurements by levelling, (a) by aneroid-barometer. The heights of the Tapes-line computed by our formula (2) are given in the fourth column, and the difference between these values and the ob- served heights of the Tapes-line are given in the fifth column. Heights of Shore-lines observed by W. Ramsay. Height in Metres of Locality Upper Tapes-line Difference Shore-line observed computed Waida-Guba, Ribachi Peninsula ... Ca. 55 22 20.8 ie Te Tsip-Navolok, — — VS Ca. 55 21 20.8 + 0:2 Sreduij, Kola Fjord, 0 ons 73—79 28 27 - 0.6 Malaya Goryæla, Kola Fjord ..... 86 Mys. Bykoff, Kildin Island ........ SI. Mys. Prigonnij, — SEERE ES 50 My Mogilnj, — =) Nic Sepp 55 poe eim 50 Teriberka, Murmanski Coast ...... 46 Gavrilovo, = HR: 39 Kekora, — I ER RE 38 Rynda, — D Cr de 39. Kharlofka, — — (f) =x... 35 Varsinsk — N: 24 Bonoigrlerskr Coast) as. an zx Sosnofka — sd PSU AS I5 Pyalitsa — TS Noe SENE an Chavanga — ER: >32 Munya, Gulf; of Kandalak ........ 99 (a) The observed and the computed values of the height of the Tapes-line agree fairly well, but we find here a somewhat similar distribution of the positive and negative differences. The observed heights of the Tapes- line are relatively a little too high along the north coast of the land, from Ribachi Peninsula to Kekora on the Murmanski Coast, while they are slightly too low along the coast of the eastern and southern part of the Kola Peninsula. The differences are no greater than might be expected to be within the limits of observational error, but, nevertheless, there seems to be a certain system in their geographical distribution. It was previously mentioned (p. 258) that according to Ramsay the White Sea may probable have been transformed into a fresh-water lake 268 FRIDTJOF NANSEN. M.-N. Kl. Fig. 168. Curves illustrating the upper limit of lateglacial submergence (4) and the Tapes- line B along the south coast of the Kola Peninsula. The profile is drawn at right angles to the isobases, according to Ramsay’s observations [1808]. during lateglacial time. If so, the observed heights of the upper limit of submergence may have to be somewhat reduced along the south coast of the Kola Peninsula. In that case our computed values of the height of the Tapes-line would also have to be reduced, and the observed heights of this line would not then be too low. It does not, however, seem probable that the observed heights have to be much altered. In Fig.168 are given the heights (in metres) of the upper shore-line and the Tapes-line observed by W.Ramsay at several places along the south coast of the Kola Peninsula. The stations are projected on to a profile at right angles to the isobases of this region. The upper curve (4) gives the incline of the upper limit of submergence (1. e. the upper shore- line) according to Ramsay's observations. The lower curve (B) gives the height of the Tapes-line as computed by our formula from Ramsay's values of the upper limit of submergence. This curve B agrees remarkably well with the heights of the Tapes level observed by Ramsay and indicated in the figure by rings. At Salnitza and Kashkarentsy the upper shore-line or limit of submergence was not observed, and in the figure is, therefore, given the values computed from the observed heights of the Tapes level at these stations. We do not know the height of the strandflat in this region, but if we may judge from the relation between the heights of the upper and lower shore-lines in the above table, the upheaval of the land seems to be very nearly completed, and the level of the strandflat, corresponding to 1921. No. rr. THE STRANDFLAT AND ISOSTASY. 269 the level of the shore-line before the last glacial and postglacial sub- mergence, may be assumed to stand about 17 or 18 metres above present sea-level along the north coast, but perhaps slightly lower along the south coast of the peninsula. It is, however, a remarkable fact that there seems to have been no upheaval at Ponoi on the easternmost coast. If so, we must assume that the level of the strandflat has here been depressed. We may discuss this question later. The Upper Limit of Submergence and the Tapes Level along the Norwegian Coast south of the Tromse District. In Norway south of the region of Ofoten and Vesterälen, there are as a rule no raised shore-lines cut in solid rock, corresponding to the lower shore-line, the Tapes-line, of the Tromsø and Hammerfest districts. As was previously mentioned, the explanation is, probably, that. during the warm Tapes period, the climatic conditions in these more southern regions were no longer favourable to the frost erosion of shore-ledges in solid rock. In these regions the Tapes-line is therefore marked by marine terraces only and by shore-ridges built up of loose material. J. H. L. Vogt, Rekstad, and Hoel have observed two raised shore- lines, cut in rock, in Tysfjord, Helgeland (Vik, Leka), and also near Trondhjem, but the lower of these shore-lines, at any rate, does not correspond to the Tapes-line of northern Norway. The two raised rocky shore-lines observed by Kolderup in the region near Bergen are obviously from a different period. he table pp. 270 to 272 gives the observed heights (in metres) of the upper limit of lateglacial submergence and of the Tapes-line at several places along the Norwegian coast where the observations might be con- sidered to be fairly reliable. The heights of the Tapes-line computed by our formula (2) from the observed heights of the upper limit of sub- mergence, are given in the fourth column. On the whole, the observed and the computed heights of the Tapes- line agree fairly well, considering that the observed heights are based on measurements (very often with the aneroid-barometer) of raised terraces of loose material, which may often have been somewhat lower than the level of the actual shore-line when they were formed, while on the other hand shore-ridges (of pebbles) may often have been built up by waves a few metres above the mean level of the shore-line. It is also very often difficult to decide what has been the actual level of the Tapes-line, without finds of fossil shells. And where shells of the Tapes-period are found in the terraces, it may. be very difficult to decide exactly at what depths below the sea-surface they have been living, when the terrace was formed. Nevertheless, it is a striking fact that especially those heights in our table, which are based on the most reliable observations (printed with FRIDTJOF NANSEN. M.-N. Kl. 270 Height in Metres of Locality Observer FPEM Limit | sn Difference of Sub- mergence | observed computed Væroi, Lofoten (Keilhau) ........ ca. 20 (?) ca. 9.4 9.7 -- 0.3 Røst, " (Helland).,,.... ca. 17 (?) 9 8.7 703 Alsvik, Salten (Rekstad)........ 80.4 > 22.2 28.8 Breivik, „ Cae > 122.5 46 > 42.2 Moljord , DT tS E ca. IIO 43 ca. 38.2 + 4.8 Tvervik , AN I Gal IA 43 Ca: 39-1 Ae Ae, Storjord , EN PR onu a cie 120 42 41.3 + 027 Skomo, Bronnoi (Rekstad & Vogt) ... 123 42 42.2 — 0.2 Trondhjem.(Oyen) 5.7... 201 68.5 66.9 = 26 Guldalen DENT raha aa Rompe 198 64— 67 65.9 23024 Christiania Valley, Ullern (Oyen) 218 69.5 12.3 ee » Skaugumsäs , ca. 212 66—67 69.4 Lu AS) (OVEN or rime tae ca. 200 68 66.5 +15 Nordmor. Hjelledal, Arvag Fjord (Kaldhol) .. 130.7 45-3 44.4 + 0.9 Rodal, Vinje Fjord ey x 118.8! 41.4 40.9 2055 Valsoibotten, Valsoi Fjord , us 134.52 46.5 45.9 > 0.6 Henden, Arisvik Fjord A re TT 39.3 38.6 07 Torhjul, Halse Fjord " RR 114.53 37.7 (?) 39.5 — Hi Vagbo, * 2 5 ar 134 (?) 44 (?) 45.8 ED Bruset-Talgø, Todalen 5 2n > 148.6 OLD 50.3 OZ Ulvund, Ulvund Fjord " es 132.64 45.4 45.I 150.3 Gjovikh, „ " j zu 123 39.0 (?) 42.3 = 6x8 Tingvoll, Tingvoll Fjord , oe TIT 35—42 38.4 — OnE Reinsvik—Frei (near Christiansund) 77 26.83 Pal 275] NES Visnes, Kornstad Fjord (Kaldhol) SO 22 21.0 + 1.0 to Kaldhol [1916, p.9] found a higher terrace at 147 metres, which marks the upper limit of submergence according to his opinion. It seems to me improbable that the submergence has been as great as this in this region, and I doubt therefore, the marine origin of the highest terrace. Kaldhol [1916, p. 10] thinks that this terrace may probably represent what he calls the epiglacial level, and that the upper limit of submergence is a little higher; but this seems to me to-be doubtful. Kaldhol [1916, p. 12] found a small terrace at 122.5 metres which he considers to mark the upper limit of obmergence; but this seems to be too high. The terrace may possibly have been formed on land. Kaldhol thinks that a higher terrace, attaining a height of 170.3 metres above the sea, marks the upper limit of submergence; but Rekstad considers this terrace to have been formed on land. 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 271 Height in Metres of Locality Observer Upper Limit N Difference : ER apes-level ot Sub- mergence observed computed Sondmor. Ulsteinvik, Hareid (Rekstad)...... a5 15 14.4 + 0.6 Valderhaug, Valderoi , ...... 43.0 15.3 17.5 — 3) Gjosundseter, „ MN rss 43-5 15 I7. — 2.1 Roald, Vigra SENE are 37-8 12.5 15:3 == ER Ostnes, Haram md Ae ee 39.1 i 12.6 15.7 — 3.1 Longvad, Flemsøi så meet Age 13 16.1 — 31 Slogstad, Stranden Storfjord (Kaldhol) 70.9 (?) 24.0 25.4 — 14 Stave, Stat (Kaldhol) ... 16.6 y 8.6 — 1.4 Leikanger, Stat ? ER 16.8 77: 8.7 REG Sandvik, " : ee 28.9 | 13 4 12.5 + 0.9 Hammersvik, Selje ? T 23.9! 10.4 10.8 — 0.4 Vedvik, Vagsoi 2 ER 15.8 10:5 (?) 8.4 4--2.1 Revik, = » e. 14.9 (?) 9—10 8.1 ac HE Skav poll n Sar ca. 16 8 8.4 —_ 04 Gjeitholmen, Froien " SES 767/ 9 8.8 zi 0:2 Botnene, Froi Fjord 5 SENE 16 9.2 8.4 0:8 Strommen, Rugsund FÅ ol 18.2 9.5 9.1 ap Oe Elde, Nord Fjord ? 55 ca. 22 9.2 10.3 eat: Myklebust, Alfot Fjord , Bae 36.0 13.4 14-7 = 12 Skjærdal, Hyen Fjord " vU 57-8 19.4 21.4 — 20 Langeland, Eid Fjord " +. NCA Ow 25 22.6 oi Sond Fjord. Haukå, Nordal Fjord (Rekstad) ... 28 10.5 12.2 = iy Sandvik, Eike Fjord = e. 29.5 IO.3 I2.] = Sogne Fjord. Vik, Sogne Fjord (Rekstad)...... JST S 40 39.8 + 0.2 Tune, Ortnevik D RTE MS 87.2 20:7 29.9 — Vadeim er 77-4 27 27.8 0:8 Sondhor dland. Âkre, Äkre Fjord (Rekstad) ..... 100 Sin 34-9 —— HS) Halsensi, Hardanger „ ..... 75.9 24 27.3 ÈS 1 As the map Fig. 164 shows these heights are considerably higher than the upper limit of submergence found by Kaldhol at other places in the same neighbourhood, and if these values be correct, they will give the isobases a very crooked course in this region, but as the above figures show, the observed heights of the supposed Tapes line agree fairly well with the heights computed from the observed heights of the upper limit of submergence. FRIDTJOF NANSEN. M.-N. KL N Al] D ———————————— Height in Metres of Locality Observer “HR | 2L ] ] Difference » * 2 apes-leve of Sub- P mergence observed computed Randeberg, near Stavanger (Bjor- lykken DantelSen) onen 22.5 10.6 10.5 O.I Viste-Kvernviken, near Stavanger (Oyen, Danielsen) 022... +e st Malletuva, near Stavanger (Oyen) . Klepp, Obrestad, Jæderen (Oyen, DanelSen EEE ter suche crc Lintjonn Ogne-Hobberstad (Bjor- lRken Oven) aos Re co Aen ‘Sire (Damelsen) ........... Kviljo-Borhaug, Lister (Danielsen) . Rister (Oyen) aus Ar. pe: A, Lyngdal (Danielsen) Topdal river, Christiansand , Christiansand " Askero-Bergendal, Dybvag , italics), give the most perfect agreement with the computed values, and the differences are on the whole no greater in the cases of the greatest heights than at the lower ones, which indicates that the formula is fairly correct. The observed heights of the Tapes-line are in most cases somewhat lower, often between 1 and 2 metres lower, than the computed ones. This may be due to the fact that the terraces have not, as a rule, been built quite up to mean water-level, but may have stood one or two metres below it, even in cases where shore pebbles have been found on their surface. It is also obvious that when a terrace is raised above sea-level, its surface may sink more or less, owing to compression, and to the loss of water contained in its layers, &c. Our formula is, however, based 01 the measurements of shore-ledges cut in solid rock, where this has not been the case, and which may have been formed slightly above mean sea-level. There are some observations of the upper limit of submergence and the Tapes-line by Kaldhol in Romsdal which are not given in our table because they showed too great disagreements. Introduced in a map, these observations exhibit great irregularities in their distribution, and this is also to some extent the case with Kaldhol’s observations in Nord- mor. Lower values of the heights, both of the upper limit of sub- mergence and of the Tapes-line, very often occur a good deal farther inland than higher values, and it seems very difficult to draw the probable isobases according to these observations. It seems to me to be probable 1921. No. 11 THE STRANDFLAT- AND ISOSTASY. 273 that Kaldhol’s heights of the upper limit of submergence in this region are often too high. Kolderup’s observations in the Bergen district were also to a great extent difficult to bring into harmony with our formula, but he has obviously estimated his Tapes levels much too low as a rule. The Uniform Character of the Lateglacial and Postglacial Upheaval along the West and North Coast of Fenno-Scandia. On the whole the results of the preceding investigations demonstrate that, in spite of the possible local differences in the gradient of upheaval (mentioned p. 253), the lateglacial and postglacial upheaval of the land has proceeded remarkably regularly and uniformly along the whole of the western and northern coasts of Fenno-Scandia, from the region of Christiania Fjord to the east and south coast of the Kola Peninsula. Its relative rate appears to have been so uniform along the whole of this long coast, that, when its height be reduced by 5 metres, very nearly the same proportion, or about 68.5 per cent, of the rest of the upheaval has everywhere been accomplished during the period between the time of the deepest lateglacial submergence and the transgression of the Tapes-sea; and this relation seems to be the same in the outer coastal regions where the upheaval has been relatively small, as farther inland where it has been much greater. We are thus actually able to compute approximately the probable level of the Tapes-sea at any place where we know the upper limit of submergence, or vice versa where we know the height of the Tapes-line we can compute the height of the upper limit of submergence. An important result of our previous investigations was that, on the whole, the levels of the strandflat appear to stand at very similar heights above the sea in all regions of the Norwegian coast where they have been investigated. : These facts constitute conclusive evidence that the earth’s crust in these regions has very nearly returned to the same horizontal position which it had before the last glacial submergence, only that the shore-line stood then perhaps between 10 and 17 metres higher, in relation to the land, than it does now. The uniform relation which we have found between the heights of the observed upper limit of lateglacial submergence and those of the Tapes- line confirms in a striking manner the correctness of these conclusions. May we assume that the upheaval of the land is now practically at an end along the coast of Norway and that the earth’s crust has very nearly found its new position of equilibrium after the last glacial sub- mergence? Vid.-Selsk Skrifter. I. M.-N. Kl. ıg2r. No. 11. 18 274 FRIDTJOF NANSEN. M.-N. Kl. The nearly horizontal position of the strandflat in all regions of the Norwegian coast, and the fact that it very nearly maintains this horizontal level along lines at right angles to the direction of the isobases, seem to indicate that we may answer this question in the affirmative. We may, for instance, point to the fact that the level of the strand- flat at Varaldsoi in Hardanger Fjord, about 80 kilometres from the outer coast, has practically the same height (17— 19 metres) above the sea as the lower level of the strandflat at Haugesund and Karmsund, although the height above present sea-level of the upper limit of submergence is in the former region about go metres, while in the latter it is probably less than 50 metres. Along Sogne Fjord this relation is still more conspicuous. The level of the strandflat is nearly horizontal along the whole of this fjord, while in its inner part, in Sogndal and Norum Fjord, the total upheaval of the land may have been about 135 metres; at Vadheim it has only been 77 metres, and at Rutletangene, near the mouth of the fjord, probably less than 40 metres. As, however, the level of the strandflat appears to be a few metres, perhaps about 6 or 7 metres, lower in the inner part of the fjord than in its outer part, if our observations be correct, it is possible — either that the upheaval is not yet quite completed in the inner region of the fjord, or that the strandflat has beén raised slightly higher in the outer coastal region by the crust’s new level of equilibrium. In northern Norway we find the same striking features. The strand- flat lies very nearly in the same level along the coast of the mainland as well as on the islands of Træna, Rost, Veroi, and Lofoten far outside this coast, although the lateglacial and postglacial upheaval of the land has been about 80 to 90 metres along the coast of the mainland and probably not appreciably more than the elevation of the strandflat on Rost, and not much more along the outer coast of the Lofoten Islands. There is, however, here possibly the same difference between the levels of the strandflat in the inner and outer regions as we have found in Sogne Fjord. On Donna and Heroi the lower level of the strandflat is probably about IO metres, or less, above the sea, while on Rost and Væroi its height may be 14 to 16 metres. The explanation may be the same here as in Sogne Fjord. In the inner end of Christiania Fjord the strandflat has very nearly the same height above present sea-level as along the west coast of Norway, in spite of the great difference in the upper limit of lateglacial sub- mergence, which at Christiania was about 220 metres. There are, as we have already seen, other indications that the present shore-line has remained practically stable for a considerable time. The fairly broad modern shore-ledges cut in solid rock along the shores of the Fornebo Peninsula near Christiania, just above mean water 1921. No. rr. THE STRANDFLAT AND ISOSTASY. 245 level and below high-water level are convincing proof that, during the long time needed for the formation of these ledges, the level of the shore- line cannot have changed more than one or two metres at most. The recent shore-ledges, 8 to 10 metres broad, cut in fairly resistant solid rock (dolomite and gabbro with bands of syenite), in Kvænangen, just above high-tide level, described by Thorolf Vogt, are still more con- vincing proof that the present relation between land and sea-level cannot have changed much, perhaps one metre at most, for a very long time in that northern region. Hence we may then conclude that the postglacial upheaval of the land has been very nearly completed along the whole of the west and north coast of Fenno-Scandia, from Christiania Fjord to the Kola Peninsula, but there is a possibility that, in the inner parts of the fjords, e. g. in inner Sogne Fjord, and along the coast of Helgeland, the land may still have to rise some few metres before the upheaval is quite completed. By the find of a bronze-celt imbedded in the marine lavers of a ter- race (4 metres above present sea-level) between Skien and Porsgrund, in southern Norway, W. C. Brogger [1916] has shown that the land in that region may probably have risen about 9 or ro metres since the fourth period of the Bronze Age (about 1000 years B. C.). He thinks, however, that the upheaval of the land in south-eastern Norway was practically completed in the beginning of the Iron Age, and before the Christian era. The Lateglacial and Postglacial Submergence and Emergence in Central and Eastern Fenno-Scandia and in Jutland. If we now try to compare our results with the process of upheaval in regions further east in Fenno-Scandia (Sweden and Finland) and in Denmark we meet with several difficulties, as the conditions have been more complicated in those regions during the periods of upheaval. First. Å great part of Sweden and some part of Finland was still covered by the retreating ice-cap when the upheaval after the lateglacial submergence began, and even a long time after that. Hence the highest marks of marine action now found in those regions date from a period subsequent to the retreat of the ice, when the land had already been elevated to some extent. Their level, "the upper marine limit", is there- fore lower than the upper limit of submergence, and the difference may obviously be considerable in some regions, especially in Swedish Norrland. Secondly. By the warping of the land suríace the Baltic was during some part of the lateglacial and postglacial period transformed into a fresh-water lake, with levels higher than the actual sea-level. The height of the raised shore-lines will, therefore, have to be corrected accordingly in order to give the depression of the land below actual sea-level. 276 FRIDTJOF NANSEN. M.-N. KL Thirdly. The weight of the water masses of the extensive sea covering the submerged areas may have retarded the upheaval of the land to some extent, and may thus have made its relative rate differ somewhat from what it was along the Norwegian coast. Fourthly. In southern Sweden and in Denmark the crustal move- ments have been somewhat complicated, as during some part of the late- glacial and postglacial period there has probably been a subsidence of the land instead of an upheaval. Fifthly. Along the Baltic coasts of Sweden and Finland the land is still rising. The Present Crustal Movements in the Regions round the Baltic Sea and the Gulf of Bothnia. The present upheaval is most rapid (about 1.2 metre in 100 years) along the Swedish coast of Bottenviken and decreases southwards and south-eastwards. According to the investigations of Rolf Witting [1918] the mean yearly upheaval, during the fifteen years from 1898 to 1912, was I.1 cm. in the region of Umeä to Piteä on the west coast of Bottenviken, 1.0 cm. at Sundsvall, 0.8 cm. south of Söderhamn, 0.7 cm. at Gäfle, about 0.45 in the region of Stockholm, 0.1 at Kalmar, and 0.0 at Karlskrona. Along the southern coast of Scania there seems again to have been a slight rise of about 0.1 cm. yearly, while in southern Jutland and Schleswig; and in the region of Riga there seems to have been a sinking of 0.1 cm. yearly. Along the west coast of Sweden, in Bohuslän, there are indications of an upheaval still going on, which has been estimated to be as much as 0.4 cm. yearly. | It is a striking feature that lines drawn through the places with equal recent upheaval, according to the observations of Witting [1918, see map p.274] as well as those of Blomqvist and Renquist [1914, see map p. 83], seem to have directions roughly similar to those of the isobases of the postglacial upheaval, as has already been pointed out by Swedish writers [cf. A. G. Hógbom, 192r, p. 139]. It seems probable that the present upheaval of the coasts of the Baltic and the Gulf of Bothnia is a continuation of the postglacial up- heaval of Fenno-Scandia, which is not yet quite completed in this region. Witting points out the interesting fact that especially in the years with most seismic activity there are certain irregularities in the rise of the land. The Possibility of a Strandflat along the Baltic and Bothnian Coasts. No formation has been described along the coasts of the Baltic and the Gulf of Bothnia, which seems to correspond to the strandflat of Nor- way. The Skjærgård (belt of islands and skerries) of the Swedish and 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 277 the Finnish coasts and round the Åland Islands have certainly a great resemblance to the "Skjærgård” of the Norwegian strandflat, but it has obviously not the same kind of horizontal planes, and is more like a low flat land which has been submerged. As has been pointed out by A.G. Högbom [1910a], this low plain probably represents a precambrian plain of denudation which is widely extended in Sweden, and may be seen continuing in under cambrian-silurian deposits. As long as we do not know the level of the strandflat we have hardly any means of determining to what extent the rising land surface of this region has approached the level which it had before the last glacial sub- mergence. As the land is still rising, the strandflat, ıf there is one, may not yet have been elevated above the sea. In my opinion there may have been quite favourable conditions for the planing of a strandflat in solid rock, especially along the coast of Bottenviken, during the cold periods of the interglacial epochs. It is true that the wave action cannot have been very effective in this enclosed sea, and there was practically no tide. There was, however, a very severe climate in this northern region, favouring an active shore-erosion by frost, which also was much increased by the fact that the surface layers of the sea consisted very nearly of fresh water, which by freezing has a much greater disintegrating effect on the rocks than sea-water. The winds would also cause frequent changes in the level of the sea, which to some extent would make up for the lack of tide, and the wave-action would be sufficient to render substantial help in transporting the débris of the shore-erosion. There is, therefore, good reason to expect that a strandflat, cut in solid rock, may actually exist at some level below present sea-level. In that case it might be possible to trace it on the sea-floor. Through the kindness of Prof. A. Högbom I have obtained a chart with soundings of Bottenviken (Chart No.20 of the Swedish geodetic Survey). The soundings are not numerous enough for a study of the detailed topography of the sea-bottom. By drawing contour lines for every ten metres of depth, a great number of sharply defined submerged valleys and channels become con- spicuous. They form, as a rule, continuations of the bays and of the valleys on land. Some of them are quite narrow, with fairly steep side slopes. In Fig. 169 a small portion of this chart is reproduced as an example. They often seem to descend to depths of 60 and even 70 metres; but as they have probably been deepened by glacial erosion it is hardly possible to decide what their base-level may have been. In several places there are hollows with somewhat higher ridges outside indicating ex- cavation by glaciers. Between these submerged vallevs there are shelves or platforms, extending as much as 40 kilometres, or even more, from the coast. 278 FRIDTJOF NANSEN. M.-N. Kl. To a great extent these platforms have depths between 10 and 20 metres. They are bounded by fairly steep side slopes, descending to depths of more than 80 metres (Fig. 169), and, as it seems, by well defined edges, which along their outer margin appear to be between 20 and 30 metres helow sea-level; but the soundings are too scattered for an exact tracing of them. The north-eastern part of Bottenviken is very shallow with an ex- tremely flat bottom, at depths mostly between 10 and 20 metres, extending 60 to 70 kilometres from the coast and being bounded by a steeper slope cutside, descending to depths of 8o and 100 metres. There are not suf- ficient soundings to trace the topographical features of this flat floor; but it seems to be traversed to some extent by drowned valieys and channels. Some of them forming hollows 25 to 30 metres deep near the coast with somewhat higher platforms outside. To what extent these submerged platforms of Bottenviken are built up of waste and glacial drift is not easy to decide. The narrow drowned valleys and channels, 25 to 30 kilometres long, which the chart indicates, especially along the west coast of Bottenviken, seem, however, difficult to explain unless they are cut in rock, at least to some extent. The glaciers would hardly be able to form such narrow channels by submarine erosion in extensive terraces of loose material; and if they had been formed by fluvial erosion on land before the last submergence, they would have been more or less obliterated by the ice-cap unless they were cut in rock. The existence of these narrow drowned valleys also make it probable that Bottenviken cannot to any great extent have been filled up by glacial drift, or by waste after the beginning of the last glacial period, or after the last submergence of the land in this region. If, however, the drowned valleys are cut in solid rock, it is also obvious that the platforms between them, with their well marked edges and side slopes, are to a considerable extent cut in solid rock. It is then a question whether we here have formations which corre- spond more or less to the strandflat of the west coast of Norway. If so, we may expect that the coast has still to be elevated 20 to 30 metres before the strandflat is raised above sea-level, and if the latter shall be raised to levels similar to those of the Norwegian strandflat a still greater upheaval will be needed. In a letter A. G. Hógbom has drawn my attention to the interesting fact that at Hernösand (on the west coast of Bottenhafvet) interglacial fresh-water deposits occur at present sea-level [A. G. Högbom, 1909, pp. 578 ff.]. This also seems to prove that during the last interglaciai period the land stood higher than it does now. On the other hand it seems probable that in the southern part of Sweden the land surface has approached its level of isostasv; for the THE STRANDFLAT AND ISOSTASY. No. rr. 1921. Syyawuc]y 6, EE] SELLES SEL. BENE L — c = I—LLZ EIL we. ES Ss \ N pe \ N NN NN | N INS ARN > en SBT mr nn PEF AE | Der LS LED PS ETE. Lu p zi FL = = | _=—À Lag (? "—7 M inum AS N x at? N NO) "ALAN : rwy) 2017 panop m Dor reped 77242 20027279 9? Of 20] 1209 JUL SPAN 14:2 04 O€ OZ 27770) 704 € 2 SION OF 07 01 VÉLO] SEM OL MORD 705 wanting? 2vo SUgPQOS eh dd Pad zo uorbay ay) ua Qe. d w33421423]0g JO 15220) u.2]92/1-4]40N E CA Pb, | 280 . FRIDTJOF NANSEN. M.-N. Kl. striking evenness of the flat plain so widely extended in this region, seems to indicate a kind of base level towards which the land has been denuded, and cannot probably have been much above previous sea-level. As far as I am aware, the determinations of gravity have not given considerable deficiencies in Sweden; this also indicates that the crust has nearly attained its level of equilibrium. A.G. Hógbom has drawn my attention to W. Ramsay's statement in his textbook (2nd ed., p. 14) that "in Finland, Sweden, and in great parts of Norway the observed values of the acceleration of gravity show, as a rule, a deficiency (— — 0.004 cm.), while along the Norwegian coast, and in southern Norway as well as in Denmark the observed values of the acceleration are in most cases slightly higher than the normal. The Reasons why the Postglacial Crustal Movements have been retarded in the Regions round the Baltic Sea and the Gulf of Bothma. It seems to me to be probable that there are especially two reasons why the postglacial upheaval is still continuing in the regions round the Baltic Sea and the Gulf of Bothnia, while it was practically completed long ago along most parts of the west and north coast of Fenno-Scandia. First. While the margin of the last glacial ice-cap retreated at a comparatively early stage from the outer regions of the west and north coast of Norway and the Kola Peninsula, if they were ever covered by it, the interior parts of Fenno-Scandia were covered by ice for a much longer time, and especially in the region west of Bottenviken, where the lateglacial submergence was greatest, the last remnant of the ice-cap remained till late in postglacial time. This would naturally retard the upheaval of the land in those regions. Secondly. Long after the disappearance of the ice-cap the land was _ pressed down by the weight of the water-masses Covering the submerged land. First the Yoldia Sea was widely extended over great parts of Sweden and Finland, submerging also a wide area across middle Sweden, the regions of the great lakes, to Bohuslän, Halland, &c., and also some part of south-eastern Norway. Later the water-masses of the Ancylus Lake covered a wide area of eastern and southern Sweden and western and southern Finland. During this period Bohuslän and the surrounding regions were still greatly submerged, and also some part of south-eastern Norway in the region of the "Christiania. Fjord. Even as late as the Tapes-Littorina period considerable areas of land were still submerged round the coasts of the Baltic and the Gulf of Bothnia. It is obvious that the water covering the land weighed it down; but the addition of load over the sea-floor outside was still greater. The floors of the Gulf of Bothnia, the Baltic Sea, Kattegat, and Skagerrak were extensive parts of the depressed area of the Fenno-Scandian region. Over these de- I92I. Nos THE STRANDFLAT AND ISOSTASY. 281 pressed sea-floors the depth of the water was increased by the whole height of the depression. During the deepest submergence after the retreat of the ice-sheet, the additional layer of water over Bottenviken was at least 280 metres thick probably a great deal more, over the Baltic Sea in the latitude of Stockholm it was about 120 metres or more, in the northern part of Skagerrak, at the mouth of Christiania Fjord, it was about 160 metres thick, and along a line between Christiansand, Skagen, and Scania it Was more than 50 metres thick. Even as late as the Tapes-Littorina period the sea in Skagerrak was about 50 metres deeper than now at the mouth of Christiania Fjord, and about 13 to 20 metres between Christiansand and Skagen. In Botten- viken the sea may then have been more than 100 metres deeper than now. The great weight of these extensive water-masses covering the central, as well as the southern and south-eastern parts of the depressed Fenno-Scandian area, must naturally have greatly retarded the lateglacial and postglacial upheaval of the sea-floor and the land; and this retard- ation has obviously been of much greater importance than that caused by the late disappearance of the last remnants of the ice-caps in Swedish Norrland. In this manner we obtain a simple explanation of the fact that the upheaval of the land has not vet been completed along the coasts of the Gulf of Bothnia and the Baltic Sea, and perhaps also along the Swedish coast of Kattegat and Skagerrak. We also understand that the upheaval of the land may have con- tinued until comparatively lately along the Norwegian coast of Skagerrak and especially near the outer part of Christiania Fjord, while it was completed much earlier along the west and northern coast of Norway, where there was hardly any depression of the sea-floor outside the coast, and where only a very small area of the steeply ascending coast-land was submerged. An exception forms the coast of Nordland, between Trondhjem and Lofoten, as previously mentioned (p. 225), where a great deal of the broad continental shelf outside the coast was also depressed, and the sea in its inner part was as much as 90 metres deeper than now. When we here speak of the upheaval of the land having been com- pleted, ıt is of course, not meant absolutely completed. The probability is that after the removal of the load of the ice-cap it will take some considerable time before the upheaval of the crust be- gins, but when fairly started, it may probably increase in a comparatively short time till it attains a maximum rate, and will then procede according to an asymptotic curve, being relatively rapid at first, then decreasing gradually, and the crust will approach its level of equilibrium asympto- tically. This process may, however, be modified more or less, where the whole load is not yet removed when the upheaval starts, and is only 282 FRIDTJOF NANSEN. gradually diminished by the melting and retreat of the ice, and by the decrease (caused by the upheaval itself) of the water-masses covering the rising land and sea-floor. Relation between the Heights of the Tapes Level and of the Upper Marine Limit in Central and Southern Fenno-Scandia. A retardation of the upheaval of the land caused in the manner described above, may influence the relation between the heights to which the land was raised during the periods before and after the Tapes- Littorina period. We may, therefore, be prepared to find that our formula, based on the upheaval of the north-western coast of Fenno- Scandia, will not hold good in its central and eastern regions. The retardation of the upheaval caused by the weight of the trans- pressing sea, may be expected to have been most considerable, compara- tively, during the earlier periods of the upheaval, when the transgressing sea was deepest. Hence we may expect that in the regions where this sea was especially deep, the height of upheaval between the upper limit of submergence and the Tapes-line was lower in relation to the upheaval after the Tapes period, than it was in other regions. This seems to be borne out by the observations. In southern Sweden the observed heights of the Tapes-Littorina level depart, on the whole, less from the values, computed by our formula from the heights of “the upper marine limit”, than they do further north in Sweden. A. G. Högbom has attempted a comparison at the following localities: Height of Height of Littorina Locality Upper Marine Level Difference Limit Observed | Computed PBollnais = Nome andy. et cc 240 II4 19 1235 Salpanulka, Tavastehus, Finland ...... 136 53 47-2 TS Martestad, Waker Veners.. ee. eue u... 130 6 44.3 ns, Lino OLIN Seavey Aoc seeren sperren er 120 40 41.2 — LS SFA Pen I utan dr SE ete 60 I4 22.3 — Gu This is already sufficient to show that the departures of the ob- served values from the computed ones of the heights of the Tapes- Littorina level are in these regions of quite a different order than those we have found along the whole of the north and west coast of Fenno- Scandia. It may especially seem striking to find such a great departure of +15.7 at Mariestad, Lake Vener, while in the region of Christiania Fjord, about 200 kilometres to the north-west, the departures were between —1.8 and +1.5. The fact that the region of Lake Vener was covered I92I. No. 11. THE STRANDFLAT AND ISOSTASY. 283 by the Yoldia Sea after the retreat of the ice-sheet does not seem suf- ficient to account for this remarkable difference, as the Yoldia Sea also extended over the Christiania region, and had there even a greater depth, but its extent was less. The isobases of "the upper marine limit" seem, however, to have very irregular shapes in the region of Lake Vener [cf. Munthe's map, 1910, Pl. 46]. Taking the heights of "the upper marine limit" from H. Munthe's isobase map of southern Sweden [1010, Pl. 471, and the heights of the Tapes-Littorina level from his map of the Littorina isobases [r9ro, Pl. 46], and from Sundelin's map [1919, Pl. X] of the Swedish east coast between Norrkóping and Kalmar, I have compiled the values given in the following table. The heights at a few places in Jutland taken from A. Jessen [1920] have also been added. Height of Height of Littorina Locality Upper Marine Level Limit Observed | Computed Difference Swedish East Coast: SoderkopingE .. 3.2.2. 122 43 4I.9 EE Master. 5 ister one 0 ae eas RE 03 25 32.7 — 1-1 Scars RAM M Re 83 21 29.5 —85 IRCA TT a EC Case 65 16 23.9 — 9 IKarISkT Ona = LL. 48 EE 18.7 I Swedish West Coast: Kullens Scania ES re 50 12 19.2 —»1:2 (GotenbOLsg- Sr acer. re 90 24 31.8 v Jutland : Brederikshayun® Sean. SEKS Sjal er ca. 58 Cay o 2T] — 07 ARBOE (uer ere See oes ca. 22 1-5 IO.3 2:0 It seems surprising that along the Swedish west coast, e. g. at Gotenborg about 150 kilometres from Mariehamn, the departure is found to be —7.8, which differs much from +15.7 at the latter place. The figures of the above table seem, however, to prove that along the Swedish west coast, as well as along the Swedish east coast, south of the region of Söderköping and Linkôping, the Tapes-Littorina level is considerably lower, about 8 metres lower, than it should be if computed by our formula from the height of "the upper marine limit". This is obviously the same relation between the Tapes-Littorina level and "the upper marine limit" as is found in the northern part of Jutland, at Skagen and Frederikshavn, where the departure of the observed height of the Tapes-Littorina level is also about —8 metres (see the tables p. 282 and above), according to the figures given bv Axel Jessen [1920]. In Jutland the departure seems to decrease somewhat towards the south. It was found to be about —3 in the region of Aalborg. 284 FRIDTJOF NANSEN. M.-N. Kl. The cause of these great minus departures of the heights of the Tapes-Littorina level in southern Sweden and in northern Jutland may probably be that the lateglacial and postglacial crustal movements have been more complicated in these regions than they probably were along the west and north coast of Fenno-Scandia. During the Ancylus period these coasts were upheaved partly even to a higher level than they have at present. Then they again sank to their maximum submergence before or during the Tapes-Littorina period, after which time they have again risen. It has to be remembered, however, that the determinations of the levels of “the upper marine limit” as well as of the Tapes-Littorina submergence are always difficult and more or less uncertain, where they cannot be based on direct measurements of raised shore-lines cut in solid rock. If, for instance, they are based on marine deposits, it may often be doubtful at what depth below the surface of the sea they were de- posited, &c. It is, therefore, easy to understand that in the course of time the heights given by the various investigators for the Tapes- Littorina level have differed a great deal. Nevertheless, there seems to be a certain regular system in the distribution of the positive and negative departures of the heights of the Tapes-Littorina level found in Sweden and Denmark, which may indicate that these differences are real, and that the process of upheaval of these regions has differed from that of the west and north coasts of Fenno-Scandia. In this connection I may mention an apparent anomaly which A. G. Högbom thinks [1920] to have occurred in the upheaval of Finland and eastern Sweden after the Stone Age. He points out that the height which the land has risen after the time of the characteristic Stone Age culture, generally called the Äloppe culture, differs a great deal in relation to the total upheaval after the Littorina period in the various regions. He gives the following table: Height above Height in Relation of 1 sea-level in Metres of former Upheaval Locality : : ; Metres of Littorina Level to latter Up- Åloppe-Level above Sea-Level | heaval in per cent Upland, Åloppe CAE) UM oU opo Sod be 5 ANlUndare diede te ee a ee se 29.5 70 42 Äland, AARC Detects re 30 61! 481 Einland 4s Vib orem 0e ap ee ane na 173 221 HT 56. Ostersotlandi Sterne COE 25 47 53 Gottland, Gullrum Hemmor .......... LOS SIT I5— 16 10—12 I The heights of the Littorina level have been reduced at these two places according to Ramsay's latest map of the Littorina isobases of southern Finland [1920, p. 257]. 1921. No. rr THE STRANDFLAT AND ISOSTASY. 285 According to this table the land in southern Gottland should only have been raised 28 to 3o per cent of the whole upheaval between the maximum submergence of the Littorina period and the Aloppe period, at the same time as the land in Ostergótland and Viborg, Finland was raised 44 to 49 per cent of that amount, and the land in the other northern regions, mentioned in the table, was raised 52 to 58 per cent. Hôgbom thinks this is entirely opposite to what might be expected, as we know that the upheaval of Gottland was "completed long ago", while the upheaval of the other regions mentioned is stili continuing. I cannot quite follow Hogbom’s argument, for as far as I can see, a continued upheaval of the land in the northern regions would reduce the anomalies. If we assume, for instance, that in Upland the land will still be raised as much as 20 metres before the upheaval is completed, we see that the Aloppe level will be raised to 55—58 metres above sea- level and the Littorina level to roo metres. Hence the upheaval of the former level will be 55 to 58 per cent of that of the latter one, which will be nearer to the relation found on Gottland. A still better explanation of the observed anomalies may possibly be obtained if we assume that there have also been two kinds of move- ments of the shore-line after the time of the Äloppe culture, viz. one due to the upheaval of the land, and another due to a sinking of the sea-level. Let us assume, for instance, that the sea-level has sunk about 6 metres after the Âloppe period. Let us furthermore assume that before the upheaval is completed, the land will still have to rise, for instance, 15 metres at the Äloppe group, 13 metres at Alunda, 11 metres at Jått- bole (Aland), 2 metres at Viborg, and 7 metres at Sater (Östergötland), and nil on Gottland. The actual upheaval of the two levels, the sinking of sea-level being deducted, will then be the following: Upheaval (in Upheaval (in Relation of Locality Metres) of Metres) of former Upheaval Åloppe Level | Littorina Level | to latter Up- | heaval in per cent MIG PE MELO [iste stare TE EE ES 44—4] ie HISTOR SALAS oon ie er e destro ee ae 36.5 Hole. cec des eee The differences in the relation between the heights of the two raised levels given in this table are hardly greater than may well be due to errors in the determinations of the heights of these levels. On the other 286 FRIDTJOF NANSEN. M.-N. KL hand, our estimates of the amounts which the sea-level has sunk, and which the land will still rise before the upheaval is completed, are quite arbitrary. With other estimates a still greater agreement might be ob- tained. Æ. g. at Viborg in Finland the land may probably rise more than here assumed before the upheaval is completed. It seems also doubtful whether the upheaval of Gottland is already completed. The Cause of the Transgression of the Sea in the Tapes-Littorina Period. If we assume that the postglacial crustal movements of Fenno- Scandia were entirely isostatic, it seems difficult to understand that the apparent pause in the upheaval or even a transgression of the sea in the Tapes-Littorina period can have been due to a temporary sinking of the land as a whole; for the Scandinavian ice-cap can certainly not have been extended again during that warm period. It is more probable that this transgression. was caused by a rise of sea-level which took place while the greater part of the land continued to rise. Such an assumption agrees well with the observed facts. It is obvious that the height of the actual transgression of the sea, caused by a rise of the sea-level, would vary inversely to the rate of the upheaval of the coast. If the sea-level rose at about the same rate as the land, there would be no transgression; but the shore-line would remain more or less stable as long as the sea was rising with the land, and a beach might be formed, or ledges cut in the rock where the climate favoured it. If the sea-level rose more rapidly than the land, there would be a transgression of the sea, which would be greater in proportion as the upheaval of the land was slower. During this transgression marine terraces and even broad beaches may be formed, as a comparatively long time would pass before a negative shift of the shore-line again began, and a lengthened stand of the shore-line at about the same level of the coast would thus be caused. Along the coast of Norway the transgression of the sea during the Tapes period was obviously greatest in regions where the postglacial upheaval of the land was slow, while it was small in regions where there has been a considerable upheaval. i On Jæderen where the upheaval of the land after the Tapes period has only been about 12 to 15 metres, J. Holmboe’s [1901] and P. A. Öyen’s [1903] investigations seem to indicate that the Tapes transgres- sion of the sea has been as much as 8 or 9 metres in height. In the region of Christiania Fjord, where the upheaval after the Tapes period has been 60 to 70 metres, the Tapes transgression has been at most a few metres in height. P. A. Öyen [1905, p. Io] thinks he has discovered #921. No: rr. THE STRANDFLAT AND ISOSTASY. 287 evidence to show that it was about 3 metres in the Christiania valley, but no quite conclusive proof of such a transgression has been found. Considerably greater than in Norway has been the transgression of the Littorina sea in southern Sweden, where there was partly a sinking of the land before the Tapes-Littorina period, and the upheaval after that time has been very small, and in Denmark, where there has been a sinking of the land after that period. A.G. Högbom [1919, p. 177] estimates the height of this transgression to have been about 16 metres in the region of Kalmar, and about 30 metres in the region of the Great Belt, an estimate which, however, is uncertain. Where the land has sunk and the marks of the transgression are now under the sea, it is difficult to determine what its height may have been. If the sea-level rises along a coast which is sinking, the transgression will obviously be increased in a similar manner as it is decreased along a rising coast. A part of the great apparent transgression of the sea in these southern regions, however, may have occurred already before the Littorina period by the sinking of the land in these regions, which may have been caused by the comparatively rapid upheaval of the land to the north. The transgression of the Littorina sea seems to have decreased towards the north along the east coast of Sweden, and as Sundelin points out [1919, p. 204], no traces of a transgression could be found north of the region of Västervik. What may have been the Cause of a Rise of the Sea-Level during the Tapes-Littorina Period? As was previously mentioned (p. 222) the principal cause of changes in the sea-level in recent times, which cannot be ascribed to crustal move- ment, is probably the abstraction of water from the Ocean by the increase of the glaciers on land, and the addition of water to the Ocean by their decrease. If the rise of climatic temperature during the Tapes-Littorina period was universal for the whole earth, as seems probable, it may have caused a considerable reduction in thickness of the ice-caps of the Antarctic as well as of Greenland, which will have caused an immediate rise of the general sea-level. According to the computations made on p. 223, we see that if the average thickness of the present ice-caps and glaciers of the world were reduced by an amount of about 257 metres the immediate result would be a rise of the Ocean-level and the shore-line of about 10 metres, which would remain until it was gradually somewhat reduced by the crustal movements of the sea-floor and the coasts, in the manner discussed on pp. 234 ff. As, however, the crustal movements are extremely slow, and are gradually started only a considerable time after the isostasy has been 288 FRIDTJOF NANSEN. M.-N. Kl. disturbed, the sea-level may have remained fairly stable for a considerable time after its rise. As far as I can see, a shift of the sea-level and the shore-line such as this would be sufficient to give a simple explanation of the Tapes-Littorina transgression. During the periods preceeding the Tapes-Littorina period the climatic temperature of the earth was on the whole rising, but there were probably several fluctuations in this rise, due to fluctuations in the radiation of heat from the sun. There has been a corresponding reduction of the ice- caps of the earth, with similar fluctuations, which caused a correspondingly fluctuating rise of the general sea-level. Along great parts of the coasts of Fenno-Scandia, this rise of sea- level was more or less masked by the still faster upheaval of the land, and it was only during certain periods when the temperature was much raised and the melting of the ice-caps much increased, that the rise of sea-level was sufficiently rapid to cause a pause in the negative shift of the shore- line so considerable that conspicuous marine terraces, beaches, or shore- lines could be developed. It seems possible that the different stages or interruptions in the upheaval of the land, marked by the series of marine terraces and raised beaches along the coast of Norway may be thus explained. In the Tapes-Littorina period the rise of the general sea-level was sufficiently rapid to cause a transgression of the sea along some parts of the slowly rising coasts. After this period the climates of the earth have again become some- what colder. It is, therefore, possible that the ice-caps of the Antarctic and of Greenland have increased somewhat in thickness. In Spitsbergen, as was previously mentioned, there are indications of such a recent in- crease of the glaciers. Hence a slight sinking of the general sea-level would be caused after the Tapes-Littorina period. A sinking of sea-level would also be caused by the gradual isostatic depression of the sea-floor, caused by the previous increase of the water masses of the Ocean. If at the same time there has been some upheaval of the coasts caused by the depression of the sea-floor, the negative shift of the general shore-line would be increased accordingly. We would thus obtain an explanation of the general negative shift of the shore-line, or apparent sinking of the general sea-level, of about 20 feet or 6 metres in recent time to which Reginald A. Daly [1920] has drawn attention. It was previously mentioned that the apparent anomalies pointed out by A.G. Hégbom in the relation between the upheaval of the land since the Aloppe culture (of the Stone Age), and the upheaval since the Littorina period, may be explained by a sinking of sea-level since that time. 1921. NOSTE THE STRANDFLAT AND ISOSTASY. 289 It should, however, be kept in view that the lower level of the emerged strandflat in Norway may have a low height similar to that of the trans- gression of the Tapes-Littorina sea, and that this level dates from a time before the last glacial epoch. If its apparent upheaval is to some extent due to a sinking of sea-level, as seems probable, we must conclude that there have been several oscillations of sea-level during and after the last glacial period. When the relation between the inclinations of the upper and lower shore-lines of northern Norway was discussed (pp. 256 ff.), it was assumed that a general movement of the level, equal to a sinking of the sea-level, has occurred. It may here be pointed out, that the relation between the inclinations of the two raised shore-lines may of course also be explained only by a rise of the sea-level of about 6 metres during the Tapes period and a subsequent sinking of the same amount. The horizontal, raised levels of the strandflat seem, however, to indi- cate that there has actually been some sinking of sea-level since inter- glacial times, and the observations of Kaldhol, previously mentioned (pp. 248 ff.), in the regions near the mouth of Nord Fjord, would be difficult to explain without such an assumption. Vid.-Selsk. Skrifter. 1. M.-N. Kl. 1921. No. 11. 19 290 FRIDTJOF NANSEN. M.-N. KL XVII. ISOSTASY. What is the cause of the late-glacial submergence and the postglacial upheaval of the land in Fenno-Scanaia, Spitsbergen, Scotland, Iceland, Greenland, and North America? T. F. Jamieson was the first to suggest [1865, 1882, 1887] that the earth’s crust had been depressed by the load of the ice-caps, and that the postglacial upheaval of the land was due to the removal of this load. N. S. Shaler [1874], evidently without knowing Jamieson's first paper, gave a similar explanation of the quaternary changes in the level of the land. After this theory had been supported by the investigations of Gilbert [1882, 1890] and of Russell [1885] in the United States, and especially by Gerard de Geer [1888, 1890] in Sweden, and by Andr. M. Hansen [1890] in Norway, it has more and more universally been accepted by geologists. The fact, proved by the strandflat and by the raised shore-lines, that the coast of Norway has been depressed during the last glacial period, and has again in postglacial time risen to a level slightly higher than the level it had before the subsidence, while the upheaval of the land is not yet completed in the central and Baltic regions of the depressed area, which after the retreat of the ice was covered by a thick layer of sea, seems to me to form convincing evidence of the correctness of the theory that it was the load of the ice which caused the depression of the crust, and the unloading which caused its upheaval. I do not think that serious objections can any longer be raised against this theory. It 1s, therefore, hardly necessarv to spend much time in discussing the other attempts made to explain the cause of the postglacial upheaval of the land, e. g. the suggestion that it was due to a rise of the temperature of the earth's crust after it had been cooled by the ice-cap — or that it was due to some kind of tangential pressure in the earth's crust similar to that causing mountain-folding IR. Sieger 1993, A. G. Nathorst 1894] — or that the upheaval of the land was not real, but that the appearance was produced by the sinking of the sea which had been attracted by the mass of the ice-cap [Penck 1882]. The first explanation is sufficiently disproved by the fact that e. g. in northern Fenno-Scandia and in Spitsbergen the temperature of the 1927. No: r1. THE STRANDFLAT AND ISOSTASY. 29I upper strata of the crust would be raised, in Spitsbergen even as much as about ten degrees centigrade, and not lowered if the land were covered by a thick ice-sheet. As to the second theory, it is in itself inconceivable that tangential pressure of any kind should be able to produce an upheaval so regular and so gradual over an area as extensive as Fenno-Scandia, especially con- sidering the comparativelv narrow ridges produced by mountain-folding. A conclusive proof against this theory, however, is given by the strandflat, showing that the crust has first been pressed down in late-glacial time, and has then again been raised to its original level. A tangential pressure or strain causing such regular vertical movements of the crust is not conceivable. Penck's theory has been disproved by Hergesell [1887], Drvgalski [1887], Woodward [1888], and de Geer [1888] and was abandoned by Penck himself. The fact that the rise of sea-level caused by the attraction of the ice-masses would cease the moment the ice retreated, while the upheaval of the land occurred long after that time, is in itself conclusive proof against this theory. It seems to me that the more one studies the whole process of the late-glacial and postglacial subsidence and upheaval of Fenno-Scandia, and the related crustal movements in the surrounding regions, in all their details, the more one must be convinced that these movements are iso- static. One will tind that the theory of isostasy gives a simple and natural explanation of almost all phenomena, and even of many details which may seem startling at the first glance. The Theory of Isostasy. It seems strange that although the idea of isostasy is now more than seventy years old in literature, and in spite of all that has been written about it, the views regarding it still differ widely, especially amongst geologists. Elie de Beaumont suggested already in 1848 that accumulation of load depresses the disks of the crust, and removal of load will cause their upheaval. Some years later Pratt [1855 and 1859] and Airy [1855] clearly propounded the theory of the isostasy of the lithosphere. The name isostasy was, however, introduced much later by C. E.Dutton [1892]. A long series of prominent geophysicists have further developed the theory of isostasy, and the correctness of Airy's views seems to have been sup- ported by numerous observations. Airy's theory was based on Archdeacon Pratt's determinations of the deflection of the plumb line in India, showing that the attraction of the Himalaya mountains was less than might be expected to be exerted FRIDTJOF NANSEN. M.-N. Kl. D Ne) D by such great masses of rock above sea-level. According to Airy, the natural explanation was that the excessive mass of the high mountains was compensated for by a relatively low density of the masses of the crust below the mountain system. This might seem to indicate that the rigid continental crust is, as it were, floating on a plastic, denser substratum, and, as also assumed by Heim, the lighter "floating” lithosphere seems to be thicker under the mountain region, being there submerged deeper into the denser substratum or magma. Later observations seem to have borne out in essentials the correctness of Airy’s views. A series of pendulum observations made during the Fram-Expedition in 1893 to 1896 by Captain S. Scott-Hansen on the floating ice over the deep North Polar Sea, seemed to prove that similar conditions also prevail under the Ocean. By the computation of these observations Prof. O. E. Schiøtz [1901] found the gravity over the North Polar Sea to be normal, which proves that the deficiency of density of the deep layer of water, 3800 metres thick, being not much more than one third of that of rock, must be compensated for by an excess of density of the lithosphere under the Ocean, which must be appreciably denser than the continental crust. It is also in remarkably good harmony with this result that a deficiency of gravity was observed over the deep sea near the edge of the continental shelf, corresponding to the excess of gravity found on land near the coast- lines of the continents. In addition to the dynamic reasons for this peculiar distribution of the variations in gravity near the edge of the continental shelf, I think that it cught also to be taken into consideration that by the deposition of sediments, the continental shelves and the slope towards the deep Ocean floor will gradually sink towards their level of equilibrium; but owing to the rigidity of the crust, the Ocean floor outside the slope will also be bent down to some extent, although no appreciable addition of sediments has been deposited on it. A deficiency of mass will consequently arise in this boundary region of the Ocean. The important discovery that the gravity is normal over the Ocean, has been confirmed by numerous observations by Hecker [1903, 1908, 1910] over the deep Ocean in various regions of the earth. Hecker’s determinations of gravity were made onboard ship by simultaneous meas- urements of atmospheric pressure by means of boiling-point thermometers and the mercury barometer, a method first suggested by H. Mohn of Christiania. Although the accuracy of this method is much less than that of deter- minations with the pendulum, still Hecker’s observations over various parts of the Ocean agree on the whole so well that, in connection with the pendulum observations on the Fram-Expedition, they may be considered to prove that the gravity is, on the whole, approximately normal over the deep Oceans. The deficiency of mass of the Ocean water must be com- 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 293 pensated for by a relative excess of mass of the crust under the Ocean floor, due to a higher density than that of the continental crust at corre- sponding depths. In other words we may assume that the earth’s crust has attained its level of isostatic equilibrium, under the Ocean as well as under the con- tinents. The theory of isostasy was placed upon a more solid physical basis of numerous reliable observations by F. R. Helmert [1908, 1909] and especially by J. F. Hayford’s report [1909] on "The Figure of the Earth and Isostasy from Measurements in the United States”, and by later publications by Hayford and Bowie. While the theory has been accepted by most leading geophysicists, the attitude of the geologist towards this theory has differed more. Some geologists like Reid, in 1911, and Becker, in 1908 and 1915, accepted Hay- ford’s geodetic analysis and interpretation unreservedly, and even assumed a nearly perfect isostasy to exist. | Others, like Hobbs, in 1909, were more or less opposed to the idea of isostasv, while some, like Bailey Willis [1907, 1911, 1920], received the theory with much reserve and criticism. Gilbert, who was an early advocate of a partial isostasy, thinks that the rigidity of the earth’s crust can only permit of a regional compensation distributed over wide areas, and Barrell arrived at very much the same result. It would be out of place here to go more deeply into the vivid dis- cussion which has been going on, especially between American geologists and geophysicists, about the theory of ısostasy. The controversies show that the observed apparent anomalies of gravity may be interpreted in different ways, depending on the postulates as regards the vertical distri- bution of density in the lithosphere, on which the argumentation is based. An instructive summary of the outstanding points in this discussion has been given by Barrell [1919a]. It seems to me that the results of the synthetic discussion, though interesting, must remain very uncertain as long as the speculations have to be based upon assumptions regarding the conditions of the lithosphere prevailing at great depths below the surface, which our present knowledge gives us no means of controlling. If these assumptions should prove fallacious, as*they easily may, the whole structure of conclusions will be more or less overthrown. The fact is that at present we do not know the conditions of the rock at the high temperature and pressure prevailing at great depths below the earth's crust; we know nothing about the degree of plasticity or viscosity of the rock at these depths; and we do not know even approximately the vertical distribution of density in the lithosphere. 294 FRIDTJOF NANSEN. M.-N. Kl. As long as such fundamental factors are unknown, it seems to be somewhat hopeless to make certain assumptions and then try to find out what can take place at the surface of the lithosphere. A more natural way may be to examine as closely as possible what has actually happened at this surface, and from this we may possibly draw some conclusions as to the state of the deeper strata. I think that, for a better understanding of the isostatic problem, it may be especially valuable to study in all possible detail the vertical move- ments of the crust in the regions where it has been depressed by the load of the ice-caps, and has again been upheaved after their removal. For this kind of study there is at present hardly any better field than Fenno-Scandia, and especially the coast of Norway, where the limits and the process of the vertical movements are now fairly well established, where the postglacial upheaval of the land is practically completed, and where there is a strandflat indicating the level of the shore-line beføre the land was depressed by the load of the ice. The Crust's Capacity of Isostatic Readjustment. There.has been much difference of opinion as to how far the crust may be able to approach its level of perfect isostatic equilibrium. Most geologists have assumed that, owing to the rigidity of the crust, there can only be a rough approximation to isostasy. layford's computations seemed to indicate a high degree of local isostasy of the continental crust inside even comparatively limited areas, with a radius of no more than 19 kilometres. He predicted that future investigations would show that the horizontal extent which a topographic feature may have without a corresponding compensation of density would be between one square mile (2.6 square kilometres) and one square degree. The average vertical departure of the land surface from the elevation giving perfect isostasy he stated to be less than 73 metres (250 feet). J. Barrell 1914, 1915] although an adherent of the theory of isostasy, does not consider local compensation to be probable, as he thinks that the diameters of the areas of notable departure from normal gravity run up to about 300 kilometres, and he and Putnam [1912] are of the opinion that only regional isostasy may be attained inside areas with radial distances of at least 167 kilometres. Even there Barrell thinks that the distribution of compensation gives only a very rough approximation to isostasy. Bowie [1917], however, finds that in mountainous regions regional compensation with a radius of 59 kilometres satisfies the data as well as does local compensation, but regional compensation to a distance of 167 kilometres does not do so quite so well, and he considers that local com- 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 295 pensation is much nearer the truth than this degree of regional com- pensation [cf. Barrell, 1919a, p. 306]. Barrell, in his opposition to the hypothesis of local compensation, even goes as far as to postulate that a great local load wiil have no ability to depress the crust isostatically while even a smaller load distributed over a sufficiently wide area will produce an isostatic depression of the crust. It is hard to see the validity of this statement. If the crust is so rigid that it does not yield to the local load, the depressive effect of this load will naturally be distributed over as wide an area as the crust is capable of retaining perfectly rigid, and there will be no essential dif- ference in this respect if the load be equally distributed over this area. But if the crust is not so rigid as to cause the effect of the load to be distributed in this manner, then the crust will yield within a smaller area to the local load, and the result will be a deficiency of compensation (1. e. an excess of gravity and deflection of the vertical) near the local load, and an excess of compensation (1. e. deficiency of gravity) in the depressed region round it. It has also been maintained that great disturbances over extensive areas are necessary to start the crustal movements for adjustment of iso- stasv, and such movements will occur, as a rule, only during periods of special mobility of the earth’s crust, and within certain specially mobile regions. As far as I can judge the late-glacial and postglacial vertical move- ments of Fenno-Scandia and surrounding regions, and especially the movements of the Norwegian coast, and the present position of its strandflat, conclusively disprove the correctness of views such as these. They indicate that the earth’s crust in the course of time approaches its level of perfect isostatic equilibrium much more closely than even the most extreme advccates (like Hayford) of perfect isostasy have considered to be possible. Our studies of the present level of the strardflat in the Norwegian fjords as well as along the outer coast of Norway, in connection with the measurements of the heights of the upper limit of late-glacial submergence and the heights of the Tapes-line, may be considered to prove conclusively that the earth’s crust in these regions has returned, at least within a few metres, and along the outer coast probably even nearer, to the same hori- zontal level which it had before the last glacial submergence. And this level of equilibrium has been reached along the whole coast although the late-glacial submergence of the land has differed very much in magnitude. In some regions it was as much as 90 and 100 metres (along the coast of Helgeland) and 120 to 150 metres (in the inner parts of the western fjords) or even more than 200 metres (at Christiania), while in some parts of the outer coast, at Stat and outside Nordfjord, there has hardly been any submergence below the level of the strandflat. Nevertheless 296 FRIDTJOF NANSEN. M.-N. KL the strandflat has returned to its previous horizontal level in the outer regions along the coast, while in the inner regions of the fjords, and perhaps also along the coast of Helgeland, there may perhaps be some few metres left before this level is attained. At the same time, however, the strandflat as a whole is now standing perhaps 10 to 17 metres rela- tivelv higher above sea-level, than it did before the submergence, which may at least to some extent be due, as was previously mentioned, to a vertical movement of sea-level. The different leveis of the extensive strandflat of Norway prove that the Norwegian coast must have stood at these levels during very long periods before the last submergence, and probably even in preglacial time, and it seems probable that after each submergence during the different glacial periods, the earth’s crust has returned to the horizontal level of the strandflat. A natural conclusion must then be that the level of the strandflat represented the level of isostasy at times when the land was not depressed by the load of the ice-caps; for otherwise it seems to be inconceivable why the crust should always return to the samie horizontal level after each depression. The crust in these regions is to a great extent built up of very old Archean rocks, while in others, especially in northern Norway, there are younger formations, but they all show the same horizontal levels of the strandflat and very nearly the same relative degree of submergence. Moreover this is a region of exeptionally stable and tranquil character. During the long ages since the great Caledonian mountain-folding at the end of Paleozoic time, there has been singularly little crustal movement in the region of Fenno-Scandia. Besides, the Pleistocene age has certainly not been a period of special crustal mobility in any parts of the globe. When we, nevertheless, find that during the tranquil Pleistocene period this stable part of the earth’s crust has been so responsive to the load and removal of the last, not very extensive, ice-sheet of Fenno- Scandia, as well as those of each previous glacial period, and the sinking and rising movements have proceeded so continuously, and have been so regularly distributed over the whole area concerned, as is proved by the raised beaches, the relation between the heights of the upper limit of submergence and the Tapes-line &c., and by the strandflat — then a logical conclusion obviously is that this cannot be due to a specia! quality of an exceptionally flexible or mobile area of the earth’s crust, but must indicate a general quality of the lithosphere, nor can the isostatic crustal move- ments be limited to periods of special crustal mobility. We may, therefore, infer that the earth’s crust is on the whole very responsive to disturbances of its equilibrium, and has a great ability to re-establish it. After a sufficient time it will attain its level of isostasy at least within some few metres. 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 297 The above inference is strongly supported by the fact that similar evidences of a late-glacial submergence and a postglacial elevation of the land have been found in all other regions that were covered by fairly extensive ice-sheets during the last glacial epoch, although these regions may have so very different geologic structure as Fenno-Scandia, Novaya Zemlya, Franz Joseph Land, Spitsbergen, Scotland, Iceland, Greenland, and North America. Some of these regions, e. g. Southern Greenland, Labrador, and Eastern Canada, are especially stable and tranquil Archæan regions. The fairly regular distribution of postglacial elevation in Fenno- Scandia, e. g. the regular rise of the raised beaches from the outer coast inland, the uniform relation between the heights of the upper limit of elevation and the Tapes-line along the whole of the west and north coast of Norway and the Kola Peninsula, furthermore the retardation of the elevation in the flooded regions &c., prove that the upheaval of the land cannot have proceeded by jerks and irregularly, but must have been on the whole a very gradual and regular process. It is true that there seems to be a connection between certain irregularities in the slow emergence of the land i Sweden and Finland, and the seismic activity of the crust, as is indicated by Witting’s in- vestigations; but, on the one hand, these seismic movements are in fact very insignificant, and, on the other hand, they are obviously fairly local. They must not, therefore, be connected with the general crustal upheaval over extensive areas, but are due to more local strain in the crust, in regions where local deformities cause greater local disturbances of equili- brium. I may mention cur deep fjords and the submarine Norwegian channel as such regions, where there may be a special strain in the crust, owing to the erosion of these deep channels. We may summarize the results of the above investigations as follows: It is a general tendency of the lithosphere to readjust its tsostasy after disturbances, and in the course of time to approach its average level of isostatic equilibrium within som few metres at least. The isostatic movements of the lithosphere are not limited to especially mobile regions, nor to periods of special crustal mobility. How are the Isostatic Vertical Movements of the Lithosphere effected ? Pentti Eskola has recently [1920] put forward some ideas regarding transformations in the chemical composition of minerals and rocks effected by changes in pressure, which, if correct, may prove to be of great im- portance when the above question comes to be answered. He draws attention to the fact that pressure influences the nature of minerals “by moving the equilibria towards the associations and modi- 298 FRIDTJOF NANSEN. M.-N. Kl. fications which have the smallest volume”, and he points out that certain rocks, belonging to what he calls the “eclogite facies”, which have probably been suddenly pressed up from very great depths, are all of them very heavy with a specific gravity of about 3.3 to 3.5, and contain heavy minerals like garnet and diamond. These rocks are unstable at the pres- sure at which they are now found near the surface, and have, as it were, been "quenched” by the sudden reduction of the pressure. If the pressure had been reduced slowly, as would have been the case if these deep-seated rocks had been brought up towards the earth's surface by gradual denud- ation, they would gradually have been transformed into rocks composed of more voluminous and lighter minerals, conditioned by the existing pressure. Eskola points out that "eclogites occupy a volume about 15 per cent smaller than that of corresponding gabbros, and the magma probably has a still larger volume. The volume of jadeitite (sp. gravity — 3.33) is as much as 22 per cent smaller than that of the corresponding molecular mixture of albite and nephelite (sp. gravity — 2.61)”. He also maintains that as the melting point of eclogites is raised by pressure, it seems “likely that there exists a zone in the deepest parts of the earth’s crust where gabbroid material exists stable in the form of eclogite, at temperatures under which a gabbro would melt if the pressure were reduced”. Eskola mentions that this conclusion was formerly drawn by L.L. Fermor, who states that eclogite must be the high pressure form of gabbro, and that "we must, therefore, assume that in the infra-plutonic zone the basic rocks are present as eclogites and the more acıd rocks as garneti- ferous granites”. Fermor thinks that this infra-plutonic zone may form “a continuous shell round the earth, the whole of which shell is a potential magma. This shell, being composed of rocks of the consistency of a plastic solid, may afford a cushion upon which the isostatic operations of the earth, believed in by some geologists, have their foundation”. It is in my opinion obvious that if changes in volume, of the order mentioned above, can be effected by changes of pressure, appreciable vertical movements of the surface level of the lithosphere may be thus produced. The magnitude of these movements would depend on the thickness of the layer of those deep-seated rocks, the pressure of which is changed beyond the critical point. If we suppose, for instance, that, by the denud- ation of 100 metres of the continental surface (sp. g. — 2.6), the pressure in a layer of deep-seated eclogite (sp. g. — 3.45), 75 metres thick, be reduced below the critical point, and this layer of rock gradually be trans- formed, it may cause an upheaval of the continental surface of about T2 metres: 1921. No. Er. THE STRANDFLAT AND ISOSTASY. 299 This vertical movement would be effected without any "flow" of the plastic substratum underlying the rigid crust. If the transformed rocks form parts of the lithosphere the rise of the crustal surface caused bv their expansion would be added to the isostatic upheaval of the crust caused by the denudation. If it is rocks of the plastic substratum underlying the lighter, rigid crust, which are transformed, they may by their expansion become parts of the lighter crust, and will then increase the upheaval of the latter caused by the denudation. In that case the thickness of the lighter crust would not be much reduced by denudation. If the transformed rocks remain parts of the plastic substratum, their expansion may reduce the isostatic upheaval of the latter, because the expansion makes the lavers of the substratum lighter, and the crust may sink deeper into it, which would, however, necessitate a “flow” in the substratum. If instead of a reduction of the weight of the crust (e g. by denudation) we suppose an increase of its weight by deposition of sedi- ment, or by the formation of an ice-cap, the deep-seated rocks may be inversely transformed, and a gradual increased sinking of the crustal surface would be caused. As, however, we still know much too little about the actual conditions at these depths below the earth’s surface and about the possible trans- formations that may take place there, we must leave the crustal movements, thus caused, out of our present considerations. | If we try to form an idea of the isostatic movements of the earth’s crust caused by a load, e. g. by an ice-cap, the simplest supposition is that the crust is floating on a semifluid or viscous, molten magma, in a manner similar to that in which an ice-sheet floats on water. In that case the conditions may be considered as being practically hydrostatic below a certain depth. J. e. there is practically a uniform pressure in all direc- tions, and when the crust is depressed by an additional load, it will eradually sink down into the magma, in a manner similar to that in which a loaded ice-sheet will bend under a load and sink deeper into the water, until it attains its new level of equilibrium. The plastic magma under the sinking crust will be gradually pressed out towards the sides, and an “undertow” will arise. This will continue till the crust has reached its new level of equilibrium. The volume of the magma displaced sideways by the “undertow” will be equal to the total volume of the depression of the crust below its initial level, the possible changes in the volume of the magma caused by pressure not being taken into consideration. We do not know what the state of matter may be at the depth of the zone of compensation, perhaps at 120 kilometres, or more, below the earth’s surface — whether it is solid, viscous, fluid, or some other state unknown to us. The experimental researches by F. D. Adams [1912, 1917] 300 FRIDTJOF NANSEN. M.-N. Kl. and also those made at the Carnegie Geophysical Laboratory indicate that the problem is a complicated one [cf. Bailey Willis, 1920]. As the interior friction of solid rock, and thus its absolute strength or rigidity, is increased by pressure to a certain limit, where the rock is potentially crushed, the “zone of flowage”, where the rock may be considered to be plastic, lies much deeper than was generally estimated. We may, however, assume that this zone begins a great deal higher than the zone of compensation. As high temperature is essential to the mobility of the rock, and as the temperature of the lithosphere increases rapidly with depth, we may assume that at a depth of 50 to 60 kilometres the rock is in what may be called a plastic state, and that its plasticity increases with the depth. We shall not here try to discuss whether at a certain depth there is a continuous substratum of molten magma or not. The chief point for our consideration is that at some depth under the rigid surface of the lithosphere there is a zone of flowage, where the rock material, in what- ever state it may be, is plastic and mobile. That it must be so, and that this plastic substratum behaves to a certain extent like a viscous fluid, seems to be fully corroberated by our investigations of the strandflat and the crustal movements of Norway after the last glacial epoch. The coefficient of viscosity of this plastic substratum is probably very high, but even if it be as high as estimated by Schweydar [1921], i. e. ten thousand times that of sealing-wax at normal room temperature, we must keep in mind that the pressure is also extremely high, and the substratum, therefore, is responsive to changes of pressure, and possesses a certain degree of mobility, so that in the course of time, as is proved by our observations, it gradually adapts itself to the conditions of equili- brium. It is, however, obvious that this must require a very long time. On the one hand because the rigidity of the crust will offer great resistance to deformation, and it will give way only very slowly, probably by shearing. On the other hand because, as was just mentioned, the internal friction of the plastic substratum is so very great. The flow in the plastic substratum will, therefore, be extremely slow, and besides it will meet with great resistance, because, for instance, the crust, in the zone surrounding a depressed area, will have to be lifted in order to make room for the displaced plastic matter. Let us try to imagine what will happen, if the crust be gradually pressed down by an increasing ice-cap, provided that the conditions are fairly hydrostatic at a certain depth under the earth's surface. Supposing the ice-cap begins to be formed in the central area of an extensive region like Fenno-Scandia, the load of the ice-cap will press the crust down in this central area, and in a zone surrounding it the crust will be pressed up and will there form a kind of concentric wave, as in- 1921. No. 11. THE STRANDFLAT AND ISOSTASY. 301 Fig. 170. Diagram showing, with much exaggeration, the depression of the crust under an ice sheet, and the upheaval on the sides. The vertical arrows indicate the vertical movement of the crust, the horizontal arrows the "undertow” in the plastic substratum. dicated in Fig. 170, I. As, however, this wave will not represent a state of equilibrium, it will gradually extend outwards, and will be flattened down as it becomes wider and wider. If now the ice-cap increases in thickness and in extent, the crust wil! continue to be pressed down, and the surrounding upheaval wave will increase somewhat in height, while it will be moved outwards by the advance of the ice-cap (Fig. 170, IT). The depression of the crust will continue a long time after the ice-cap has ceased to increase, and will only very slowly and asymptotically ap- proach its level of isostatic equilibrium. The wave of upheaval surrounding the depressed area, will continue to widen, and the real level of isostatic equilibrium will not be fully reached, before this surrounding wave is entirely flattened out, and the depression of the ice-covered area is fully compensated for by the upheaval of the floor of the Ocean, as was men- tioned on p.233, but this is a state which is never reached. When the ice-cap begins to decrease towards the end of the glacial period, the underlving crust will probably not yet have been fully depressed to the level of equilibrium conditioned by the weight of the ice. The sub- sidence will, therefore, continue inside the area which is still covered by the retreating ice-cap, and it will not stop as long as the weight of the 302 FRIDTJOF NANSEN. M.-N. Kl. * ice masses is in excess of the load corresponding to the amount of depres- sion. After that time an upheaval of the crust will gradually begin. Meanwhile an upheaval of the land will start in the outer zone of the previously ice-covered region, soon after it has been left free by the retreating ice. This upheaval may be facilitated by a double “‘undertow” of matter coming from the still subsiding area inside, under the ice-cap, as well as from the upheaved peripheral zone (the upheaved wave) outside, as is indicated in Fig. 170, III. This may possibly have been what hap- pened during the period before the Tapes-Littorina period in the regions of Skagen and Kalmar, &c. (cf. above p. 284). When the upheaval of the more central area began, an undertow of matter towards this rising area from the surrounding previously upheaved zone would arise, and this would cause a sinking of the land in that zone (Fig. 170, IV), corresponding to the previouslv mentioned sinking of the land in the region of Skagen and Kalmar, &c. (cf. p. 284), before or at the beginning of the Tapes-Littorina period. As, however, the upheaval of the depressed area advanced, the under- tow of matter from the peripheral, formerly upheaved regions (outside the ice-cap at its widest extent) would be increased, and a general upheaval of the whole depressed region would be developed, and this would now continue, till the upheaval was completed. At the same time, the land in the peripheral, formerly upheaved zone, surrounding the ice-covered region, would gradually sink. Where the retreating ice-cap was to some extent replaced by a trans- eressing sea, the upheaval of the crust would be retarded, as was previously pointed out (cf. p. 280). It seems to me, that a development as here indicated agrees well with what we now know about the late-glacial and postglacial crustal move- ments which probably have taken place in Fenno-Scandia and the sur- rounding regions. Along the coast of Norway, where the retreat of the margin of the ice-cap was very much slower e. g. than in Southern Sweden and in Den- mark, and where the ice remained near the coast till late-glacial times, the crustal movements have probably been less complicated, and the up- heaval may have been fairly continuous from its beginning. In regions where the ice-cap left great quantities of moraine material, as for instance in Denmark and in Northern Germany, the crust was naturally depressed by the weight of these deposits, and this fact would also cause a sinking of the land which may have continued long after the ice retreated. The quantity of moraine material, however, carried by the last ice-cap, may probably not have been very great, and the sinking of the land thus caused after the last glacial period may, therefore, have been less considerable than after the previous glacial periods. 1921. No. rr. THE STRANDFLAT AND ISOSTASY. 303 Of much importance are the two questions of the time required for the isostatic readjustment of the crust, and of the size of the area within which it can take place. How long a time does the earth’s crust require to reach its new isostatic level after a disturbance of its equilibrium? As the internal fricticn in the plastic or mobile substratum, under the rigid crust, is, at any rate, extremely great, whatever the state of this matter may be, we may expect that when the substratum is exposed to stress it will take a long time before this friction is gradually overcome, and motion is started. In addition to this there is naturally also an enormous resistance to overcome in the rigid crust itself, before it can be depressed or upheaved. Hence the isostatic movements of the crust will always show a great deal of lag: For this reason many geologists have assumed that the establishnent of isostasy at the earth’s surface will require extremely long geological periods. I think, however, that our study of the strandflat and the raised shore-lines of Norway may prove that the time required for the attain- ment of approximate equilibrium is very much shorter than is generally believed. Although it may be very difficult to estimate the length of. time elapsed since the ice-cap of the last glacial epoch actually began to de- crease, there are now many careful researches by Gerard de Geer and his school in Sweden as well as by others, especially in North America, which will help to estimate the length of the late-glacial and postglacial periods. According to the results of De Geer's investigations, it is not more than 13,000 years since the margin of the retreating ice-sheet stood in Southern Scania. Even if we take other estimates we cannot possibly assume the time since then to have been more than 16,000 or 20,000 years. Purirg this period nearly the whole of the late-glacial and postglacial upheaval of Fenno-Scandia has been accomplished. A very considerable part of the upheaval has even been accomplished in about half that time, since the ice-margin had retreated to Northern Sweden, 8,000 years ago, e. g. the land near Bottenviken has been upheaved about 270 metres during that space of time. We know that along the coast of Norway the upheaval of the land was practically completed at least before the beginning of the Christian era. Hence we may assume that along the Norwegian coast the upheaval of the land and the re-establishment of equilibrium was completed during a period of probably 11,000 vears, and at any rate of not more than 18,000 years. This is a remarkably short period, and seems to indicate that the plastic substratum of the earth’s crust is more mobile, than many geologists are prepared to allow. 304 FRIDTJOF NANSEN. M.-N. Kl. What is the extent of the smallest area within which isostatic movements may occur? This is a very difficult question, which we cannot answer at present. It is obvious that the question of time is here of much importance. The smaller the area is within which the equilibrium is disturbed, the longer it will take before it can be re-established. It may be possible that in the course of a very long time equilibrium may be more or less attained within quite small areas, although the process is so extremely slow that it is not yet the case in many localities examined. We have seen (pp. 253 f.) that in Norway and Sweden there may be quite considerable differences in the upheaval of the land within small distances of no more than a few kilometres. As, however, we do not know the causes of these differences, they can hardly be used as proofs of a great locai adaptability of the crust to isostasy. It may, however, be pointed out, that the comparatively small ice-cap of Scotland, of the last glacial period, has caused a considerable depression and subsequent upheaval of the land, within an area with a diameter of less than 500 kilometres. The last glacial ice-cap of Iceland also caused a depression and subsequent upheaval of that island. Lake Bonneville in the region of the present Great Salt Lake, in Utah, with a diameter across of probably about 230 kilometres, caused a de- pression and subsequent upheaval of the flooded land, although the depth of the water above the present level of Great Salt Lake may have been no more than 320 metres [cf. Gilbert, 1890]. The depression caused by the load of water may possibly have been about 45 metres in the central area of the lake. These facts indicate that considerable isostatic movements may take place within areas no more than a few hundred kilometres wide, and probably even much smaller. Isostasy and Erosion. Our views regarding the ability of the earth’s crust to attain its level of isostasy must greatly influence our views as regards the morpho- logical changes due to erosion on the continental surfaces. The rapidity with which the crust responds to the changes of pres- sure caused by the deposition of sediments or by denudation is of essential importance for the development of these processes and for their effect upon the surface topography of the crust. Let us consider the probable effect of the isostatic crustal movements upon the denudation of the land surface and especially upon the develop- ment of peneplains. It is obvious that the time required for the planing down of a mountainous region to a peneplaiu. will be essentially increased by the 1921. No. rr. THE STRANDELAT AND ISOSTASY. 305 isostatic upheaval of the land taking place according as its surface is denuded by erosion. lf the density of the rocks eroded from the surface of the crust be 2.6 and the density of the plastic substratum underlying the rigid crust be 3.5, it would be necessary to erode a surface layer with an average thickness of about 385 metres in order to reduce the average height of the land above the sea by 100 metres, provided that the isostatic readjustment be complete. If there is less difference than assumed above between the density of the Surface rocks and that of the plastic substratum, the thickness of the surface layer which has to be eroded in order to reduce the average height of the land above the sea by 100 metres, will be proportionately greater. If the density of the surface rocks be 2.6 and that of the substratum be 3.0, a surface laver with an average thickness of about 770 metres would have to be eroded in order to reduce the average height of the land above the sea by 100 metres. As the subaërial and fluvial erosion of a high land is most active along the mountain slopes and in the river valleys as long as the floors of the latter have sufficiently steep gradients and are sufficientlv elevated above the sea — it is obvious that in many cases the ridges of the mountains may be raised by the isostatic upheaval to levels higher above the sea than those at which the summits of the mountains stood before the erosion began. The result of the erosion during its first stage may thus be to make the mountain ridges higher above the sea than thev were before, while the valleys are made lower. This may probably continue until the level of the floors of the great river valleys approach the base level, after which time the erosion will actually begin to reduce the height of the mountains above sea-level, and will tend towards making the land less uneven. If, as above, we assume the density of the eroded rocks to be 2.6 and that of the plastic substratum to be 3.5, the erosion will not begin to reduce the height above sea-level of the mountain ridges before the thickness of the layer of rock removed from above them is as much as 74 per cent of the average thickness of rock removed by the erosion from the whole land surface. If the density of the plastic substratum be only 3, the thickness of rock removed from above the mountain ridges would have to be as much as 87 per cent of the average thickness of the layer of rock removed by érosion from the whole land surface, in order for the height of the mountain ridges above sea-level to be reduced. The relation between the erosion, the isostatic movement and the reduction of the mountain heights may be somewhat altered where there is an active erosion by frost (local g.asial erosion) in the higher parts of Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. 17. 20 306 FRIDTJOF NANSEN. M.-N. Kl. the mountains, in which case their heights above the sea may possibly be reduced even during the first stage of erosion. As the erosive effect of a moving glacier is so enormously increased with the velocity of the movement (probably by the third power of the velocity, cf. p. 21) the denudation of the land caused by the erøsion of a big ice-cap will obviously be concentrated on the deepening of the valleys and fjords, while the surface of the higher parts of the mountains between them may be comparatively little denuded. 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Wurıs, Bailey: Research in China. Carnegie Institution of Washington, Publication No. 54, ll, 1907. WhiLus, Bailey: Discoidal structure of the Lithosphere. Bull. of the Geol. Soc. of America XXXI, No. 2. 1920. WirriG, Rolf: Haisytan, geoidytan och landhojningen utmed baltıska hafvet och vid Nordsjon. Fennia XXXIX. No.5. Helsingfors 1918. Woopwarp, R. S.: On the form and position of the sea-level. U.S. Geol. Soc. Bulletin No. 48. WRIGHT, W.B.: The Quarternary Ice Age. London 1914. HIPPOPHAES RHAMNOIDES BISACIEENSNOISSK- KREK FUR AV P. A. OYEN (VIDENSKAPSSELSKAPETS SKRIFTER. I. MAT.-NATURV. KLASSE. ro21. No. 12) KRISTIANIA I KOMMISSION HOS JACOB DYBWAD 1921 Fremlagt i den mat.-naturv. klasses møte den 20. septbr. 1918. Pa Utbredelsen av denne merkelige plante inden norsk omraade angives av Biytr & Danı saaledes: „Torre strand- og elvbredder nordenfjelds fra Trondhjemsfjorden til Stegen 67° 56/. Angives ogsaa for Nordfjord“ (Norges Flora, 1906, pag. 511). Og Dyrine har bemerket: „Denne busk, der ellers er bunden til havkysten, optræder merkelig nok i Junkersdalsuren ved et af de midtre flaug i en liden koloni“ (Nyt Mag. f. Naturv. B. 37, pag. 297). Man kan ellers merke sig dens temmelig almindelige forekomst i egnene omkring Trondhjemsfjorden, hvor den almindelig naar en hoide av 3—4 m., saaledes f. eks. Strinden, Frosta, Stjordalen, Levanger og Inderoen. Den gaar langs kysten fra Orlandet til Valdersund og Helge- landskysten, saaledes Lovo, Tjotta, Donna og Alstenoen. Den findes ved Leines yiterst i Meisfjorden og i Dunderlandsdalen indtil ca. 450 m. o. h. et par mil fra riksgrænsen. Den er endvidere fundet paa Fiskvaagfjeldet i Saltdalen og ved Prestkontindens fot i Steigen 67° 35-56‘, dens nord- grænse. Man bor merke sig at deni Nordland særlig holder sig paa kalk- grusbund. Litteratur: — Brytr: Norges Flora, s. 552, SCHÜBELER: Virid. Norv. I, s. 598, Norman: Norges Arktiske Flora I, s. 937 og Il, s. 486, O. Dau: Bot. Undersokelser i Helgeland I, s. 175. I den forbindelse her omhandlede plante ved denne anledning drages frem, kan vi ikke gi os til at diskutere dens forekomst ut over hele jord- flaten, men det har dog en betydelig interesse at kaste et ganske kort til- bakeblik paa dens utbredelse inden de nærmest tilgrænsende landomraader. Naar vi lar ute av betragtning den gamle og kanske ikke helt sikre findestedsangivelse fra Indviken i Nordfjord, saa ser vi at dens nuværende forekomst i Norge er meget karakteristisk og bestemt avgrænset. Gaar vi saa over til vort naboland i ost, Sverige, saa finder vi den her og der meget almindelig langs den Botniske Bugts sandede strandkanter tra Hapa- randa helt ned til Roslagen, hvor den dog i Uppland gaar en halvfjerde mil ind i landet. Men som Höcsom sier: ,Hippophaë rhamnoides (haftorn) som numera vaxer i Norrland endast vid kusten, men, såsom flera fynd i kalktuffer utvisa, fordom förekommit i västra Norrland" (Norrland, naturbe- skrifning, 1906, pag. 335). Desuten angives en enkelt forekomst ved Gull- marsfjorden i Bohuslän. Og gaar vi over til den anden side av den Botniske Bugt, saa finder vi den i Finland som en kystplante paa samme maate som i Norrland fra Torneå til omegnen av Nystad, hvor sydgrænsen falder ute i skjærgaarden i „regio aboensis". Og her sammenbindes den finske fore- 4 P. A. OYEN. M.-N. KI. komst med den svenske ved den av PArMGREN beskrevne rike forekomst av arten paa Alandsoene (Hippophaës rhamnoides auf Aland, Helsingfors 1912). Den mangler fuldstændig i det europæiske Rusland med undtagelse av et par noget tvilsomme findesteder i Kurland, men saa optrær den ofte i mandshoide paa den tyske Ostersjokyst. Og man kunde nok med KórrEN spørge: ,warum er im südwestlichen Finland wåchst und dann, das west- liche Estland, Livland und Oesel überspringend, erst wieder in Kurland auftritt?“ Körren slutter sig saa til NATHOnsTS hypotese, at dens forekomst sammen med Dryas i norrlandske kalktuffer viser dens alpine karakter, og at den derfor er trængt ned til kysten av senere indvandrede planter. Det er til denne anskuelse ogsaa HåGgom har sluttet sig: ,hvad forklaringen af nu vidrórda våxtgeografiska foreteelse angår, så synes det vara antagligt, att dessa växter förut haft ett mera sammanhångande utbredningsområde, men att de blifvit sprängda genom fürändrade geografiska och klimatologiska forhållanden och dårmed fåljande invasioner af nya florelement" (Norrland, naturbeskrifning, 1906, pag. 335). (GUNNAR ANDERSSON synes derimot at ha sluttet sig til den av Hansen fremhævede betragtningsmaate: „Ich habe schon, wo die Verbreitungswege der arktisch-alpinen Flora besprochen wurden, hervorgehoben, wie von dem früher eisfreien Land im Westen dieselbe sich gegen Osten verbreitet. Diese Verbreitung talaufwärts von der milderen Westküste der Halbinsel aus ist während der ganzen Spät- quartärzeit in bedeutendem Umfange weitergegangen, besonders in gewissen Gebieten und während des Temperaturmaximums. Die Pässe lagen teils infolge des wärmeren Klimas, teils wegen der Landsenkung biologisch um rund ca. 300 m. niedriger als heutzutage. Besonders im nördlichen Skandi- navien haben wir aus dieser Ursache in unseren Tagen von vielen Pflanzen nicht weniger als drei verschiedene, der Längsaxe der Halbinsel parallel verlaufende Verbreitungsgebiete“ (Résultats scientifiques du Congrès Inter- national de Botanique Vienne 1905, pag. 79), og derpaa utvikler han dette sammesteds i tekst og kartografisk som 1) Atlantisches Gebiet, 2) Alpen- täler-Gebiet, 3) Bottnisches Gebiet, og tilfoier: „in einigen Fällen, wie Hippophaë rhamnoides, kann die Art in einem von dem drei Gebieten ganz ausgestorben sein, wird aber fossil gefunden“ (l. c. pag. 79). HaLLE, der diskuterer artens forekomst i de jemtlandske kalktuffer, anfører saavel NATHORSTS opfatning av disse som tidligere liggende nær- mere kysten som den ogsaa ovenfor anførte sprængningsteori med hensyn til vegetationsforholdene. Desuten omtaler han ogsaa ANDERSSONS anskuelse: ,Hippophaé har med björkskogen spridt sig ötver Sverige till norra Skan- dinaviens sávàl kust- som fjälltrakter. Från dessa har den genom de jàmt- làndska och lappländska fjällpassen utbredt sig utefter floddalarna till Atlan- tiska hafvets strander. På grund af förhällanden, som det ännu icke år möjligt att med bestämdhet afgóra, har arten troligen under senare delen af furens tid äfven utdött i Norrlands centralare delar“ (cfr. ogsaa ANDERS- son: Svenska Våxtvårldens Historia, 1896, pag. 27—29), og videre fort- 1921. No. 12. HIPPOPHAES RHAMNOIDES L. : 5 sætter Harte: , Vad Hippophaés vertikala utbredning i tufferna angår, har ett rätt märkligt förhällande framgatt ur undersökningen av de ovan be- skrivna avlagringarna. Hippophaës vertikala utbredning i de undersökta kalktufferna inom nordóstra delen av kalktufomradet sammanfallar i stort sett med Dryas, d. v. s. arten år inskränkt till de undre delarna av tuf- ferna“ (Sveriges geol. unders. Ärsbok 8, 1914, No. 1, pag. 38—39). Og HALLE synes nærmest at stanse ved den ogsaa av tidligere forfattere frem- hævede „ständortens avgörande betydelse — — — underlägsenheten i kon- kurrensen med andra former jämte en stor plasticitet i förhällande till klimatet" (1. c. pag. 40) som betingelse for den eiendommelige utbredelse. Og han finder da at „ur denna synpunkt synes associationen Dryas— Hippophaë \att förklarlig och naturlig. Det år i bada fallen den rikliga tillgangen på nytt land vid isens recession och issjöarnas avtappning, som varit bestämmande. Särskilt år det klart, att synnerligen gynnsamma växt- platser måste ha statt Hrppophaé till buds utmed issjöarnas stränder, dar de successiva avtappningarna framkallade nya landvinningar. Genom dessa avtappningar näddes alltså samma resultat som genom den pågående land- höjningen vid Bottniska viken" (1.-c. pag. 40). Og Harre kommer med den forresten meget fornuftige bemerkning: „för övrigt år det ju möjligt — då det år ovisst, om vi kånna den alra första flora, som tog landet i besitt- ning — att Hrippophaé inkommit något efter Dryas liksom den sannolikt kvarlevat långre" (1. c. pag. 41). Men naar han saa direkte fortsætter: „pä grund av klimatets snabba förbättring behöver 1 alla handelser tidsskillnaden ei hava varit lang“ (l. c. pag. 41), saa berører han med en gang netop et av de punkter hvor jeg, paa grund av den maate hvorpaa den kvarteer- geologiske utvikling viser: sig at ha fundet sted i vort land, har set mig nødsaget til at stille mig i skarp opposition til den svenske kvartærgeo- logiske forsknings resultater med hensyn til tidsspersmaalet. Og til en nærmere belysning av dette forhold igjen blir det nødven- dig at vi fortsætter vor undersokelse av Æippophaës nuværende forekomst i syd og sydvest for om mulig at bli istand til at se dens utbredelsesfor- hold under en noget anden synsvinkel, i lys av fund jeg gjorde av denne merkveerdige plante i kalktuffen ved Gillebu forrige aar, og hvorav jeg leverte en foreløbig oversigt under titelen „Norges største Kalktuf" (Aften- posten, 1917, Nr. 440), likesom jeg ogsaa i en senere artikel , Vor plante- verdens utspring og dens utbredelse til det nuværende omraade“ (Trond- hjems Adresseavis, 8de april 1918) har behandlet det samme emne paa en mere korrelativ maate, om end rent populært. En mere systematisk frem- stilling saavel i geografisk som geologisk henseende har jeg netop under trykning i ,Norsk Geologisk Forenings Tidsskrift", Der ligger i grunden en skjæbnens og utviklingens ironi deri, at HALLE og nærværende forfatter, som anskuer de her omhandlede forhold saa vidt forskjellig, dog kan enes om følgende, som Harre har formet side 41 i sin allerede ovenfor citerte avhandling: „De edafiska förhällanden, som med- 6 P. A. ØYEN. M.-N. KL forde, att arter med väsentligen så olika utbredning som Dryas og Hippo- phaö kunna i så stor utsträckning förekomma tillsammans i kalktufferna, äro pâtagligen ganska analoga med dem, som göra att nordliga och sydliga former mötas i de s. k. sydbergen. Det torde därför kunna anses vara mer än en tillfällighet, att bada de nämnda arterna ingä i den bekanta syd- bergsfloran från Junkerdalsuren i Saltdalen" (cfr. Dyrincs avhandling i Nyt Mag. f. Naturv. B. 37, 1900, pag. 297 og 298). Vi stanset ovenfor med Hıppophaös forekomst paa den tyske Ostersjo- kyst. Den mangler fuldstændig paa den tyske Nordsjokyst, men forekommer paa de Østfrisiske øer, hvor den i det rgde aarhundrede har utbredt sig mot øst uten dog at naa Spiekeroog og Wangeroog. Paa Borkum, som jeg besøkte sommeren 1910, fylder den hele dynedale, som den gjør ganske ufarbare, og truer der med at bli en virkelig landeplage. Paa de Nord- frisiske øer mangler den. I Danmark er den almindelig i klitterrænget nord for Limfjorden, findes enkelte steder inde i landet, hist og her paa østkysten samt spredt og sjelden paa den sydlige vestkyst, likeledes paa Møens Klint og paa Skagens nordstrand. Gaar vi videre mot sydvest og vest, finder vi den meget almindelig paa Hollands og Belgiens dyner og kyster og videre ,in Britain, very local, and only near the seacoasts of some of the eastern and southern counties of England" (BENTHAM & Hooker: Handbook of the British Flora, 1912, pag. 389), saaledes f. eks. 1 York, Norfolk, Suffolk, Sussex (Watson: Topographical Botany, 1883, pag. 361). Dermed har vi vundet et grundlag for en videre betragtningsmaate av den arts utbredelsesomraade og utbredelsesmaate. Og der kan nok være grund til med Harre at opkaste folgende sporsmaal: „da Dryas i kalk- tufferna säkerligen år av västligt ursprung, kan man fraga sig, om ej också Hippophaé kan ha inkommit pa samma vag" (Sveriges geol. unders. Ärs- bok 8, 1914, no. 1, pag. 42). Nu, vi har i det foregaaende set HALLES anskuelse, der slutter sig temmelig neie til PALMGRENS, ANDERSSONS og Warmincs (Acta Soc. pro Fauna et Flora Fennica, B. 36, 1912, no. 3, pag. 32), eller i det hele en østlig og sydlig oprindelse. Selv fremhæver han ogsaa den alternative karakter i folgende: ,,fran Nordsjóns sódra kusttrakter bör arten ha kunnat sprida sig till norra Skandinavien lika lått utmed Norges våstkust som genom Sverige och kan i så fall från Trondhjemstrakten över fjållpassen ha intrångt till Issjölandet. En senare spridning efter isens bi- partition ned für ålvarna till Bottniska viken bår ha kunnat gå für sig låttare ån en vandring i motsatt riktning" (Sveriges geol. unders. Årsbok 8, 1914, no. I, pag. 42). Og videre indgaar i samme ramme fortsættelsen: „det år mójligt, att den fossila forekomsten på Gottland er en framskjuten utpost av denna sydliga invandringsström. Däremot år det ej bevisat, att arten spritt sig vidare upp utefter kusten“ (l. c. pag. 42). Samtidig gjør ogsaa Harte opmerksom paa ,att en positiv strandfårskjutning allvarligt måste hota artens bestand och i de flesta fall utrota den“ (I. c. pag. 43). Og det er vel da i samklang med Haıres hele betragtningsmaate naar han 1921. No. 12. HIPPOPHAËS RHAMNOIDES L. 7 herigjennem fremhæver: „det år möjligt, att Hippophaé på detta sätt ut- rotats utmed sådra Sveriges Östersjökust under Ancylus- och Littorina- transgressionerna" (l. c. pag. 43). Det turde vel i denne forbindelse være paa sin plads at minde om det forhold Harre omtaler fra kalktuffen ved Filsta, hvor Hippophaé fore- kommer ,i undre delen av tuffavlagringen", men hvor, som han sier: »Dryas lyckades jag trots ivrigt letande ej återfinna hår, men dåremot gjordes helt nära ett fynd, som synes visa, att arten förekommit i når- heten av lokalen en avsevård tid innan den bekanta tuffavlagringen bårjade bildas" (1. c. pag. 44). Som det vil fremgaa av den ovennævnte avhandling, som jeg nu har under trykning, „Kalktuf i Norge", saa faar vi Æippophaës optræden i Gille- butuffen i et geologisk temmelig noie bestemt nivaa. Ti hvad vort lands indlandsavsætninger viser, sammenstillet med vore gamle havavsætninger, er følgende generelle geologiske hovedtræk: Havavsætninger: Indlandsavsætninger: Portlandia-nivaa Brægrus og bræelvavsætning Littorina-nivaa Rustfarvet ler uten fossiler Pholas-nivaa Bjerke-tuf Mactra-nivaa Dryas-tuf og ler Tapes-nivaa Furu-tuf Trivia-nivaa Forvitring og mulddannelse . | 1. Mulddannelse Ostræa-nivaa l 2. Erosion (gruskegle) Mya-nivaa Ter nutid med forvitring Og her viste det sig ved Gillebu at Hippophaés forekom. helt til bunden av bjerketuffen. Naar vi saa erindrer fundet av Dryas i ældre avsetning i vort land og Hattes uttalelse om Dryas og Hippophaës relative alder ved Filsta, saa ser vi der er den bedste overensstemmelse palæontologisk- stratigrafisk set. Men saa vet vi fra Leine at vi har en Dryas-tuf yngre end bjerketuffen og atter en furutuf yngre end Dryas-tuffen. Og efter furu- tuffens avsætning har der fundet saavel forvitring som erosion sted, som muldlag og furutufblokker sammen med andre tufblokker viser os i grus- keglen ved Tingvold. Et enkelt fossilfund av en art er jo ikke meget, men det kan allikevel ofte faa en noksaa stor betydning, som i dette tilfalde med henblik paa forekomsten av Hippophaés i Gillebutuffen. Kaster vi nemlig nu blikket paa et kart over den nuværende og tidligere forekomst av denne art, saa blir billedet for Skandinaviens vedkommende et helt andet end det fer op- dagelsen av denne forekomst var. Der synes nemlig ikke at være tvil om at /Zrippophaés inden de tre omraader hvorfra den kjendes som fossil: Gottland, Jemtland og Gudbrands- dalen, med hensyn til indvandring tilhører væsentlig i det store og hele 8 P. A. ØYEN: HIPPOPHAËS RHAMNOIDES L. M.-N.Kl. 1921. No. 12. set omtrent samme tid, Pholas-nivaaets. Om vi saa ser disse 1 et helhets- billede som bindeled mellem de to kystomraader for dens forekomst i nu- tiden i det nordlige Skandinavien, nemlig paa den norske kyst og om den Botniske Bugt, saa ser vi de fossile forekomster danne en naturlig forbin- delse, ikke efter nogen bestemt linje over det hele omraade i sydvestlig retning med de mere spredte forekomster i syd og sydvest. De teoretiske betragtninger over forskjellige indvandringsveier fra syd og sydvest til de forskjellige omraader av den skandinaviske halvø kan saaledes for denne arts vedkommende ikke opretholdes. Og større værd har heller ikke resul- tatet av de spekulationer som har fundet utformning i vandring, snart den ene vel, snart den anden vei, over fjeldpassene mellem det Trondhjemske og omgivelsene av den Botniske Bugt. Det hele viser os tvertimot et klart billede av en tidligere sammen- hængende langt større utbredelse av //ippophaés end den nutiden frembyr, forsaavidt det gjælder det skandinaviske omraade. Og billedet viser os mere, nemlig at denne utbredelse har været av karakteristisk sydvestlig oprindelse. Den synes derfor at være paa det noieste sammenknyttet med den her omhandlede periodes hele klimatpræg, der var av utpræget sydvestlig karakter. Det er det vestbritiske faunaselskap Pholas candida- komplekset som vi gjenfinder i vore leravsætninger fra den tid saavel inden Kristianiafeltet som inden Trondhjemsfeltet. Det er derfor heller ikke helt utelukket, at de nordlige grænser for artens nuværende utbredelse er noget snævrere end de var paa den tid. Det vigtigste resultat turde ligge deri, at utbredelsen, fremrykning og tilbakegang, ogsaa for Hippophaéæs sees at omfatte ganske bestemte land- omraader i sin helhet fuldstændig overensstemmende med forandringen i de klimatologiske forhold, som heller ikke bevæger sig kun efter nogen bestemt optrukne linjer, men indbefatter større klimatiske provinser der i sin helhet styres av klimatologiske lover, lovbestemte forandringer i temperatur og nedbør, eller som jeg for en tid siden i en artikel, ,,Fimbulkulde" (Aften- posten 1918, 2ıde April, Nr. 198) søkte at vise at dette helt enkelt kan tilbakeføres til forandringer i lufttrykkets fordeling over jordoverflaten, og at dette er et helt generelt forhold der kan følges fra nutidens rent empi- riske iagttagelsesrækker tilbake gjennem den historiske tid og sagntiden helt til de store jordperioder med ogsaa deres klimatiske vekslinger, der da som nu var av samme overordentlig store betydning for det organiske livs utbredningsformer, planter saavel som dyr, end ikke mennesket undtat. Trykt 18, oktober 1921, ETWDTER OVER CIRRIPEDIENES FYROGENETISKESSCEGESKAPRS: BORD AV HJALMAR BROCH mr OS —— E KRISTIANIA I KOMMISSION HOS JACOB DYBWAD 1921 Fremlagt i den mat.-naturv. klasses mote den ı5de april r921 ved prof. H. H. Gran. A. W. BROGGERS BOKTRYKKERI A/S E. gjennemsyn av litteraturen om cirripediene viser os at man endnu er et godt stykke borte fra en velbegrundet dom om gruppens avstamning, og man finder ogsaa at meningene om hvilke av de nulevende former man maa anse som de mest oprindelige, er ganske delte. Darwins klas- siske monografi over gruppen (1852— 53) indeholder vistnok ikke nogen klart formulert dom; men saa meget fremgaar dog av fremstillingene, at vi kan se at han anser Oxynaspis eller denne slegtstype som meget primitiv, og at han utleder de øvrige cirripedier fra den. En diametralt motsat opfatning blev fremholdt av P. P. C. Hoex (1883) i hans bearbeideise av cirripediene fra »Challenger«; han anser Mitella (Pollicipes) som alle nulevende cirripediers stamform. Da Mitella har flere skeletplater end alle andre cirripedier, maa derfor efter hans teori alle andre slegter vaere opstaat gjennem en sukcessiv reduktion av plateantallet. Hcek baserer væsentlig sin opfatning paa de palæontologiske data, og da særlig derpaa, at Mitella er den av de nulevende slegter som er fundet tidligst 1 jordens historie, om end bare kort fer Scalpellum. GRUVEL adopterer i sin monografi (1905) Hoeks teori og feier ind i stamformenes rækker de utdedde slegter Turrilepas og Loricula med deres platerike skeletter, trods rækkefølgen geologisk set her ikke helt stemmer. Ganske nylig har ogsaa KRÜGER (1920) fastholdt Hoeks teori paa samme grundlag. Studiet av skeletutviklingen hos Scalpellum Stromii førte mig (1912) til det resultat, at Darwıns opfatning bedre lar sig forene med den post- embryonale utvikling end Hoeks teori, og i en netop offentliggjort foreløbig notis om utviklingen av Mitella (1921) har jeg fundet at maatte hævde det samme standpunkt, om end med en liten reservation. Senere har jeg ogsaa hat anledning til at studere andre arters utvikling og morfologiske forhold under mit arbeide med de rikholdige samlinger av cirripedier som den danske forsker, curator ved universitetets zoologiske museum i Kjøbenhavn dr. TH. Morrensen har bragt hjem fra sin reise i Stillehavets forskjellige egne 1914 og 1915 og med stor elskværdighet stillet til disposition for mine undersøkelser. Naar vi trækker en sammenligning med de fleste andre krebsdyr, vil det være vanskelig at fastholde at utskillelsen av kalkskeletter er et primært 4 HJALMAR BROCH. M.-N. KI. træk; dette rent teoretiske ræsonnement vil med engang kaste et tvilsomt skjær over den hypotese som opstiller de former som har det sterkeste kalkpanser, som stamformene for hele gruppen. Derimot er det likesaa klart at netop slike sterkt bepansrede dyr har ulike større sandsynlighet for at bevares som fossiler end dyr med et tyndt eller kanske helt chitinest skelet uten kalkinkrustationer; forsteningenes fylogenetiske bevisværdi blir derfor betydelig svækket i det foreliggende tilfælde. Man er derfor nødt til at søke efter bevisene ad andre veier, og der er da ingen tvil om, at der er flere ting som taler mot end for teorien om at de cirripedier som har det største antal plater i sit skelet, er de fylogenetisk ældste inden hele gruppen. Det er tilstrækkelig at holde sig til de stilkete cirripedier — Darwins familie Lepadidae — i dette tilfælde; der er ingen tvil om at de i sin hele organisation er mere oprindelige end de øvrige fritlevende former og danner utspringet for disse. I alle de tilfælder hvor det er lykkedes at studere de stilkete cirri- pediers postembryonale utvikling helt ut, viser det sig at cyprislarven eller puppestadiet, som det ogsaa nævnes, først danner fem chitinplater eller »primordialplater«, som Darwin har kaldt dem, nemlig dorsalsidens uparrede carina og paa sidene de parrede terga og scuta. Dette holder ogsaa stik i slegter som Mitella og Scalpellum, hvor den voksne form har et skelet bestaaende av mange flere plater. Disse chitinøse primordialplater er fylo- genetisk av betydelig større interesse end Hoek og GRUVEL synes at ha været opmerksomme paa. De viser os, at cirripedienes stamformer har hat fem chitinplater eller. chitinfortykkelser i kappen fer de utviklet sin nu- værende evne til at utskille kraftige kalkplater; det tyder ogsaa utpræget 1 retning av at de akcessoriske plater som ikke er chitinpræformert, er en senere akkvisition. Vi kommer paa denne maate tilbake til Darwins hypotese, men med det forbehold, at stamformen neppe vil findes hverken blandt de nulevende arter eller blandt de cirripedier som har efterlatt sig spor i forsteningene; den har hat fem chitinplater paa capitulum, men neppe anden antydning av de skeletplater man ellers finder paa capitulum og paa stilken hos mange av cirripediene. Vi maa derfor forkaste teorien om at Mitella er en stamform for nutidens cirripedier, og kommer derved ogsaa til at maatte foreta adskillige ændringer i de fylogenetiske og systematiske linjer som er optrukket av Hoek, GRUVEL, PıLsBRY og ANNANDALE. Jeg skal her søke at gi et billede av den opfatning som studiet av dr. MonrENsENs samlinger fører frem til; disse samlinger synes at være mere systematisk indsamlet end de fleste andre, og der er lagt en betydelig vegt netop paa de smaa former og utviklingsstadier som synes at være borte i tidligere indsamlede materialer. 1921. No. I3. CIRRIPEDIENES FYLOGEN. SLEGTSKAPSFORHOLD. 5 Hvis vi tar et overblik over krebsdyrenes kolossale gruppe i sin helhet, falder det i oinene at hermafroditismen ikke alene er en undtagelse, men at den er et sekundært fænomen og beror paa særlige biologiske tilpas- ninger. I analogi hermed maa vi anse cirripedienes hermafroditisme som en sekundær tilpasning til deres fastsittende levevis og gaa ut fra at deres forfædre har hat adskilte kjen, sandsynligvis ogsaa like heit organiserte nanner og hunner. Vi finder i KRÜGERS sidste avhandling (1920) gjentat det gamle postulat at »Als ursprüngliche Geschlechtsform müssen wir bei Tieren die hermaphroditische ansehen«. Det er en gaate, hvorfor dette aksiom skal sokes gjort gjældende for hver stor eller liten dyregruppe i særdeleshet. Allerede i de primitivere grupper opgives hermafroditismen, og det er ufor- klarlig, hvordan man da ved hver heiere dyregruppe kan hævde at dens stamformer atter skal maatte ha været hermafroditer. Hos krebsdyrene er hermafroditismen, hvor den optrær, et tydelig sekundært fænomen som nævnt. Da vi nu ikke kan gaa ut fra andet end at cirripediene har sit utspring hos en eller anden krebsdyregruppe av de mere primitive, tvinges vi til at benegte postulatets gyldighet her. KRUGER kommer til den slutning, at dverghannene hos cirripediene er en sekundær akkvisition; denne slutning gir sig dels av det nævnte postulat, dels av teorien om at ZZife/lla er en av de ældste former og ren hermafrodit. Han overser at Scalpellum synes at være næsten likesaa gammel i de geologiske fund, trods denne slegt er en dypvandsslegt med spredt optræden, mens Mitella med sit kraftigere skelet er en strandform og derfor har større sandsynlighet for at optræ blandt forsteningene. Hos Scalpellum optrær dvergmaend dels som »erstatningsmaend« hos her- mafroditer og dels som dvergmænd paa rene hunlige individer. Efter Hoeks teori gaar utviklingen fra Mitella gjennem Ca/antica og Smilium til Scalpellum. Det blir da en uforklarlig selvmotsigelse at dverg- mændene hos Calantica og Smilium viser en betydelig heiere organisation end hos Scalpellum, at altsaa den nye biologiske tilpasning er hoiest ut- viklet hos de mest primitive gjennemgangsformer. Det blir ikke lettere at forstaa hvordan den aberrante slegt /bla ogsaa har en dverghan at opvise. KRUGER forklarer dette ved en ny hypotese, som bringer ham selv i oppo- sition mot det førnævnte postulat; han hævder nemlig at Mitella og Scal- pellum allerede i oversilur paa grund av sin fastsittende levevis »wieder hermaphroditisch geworden waren«. Der maa altsaa i cirripedienes utvik- ling ogsaa efter Kricers mening ha været indskutt et fylogenetisk inter- regnum med særkjønnete individer. 6 HJALMAR BROCH. M.-N. Kl. Er dette rigtig, og der er som nævnt al mulig grund til at hævde det, saa maa vi soke de mest primitive former blandt dem som har de højest organiserte dvergmaend. Alle er enige i at av slegtene Calantıca, Smilium og Scalpellum maa Calantica anses som mest primitiv. Det har derfor sin store interesse at merke sig, at dr. MorTENSEN har bragt hjem fra farvandene ved Ny Zealand en ny art som jeg har tillat mig at kalde Calantica Mortenseni efter opdageren, og som har en forholdsvis stor dverg- han med det bedst utviklede skelet som endnu er fundet hos nogen cirriped. Den har en Scalpellums komplette platetal. Dette viser os dels at nævnte slegt er meget primitiv, dels at reduktionen av hannen først er indtraadt efterat dyrene alt har naadd frem til et høit utviklingstrin. Der maa altsaa ha forekommet en hel utviklingsrække av mellemformer mellem Calantıca og den hypotetiske stamform med sine fem chitinplater. Idet nu en av de akcessoriske plater i nedre række forskyves op og emanciperer sig for at indgaa som fast komponent i øvre række, kommer vi over i slegten Smilium, hvor hannens reduktion skrider fremad og danner overgangen til Scalpellum, hvor hannene reduceres til nogen smaa forplant- ningssækker eller helt forsvinder, og utviklingen fører videre op til den nye slegt Scalpellopsis +, hvor en reduktion av den nedre platerække har fundet sted paa ventralsiden av dyret. Begge de sidstnævnte slegter skiller sig fra Calantica og Smilium ved at mangle dorsalsidens akcessoriske subcarina. Teoretisk maatte man nu forutsætte, hvis Calantica er stamformen for Mitella, at der maa ha eksistert mellemformer, d. v. s. Mitella-lignende cirripedier med dverghanner. Naar man betænker, at Mitella er en slegt som ialfald har eksistert siden silurtiden, vil man forstaa min overraskelse da jeg i dr. MORTENSENS materiale fandt denne mellemform repræsentert i nogen faa eksemplarer fra Plimmerton og Slipper Island, Ny Zealand; det er en strandform som jeg har fundet at maatte stille i en egen slegt Protomitella?. Hvis ikke dverghannene var tilstede, vilde man utvilsomt indordnet arten i slegten Mitella, og jeg kan ikke benegte muligheten av at det er denne art som har dannet grundlaget for Hurrons Mitella (Polli- cipes) DARWINI; men dette sporsmaal kan først avgjeres ved studiet av originaleksemplarene, som findes i de australske museer. Hannen viser her 1 Scalpellopsis n.gen. Capitulum med o eller rz plater: rostrum og rostral latus mangler, inframedium latus rudimentær, carinal latus velutviklet. Superior latus indskutt mellem carina, tergum og scutum. Stilken med kalkplater. — Hermafroditer uten dvergmænd. Type: Scalpellopsis striatociliata n.sp. kjendelig ved sine kransstillede haar paa capitulum. to Protomitella n. gen. Capitulumplatene talrike, av to slags. Carina, terga, scuta og rostrum velutviklede, ofte ogsaa superior latus og subcarina. De nedre latera lange og smale, fingerformige og meget talrike. Stilkens skelet smaa, sammentraengt stillede pigger. — Dverghannen med carina, terga, scuta og rostrum; akcessoriske plater kan forekomme. Type: Protomitella paradoxa n. sp. 1921. No. 13. CIRRIPEDIENES FYLOGEN. SLEGTSKAPSFORHOLD. 7i noksaa nar samme forhold som hos Calantica; men den optrær tydelig i et faatal og varierer i sin skeletutvikling, et tegn paa at den er under degeneration. Fra Protomitella fører et kort skridt over til Mitella, hvis individer er hermafroditer; her er hannene helt forsvundet. En anden slegt som morfologisk staar meget nær Mitella, er Lithotrya, hvor ogsaa dverghannene mangler; her er de øvre stilkskjæl kraftigere utviklet, men tilhører tydelig stilkens skelet og er ikke gaat ind i capitulumskelettet som hos Mitella. Herhen hører da ogsaa den gaatefulde slegt /6/a, hvis utvikling des- værre er daarlig kjendt. I denne slegt er der ikke nogen kalkinkrustation av skelettet; dette bestaar for capitulums vedkommende bare av terga og scuta; utviklingsstadier av slegten var i dr. MORTENSENS materiale bare at finde av en liten dvergart fra farvandene ved Ny Zealand, /b/a pygmaea n. sp., og deres diminutive størrelse tillot ikke med sikkerhet at fastslaa forekomsten av en embryonal carina, selv om den synes at vise sig under visse belysninger. Stilkskelettet repræsenteres av chitinhaar, som hos en av artene igjen forsvinder hos fuldt utvoksede individer. Naar man tar hensyn til de forskjelligheter som betinges av tilstedeværelsen og manglen paa kalkdannelser, blir dog forskjellen mellem /b/a og Protomitella temmelig liten, og dertil har /6/a beholdt en relativt heit organisert dverghan und- tagen hos /b/a pygmaea, hvor hannen stanser sin utvikling paa cypris- stadiet med et par ualmindelig store sammensatte oine ved siden av naupliuseiet. Inden vi forlater denne gruppe av slegter, skal vi se litt paa om man kan finde en forklaring for dvergmaendenes optræden. Denne maa sokes i slegtenes biologiske forhold. Vi skal da forst se paa de slegter som har dverghanner. Calantica, Smilium og Scalpellum er, stort set, dypt levende former hvis individer sjelden optrær sammenhopet i større ansamlinger ; skrapetrækkene bringer sjelden mere end et par individer op av samme art. En undtagelse danner nogen enkelte Scalpellum-arter, og det er da netop hos disse, man av og til har kunnet fastslaa at dverghannene helt er forsvundne. Denne enkeltvise optræden vilde da utelukke krydsbefrugt- ninger i de fleste tilfælder om ikke hannen var bibeholdt. Det samme ræsonnement passer for /bla, trods arten lever grundt. For Protomitella mangler vi endnu alle biologiske data; den er en strandform, men dens upaaagtethet synes at tyde paa at den ikke er særlig hyppig, og da dr. MORTENSEN i alt bare har tat med 5 individer, mens han av almindeligere arter altid har sikret sig et større materiale, antar jeg at ha lov til at slutte at den ikke lever i store samfund. Paa den anden side er hannene tydelig sjeldne: 8 HJALMAR BROCH. M.-N. Kl. om dette er et temporært fænomen, eller om det er et konstant forhold, maa fremtidige undersokelser avgjore. Hvor vi kjender de biologiske forhold for de andre slegter, er de ganske andre. Mitella er en strandform som lever i tætte ansamlinger. Noget lignende synes at gjælde for Lithotrya; men da den fører en mere skjult tilværelse, er dens biologiske forhold endnu litet opklaret; vi faar haabe at den projekterte tropestation vil løse denne opgave blandt mange andre. For Scalpellopsis’ vedkommende kan nævnes at denne dypere levende art bare er fundet en eneste gang nede ved Philippinerne, men da i stort antal paa en enkelt hydroidekoloni. Saavidt vi kan bedømme det, trænges der altsaa her ingen adskilte kjøn for at sikre krydsbefrugt- ningen, og følgelig er her dverghannene forsvundet helt. Den gruppe av pedunkulate cirripedier vi har betragtet hittil, bestaar av en række nært beslegtede genera, som alle har to grundtræk fælles, nemlig for det første at deres stilk er forsynt med skelet; dette stilk- skelet forsvinde® hos den utvoksne /ó/a quadrivalvis Cuv. og mangler helt hos Ca/antica affinis n. sp. fra Philippinerne, saavidt jeg har kunnet finde; imidlertid maa for sidstnævnte art merkes at utviklingsstadiene er ukjendt. Det andet træk som forener alle de nævnte slegter, er at carina, terga og scuta samtlige har apikalt stillet vekstcentrum, som bare hos en del Scalpellum-arter sekundært forskyves nedover mot midten av carina hos ældre individer. Hos alle de andre pedunkulate cirripedier mangler ethvert spor av stilkskelet, og scuta og carina viser en fundamentalt forskjellig vekst, idet her umbo er basalt beliggende. Hos to slegter — Oxynaspis og Megal- asma — blir umbo for scutums vedkommende gjennem en eiendommelig vridning av basalkanten sekundært forlagt et stykke opover langs for- kanten, men naar ikke halvveis op mot apex, og hos Oxymaspis ser vi en paralel foreteelse til Scalpellum, idet umbo sekundært forskyves opover under den senere vekst, uten at den dog naar midten av carina. De to skillemerker kan høres smaa ut; men specielt den fundamentalt forskjellige vekstretning hos primordialplatene maa tillægges stor vegt, saa stor at man er berettiget til at basere en familiegrænse paa den. Hele den gruppe av slegter som hittil er behandlet, danner da familien Sca/- pellidae. Den anden gruppe er Lepadidae i nyere forstand. Her kan vi se bort fra dverghannene, da saadanne ikke er paavist hos nogen av sleg- tene. Platetallet er fem eller færre, og vi maa da gaa ut fra at den av dem som staar stamformen nærmest, maa vere i besiddelse av de fem 1921. No. 13. CIRRIPEDIENES FYLOGEN. SLEGTSKAPSFORHOLD. 9 primordiale plater. Vi har da at vælge mellem slegtene Oxynaspis, Lepas, Poecilasma, Megalasma og Octolasmis. Hos sidstnævnte slegt er der som felge av biologiske forhold indtraadt en svakere eller sterkere reduktion av skelettet ved en underlig opsplitning av platene, saa den kan med én gang sættes ut av betragtning. Oxynaspis blev av DARWIN anset som meget primitiv;men jeg kan ikke følge ham heri: Oxynaspis viser paa den ene side forskyvninger av vekstcentrene hos scuta og carina, og at dette paa den anden side er sekundært; antydes ogsaa av slegtens eiendommelige sym- bioseforhold med Antipatharier, et træk som ikke kan være primitivt. Dr. MORTENSENS materiale indeholder komplette utviklingsserier av Megalasma, og da de tydelig viser at vekstcentrets forskyvning langs den ventrale kant av scutum ogsaa her er et sekundært fænomen, som først indtrær senere i utviklingen, kan heller ikke denne slegt anses som primitiv. Vi har altsaa borteliminert alle slegter paa to nær, og studiet av disse to — Lepas og Poecilasma — gir for nærværende ingen grund til at anse den ene som mere primitiv end den anden. De staar hverandre meget nær, saa nær endog at Darwin gjør undskyldning fordi han skiller dem ad. Senere tider har ved den større vegt man nu tillægger f. eks. munddelenes struktur, ydet DARWIN sin tribut for hans skarpsyn ved at trække skillet mellem de to slegter. De er utvilsomt utgangspunktene for de andre Lepadid-slegter, og det synes at være likesaa sikkert at man ikke kan aviede dem fra nogen av Scalpellidae-familiens former. Studiet av munddelene gir os her to konvergente utviklingslinjer. Fra Lepas har slegten Conchoderma utviklet sig ved reduktion av platenes forkalkede partier, og tilpasningen til'livet som manetbeboer gjennem en komplet forsvinden av alle plater undtagen en liten chitinrest av scutum fører til slut op til Gymnolepas. Inden den anden gruppe av slegter finder vi at Zoecilasma gjennem reduktion av kalkutskillelsen gaar over i slegten Octolasmis og videre til Heteralepas-artene, hvor platene helt er forsvundet, eller hvor i det heieste en chitinøs rest av scutum har formaadd at persistere. Hvilke biologiske forhold som har betinget utviklingen av Heteralepas, kan man endnu ikke bedømme, trods der er kjendt adskillige arter av denne slegt. Megalasma er ved flere overgangsformer saa tæt knyttet til Poecilasma at man har vanskelig for at trække en tydelig grænse mellem de to slegter, og munddelene hos Oxynaspis tyder paa at ogsaa denne slegt staar nærmere ved Poecilasma end ved Lepas; dens leveomraade er da ogsaa i bedste overensstemmelse med Poecilasma. Det er ikke uten interesse selv ved en saa gammel gruppe som cirri- pediene er, at se om man i de geografiske forhold kan finde sammenhæng IO HJ. BROCH. CIRRIPEDIENES SLEGTSKAPSFORHOLD. M.-N. KI. 1921. No. 13. med de fylogenetiske linjer som andre studier av gruppen gir. Mens nu Lepadidae for samtlige slegter viser en temmelig uniform utbredelse gjennem alle varmere have, gir Scalpellidae et meget interessant zoogeo- grafisk billede. Ca/antica, den mest primitive av dem, lever hovedsagelig i de indomalayisk-østaustralske farvand i noget større dybder. Dens ætlinger Smiltum-artene har spredt sig videre ut og optrær med hovedmassen i den indopacifike regions varmere have; dertil har den specialisert ut en egen artgruppe i Atlanterhavets dypere partier. Dypvandsslegten Sca/- pellum er rent kosmopolitisk, men har, sandsynligvis i meget ny tid, utkry- stallisert slegten Scalpellopsis i det indomalayiske arkipel. Protomitella er en Ny-Zealandsk strandform; Mitella har spredt sig ut langs alle trope- havenes strandpartier, mens /b/a holder sig samlet i det indomalayisk- ostaustralske havomraades grundere partier. Lithotrya endelig har spredt sig ut i tropehavenes grunde regioner jorden rundt. De geografiske forhold tyder altsaa bestemt i retning av at Scalpellidae er opstaat i det indoma- layiske omraade, hvor de ogsaa nu har sin sterkeste repræsentation, og herfra har de saa spredt sig ut mere eller mindre i forhold til sine speci- elle livskrav, og under en mere eller mindre livlig artsdannelse paa grund av de tillempninger som det enkelte livsomraade har fremtvunget. Trykt 24. oktober ıgar. BIDRAG TIL KJENDSKAPET TIL TRONDELAGENS RUSTFLORA AV IVAR JORSTAD (V S I, M TATU K 9 N 4)

0). Dem Beweis gehen drei Hilfssätze voraus: Hilfssatz r. Es sei & eine reelle ganze algebraische Zahl des Grades 7 = 2; es seien * und s zwei natürliche Zahlen, und zwar s 0 beweisen; — diese Zahl ist = V4 n + 1—1 + 0, also <2 yn fir hinreichend kleines 9, und kleiner n = als der Thuesche Exponent = +1-+ 6 fir n=7. 2 Grad bedeutet bei Polynomen nicht den »genauen« Grad. Für reelles .r bedeutet [r] die größte ganze rationale Zahl <.r. Die durch (1) er- klärte ganze rationale Zahl m ist — 0. 4 CARL SIEGEL. M.-N. Kl. in 2, s in y, und m + r in z, s—1 in y, mit ganzen Coefficienten aus dem durch & erzeugten Körper K, 2) ein ebenfalls von &,r,s, 9 abhàngiges nicht identisch verschwinden- des Polynom R (x, y) vom Grade m +7 in %,s in y mit ganzen rationalen Coefficienten, 3) zwei nur von Ë, J und nicht von 7, s abhängige positive Zahlen €, c» mit folgenden Eigenschaften: I) Es gilt identisch in z, y (2) (x—8y F(x, y) + (y—S) € (2, y) = ke, y), II) jeder Coefficient von Z (x, y) ist absolut — cı”, III) wird für jede Zahl o der Reihe 0,1, . : .7—1 oO E i 1 9^ F (x, y) Fb) 3 er S262 (3) n lei) 5) meu 2*G (x, y) (4) Go (7, y) 3x o! 27? 3 3° Ie (ar, y) (5) Ro (7, y) = o! 2x gesetzt, so ist (6) (2579 Fo (x, y) + (y—3) Ce (x, y) = Ro (x, y), | Fo(z,y) | e (+le "+ Seal + le)" +l yp (7) u + s [Get M e xr ay Sa" 0 + dep y Beweis: Es sei a eine natürliche Zahl. Es gibt genau (8) N=(2a+ 1) nt e DG D) verschiedene Polynome P(x, y) vom Grade m + in x, s in y, mit ganzen rationalen Coefficienten vom absoluten Betrage in SF ): Sent r BE A y 9 —0 Im Folgenden bedeuten c3,¢y, ... natürliche, nur von &, 9 abhängige Zahlen; mit dieser Bezeichnung gilt für die Zahl P; (§, 5) und alle Con- jugierten | Py (8) | C2" * a (1 + eg +... + er) Le e + … +0) c emnt a, oder, da nach (1) 9 i Menu EE AE NET: r+n (2 a (2 "(eal = = (36,7 ur — (3 A ad Von den zu K conjugierten Körpern seien KU)... KC) reell und die Paare K(1+7) Kbitretr) (y — 1,...79; 4 + 279 =n) conjugiert com- plex!. Bedeutet & eine der 7 ganzen algebraischen Zahlen Pj (E, €) (4 — 0, .r—1), so wird durch die Gleichungen (11) ,= a”) für v = ler 0, iod On, ty =”) für y= 042-1,... 04 +70 diesem « ein System von 7 reellen Zahlen «,,... a, zugeordnet. Für jedes Polynom P(x, y) entsprechen daher den » Zahlen P;(i,i) insgesamt nr reelle Zahlen, also ein Punkt eines n»-dimensionalen Raumes; und zwar liegt nach (9) jeder der N Punkte, die den N Polynomen zugeordnet sind, in einem festen Würfel der Kantenlänge 2¢. Diesen Würfel zertrenne ich n (51) congruente Teilwürfel von der Kantenlänge +; dann ist wegen (10) für mindestens zwei Polynome P* und P** der zugehörige Punkt in oder auf demselben Teilwürfel gelegen. Mit Rücksicht auf die Definition (11) der Coordinaten gilt also nr: £5)—P"(6g|zxiy)-!i (4— 0,... r—1) 1 7, oder 7, kann auch 0 sein, 6 CARL SIEGEL. M.-N. Kl. für sämtliche Conjugierten von P;" (E, &)—P,** (E, Die Norm dieser gan- zen algebraischen Zahl ist demnach absolut <1, ind à daher ist sie 0. Folglich fehlen in der la: Entwicklung von P*— P** = PR nach Potenzen von 7—& und y—$ die Glieder mit (x—&f( y —E für 1 =0,...r—1 2 Setzt man also : ART t = À > 3 F(x, y) — x > (2 — 8)” (y- EY ( Qo fA (2, if) ), (x + x—0 1=0 vr)! AL ox*tr2y^ Jr —£,y— € r—1 s—l , i 4+1+1 G (7, yj (x —E js (y—:)* | 0% R (ac 11) | #—0,1—0 x! (1+ 1)! 27799741 os y=E so gilt die Identität (2). Ferner ist für ein gewisses positives c — c; (£, 9) Hu jeder Coefficient von A (x, y) absolut «224 — 2 (34) 2 « C7. "Damit = 2 ^e sind die Behauptungen I) und Il) bewiesen. Ich differentiiere (2) g-mal nach % und erhalte wegen (3), (4), (5) oF (m, y) À! art FE (væS)ol! G or, y) — 01 E, (r, y), A! (g—4)! 1 SE (x, y) ; r—0 ) NIE EEE EAU tocca nn @ en a + (y—§) Go (v, y) = Bo (x, y), ! also (6), wegen (£) = 55 Bes e*t É R (x, y) a! 2 ez" ayP m lut < Kr a J (3) 2a PATE: = Ke — 8y F (a, 8). a — 0 da U, (y) ist vom Grade s « n, und daher ist U,(5) + 0. Nach (18) ist 4 (x) teilbar durch (m Sa hierbei ist der Exponent r—s' 7 0 nach (14). Bedeutet q (x) = 0 die irreducible Gleichung nten Grades für §, so ist das rationalzahlige Polynom 4 (x) teilbar durch q (x) ^? (19) Z (x) U, (E) — m (xY—3 TE, wo JD (x) nicht identisch 0 ist. Die Elemente der s + l-reihigen Deter- minante J (x) sind vom Grade < m + r; der Grad von J (x) ist also — (s'-E!)(m-4-7). Bedeutet d den wahren Grad von D(x), so ist nach (19) à x (s' + 1) (m + 7) — n (r—s') < (s + 1) (in + 7) — n (r—3). Nach Voraussetzung ist p(y) 0; das Polynom 4 (x) verschwindet also für x — y höchstens von der Ordnung d. Daher gibt es in der Reihe 01/0 eine Zahl y, so daß JU (1) + 0 ist, und für dieses y gilt nach (1) y sg ess (S ntl r—nr + ns <= 9r + n (n—1). 1 Besteht zwischen mehreren rationalzahligen Polynomen p, (x), ... p, (x) eine homogene lineare Gleichung mit constanten Coefficienten, so ist die aus den Coefficienten von p,(x),...p, (x) gebildete Matrix vom Range — v; da aber ein auflósbares System linearer rationalzahliger Gleichungen stets durch rationale Werte der Unbekannten befriedigt werden kann, so sind dann auch die v Polynome im Körper der rationalen Zahlen linear abhängig. Sind also andererseits p, (x), ... p, (x) im Körper der ratio- nalen Zahlen linear unabhàngig, so gilt dies auch für den Kórper aller Zahlen. Folglich ist dann die Wronkische Determinante der » Polynome nicht identisch 0, 1921. No. 16. UEBER DEN THUESCHEN SATZ. 9 Hilfssatz 3. Es mögen Ë,m,n,7,s,C,4 die Bedeutung des Hilfssatzes 1 haben; für ) I: : : r und J seien (r4) und (15) erfüllt. Es seien Ya und qe zwei reducierte 1 2 rationale Brüche mit positiven Nennern, von denen 9 2€” ist. Dann gibt es eine nicht negative ganze Zahl o << 9r + n°, also nach (14) und (15) y){ Pi ; ; | y ) 1 Y p» - ^ 3 A verschiedene Zahl 4 " U, go } eine homogene lineare Verbindung Pr ups di de len ist also mindestens eine + 0; und für den zugehórigen Index z = o gilt der Zahlen 5H Je =(,...y+s). Unter diesen y+s’+ 1 Zah- (22) eLy+s | die Zahlen z— "t. | qi ER 614 ; | 21 | le | Pe | I + ——- < 24 {5 SAG: 1+ = qi | El aT (Jo und es gibt nach (23) ein positives nur von $ und 9 abhängiges C;3, so daß c n > 1582; m rl) S Ga te ay | ist. Hieraus folgt die Behauptung. Ich komme jetzt zum Beweis des Satzes. Es sei 0 — 0 — 1 und s eine natürliche Zahl 0) - (25) Sa x y habe unendlich viele Lösungen in ganzen rationalen x, y. Die Constante J des Hilfssatzes 1 werde durch 8 ges (26) 8n definiert; die Zahlen & und (43 der Hilfssätze 1 und 3 mögen die zu die- sem 9 gehörige Bedeutung haben. Dann wähle ich aus den unendlich vielen Lösungen von (25) eine solche Lösung x = p, y = q in teiler- fremden Zahlen, welche der Bedingung 4 (27) q > max (C1, 613) genügen. Hierauf nehme ich eine zweite Lösung 7 = ps, y = q in teiler fremden Zahlen, so daß 8n3 (28) gon? ist, und setze log q» i 29) r = | — > = gi Für dieses » ist nach (28) und (29) 8 8 n° A (30) ce Ek +1] > = San, nach (27) und (29) gz > c"; ferner ist nach (26) 9 — 4. Die Vorausset- zungen des Hilfssatzes 3 sind also sämtlich erfüllt; folglich ist eine der beiden Zahlen Ej, Ex» aus (20) größer als 1. Für das zugehörige o gilt o — dr + i?, also nach (26) und (30) Q REP PR LIE r p mU Ug CEP La ferner ist nach (24) 8 ee ME NI. (+) <= 3 = s = een S x 1 NES dont À pd setzt man also noch zur Abkürzung 9 0 log C13 Dll Nenn s +1 ip log 41 so ist mit Rücksicht auf (26) und (27) 12 CARL SIEGEL: UEBER DEN THUESCHEN SATZ. M.-N. Kl. 1921. No. 16. : >60 = —1 | (31) ps 8n 9 ^ an LOS ARS Wegen log ci; = 0 ist i n + Ÿ log (43 J log C3 ( 0 ‘ 0c = — $s — 0 -= — —$ — (32) s +1 log q BR 8 +1 + log gı 8 |1 y "qub und folglich nach (29) und (31) .—logg2 .log qe B—s (B — 5) log qe (33) (hm vo do 0 METTE 84 e DAMES 53, —s—€ E log q1 + log C3 Ferner ist nach (31) und (32) [^ N ta vi |. log C13 u E EM zem ———— — a ) 6 (1 u = Re S+-e — 0, also nach (29), (30), (31) 0 ] 2 log gz E log g: 4 "IE o ne eU 08 q1 o8 g1 s+— 28591 Hier 3 low. usc q Sou NE ^ log gq, ste 6 4n : (34) AUTRE EL —_ lon ste (8 (1— £)-"* = log q1 — log &is 7 Aus (33) und (34) folgt mit Rücksicht auf (1) s log ge — iB (r—9) — (m + ») log q1 — r log C3 und (m+r) log g + r log C3 < (B —Ss) log 9, oder, da p,, 4, und ps, g3 Lösungen von (25) sind, a fortiori nach (20) iy cec nds d» el was ein Widerspruch ist. Folglich hat (25) nur endlich viele Lósungen. Góttingen, 1920 August 7. Gedruckt 29. Mai 1922. UNTERSUCHUNGEN UBER DIE MOGLICHEN VERTEILUNGEN GANZZAHLIGER LOSUNGEN GEWISSER GLEICHUNGEN VON TH SKOLEM UTGIT FOR FRIDTJOF NANSENS FOND KRISTIANIA IN KOMMISSION BEI JACOB DYBWAD 1921 Fremlagt i den mat.-naturv. klasses møte den 4de mai 1921. A. W. BRØGGERS BOKTRYKKERI A/S I: WG 2) Uber Verteilungsdichten. Es sei K eine Klasse ganzer positiver Zahlen. Wir können durch Mv) die Anzahl der Zahlen in Ä bezeichnen, welche > 1 und < y sind, und betrachten die Werte des Quotienten y Es wird dann oft geschehen, daß dieser Quotient sich einer Grenze 5 nähert, wenn » ins Unendliche wächst. Dann nenne ich g die durchschnittliche Verteilungsdichte der Zahlen der Klasse K. Es kann aber auch geschehen, dafs kein eindeutig bestimmter Grenz- Nr) y wert existiert; da indessen die Zahlen alle zwischen 0 und 1 liegen, müssen Häufungswerte für y= existieren. Ist y ein solcher Häufungs- wert, so gibt es also eine unendliche Reihe von Werten von y, *»4 << ys — ..., N (».) : : . , so beschaffen, dafs Gr gegen y konvergiert, wenn x ins Unendliche wächst. Yr Ich sage dann, daf y eine durchschnittliche Verteilungsdichte der Zahlen in K ist!. Satz 1. Ist die Klasse K die Summe einer endlichen Zahl von Klassen Ki, Ka,..., Ka, so hat jede Teilklasse K, nur die Verteilungs- dichte Null, wenn K selbst nur die Verteilungsdichte Null hat, und umgekehrt. Beweis: Die erste Behauptung des Satzes ist unmittelbar einleuchtend und beruht nur darauf, daß eine Unterklasse K’ von X nur die Verteilungs- dichte Null haben kann, falls A selbst nur eine solche hat. Die Richtig- keit der Umkehrung sieht man auch äußerst leicht so: Es sei N,(v) die Anzahl der Zahlen in A, und N(v) die Anzahl der n Zahlen in K, welche <» sind. Es ist also Nv)< + N.(». Dann kon- EZ r=1 vergiert nach der Voraussetzung jeder der Quotienten 1 Statt von Verteilungsdichten zu reden; könnte man die bekannten Symbole O(n) und o(n) benutzen. Ich glaube aber, daf der Begriff der Ver- teilungsdichte hier mehr anschaulich ist. 4 | TH. SKOLEM. M.-N. KI. N (v) N, (v) " Ny (v) y £ Vy 4 i y für unendlich wachsendes » gegen Null. Folglich konvergiert auch die Summe EE Ny (v) = N (v) ri 9 y gegen Null. Man kann dies auch so ausdrücken: Gibt es für die Klasse A eine Verteilungsdichte > 0, so gibt es eine solche auch für mindestens eine der Klassen K,,..., Kn. Satz 9. Ist die Klasse K die Summe der m Klassen K4,... Ky, : Re; : à ; 1 : : und hat K eine Verteilungsdichte u so hat mindestens eine der a 2 -T 8 : : ; 1 Klassen K,.. Ky eine Verteilungsdichte > = Beweis: Hat nämlich jede Klasse K,(r = 1,2,..,n) nur Verteilungs- 22] T. M. dichten = —, so muß eine so grofse positive Zahl », existieren, daß 9) ES + mm wenn e eine beliebig kleine positive Größe ist, für alle » 7» »,. Es sei v!= Max (v1, ¥2,--%n). So bald » >»! ist, wird dann für alle 7 mE" < mn a n’ wodurch man erhält N (v) MEN 1 SEN ee VINS E vy < m t : "EM : 1 Es können somit die Zahlen A keine Häufungsstelle E haben. Satz 3. Gibt es für K eine durchschnittliche Verteilungsdichte 1 se aid > — , und wird die Zahlenreihe in Intervalle, von welchen jedes aus m mu Zahlen besteht, eingeteilt, so gibt es in unendlich vielen dieser Inter- valle mindestens u Zahlen aus K. Beweis: Im entgegengesetzen Falle müßte die Klasse K innerhalb jedes Intervalles von dem (/ + 1) an, wo / eine ganze positive Zahl ist, höchstens u — 1 Zahlen besitzen. Es sei t die Anzahl der Zahlen in X, welche — mul sind. Weiter sei m u k x »« m u(k- 1), und folglich Ny) t + («— 1) —14- 1), 1921. No. 17. VERTEILUNGEN GANZZAHLIGER LÖSUNGEN GEWISSER GLEICHUNGEN. > woraus ND) EBENE Iu) er ta le E E MM muk mu ' m uk Wäre nun erstens t < (u — 1) (k — 1), so müßte immer INO) — 1 ns 1 y —m mu : ME nes ; 1 : so daß eine durchschnittliche Verteilungsdiche > = unmöglich wäre. Wäre zweitens t > (u — 1) (/ — 1), so würde für alle À, für welche k > t — (u — 1) (/ — 1), augenscheinlich N (v) _ u— 1 1 1 — == y in u mu m — : 1 so daß wieder eine Verteilungsdichte > — unmöglich wäre. m In dieser Abhandlung werden wir oft Klassen A von Paaren ganzer Zahlen (x, y) zu betrachten haben, die von folgender Beschaffenheit sind. Es sei k die Klasse der Zahlen x, die überhaupt in den Paaren von K vorkommen. Weiter sei A(x) für jedes x in k die Klasse der Zahlen y, die mit diesem x in den Paaren von Ä auftreten. Dann sollen: 1) Die Klasse À eine Verteilungsdichte >> 0 haben. 2) Die Klassen A (x) gleichmäßig Verteilungsdichten >> 0 haben, d. h. jede Klasse k(x) hat eine Verteilungsdichte > = wobei m eine von X unabhängige ganze positive Zahl ist. So oft im folgenden eine solche Klasse K von Paaren betrachtet wird, werde ich kurz sagen, daß sie die Eigenschaften 1) und 2) haben. Weiter werden auch Klassen von Tripeln zur Anwendung kommen, die von folgender Art sind: Es sei & die Klasse der x, welche überhaupt in den Tripeln von K vorkommen. Für jedes z in k sei k(x) die Klasse der y, die überhaupt in irgend einem der Tripel in Ä mit dem betreffenden x zusammen vor- kommen. Weiter sei A(x,y) für jedes x in k und jedes y in À (x) die Klasse der z, welche mit x und 7 zusammen in den Tripeln in A vorkommen. Dann sollen: 1) & eine Verteilungsdichte >> 0 haben; 2) die Klassen & (x) gleichmäßig eine Verteilungsdichte > " haben; 3) die Klassen k (x, y) gleichmäßig eine Verteilungsdichte > haben. 6 TH. SKOLEM. M.-N. Kl. Die Forderung 3) bedeutet natürlich, daß für die Klassen k (x, y) Ver- teilungsdichten gefunden werden können, die alle > -: sind, wobei m; eine ganze positive und von x und y unabhängige Zahl ist. So oft im folgenden eine solche Klasse A von Tripeln betrachtet wird, werde ich sagen, dafs sie die Eigenschaften 1), 2) und 3) haben. Man kann natürlich weiter gehen und entsprechende Klassen von Quadrupeln usw. bilden. Satz 4. Es sei K eine Klasse von Paaren mit den Eigenschaften I) und 2). Ist dann K die Summe einer endlichen Zahl von Klassen K,... Ka, so hat mindestens einer dieser Teile eine Unterklasse mit den Eigenschaften 1) und 2). Beweis: Es sei x eine Zahl in k. Für jedes r(r — 1,28,..., 4). set k,(x) die Klasse der y, welche mit x Paare in A, bilden. Dann zerfällt also k(x), welche eine Verteilungsdichte > - hat, in die 2:7 "Eeile ky (x), ..., kn (x) und folglich muß nach Satz 2 mindestens eine dieser Teil- klassen, kr, (x), eine Verteilungsdichte > — haben. Da m von x unabhängig ist, so ist auch mn von z unabhängig. Nun braucht aber nicht 7x dieselbe Zahl für alle x in k zu sein. Es seien deshalb fy, hy, ... Kg die Teile von k, für welche bezw. ry = 1, 2,..., ist. Nach Satz 1 muß mindestens einer der Teile Ay... kn eine nichtverschwindende Ver- teilungsdichte haben. Ist À; ein solcher Teil, so hat also À; eine Ver- teilungsdichte —> 0 ünd für jedes x in 4; die Klasse fy, (x) eine I Verteilungsdichte > zn Satz 5. Es sei K eine Klasse von Tripeln mit den Eigenschaften I), 2) und 3). Ist damn K die Summe einer endlichen Zahl von Klassen K,..., Kn, so hat mindestens eine der letzteren Klassen eine Unterklasse mit den Eigenschaften 1), 2) und 5). Beweis: Es sei A, (x, y) für jedes x und jedes y in k (x) die Klasse der z, welche mit z und y zusammen Tripel in A, bilden. Mindestens eine der Klassen A (x, y), .. ., ka (x, y) hat dann nach Satz 2, eine Verteilungsdichte TUS Falls mehrere solche für gegebene x und y vorhanden sind, on können wir z. B. die mit dem kleinsten Index wählen; dieser durch x und y eindeutig bestimmte Index heiße rx,,. Es seien nun A, (x),.. , ky, (x) die Klassen der y für gegebenes x in k, für welche bezw. rx,y = 1,2 ... A ist. Mindestens eine der Klassen /y (x),..., kn (x) muß dann eine IQ2I. No. 17. VERTEILUNGEN GANZZAHLIGER LÖSUNGEN GEWISSER GLEICHUNGEN. 7 1 VE haben (Satz 2). Falls mehrere solche für i Verteilungsdichte > gegebenes z vorhanden sind, wählen wir z. B. die mit kleinstem Index; der Index sei 7x. Weiter seien Ay... An die Teile von A4 für welche bezw. 7x = 1, 2,...,n ist. Dann hat nach Satz 1 mindestens einer dieser Teile eine Verteilungsdichte > 0. Ist 4; diese Teilklasse, so hat also k; eine Verteilungsdichte 7 0; für jedes x in A; hat die Klasse k,(x) eine Verteilungsdichte > , und für jedes x in k und jedes y in kj (x) hat ni n die Klasse A; (x, y) eine Verteilungsdichte > FE Der Satz ist hier- lg durch bewiesen. Es ist klar, dafs analoge Sätze für die entsprechenden Klassen von Quadrupeln usw. aufgestellt werden kénnen. (à S 2. Ein Paar Hilfssätze über unendliche Reihen. Es sei die Reihe eg Fe) IR x? konvergent, wenn |x| > KR. Auf dem Kreise um den Nullpunkt mit dem Radius À gibt es dann notwendig Singularitäten für f(x). Es seien weiter i SENE Eu). positive Konstanten. Die Reihen RS TE (3 da ie De a Une di (15 at rz "RUE Ser en konvergieren dann außerhalb Kreise mit Radius R und bezw. den Punkten f (€ + 1%) — — 11, —o,..., — x als Zentra. Ich behaupte, dafs entweder die Funktion f (x + va) mindestens eine Singularitüt besitzt, welche eine reguläre Stelle für jede der Funktionen f(a),..., f (x rx) ist, oder f(x) eine Singularität, die eine reguläre Stelle der Funktionen f (x + vi) ... f(x + rx) ist. Hat f(x) eine Singularität Z — & + ni auf dem Kreise um den Null- punkt mit Radius À, so beschaffen, daß £ — 0 ist, so muß Z eine reguläre Stelle sein für die anderen Funktionen f. Hat dagegenf (x) eine Singularität 8 TH. SKOLEM. M.-N. Kl. C — E +71 auf demselben Kreise, so daß §< 0 ist, so hat f(x + r+) die- selbe Singularität £^ = € — r4 + ni auf dem Kreise um den Punkt — rz, und Z' ist dann eine reguláre Stelle der anderen Funktionen f. Anmerkung: Ich verstehe unter Singularität für f(x) ein Punkt, über welchen die Reihe für f(x) nicht analytisch fortsetzbar ist. Falls f(x) ein Element einer mehrdeutigen Funktion ist, kónnen ja Zweige existieren, die Singularitäten außerhalb des Kreises mit Radius Æ um den Nullpunkt haben. Der Fall A = 0 macht keine Ausnahme; denn dann ist x = 0 die ein- zige Singularitát für f(x) und entsprechend x == — 7, —7:,.., — rz für bezw. fe + ),... f(x + ra). Sind deshalb A,..., Ax Konstanten, wobei A und Az + 0 sind, so muß die Summe Af(@e)t Afletr)+--- + An fi d 74) notwendig Singularitäten im Endlichen haben. Hieraus folgt umgekehrt: Satz 6. Im Falle diese Summe überall im Endlichen regulär ist (z. B. eine Konstante, speziell identisch Null), so muß f(x) identisch ver- schwinden, d.h. alle Koeffizienten ay, dg, ... sind Null. Wir können auch in einer mehr rechnenden Weise zeigen, daß f (x) identisch verschwinden muß, falls die erwähnte Summe identisch Null ist. Es sei wieder f) — T + t DUE s gee EM ao su + A . Es sei rj — 0 und 3 À,f(x + 7r;) =0 identisch, wobei Ag und Ax von 1—0 Null verschieden sind. Die Koeffizienten der Entwicklung von 4,f (x +1) i—0 nach fallenden Potenzen von x werden 44-24, —d,: X Ajrjd- a9 X Aj qq: X ÀAj;r?-—28.- XAj;rj-d- a4: X Aj —a:2ZXA,r3--3a, 2 Ar? — 343-5 A,7; + a X A, In der Reihe der Zahlen SÅ Dd 2 A, CHE 1921. No.17. VERTEILUNGEN GANZZAHLIGER LOSUNGEN GEWISSER GLEICHUNGEN. 9 können die x + 1 ersten Glieder nicht alle verschwinden; denn aus den Gleichungen SA == 0, DAT; ——0. ev. SPÅR ne = wurde folgen Ag — 0, tig — Oo AOR weil die Determinante TE Fa tee SRE ee (ESSEN % % x | FT, ze +0 ist. Sind nun Z'A;, X A;ir;,..., X A;?? alle Null, wahrend X A,7?™ +0 ist, bekommt man aus dem Ausdruck für den (p + 2)» Koeffizienten in der obigen Entwicklung von 2 4;f (x + rj, daß a, — 0 ist. Weiter folgen dann aus den Ausdrücken für die folgenden Koeffizienten 42 — 0, a4 = 0, . in. inf. Es genügt übrigens augenscheinlich vorauszusetzen, daß nicht alle Zahlen À verschwinden. Weiter betrachten wir die Reihen f (x) = E => = +... q ganze positive Zahl. mq cuu = a (1o fete 4 + (@<+ri)a (x+ri)a a ls f (e+ re) =—2— + — 4 -- (ce + 7x)a (x Horz)a hi lo, h(a)= ++... “qa £4 lx lx gs (x) — 1 EIU xq za wobei die Reihe für f(x) außerhalb eines Kreises um den Nullpunkt mit dem Radius À konvergiert, während (2) (i= 1, 2,..., x) nur zwei singu- läre Stellen hat, falls sie nicht identisch verschwindet, nämlich z — — +, und £=0. Diese sollen Verzweigungsstellen, aber nicht Unendlichkeits- stellen !, sein. 1 D.h. es sollen alle Zweige von g,(x) | innerhalb Kreise mit Radius e um die Punkte 2 — 0 und z = — r, beschränkt sein. 10 TH. SKOLEM. M.-N. KI. Die Ebene soll lángs der negativen reellen Axe aufgeschnitten gedacht 1 werden, so dafs x4 eine bestimmte der g/en Wurzeln von x bedeutet. Die Funktionen g werden dabei eindeutig. f (x) ist augenscheinlich ein eindeutig bestimmtes Funktionselement einer mehrdeutigen Funktion. (Weiter soll f (zx--"j) für z —a der Wert von f (x) für z — a + r; sein, so daß auch alle Funktionselemente f (x + rj eindeutig bestimmt sind. Hat nun f (x) eine solche Singularität $ — £ + 1 ? auf dem Kreise mit R um den Nullpunkt, daß 850 ist, so ist € eine reguläre Stelle für alle g und alle anderen f. Hat aber f(x) auf demselben Kreise eine singuláre Stelle =£-++ nt, so daß $ «CO ist, so hat f(x + r4) auf dem Kreise mit Radius À um den Punkt — 7% eine solche Singularitat 7' — £' + 7/1, 4 wobei? = € — r4 <— r« ist, und dann ist Z^ eine reguläre Stelle für alle g und alle anderen f. 1 Im Falle R—0 ist f(x) eine ganze transcendente Funktion von xa und dann ist, falls f(x) nicht identisch verschwindet, x = 0 eine solche singuläre Stelle für f (x), daß sie auch eine Singularität sein muf für jede lineare Kombination von f mit den Funktionen 9. Zugleich ist æ —0 regulär für die anderen f. Man hat also: Satz 7. Sind A,..., Az von Null verschiedene Konstanten, muß die Summe A f (x) + Ai (fF c + v) + m (0) +++ + Ax (Fe + 79 + gx (2), notwendig Singulüriteten im Endlichen haben, falls nicht f(x) und auch alle Funktionen g identisch verschwinden. 83 Funktionen einer Variabeln x, welche ganzzahlige Werte haben für unendlich viele ganze Werte von x. Satz 8. Ist z=w entweder eine regulüre Stelle oder ein Pol für die eindeutige analytische Funktion f(x), und im letzteren Falle die Koeffizienten des zugehörigen Hauptteiles rationale Zahlen sind, so kann f(x) nicht eine ganze Zahl sein für unendlich viele ganze Zahlen x, ohne daß f(x) ein Polynom ist mit rationalen Koeffizienten!. Beweis: Es sei die Reihe . f (x) — a, a + a, per SE oS, + UE 1 Ich gebe hier den Beweis dieses ziemlich trivialen Satzes, weil er eine passende Einleitung zu den folgenden Sätzen bildet. IO2I. No. I7. VERTEILUNGEN GANZZAHLIGER LÓSUNGEN GEWISSER GLEICHUNGEN. 1I . 4 4 . . konvergent, wenn |x|> A, wobei do, ***, 0, , rationale Zahlen sind. Diese haben dann einen gemeinsamen Nenner NN. Folglich wird ^ = (ae Nf (7) } Sr PAS x“ 9 (7) = N f(x) — 402 —aqz ^ 22 — ay 4x2 — An + auch eine ganze Zahl für dieselben unendlich vielen ganzen x. Wenn x ins Unendliche wächst, konvergiert p(x) gegen dp. Es muß also 4, eine ganze Zahl sein, und außerdem muß für alle betreffenden ganzen Zahlen +, welche > eine gewisse Zahl M sind, p(x) = a, sein. Da indessen z — cc eine reguläre Stelle der Funktion (x) ist, so kann die Gleichung p (x) = a, nicht unendlich viele Wurzeln, die sich um x = æ häufen, haben, ohne eine Identität zu sein. (x) ist also identisch = v,, und wir erhalten Nf(z) — ao 3^ +--+ + an, wodurch der Satz bewiesen ist.. Satz 9. Es sei y — x entweder eine regulüre Stelle oder ein Pol einer eindeutigen analytischen Funktion f (x). Weiter sei f (x) eine ganze Zahl für unendlich viele ganze Werte von x, welche eine Verteilungs- dichte > 0 haben. Dann ist f (x) ein Polynom mit rationalen Koeffizienten. Beweis: Es sei die Reihe ^ n In+ f (7) mE dba 2 Oy Eee, konvergent, wenn |x > À, und es sei K die Klasse der ganzen Zahlen x, für welche f (x) eine ganze Zahl ist. Besitzen die Zahlen in K eine Verteilungsdichte 7 0, so haben : ; Bar . RAR sie auch eine, welche > = ist, wenn m eine hinreichend große ganze positive Zahl ist. Teilt man nun die Zahlenreihe in Intervalle, jedes aus m (u + 1) Zahlen bestehend, so gibt es zufolge Satz 3 in unendlich vielen der Intervalle mindestens u 4-1 Zahlen, die zu K gehören. Es seien E RO Bass die 4 + 1 (kleinsten dieser) Zahlen innerhalb eines beliebigen dieser Intervalle. Bildet man die Differenzen Lo —2434, 23 — 12,775 Lu Kun Luis Tu» so hat man eine Reihe von u Zahlen, die alle => 0 und < m(u + 1) sind. Von solchen Reihen gibt es aber nur eine endliche Zahl. Es muß folglich I2 TH. SKOLEM. M.-N. Kl. unendlich oft, d. h. für unendlich viele Intervalle, geschehen, daf eine solche Reihe wiederholt wird. Dies bedeutet aber, daß man in unendlich vielen der Intervalle «+ 1 zu K gehörende Zahlen finden kann, die in der Form C+ rH, ee, Ob ru geschrieben werden können, wobei die Zahl x von Intervall zu Intervall variiert, während die Zahlen 74,...,7%,, konstant sind. Diese x bilden eine Unterklasse K! von K. Man kann nun die Gleichungen bilden: f (x) — ay a? 4+ aa? t+... : n n— (n+ f (1 + 77) = ao (@ 7) + a (2 +74) Tee mg np - Tow a+r, n rem =1 1 An-+ı = (yc GENE tee a ———— eletto uL E Pe lee) a le es u 21 An-1 = (ly X^ + d, x” tee Ha tee m L SE ) u 2 i : 1 1 2 2 u IE ze Hier sind-die Zahlen @,+--@_, d4*-*-45, --:, d, ««* @ linearerher mogene Funktionen von &6,-:::, dn, deren Koeffizienten ganze Zahlen sind, welche nur von 74 ++ > r, abhängen. Die Zahl u ist noch nicht bestimmt; wir können sie jetzt so groß wählen, daß die Größen 2 n—2 J— n— 3 x UML 30005 092,04 0, *** An 1%; 1 n— 1 n—2 , MR ge Oe CODEC T RET TE, die ja alle linear mit ganzen Koeffizienten vorkommen, zwischen den Gleichungen eliminiert werden kónnen. Das Eliminationsresultat ist von der Form: Af() d- A fio an) ob 4, fle ru) B4 A | TS Sn pe ). nel c ue rc esM + A ae i == (x + QE + ) , wobei A, 4,,..., A, ganze Zahlen sind, die nicht alle verschwinden, während B — Aa, + A, a. + ...-+-A, a^ eine Konstante ist. IO2I. No. I7. VERTEILUNGEN GANZZAHLIGER LÓSUNGEN GEWISSER GLEICHUNGEN. I3 Für jedes z in K! nehmen f(x), f (x + 1)...., f(x + r,) gleichzeitig ganze Werte an, wodurch auch À f(x) + 4; f (x + 1) +... + A, f (z4- 92) eine ganze Zahl wird. Da die rechte Seite der letzten Gleichung für un- endliches x gegen D konvergiert, muß B eine ganze Zahl sein, und für alle x in K!, welche > eine gewisse Zahl M sind, muß die Summe der übrigen Glieder rechts verschwinden. Da aber x =o eine reguläre Stelle dieser Summe ist, muf3 sie identisch Null sein. Dies bewirkt aber nach § 1 (Satz 6), daß die Koeffizienten An+ı , 454,2, ... alle Null sein müssen. Es ist also f(x) ein Polynom in z, und daf die Koeffizienten rational sein müssen folgt sofort daraus, dafs es für unendlich viele rationale (nàmlich ganze) Werte von x einen rationalen (nàmlich ganzen) Wert hat. In der Tat müssen ja die Koeffizienten eines Polynoms men Grades rational sein, falls es einen rationalen Wert hat für n + 1 verschiedene Werte von 4. Anmerkung: Die Voraussetzung des Satzes, daß f(x) eindeutig sein soll ist nicht nötig, wenn man nur weiß, im Falle sie mehrdeutig ist, daf derselbe Zweig eine ganze Zahl ist für eine Klasse A ganzer x mit einer Verteilungsdichte > 0. Dies folgt sofort daraus, daß der Satz 6 auch in diesem Falle anwendbar ist. Satz 10. Es sei die Reihe p pl ; Ap+1 f (x) =a 29+ ay x SS e uam ere E xa gegeben. Die Reihe sei konvergent für |x| > R: p und q seien zwei ganze positive Zahlen. Die Ebene soll längs der negativen reellen Axe - aufgeschnitten sein, so daß za eine bestimmte der gten Wurzeln von x bedeutet. Gibt es dann unendlich viele ganze Werte von x, wobei | y > R ist, mit einer Verteilungsdichte >>0, für welche f(x) eine ganze Zahl ast, so ist f(x) ein Polynom mit rationalen Koeffizienten. Beweis: Es sei K die Klasse der ganzen x, für welche f(x) ganz ist. Da K eine nicht verschwindende Verteilungsdichte hat, so gibt es auch eine solche baee wenn m eine hinreichend große ganze positive Zahl ist. Denken wir uns wieder die Zahlenreihe in Intervalle, jedes aus m (uw + 1) Zahlen bestehend geteilt, so gibt es in unendlich vielen unter ihnen u +1 zu A gehórige Zahlen und dann wie wir früher gesehen haben auch in unend- lich vielen «+ 1 zu K gehörige Zahlen mit denselben Differenzen. Für unendlich viele ganze x, die eine Unterklasse AK! von KX bilden, gehören also die u 4- 1 Zahlen | LLM, LTV, 14 TH. SKOLEM. M. -N. KI. zu K, wobei 7,°*+, 7, von x unabhängige ganze Zahlen sind, so daß cud ed cM Es ist nun (7 ist positiv reel gedacht) i E p der f(z4- T) — à (e -- r)à + mr +74 +++ HS (x + r)1 Hier können wir aber jedes Glied, das einen positiven Exponenten hat, nach fallenden Potenzen von x entwickeln. Wir haben ja die Entwicklung P1 På Pi | Pi Pi y\a Pi py 8 qia y? ' c 2 wr — 74 ME — ^q ^ = e eee r1 Id ad (v+r)4 x predi gi uri oe D HEE , füur|z|r, wodurch für alle x, für welche | x | ^ À und — ist, p—1 1 a p+2 en De + + bp + + — - PE) Tr ER bp+1 b +2 = i 1 =F r 2 == FAT rr za wobei di, b,... lineare homogene Funktionen von Ag... 4, sind mit rationalen Zahlen als Koeffizienten. In dieser Weise erhalten wir folgendes System von Gleichungen: p—1 12 Dess Po x + 474% +... + ap + Go (x) Dae fet) = 002% + abet fe 0! d qu (o) + qu (0) pl f (x st: ne = (lo us + a^ x4 mor + ar == Pu (x) + Vu (7), wobei hier TE Ap--2 ae + ee xa za qi (x) = qo (x + fa) Pu (x) = fo (7 F Y,) 1 1 a a +1 +2 LA xa m di". p [ D w(x) = E sis : Sur LA Ap gesetzt ist. 1921.No. I7. VERTEILUNGEN GANZZAHLIGER LÖSUNGEN GEWISSER GLEICHUNGEN. 15 à A 1 . Q Eherssind a, sss an lineare homogene Funktionen von dg, ..., (ly mit rationalen Koeffizienten. Wählt man jetzt w hinreichend groß, können hieraus wieder alle die linear vorkommenden Größen 1 Pi pa PSE pu i A a Tg s sett e sse UE ID s deren Zahl ja endlich und von u unabhängig ist, eliminiert werden. Das Eliminationsresultat ist von der Form Å f (x) == À; f (x 2% i) SE Hes E ab f(x RE 27) — D sir A fo (x) ae Ay (pi (x) xis U^ (x) Sp =F er (Pu (x) SF Wy (x) wo À, 44, ..., A, ganze Zahlen sind, die nicht alle verschwinden, und 1 . - d B — A ay + À: a,+---+ A, a eine Konstante ist. Nun sind f(x), f(x + ri), ..., f(¢+7,) alle gleichzeitig ganz für alle x in K!. Da die rechte Seite der letzten Gleichung für unendliches x gegen D konvergiert, muß 5 eine ganze Zahl sein, und weiter muß für alle Zahlen x in K!, welche > eine Zahl M sind, die Summe der übrigen Glieder rechts verschwinden. Weiter läßt sich jede der Funktionen fo (7), 71 (x), ae! (7), Wi Ce Du (x) 1 in eine Reihe nach fallenden Potenzen von xz entwickeln, die mit einem 1 Konstanten mal x 9 anfängt, und alle diese Reihen haben ein gemein- sames Konvergenzgebiet ‚x | > c wobei eZ R+7r, ist. Setzen wir p (2) = À Go (x) + Ar (gi @) + un (2)) + +++ + 4, (pu @ + Va @), so läfst sich also auch (x) in eine Reihe nach fallenden Potenzen von dE ae r* entwickeln, wo x “4 die erste auftretende Potenz ist, und welche für |z| > ç konvergent ist. Nun ist p(r)-— 0 für alle z in KE für welche |z| > M ist. Setzt 1 man also weiter x4 — 2 und (x) = X(z, so muß X(z) für eine ge Wurzel von jedem derselben unendlich vielen æ in A! verschwinden, und : l außerdem ist X (z) eine gewöhnliche Potenzreihe von pu Nach einem bekannten Satz über Potenzreihen muß deshalb X (z) und also auch ¢ (2) identisch. verschwinden. 16 TH. SKOLEM. M.-N. Kl. Da die Reihen yy (x), We (X), **, w, (x), wie man aus ihrer Entstehung 1 oben leicht sehen kann, ganze rationale Funktionen sind von z^ und bezw, 1 1 1 (a + 74)9, (vw + 73)9,---, (2 +7,)9, können wir Satz 7 anwenden. Sowohl . . . . . a -1 a »+2 Be . diese « Reihen wie auch die Reihe = ++... müssen also iden- aq x tisch verschwinden. Dies ist aber nur möglich, wenn f(x) ein Polynom ist. Denn da Ap+ı, Ap+2, ... alle Null sind, so ist jedenfalls p pi f (x) = 4% tur 3 +... la, und falls f (x) nicht ein Polynom ist, ist z — 0 die einzige singulàre Stelle im Endlichen. Dann müßte aber f (x + 7,) (nur) die (einzige) Singularität rz -— —n, im Endlichen haben und könnte also nicht zugleich die Form p p—1 x a I s 1 üagX* + a. c À rip LE besitzen. Die Koeffizienten des Polynoms müssen natürlich aus demselben Grunde wie früher rational sein. Satz ll. Es sei die Gleichung gegeben: Ao (x) y" + iG) y "++ 4s (7) =0, worin Ag (x), ..., An (x) eindeutige analytische Funktionen sind, für welche x — o» entweder eine reguliire Stelle oder ein Pol ist. Es sei K eine Klasse ganzer Zahlen x mit einer Verteilungsdichte 70, so daß für jedes x in K eine solche ganze Zahl y existiert, daß die Gleichung befriedigt wird. Dann wird die Gleichung identisch in bezug auf x befriedigt, wenn man statt y ein gewisses Polynom P (x) mit rationalen Koeffizienten setzt. Beweis: Die Diskriminante der Gleichung (in bezug auf y) ist augen- scheinlich eine eindeutige analytische Funktion D(x) von x, für welche x — oc höchstens ein Pol ist. Ist D(x) identisch = 0, so hat die gege- bene Gleichung eine Doppelwurzel y for alle x. In jedem solchen Falle läßt sich aber bekanntlich durch rationale Rechnungen eine Gleichung finden, welche dieselben Funktionen y von x als einfache Wurzeln hat wie die gegebene Gleichung, während die Koeffizienten der neuen Gleichung Funktionen derselben Natur sind wie die Koeffizienten der gegebenen 1 Ao (x) kann übrigens offenbar ohne Einschränkung der Allgemeinheit gleich A, (x) Sh Ap (x) A)" "'Ao(x) l gesetzt werden. Die Quotienten sind ja Funktionen derselben Natur. IO2I. No.r 7. VERTEILUNGEN GANZZAHLIGER LÖSUNGEN GEWISSER GLEICHUNGEN. I 7 Gleichung. Es wird deshalb hinreichend sein den Satz in dem Falle zu beweisen, da D (x) nicht identisch verschwindet. Dann kann die Gleichung D (x) — 0 nur eine endliche Zahl von Wur- zeln haben, deren absoluter Betrag eine gewisse positive Größe überschreitet. Es gibt also eine positive Zahl W,, so daß D(z) nie verschwindet, wenn |z|2 Mi ist. Außerhalb des Kreises um den Nullpunkt mit Radius M, gibt es dann, x — o» eventuell ausgenommen, kein Punkt, wo zwei oder mehr der Wurzeln der gegebenen Gleichung gleich sein kónnen (Verzwei- gungsstelle der mehrdeutigen Funktion y, welche durch die gegebene Gleichung definiert ist), d.h. die n Wurzeln können in diesem Gebiete als n distinkte Funktionen von & betrachtet werden, wenn außerdem die Ebene làngs der negativen reellen Axe aufgeschnitten wird; wir kónnen sie durch Yi, Jas---, Yn bezeichnen. A, (x) 2... Ant) Ao (2) ' - Ao (2) ist, so sind diese alle immer endlich für endliche x, absolut > eine gewisse Zahl Ms. Dann bleiben also auch yı....%n endlich, wenn |x| > Ms. Es sei M = Max (M, M). Die Zahlen x in À, die- > M sind, bilden eine Unterklasse Ky von A. Weiter sei A; (i = 1, 2,..., n) die Unterklasse von Ky, für welche y; eine Da x =o höchstens ein Pol für die Funktionen ganze Zahl ist. Dann muf mindestens eine der Klassen A; (Satz 1) eine Verteilungsdichte — 0 haben. Außerdem lassen sich y,... Yn in der im Satze 10 angegebenen Weise entwickeln. Zufolge Satz 10 muß aber dann das betreffende jy, eine ganze rationale Funktion von z sein mit rationalen Koeffizienten. Der Beweis des Satzes 11 läßt sich auch etwas anders führen nämlich mit Hilfe folgender Betrachtungen, die auch sonst ein allgemeines Interesse haben. Wir betrachten Funktionen der Form f (x, y) = A, (x) y^ + Ay (x) y +---+ 4,(x), wo À4o::: An eindeutige Funktionen von x sind, für welche xz — o höchstens ein Pol ist. Ist eine solche Funktion f(x, y) für alle x und y gleich dem Produkte 9 (x, y) h (x, y) zweier solcher Funktionen g (x,y) und h (z, y), so kann man sagen, daß f(z, y) durch g(z,y) teilbar ist. Ist f nicht durch g teil- bar, so gibt es zwei andere Funktionen der betrachteten Art, / (x, y) und r(x, y), so daß f(z, y) — g (x, y) k (x, y) + v (x, y) ist, und außerdem r (x, y) von kleinerem Grade in y ist als g(a, y). Nun gibt es für zwei Funktionen f und g immer gemeinschaftliche Teiler, da z. B. die Konstante + 1 ein solcher ist. Weiter ist also das Euklidische Verfahren zum Aufsuchen des größten gemeinschaftlichen Teilers Vid.-Selsk. Skrifter. I. M.-N. Kl. i921. No. 17. 2 18 TH. SKOLEM. M.-N. Kl. gültig, d. h. es gibt immer einen eindeutig bestimmten gemeinschaftlichen Teiler vom håchsten Grad, der durch alle anderen gemeinsamen Teiler teilbar ist. Versteht man nun unter einer irreduktiblen Funktion eine, die nur durch sich selbst und Funktionen von x allein teilbar und nicht nur eine Funktion von x ist, während alle anderen (Funktionen von z ausgenommen) reduktibel .genannt werden, hat man natürlich wie in der Algebra, daß eine reduktible Funktion immer und wesentlich nur auf eine Weise das Produkt von gewissen wreduktiblen Funktionen ist}. Es genügt nun augenscheinlich, wenn man Satz 1 beachtet, den Satz 11 für irreduktible Gleichungen zu beweisen. Diese können also nicht für jedes x eine Doppelwurzel haben. Dann kann die Diskriminante D (x) nicht identisch verschwinden, und der Beweis wird weiter geführt wie oben angegeben. Ich gebe jetzt einige Anwendungen auf algebraische Gleichungen. Satz 12. Es set in der Gleichung H (x, y) — 0, wo H ein ganzzahliges? Polynom ist, für jede ganze Zahl x einer Klasse K mit einer Verteilungsdichte > 0 mindestens eine der Wurzeln y eine ganze Zahl. Dann wird die Gleichung identisch in x befriedigt, wenn man statt y ein gewisses Polynom P (x) mit rationalen Koeffizienten setzt. Dies ist ja ein bloßes Korollar von Satz 11. Satz 13. Wenn für jede ganze Zahl x einer Klasse K mit einer Verteilungsdichte > 0 mindestens y Wurzeln y der Gleichung H (2, y) —0 ganz sind, so gibt es v Polynome P, (x), P» (x), ..., Py (x), die statt y in die Gleichung eingesetzt Identitüten in bezug auf x liefern. Beweis durch Induktion: Nach dem vorhergehenden Satze ist diese Behauptung richtig, wenn » = 1. Ich setze die Richtigkeit für » — 1 voraus und beweise sie dann für ». Nach Satz 12 gibt es jedenfalls et» solches Polynom P; (r). Schreiben die gegebene Gleichung in der Form y. == Ay (x) VER SD EE lm (x) = 0, i. = Ww 1 D.h, von der Anordnung der Faktoren und von Faktoren, die Funktionen von & allein sind, abgesehen. Man brauchte natürlich nicht vorauszusetzen, dafs die Koeffizienten ganze Zahlen sind. Es ist aber nur dieser Fall von Interesse, da es ja sonst ganz trivial ist, dafs sogar blof endlich viele Lösungen in ganzen Zahlen x,y vorhanden sind. [59] 1921. No. 17. VERTEILUNGEN GANZZAHLIGER LOSUNGEN GEWISSER GLEICHUNGEN. 19 wo jetzt A, (z),..., Ån (x) rationale Funktionen von x sind, so haben wir für alle x y^ + Ay (x) y^^ He. + As (7) = (y — Pi (x) (y^^ + A, (r)y +... + RD (x), . . ‘ 4 und hier sind A, ae doe wieder rationale Funktionen von æ mit ratio- nalen Koeffizienten. Da für jede Zahl x in A mindestens » der Wurzeln y ganz sein sollen, so müssen augenscheinlich mindestens » — 1 der Wurzeln der Gleichung He Creer rro ganz sein für eben diese x. Hieraus folgt nach der Voraussetzung, dafs y — 1 Polynome P5(z),..., Py(x) mit rationalen Koeffizienten existieren müssen, so daß die letzte Gleichung von y = P (x) (1 — 2,..., v) identisch in «x befriedigt wird. Dann wird aber die gegebene Gleichung für alle x befriedigt, wenn man y— P (@)(!=1,2,---,») setzt. Man kann auch folgenden Satz aufstellen, der etwas mehr aussagt als Satz 12. Satz 14. Es sei für jede ganze Zahl x einer Klasse K mit einer Verteilungsdichte > 0 mindestens eine Wurzel y in EE m eine ganze Zahl. Dann gibt es u Polynome P, (x),..., P, (x) (selbst- verständlich u xn, wenn H (x, y) vom Grade m in y ist) mit rationalen Koeffizienten, so daß H(z, P, (x)) (i — 1, 2,..., u) identisch verschwindet, während außerdem für jede Zahl in K, höchstens ausgenommen eine Unterklasse K’ mit der einzigen Verteilungsdichte Null, mindestens eines der u Polynome eine ganze Zahl ist. Beweis: Zufolge Satz 12 mufs jedenfalls ein P,(x) mit rationalen Koeffizienten existieren, so daß H(z, Va (x)) identisch verschwindet. Ist P, (x) eine ganze Zahl für jede Zahl x in K oder höchstens ausgenommen die Zahlen einer Unterklasse K’ mit nur verschwindender Verteilungsdichte, so ist der Satz richtig. Im entgegengesetzten Falle miissen die Zahlen einer Unterklasse K,, welche sogar mit K identisch sein kann, ausgenom- men sein, wobei Ay eine Verteilungsdichte 7 0 hat. Da aber auch für jede Zahl in A, mindestens eine der Wurzeln y ganz sein sollen, während P, (x) nicht ganz ist, so muf3 augenscheinlich mindestens eine der Wurzeln y der Gleichung Z4 (x, y) = 0, die man aus H(z, y) durch Wegdividieren des Faktors y — Pı (x) erhält, ganz sein. Deshalb muß ein Polynom P;(x) mit rationalen Koeffizienten existieren, so daß A, (x, P, (x)) und folglich auch H (x, Py (x)) identisch verschwindet. Ist nun P, (x) eine ganze 20 TH. SKOLEM. M.-N. Kl. Zahl für alle x in A,, höchstens ausgenommen eine Unterklasse mit nur verschwindender Verteilungsdichte, so ist wieder der Satz richtig. Die Betrachtung kann in dieser Weise fortgesetzt werden, wodurch die Rich- tigkeit der Behauptung einleuchtet. Ein einfaches Beispiel hierzu ist die Gleichung (Qy+1—x2)(2y—2)=0. Hier ist u=2; K ist die ganze Zahlenreihe und AK’ — 0. Die beiden Polynome P; (x) und P, (x) sind 5 und a Für jede ganze Zahl x ist ja entweder bs oder — g cine ganze Zahl. Satz 15. Es sei für jede ganze Zahl x einer Klasse K mit einer Verteilungsdichte > 0 mindestens eine Wurzel y der Gleichung dame eine rationale Zahl. Dann gibt es eine rationale Funktion R(x) mit rationalen Koeffizienten so beschaffen, daß H (x, R (xj) identisch = 0 ist. 3eweis: Die gegebene Gleichung kann in der Form Av (x) y. + À; (x) uds + SAP + A (x) — 0 geschrieben werden, wobei 45,..., An ganzzahlige Polynome sind. Wird nun Ap (x) ÿ = Yi gesetzt, so bekommt man y; + A; (2) Maes + 4o (x) As (x) DE To + Al)" An (7) — 0. Für jede Zahl x in K ist augenscheinlich auch y, rational; da aber gleichzeitig alle Koeffizienten der letzteren Gleichung ganze Zahlen werden, muß %, ganz sein. Es ist also y, eine ganze Zahl für alle Zahlen der Klasse A, und folglich gibt es (Satz 12) eine ganze rationale Funktion P (x) mit rationalen Koeffizienten so beschaffen, daf3 die letzte Gleichung iden- tisch in x befriedigt wird, wenn man y; = P(x) setzt. Dann muß aber gj an die ursprüngliche Gleichung H(z, y)=0 zu einer Identität 40 machen. Satz 16. Es ser das System von Gleichungen H (x, Oia 7299 85 Yn) — 0, H» (x, Yi, 3r Yn)=0, Deb à ’ Hy (2,1, Eve, Yn) =0 gegeben, wobei H,:-- Hy solche ganze rationale Funktionen bedeuten, daß die n Gleichungen von einander unabhängig sind. Weiter bestehe für jede Zahl x einer Klasse K mit einer Verteilungsdichte > 0 min- destens eine der zugehörigen Wertekombinationen y: +++ Yn nur aus ganzen 1921. No.1 7. VERTEILUNGEN GANZZAHLIGER LOSUNGEN GEWISSER GLEICHUNGEN. 2I Zahlen. Dann gibt es n Polynome mit rationalen Koeffizienten P, (x) - P, (x), so daß die n Gleichungen zu Identitäten in x werden, wenn man y, = Py (x), +++ Yn = Pr (x) setzt. Beweis: Die n Gleichungen bestimmen %4...%Yn als Funktionen von a, für welche Reihenentwicklungen der Form pi p1—1 pe pa—1 Yi = 09,1291 + 4,72% fee, Yo = 40,2 LU + 04,9 x 9? EEE Pn Pn-1 *, Yn = don X*n + d, 5 2 In d gelten, wobei die verschiedenen Wertekombinationen teils durch verschie- dene Werte der Koeffizienten « und teils durch verschiedene Werte von di’ de endlich. Nach Satz 1 muß deshalb eine Unterklasse A’ von Ä existieren so beschaffen, dafs für jedes x in KA" ein bestimmtes dieser Wurzelsysteme ‚+ geliefert werden. Die Zahl dieser Wurzelsysteme ist aber nur aus ganzen Zahlen besteht. Dann müssen aber, wenn yj... Yn dies Wurzelsystem ist, kraft Satz 10 1... Yn ganze rationale Funktionen von. x sein mit rationalen Koeffizienten. Man kann natürlich hier einen allgemeineren Satz aufstellen, der in einem ähnlichen Verhältnis zu Satz 11 wie Satz 16 zu Satz 12 steht, nämlich folgenden: Satz 16°. Es seien die n unabhängigen Gleichungen H, =0,---, H,=0 gegeben, worin Hy... Hy ganze rationale Funktionen von y, .. . Yn sind, deren Koeffizienten eindeutige analytische Funktionen einer Variabeln x sind, die nach fallenden ganzen Potenzen von x entwickelt werden können. Weiter sei mindestens ein Wurzelsystem yı ...Ym ganzzahlig für jede Zahl x einer Klasse K mit einer Verteilungsdichte > 0. Dann gibt es n Polynome mit rationalen Koeffizienten, P, (x), ..., Pr (x), so beschaffen, daß die n Gleichungen identisch befriedigt werden, wenn man eae Uno, la) set Beweis: Da die Gleichungen unabhängig sind, kann man durch Elimi- nation von 2... Yn eine nicht identische Gleichung in x und yj Ry (x, Yı) =0 erhalten. Weiter seien Rs (7, Ya) = 0, Ho Ry (x, Un) = 0 die analogen. Die Diskriminanten der Gleichungen seien bezw. D; (x), --., Dy(x). Sollte z. B. D, (x) identisch — 0 seien, könnte man durch rationale TH. SKOLEM. M.-N. Kl. N D Rechnungen die mehrfache(n) Wurzel(n) von Zi (x, yı) = 0 wegschaffen oder m. a. W. diese Gleichung durch eine andere Ri (x, 14) = 0 ersetzen, welche dieselben Wurzeln wie Ry (x, y1) = 0, aber jede einfach, hat. Deshalb kón- nen wir annehmen, daß die Gleichungen PB; —0,..., Pu == 0 schon von mehrfachen Wurzeln befreit sind, oder m. a. W. dafs keine der zugehórigen Diskriminanten A (x),..., D, (x) identisch verschwindet. Nun läßt sich die Funktion D, (x) Ds (x)... Dy (x) nach fallenden ganzen Potenzen von x entwickeln, und deshalb kann die Gleichung D; (x) D (2) FEDE (x) =0 nie mehr stattfinden, wenn |x| > eine Zahl M, geworden ist. Da außer- dem alle Koeffizientfunktionen von x der Funktionen H regulär sind, wenn |z| > eine Zahl Ms, so verhalten sich außerhalb eines Kreises der .r. Ebene um den Nullpunkt mit Radius M = Max (M;, M;) die Funktionen Y1:..Yn überall regulär und eindeutig im Endlichen, während == höchstens eine algebraische Singularität sein kann. Hieraus folgt, daß Yı-..%n nach fallenden ganzen oder gebrochenen Potenzen von x ent- wickelt werden können, und für |x| > M können die verschiedenen Wurzel- kombinationen konsekvent unterschieden werden. Da nun die Zahl der Wurzelkombinationen endlich ist, muß eine Unter- klasse A’ von K mit Dichte 7» 0 existieren so beschaffen, daß eine be- stimmte Wurzelkombination ganzzahlig ist für alle x in A’. Nach Satz 10 sind also die betreffenden y, ...Yn Polynome mit rationalen Koeffizienten. Zusatz zu Satz Ge Falls mehr Gleichungen 4,1; = 0; Has = 0, . "zwischen t'y 0 hinzukommen, während noch für jede Zahl x in AK mindestens ein ganz- zahliges Wurzelsystem 7/;... %/n existiert, das alle Gleichungen befriedigt, so gibt es noch n Polynome mit rationalen Koeffizienten, welche statt Y1.::Yn eingesetzt alle Gleichungen identisch in x befriedigen. Denn für alle z absolut > M können die verschiedenen Wurzelsysteme der Glei- chungen H, —0,..., Hy = 0 konsekvent unterschieden werden, und es ist dann bestimmt, welche von ihnen auch die übrigen Gleichungen Hy41 — 0, Hn+2=0,... befriedigen. Unter ihnen muß der Annahme zufolge min- destens eines ganzzahlig sein für ein beliebig gewähltes x in KA. Es gibt also wieder eine Unterklasse A' von K. mit Dichte >0, so daß ein bestimmtes der betreffenden Wurzelsysteme ganzzahlig ist für alle zin A’, woraus folgt, daß dieses System aus ganzen rationalen Funktionen von x mit rationalen Koeffizienten besteht. Diese Polynome, P, (X), ..., Pa (x), befriedigen dann alle Gleichungen für jedes x» in A’, und da KA” unend- lich viele Zahlen enthält, müssen sie also die Gleichungen identisch befriedigen. 1921. No.1 7. VERTEILUNGEN GANZZAHLIGER LOSUNGEN GEWISSER GLEICHUNGEN. 23 Es wird spåter (zweiter Beweis des Satzes 24) eine Anwendung hier- von gemacht. Satz 17. Es sei K die Klasse der ganzen rationalen x, für welche mindestens eine Wurzel y der Gleichung HE y}—0 eine ganze Zahl eines algebraischen Zahlkörpers R ist, wobei H(x, y) ein Polynom ist, dessen Koeffizienten ganze Zahlen in R sind. Hat dann K eine Verteilungsdichte > 0, so gibt es ein Polynom P (x) mit Koeffizienten, welche zu R gehören, so daß H(x, P(x)) identisch ver- schwindet. Beweis: Es sei wı,..., @n eine Basis der ganzen Zahlen in À. Für jede Zahl x in Ä ist dann eine Wurzel y von der Form 94 wy + Ya wa +++ + ya Wp, wobei Yi -:-Yn ganze rationale Zahlen sind. Durch Ein- setzung dieses Ausdrucks für y zerlegt sich bekanntlich die Gleichung H (x, y) =0 in ein System von n Gleichungen H, (x, GE, Yn) = 0, H» (XT, Vaso, Yn) = 0, AOC M J HT (2 Vire, Yn) FS 0, und für jedes z in A sind diese Gleichungen von ganzen rationalen Zahlen Yı, SR … Yn befriedigt. Nach Satz 16 müssen diese Gleichungen dann Iden- titàten in bezug auf x werden, wenn statt 4,..., Yn gewisse Polynome P, (x), ..., Pa (x) mit absolut rationalen Koeffizienten gesetzt werden. Dies bedeutet aber, daß identisch in xz H (a, P, (x) v + P» (x) v + --- + Ph (à) on) = 0 ist, wodurch die Behauptung bewiesen ist. Bei diesem Satze ist die Voraussetzung wesentlich, daß H eine ganze rationale Funktion ist nicht nur in bezug auf y, sondern auch in bezug auf x. Es ist also hier nicht möglich einen Satz aufzustellen, der den Sätzen 11 und 16’ entsprechen könnte; es genügt durchaus nicht voraus- zusetzen, dafs die gegebene Gleichung ganz rational in y allein ist, während die Koeffizienten der Potenzen von y beliebige eindeutige analytische Funk- tionen wären, die sich nach fallenden Potenzen von x mit rationalen Koef- fizienten entwickeln ließen. Dies beruht darauf, daß es im allgemeinen nicht möglich ist in einem algebraischen Zahlkörper nten Grades n Zahlen zu finden, welche linear unabhängig sind in bezug auf den Zahlbereich Z, der durch die Koeffizientfunktionen für ganze rationale x und außerdem alle mögliche Verknüpfungen davon durch die vier ersten Rechnungsarten geliefert werden. In der Tat ist es nicht schwer zu sehen, daß eine passend gewählte eindeutige analytische Funktion der erwähnten Art für ein gegebenes ganzes rationales x, z.B. x — 1, gleich einer völlig belie- 24 bigen reellen Zahl & sein kann. TH. SKOLEM. M.-N. KI. Es wird augenscheinlich genügen zu zeigen, daß eine ganze transcendente Funktion mit rationalen Koeffizienten sich finden läßt, welche für x = 1 gleich & wird; denn durch die Trans- 4 ] formation x — XA geht sie in eine Funktion der erwáhnten Art über. In der folgenden Weise läßt sich dies zeigen: Es seien (1, G9, G3, N19)8 eine unendliche Reihe positiver reeller Zahlen, welche gegen 0 konver- Außerdem seien die Brüche Pi _ Pe i q1 ES 42 B gieren. SS und außerdem so gewählt, dafs was augenscheinlich möglich ist. +55 —1 Pi qi - Pn dn Pine Yn+1 Pn+1 - T Ur (|n 4-1 Dann ist Pn In n eine ganze transcendente Funktion mit rationalen Koeffizienten, welche für “% — 1 den Wert & hat. Beweis: Man hat einerseits Pn+2 Dni An+2 Qn4A und andererseits dr mu m EZ M pese > (1 — an) Beet ste 1 Po+A1 In In Qn41 In i dn ~ 1—a@y Mni ar Pn+2 Posi dn (Pott /— fn In+2 In+ı 1 — an \9n+1 In Da Ts für unendliches n gegen 0 konvergiert, muß die erwähnte — an ; ER: 2 / Reihe für alle x konvergieren. Außerdem konvergiert z= gegen &. Hier- durch ist alles bewiesen. n Es kann deshalb in diesem allgemeineren Falle sehr wohl geschehen, daß die Zahlen des Körpers AR schon im Bereiche Z enthalten sind, und die im Beweise des Satzes 17 gemachte Zerfällung in n Gleichungen wird nicht mehr möglich. Satz 18. Es sei ein System von m von einander unabhängigen Gleichungen H, (a, 11, T hy Ym) == 0, Par, Hy (x, Sy. * 55 Ym) 1921. No.ı 7. VERTEILUNGEN GANZZAHLIGER LÖSUNGEN GEWISSER GLEICHUNGEN. 25 gegeben, wobei H,... Hy ganze rationale Funktionen sind, deren Koef- fizienten ganze Zahlen eines algebraischen Zahlkörpers R sind. Sind für jede Zahl z einer Klasse K ganzer rationaler Zahlen mit einer Verteilungsdichte 70 alle m Zahlen yı ... Ym eines zugehörigen Wurzel- systems ganze Zahlen in R, so gibt es m ganze rationale Funktionen von x, P, (&),..., Pm(x), mit Koeffizienten in R, so daß die m gegebenen Gleichungen für alle Werte von x befriedigt werden, wenn man y; = P (2), Br Van s Pn) setet. Beweis: Es sei wy, @»,..., @n eine Basis der ganzen Zahlen des Körpers R vom Grade n. Für jede Zahl x in K sollen die m Gleichungen alle gleichzeitig befriedigt werden, wenn Yr=Yrıwı + "+ Un On ("= 1,-.-, m) ist, wobei alle mn Zahlen y,,s ganz und rational sind. Durch Einsetzung dieser Ausdrücke für 7. zerlegt sich bekanntlich jede der m Gleichungen in n Gleichungen zwischen den Zahlen Yr,s. Es ent- steht in dieser Weise ein System von mn Gleichungen zwischen x und den Zahlen %,,s, und diese Gleichungen sind für alle x in A von ganzen rationalen Zahlen %r,s befriedigt. Außerdem müssen natürlich diese Glei- chungen von einander unabhängig sein. Nach Satz 16 müssen sie also identisch in bezug auf «+ befriedigt werden, wenn man statt Yr,s gewisse Polynome P;,,(x) mit absolut rationalen Koeffizienten setzt. Dadurch werden aber die m gegebenen Gleichungen identisch in x befriedigt, wenn man „=Priıl)wı +---+ Phat) on(r = 1, 2,---, m) setzt. Satz 19. Es sei F(x, y) —y^ + Ay ++ As (x), wo n>1 und Ay... An Polynome sind mit ganzen rationalen Koeffizi- enten, eine irreduktible Funktion von y innerhalb des Rationalitäts- bereiches L, der aus allen rationalen Funktionen von x mit rationalen Koeffizienten besteht. Die Klasse K der ganzen rationalen Zahlen x, für welche die übrig bleibende Funktion von y reduktibel im natürlichen Rationalitätsbereich ist, kann dann nur die Verteilungsdichte Null haben!. Beweis: Soll F'(x, y) für einen Wert von x reduktibel in bezug auf y werden, so muß identisch in bezug auf y y^ + ART E... An (7) == ("duy + tn) (y? + + een) Ähnliche Sätze über Irreduktibilitäten, wie die hier bewiesenen, sind von D. HILBERT im Journal für Mathematik, B. 110, aufgestellt worden. Die Beweise Hilberts sind aber komplizierter, und außerdem haben die in dieser Abhandlung bewiesenen Sätze einen größeren Inhalt. 26 TH. SKOLEM. M.-N. Kl. Da A,... An für jede ganze Zahl x ganz sind, müssen bekanntlich für solche z auch «1... @v, Pi - - . Pn-» ganz sein. Nun gibt es bloß n— 1 mögliche Wahlen der Zahl », und wird deshalb mit Ky diejenige Unter- klasse von A bezeichnet, für welche eben eine Reduktibilität mit dem Werte v stattfindet, so müßte (Satz 1) mindestens eine dieser Klassen Ky eine Verteilungsdichte > 0 haben, falls A eine solche hatte. Weiter müßten die Gleichungen Cy + p = Ay (2 a bi + (20) EE Pa = As 2), NT ON » av Pn-» = An (x), welche von der im Satze 16 erwähnten Form sind, für alle Zahlen x in Ky von ganzen Zahlen « und f befriedigt werden. Nach Satz 16 müßten deshalb diese Gleichungen Identitäten in bezug auf z werden, wenn statt ay... 0r, Pi... Pa-» N ganze rationale Funktionen von zx mit rationalen Koeffizienten eingesetzt werden. Dies würde aber augenscheinlich bedeuten, daß F(x, y) innerhalb L reduktibel ware. Satz 20. Es sei F(a, yy=y + A (7) 4" ++ An (2), wo n>1 nnd Aj, As, ..., An Polynome sind, deren Koeffizienten ganze Zahlen eines algebraischen Zahlkörpers R sind, eine irreduktible Funk- tion von y innerhalb des Funktionenkörpers L, der aus allen rationalen Funktionen von x mit Koeffizienten in R besteht. Es sei K die Klasse der ganzen rationalen x, für welche F(x, y) reduktibel in R wird. Dann kann K nur die Verteilungsdichte Null haben. Beweis: Soll F(x, y) für ein x reduktibel werden, muß identisch in y eine Gleichung der Form y^ + Ay (a) y + + + An (2) = (yay yt fo tae) (277 + Bt et Buca) bestehen, wobei «e,...,«v, B1,..., ßn-» Zahlen in À sind. Da aber 4, ... 4, immer ganze Zahlen in RA sind, wenn zx eine ganze rationale Zahl ist, so müssen auch q,.. , «v, Bir - - -, Bn-—» ganze algebraische Zahlen sein und folglich auch ganze Zahlen in A. Weiter müßte, falls A eine Verteilungsdichte >0 hätte, wie früher eine Unterklasse A» mit nicht verschwindender Verteilungsdichte existieren, für welche » einen bestimmten seiner n— 1 möglichen Werte hätte. Für jede Zahl x in X, müßten also die Gleichungen ay + By = A) uhr + co + Ba = Ao (2), ----- , ay Bn-v = An (x) in der Weise befriedigt werden, daß «4... «v, B1... @n—» ganze Zahlen in R würden. Nach Satz 18 müßten folglich eben diese Gleichungen zu IO2I. No. 17. VERTEILUNGEN GANZZAHLIGER LÓSUNGEN GEWISSER GLEICHUNGEN. 27 Identitäten in bezug auf x werden, wenn statt «ij... «v, B1... Bn—v bezw. n ganze rationale Funktionen von x mit Koeffizienten in À gesetzt würden. Das würde aber bedeuten, daß F(x, y) eine reduktible Funktion von y wäre innerhalb L. Satz 91. Es sei die Funktion F (a, y) = Ao (2) y^ + Ar (a) y^ ++ An (7), worin Ag... An Polynome sind, deren Koeffizienten ganze Zahlen in einem algebraischen Zahlkörper R sind, eine irreduktible Funktion von y in dem Körper L, der aus allen rationalen Funktionen von x mit Koeffizienten in R besteht. Dann kann die Klasse der ganzen ratio- nalen x, für welche F (x, y) eine reduktible Funktion von y im Körper R ist, nur die Verteilungsdichte Null haben. Beweis: Gilt für ein z und alle y die Gleichung Ao (x) y^ + Ay (7) y^ ++ An (7) (ah tal te, so daß Ao (x) = «o Bo sein muß, so bekommt man durch Multiplikation mit Ao(r) = a?! pe Ao (2) y^ + Ay (2) Ao (0) "y" * + 222 + An (2) Ao (2 — («tp + aS age +) C wwe ceu uu m KE LE Uu EN oder wenn 4A, (7) y — 9, gesetzt wird: D (x, Ys) = y, + At (x) DE JF: Ao (x) An (2) = (yt ex Boy +--+ oft BL a) (V " een PT tr). Hieraus sieht man, daß F(x, y) für ein ganzes rationales x nicht eine reduktible Funktion von y in À sein kann, ohne daß 9 (x, y,) reduktibel wird und mit demselben Werte von ». Hätte also A eine Verteilungs- dichte 7 0, so wäre nach Satz 20 © (x, y) reduktibel in L. Dies würde aber bedeuten, daf3 identisch in x und 4 D (x, yı) = Wy + A, (x) D RAS An (r7! A, (2) —( ais bi (x) 1 gag +... + B» (x)) (Cr ENE p (x) gt mt Cav), wo B,,... By, Oy ..., Cn-» rationale Funktionen von x sind mit Koeffi- zienten, die zu À gehóren. Hieraus würde wieder folgen 28 TH. SKOLEM. M.-N. KI. F(x, y) = 7 m — Av (a) y? + 41 (2) y Ho + An (x) = Ao (2) 410 ) D, (x) p=) By (x) | n-v C (x) n—v—1 Cn—r (x) ? 2 ur ak ter, je (v FAR rer Fa v TA)? Dum. DÅ wodurch ersichtlich wird, daß F(æ, y) auch reduktibel in L sein müßte. S 4. Funktionen zweier oder mehrerer Variabeln x, y, ..., welche ganze Werte haben für unendlich viele ganze Werte von 7, y,... Satz 29. Es sei = Apa (x) P pol f (x, y) = Ao (x) ya + Ay (x) y * +---- + Ap (x) + ee, 22 1 ya wo p und q ganze positive Zahlen und Ao, Ay,... Funktionen von x sind, die alle in der im Satze 10 erwähnten Weise nach fallenden ganzen oder gebrochenen Potenzen von x entwickelt werden können. Es wird dabei vorausgesetzt, daß sowohl die x- wie die y-Ebene lüngs der nega- tiven reellen Axe aufgeschnitten sind, so daß die vorkommenden ge- brochenen Potenzen von x und y eindeutig bestimmt sind. Die Reihen für Ao, Ay,... sollen alle für |x| > ein positives a kon- vergieren, während für |x > a die Reihe für f(x, y) konvergieren soll, wenn 3 2» Y (x) ist, wobei Y (x) eine positive Zahl ist, die im allgemeinen von x abhängig ist. Ist dann f(x, y) eine ganze Zahl für eine Klasse K von Paaren (x, y) mit den Eigenschaften 1) und 2) (Siehe Seite 5), so muß f(x, y) ein Polynom sein mit rationalen Koeffizienten!. i 1 Beweis: Da die Zahlen y in k(x) eine Verteilungsdichte > » haben, muß für jedes x in k (Satz 10) f(x, y) ein Polynom in bezug auf y sein. ES seni B die grófste ganze Zahl S Dieses Polynom kann dann in der Form A, (x) y" + A (x) y™ | +--+ + An (7) geschrieben werden. Wir teilen dann die Zahlenreihe in Intervalle, jedes aus m (n+1) 1 Außerdem sollen natürlich die Ungleichheiten |x| >a, |y|> Y (x) für alle Paare x, in K gültig sein, sonst würden wir ja außerhalb des Konvergenzbezirks kommen. 1921. No.r 7. VERTEILUNGEN GANZZAHLIGER LÖSUNGEN GEWISSER GLEICHUNGEN. 29 Zahlen bestehend; es gibt also (Satz 3) in unendlich vielen unter ihnen n +1 Zahlen, die zu k(x) gehören. Es seien Yı... Yn+ı N + 1 solche Werte von % in einem dieser Intervalle. Bilden wir jetzt die Gleichungen Ao (x) yp ++ An (7) = My Ao (x) Mt + An (7) — Ani, ( n—1 worin also /y,...,/mn41 ganze Zahlen sind, so bekommen wir DA (a) = einer ganzen Zahl (7 — 0, 11"), wobei y | D=|. . ct nv vastat Da die Differenzen |y — Ys| alle << m(»n +1) sind, wird |D|« (n4-1) n : Lp (m(n +1)) ? , und außerdem ist n eg Die Zahl D kann selbstverständlich für die verschiedenen Intervalle (oder auch eventuell verschiedenen Wahlen von 34... Yn+1 innerhalb des- selben Intervalles) verschiedene Werte haben. Jedenfalls haben aber diese Zahlen D einen größten gemeinschaftlichen Divisor d, der dann nur von xz abhängt!. Außerdem gibt es, wenn D, D,-- Dj die Werte von D sind, ganze rationale Zahlen f, fs, ... fj, so dab D, fy + Ds f +--+ + Diti d ist. Es wird deshalb’ auch d A, (a) (r — 0, 1,...,n) eine ganze Zahl.” Da aber die Zahlen d, welche für die verschiedenen x auftreten, auch alle n—1 <(m(n+ y 2) Es wird dann 4- Ar (z)y(r.— OMEN) eine ganze Zahl fim jedes. 7 in k, und da k eine Verteilungsdichte >>0 hat, muß (Satz 10) 4 A, (z) ein Polynom sein mit rationalen Koeffizienten. Es sind also auch die Funk- sein müssen, haben sie alle ein gemeinsames Multiplum 4. tionen Å, (7) solche Polynome, wodurch die Behauptung bewiesen ist. Satz 22°. Es sei wieder f (x, y) eine Funktion, welche in der in Satz 22 erwähnten Weise entwickelt werden kann. Ist dann f(x, y) eine ganze Zahl für unendlich viele Paare ganzer Zahlen 7, y, so daß die Verteilungs- dichte > 0 ist in bezug auf y für unendlich viele z und umgekehrt >0 1 Falls der Nullpunkt 7 — 0 für jedes x als Trennungspunkt zweier Inter- valle gewählt wird. 30 TH. SKOLEM. M.-N. Kl. in bezug auf x für unendlich viele y, so muß f(x, y) ein Polynom sein mit rationalen Koeffizienten. Beweis: Betrachten wir einen der ganzen Werte von x, für welche solche Zahlen y mit einer Verteilungsdichte > 0 existieren soll, daß f(z, y) ganz wird, so muß f(x, y) nach Satz 10 für den betreffenden Wert von x eine ganze rationale Funktion von y sein, d. h. A54, (x) = 0 für r=1,2, Da dies für unendlich viele ganze x gelten soll, welche also x = © als Häufungsstelle haben, müssen die Funktionen Ay+r (x) identisch ver- schwinden. Folglich ist f(x, y) für alle z und y eine ganze rationale Funktion von y. Da man aber nach der Voraussetzung x und y in der ganzen Betrachtung vertauschen kann, muß f(x, y) auch eine ganze ratio- nale Funktion von a sein. Es reduziert sich also f (x, y) auf ein Polynom. Die Koeffizienten dieses Polynoms müssen natürlich rational sein. Anmerkung: Die Voraussetzungen des Satzes 22, daß / eine Ver- teilungsdichte > 0 und die Klassen X(x) gleichmäßig Verteilungsdichten > 0 haben, sind nötig!. In der Tat zeigt das Beispiel f (x, y) = 2 dafs es nicht hinreicht vor- auszusetzen, daf alle Klassen A(x) Verteilungsdichten > 0 haben, wenn das nicht gleichmäßig geschieht, selbst wenn / eine Verteilungsdichte > 0 hat. Jede Klasse % (x) hat hier die Verteilungsdichte - , während k die Dichte 1 hat. Weiter zeigt das Beispiel f(x, y) — V 2224-1 - P (y, wo P(y) ein ganzzahliges Polynom ist, daß es nicht hinreicht, da die Klassen A (x) gleichmäßig Verteilungsdichten > 0 haben, falls À nur eine verschwindende Dichte hat. Jede Klasse (x) hat ja hier die Dichte 1. Satz 23. Es sei B p Best Fe A pl (7; y) f(x y, = 40, y)et + Av(m y)2 + they) 3 co za wobei p und q ganze positive Zahlen bedeuten und Ao, Aj, ... solche Funktionen sind, die in der im Satze 22 erwühnten Weise entwickelt werden können. Es wird hierbei vorausgesetzt, daß die x-, die y- und die z-Ebene so aufgeschnitten sind, daß die vorkommenden gebrochenen Potenzen von x,y und z eindeutig bestimmt sind. Die Reihe soll für jedes solche Tripel (x, y, 2) konvergieren, daß |x| > a, y>Yund |2| > Z ist, wobei Y eine positive Größe ist, die von x, und Z eine positive Größe ist, die von x und y abhängen kann. 1 D.h. sie können nicht vernachlässigt, vielleicht aber geschwächt, werden. 1921. No.1 7. VERTEILUNGEN GANZZAHLIGER LÖSUNGEN GEWISSER GLEICHUNGEN E Ist dann f (a, y, 2) eine ganze Zahl für alle Tripel (x, y, 2), die zu einer Klasse K von Tripeln mit den Eigenschaften, 1), 2) und 3) (Siehe Seite 6) gehören!, so muß f(x,y,2) ein Polynom sein mit rationalen Koeffizienten. Beweis: Da die Zahlen s in k(x, y) eine Verteilungsdichte > = haben, muß für jedes æ in k und y in k(x) (Satz 10) f(x, y, 2) eine ganze Y a : A ) ; rationale Funktion von 72 sein. Es sei nf). Dann können wir f(a, y, 2) in der Form A4, (x, y) £2 +---+ An(z, y) schreiben. Wird die Zahlenreihe in Intervalle, jedes aus m(n + 1) Zahlen bestehend. geteilt, so gibt es in unendlich vielen unter ihnen (Satz 3) n + 1 Zahlen 2... Zn41 | n rea in k(x, y) Wenn D die Determinante |. . . .| ist, erhält man wie Zu . LI . *^n41 l im Satze 22, daß jede Größe D A, (x, y) (r —0,1,..., 1) eine ganze Zahl (27) sein muß. Die Zahlen D sind wieder absolut << (m (n +1) , können aber für die verschiedenen Wahlen von 24... 2141 verschieden sein. Wenn d ihr größter gemeinschaftlicher Divisor bedeutet, muß wieder d Ar(x, y) ("=0,1,...,n) ganz sein. Die Zahlen d können hier für die verschiedenen Paare (xv, y) (x zu k und y zu k(x) gehörig) verschieden EE sein; jedenfalls. ist aber |d | << (m (n + 1)) ein kleinstes gemeinschaftliches Multiplum 4. Dann ist J: 4, (x, y) (r—0, , und sie haben folglich alle l,...,n) eine ganze Zahl für jedes x in k und jedes y in Æ(x). Da aber diese Paare eine Klasse mit den Eigenschaften 1) und 2) ist (Seite 5), müssen nach Satz 22 diese Funktionen J A,(r, y) Polynome sein mit ratio- nalen Koeffizienten. Es sind also auch die A,(x,y) solche Polynome, wodurch die Behauptung bewiesen ist. Es ist ganz klar, wie man analoge Sátze für mehrere Variablen auf- stellen kann. Satz 24. Es sei die Gleichung gegeben g + Ai (x, y) ai ENS en (x, y) zu worin Ay... An eindeutige analytische Funktionen von x und y sind, die nach fallenden ganzen Potenzen von y entwickelt werden können mit Koeffizienten, die nach fallenden ganzen Potenzen von x entwickelt werden können. Die letzteren Entwicklungen der Koeffizientfunktionen 1 Außerdem natürlich immer |z>a, |y| 7» Y und 2 >Z für alle Tripel x, y, 2 in K. 32 TH. SKOLEM. M.-N. Kl. Y von A;(æ, y) seien konvergent, wenn |x| > a,,die Entwicklung für Ada, y) selbst sei konvergent, wenn zugleich |y| > Y;(x) ist. Es sei weiter min- destens eine der Wurzeln z ganz, so oft das Paar (x, y) zu einer Klasse K von Paaren mit den Eigenschaften 1) und 2) gehört. Dann gibt es ein Polynom P(x, y) mit rationalen Koeffizienten, so daß die Gleichung identisch in bezug auf x und y befriedigt wird, wenn man z= P(x, y) setzt. Beweis: Wenn |» alle a,und |y| > alle Y;(x), so sind alle Funk- tionen A, (x, y) regulär, und jede Wurzel z der Gleichung bleibt endlich. Zwei oder mehr Wurzeln kónnen nur dann gleich werden, wenn die Dis- kriminante D (x, y) der Gleichung Null ist. Aufserdem sieht man aus der Entwicklung von D(z, y) nach fallenden Potenzen von y, daß bei gege- benem x die endlichen Wurzeln y der Gleichung D (rz, y) = 0 ihrem abso- luten Werte nach eine obere Grenze l'(r) haben müssen. Da JD(xz,y) nach fallenden Potenzen von 5 entwickelt werden kann D (x, y) = Do (x) y" + Dy (az) y^ + ..., konvergent für |x| > alle a; und |y| > alle Y,(x), so sieht man, daß y nur dann unendlich werden kann in der Gleichung D (x, y) = 0, wenn Dy (x) — 0 ist, und folglich müssen die endlichen Werte von x, für welche eine Wurzel y der Gleichung D (x, y) — 0 unendlich wird, absolut genommen eine obere Grenze «' haben. Es sei B der Bereich, der aus allen Paaren (x, y) besteht, worin |z| > alle a; und a’ und ebenso |y| > alle Y,(x) und Y'(x) sind. Dann muß jede Wurzel z der gegebenen Gleichung überall regulär sein innerhalb B und auch eindeutig, wenn sowohl die x- wie die y-Ebene längs der nega- tiven reellen Axe aufgeschnitten werden. Die Wurzel z besitzt folglich eine Entwicklung p—i P e — Cfa + Cy ()y * + wo jede der Funktionen C wieder eine Entwicklung der Form Tr r-1 C(z)-— agx5 + ax +--. hat, wobei diese Entwicklungen konvergent sein müssen für alle Paare s (x, y) innerhalb B und Yx und Vy verhalten sich eindeutig bei der er- wahnten Aufschneidung. Die n Wurzeln z können 4... 2, heißen. Es sei K»(» — 1, 2, . ., n) die Unterklasse von X, für deren Zahlenpaare (x, y) eben die Wurzel z» ganz ist. Nach Satz 4 mufs dann mindestens eine der Klassen Ky eine Unterklasse A, mit den Eigenschaften 1) und 2) haben. Diejenigen Paare 1921. No.1 7. VERTEILUNGEN GANZZAHLIGER LOSUNGEN GEWISSER GLEICHUNGEN. 33 x,y in NR. die dem Bereiche B angehören, bilden eine Unterklasse HN. die augenscheinlich wieder die Eigenschaften 1) und 2) hat. Nach Satz 22 muß folglich eine der Wurzeln z eine ganze rationale Funktion von x und y sein mit rationalen Koeffizienten. .Satz 24 kann auch in der folgenden einfacheren Weise bewiesen werden. Es sei x eine Zahl der Klasse A (Siehe Seite 5). Dann hat die Klasse A(x) eine Dichte — 0, und da z ganz sein soll für dieses x für jedes y in k (x), so muß nach Satz 11 eine ganze rationale Funktion P (y) von 7 existieren, so daß z — P(y) die gegebene Gleichung identisch in y befriedigt, wahrend die Koeffizienten von P(y) Funktionen von x sind, die für jedes x in & rational sind. (y) hat höchstens einen Grad, den man mit Hilfe der Gleichung leicht angeben kann. Wir kónnen deshalb für jedes x setzen P (y) — wy y +---+4, WO ?g... 4ı Funktionen von z sind. Durch Einsetzen von 2 = P (y) bekommt man ein System (gewóhnlich sogar eine unendliche Reihe) von Gleichungen zwischen x und %o,..., 4, ganz rational in w%,..., u. Es soll weiter unten nachgewiesen werden, daf wir voraussetzen können, daß darunter / + 1 unabhängige vorhanden sind. Da die Klassen & (r) gleichmäßig Verteilungsdichten > 0 haben, erhalten wir genau in derselben Weise wie beim Beweise von Satz 22, daß uo .. 2) für alle x in À einen endlichen Hauptnenner N haben müssen. Aufserdem sind #9... mit z durch / + 1 unabhängige Gleichungen, ganz rational in bezug auf ug...?4, verknüpft. Nach Satz 16’ müssen dann / + 1 Poly- nome Q(x),..., Yi (x) mit rationalen Koeffizienten existieren, welche bezw. statt Uo,..., & eingesetzt alle Gleichungen zwischen x, %o,..., #1 iden- tisch in x befriedigen. Hierdurch wird aber /(y) eine ganze rationale Funktion von « und y, P (x, y}, mit rationalen Koeffizienten, und z = P(r, y) befriedigt die gegebene Gleichung identisch in x und y. Gäbe es nicht so viele als / + 1 unabhängige Gleichungen zwischen X, Ug. . - -, Uj, so könnte man bei beliebigem x eine oder mehrere der Größen Up... .,ıı beliebig wählen, z. B. gleich Null setzen. Dann müßten aber wieder die übrigen dieser Größen rational sein für jedes x in À, und man könnte genau dieselbe Betrachtung wie oben anstellen mit demselben Ergebnis. Satz 25. Es sei die Gleichung gegeben u” + A, (2, y,2) w** Hr An (x, y, 2) — 0, Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. 17. 3 34 TH. SKOLEM. y M.-N. Kl. worin Ay... An eindeutige analytische Funktionen von a, y und z sind, die nach fallenden Potenzen von z entwickelt werden können mit Koeffi- zienten, die Funktionen von x und y sind, welche nach fallenden Poten- zen von y entwickelt werden können mit Koeffizienten, die Funktionen von x sind, welche nach fallenden Potenzen von x entwickelt werden können. Es seien die Entwicklungen nach x allein konvergent, wenn xl > al (der Index 4 bezieht sich auf Aj (x, y, z)) die Entwicklungen nach x und y konvergent, wenn zugleich |y| > Y,(x), und endlich dic Entwicklung nach x,y und z von A,(a, y,z) konvergent, wenn zugleich \z| > Z (x, y) ist. Es sei weiter mindestens eine der Wurzeln u ganz, so oft (x,y,2) ein Tripel einer Klasse K von Tripeln mit den Eigen- schaften 1), 2) und 5) ist. (Seite 5). Dann gibt es ein solches Poly- nom P (a, y, 2) mit rationalen Koeffizienten, dap wu = P (x, y, 2) die Glei- chung identisch in x, y, 2 befriedigt. Beweis: Wenn |x| > alle a,, |y| > alle Y;(x) und z| > alle Z;(x, y), so sind alle Funktionen A,(x, y, 2) regulär, und jede Wurzel w bleibt end- lich. Zwei oder mehr Wurzeln % können nur dann gleich werden, wenn die Diskriminante D (x, y, z) der Gleichung verschwindet. Nun läßt sich jede Wurzel 2 der Gleichung D (», y, 2) = 0 nach fallenden ganzen oder gebrochenen Potenzen von jj entwickeln mit Funktionen von x als Koeffi- zienten, die wieder nach fallenden ganzen oder gebrochenen Potenzen von x entwickelt werden können, wobei diese letzteren Entwicklungen alle kon- vergieren, wenn |x| >a‘ ist. Für jedes solche x gibt es eine obere Grenze der absoluten Werte der endlichen y, für welche ein z der Gleichung D (a, y, 2) — 0 unendlich wird; es sei Y'(a) diese Grenze. Da aber auch D(r,y,z) nach fallenden ganzen Potenzen von 7, %,2 entwickelt werden kann, müssen bei gegebenen x und y die endlichen Wurzeln z absolut genommen eine obere Grenze /‘(.r, y) haben. Es sei D der Bereich, der aus allen Tripeln x, y, 2 besteht, worin |z| >a‘ und alle a,‘, |y| > Y"(z) und alle Y;(z) und >Z (x,y) und alle Z(r, y) ist. Dann ist jede Wurzel w der gegebenen Gleichung überall regulär und eindeutig inner- = halb 5, wenn die z-, y- und z-Ebene längs der negativen reellen Axe auf- geschnitten werden. Jede Wurzel w besitzt folglich eine Entwicklung iD pal wu — Cs (z, y) £3 + Ca (m, y 2 * H..., wo die Funktionen C wieder in derselben Weise wie f(x, y) im Satze 22 entwickelt werden kónnen, wobei alle diese Reihenentwicklungen für alle Tripel x,y,z in B konvergent sein müssen, und die auftretenden gebro- chenen Potenzen von x,y,z verhalten sich eindeutig bei der erwähnten Aufschneidung. » | 1921. No. 17. VERTEILUNGEN GANZZAHLIGER LÖSUNGEN GEWISSER GLEICHUNGEN. 35 Die n Wurzeln w, die also innerhalb 5 als n getrennte eindeutige Funktionen angesehen werden können, sollen %, w,..., Un heißen. Es sei Kv die Unterklasse von X v—=1,2,...,n), für deren Zahlentripel x, y,2 eben w» eine ganze Zahl ist. Nach Satz 5 muß dann mindestens eine der Klassen A» eine Unterklasse Ke mit den Eigenschaften 1), 2) und 3) haben. Diejenigen Tripel (x,y,2) in K,, die dem Bereiche B ange- hören, bilden eine Unterklasse Ks. die augenscheinlich wieder die Eigen- schaften 1), 2) und 3) hat. Nach Satz 23 muß folglich die Wurzel w» eine ganze rationale Funktion von 7, y und z sein mit rationalen Koeffizienten. Natürlich läßt sich auch für Satz 25 ein dem zweiten Beweis für Satz 24 entsprechender Beweis aufstellen. In ganz analoger Weise können entsprechende Sätze für mehrere Variabeln bewiesen werden. Satz 26. Es sei die Gleichung EP (ay KE) 0 gegeben, wo H ein ganzzahliges Polynom ist. Ist dann mindestens eine Wurzel z ganz für jedes Paar (x, y) in einer Klasse K mit den Eigen- schaften 1) und 2), so gibt es ein Polynom P (x, y) mit rationalen Koeffi- zienten, das statt z eingesetzt die Gleichung identisch befriedigt. Dieser Satz ist ja ein Spezialfall von Satz 24. Satz 27. Es sei die Gleichung gegeben Heu) = 0: wo H ein ganzzahliges Polynom ist. Es sei eine Wurzel u ganz für jedes Tripel einer Klasse K mit der Eigenschaften 1), 2) und 5). Dann gibt es ein Polynom P (v, y, z) mit rationalen Koeffizienten, das statt u eingesetzt die Gleichung identisch befriedigt Dies ist ja ein bloßes Korollar von Satz 25. Genau analoge Sätze gelten natürlich für mehrere Variabeln. Satz 28. Es sei wieder die Gleichung H (z, J, 2) =0 gegeben; es werde aber jetzt vorausgesetzt, daß für jedes Paar (x, y) der Klasse K mit den Eigenschaften 1) und 2) mindesten y der Wurzeln z ganze Zahlen sind. Dann gibt es y Polynome P, (x, y),..., P» (x, y) mit rationalen Koeffizienten, die statt z eingesetzt die Gleichung identisch befriedigen. Beweis durch Induktion: Die Behauptung ist richtig für y — 1 (Satz 26). Ich setze ihre Gültigkeit für y — 1 voraus und beweise sie für v. 36 TH, SKOLEM. M.-N. Kl. Nach Satz 26 gibt es jedenfalls ein Polynom P (z,y) mit rationalen Koeffizienten so beschaffen, daß H (x,y, P, (x, y)) identisch verschwindet. Man kann dann in H (x,y,z) den vorkommenden Linearfaktor in bezug auf z, 2 — P; (x, y), wegdividiren, wodurch eine Gleichung TEM, 0,2) erhalten wird. Da für jedes Paar (z, y) in À mindestens v der Wurzeln z der Gleichung H — 0 ganz sein sollen, müssen mindestens » — 1 der Wurzeln der Gleichung /7; — 0 ganz sein. Es gibt also nach der An- nahme » — 1 Polynome P, (r,y),..., P» (x, y), so da& die Gleichungen Hi (a, y, P» (x, y)) 0, : . -, Hy (v, y, Pr (x, y)) — 0 Identitäten sind. Es sind also auch H (x,y, P» (x, y).... H (x, y, Pr(x, y)) identisch Null ebenso wie H (x, y, P1 (x, y)). Analoges låfst sich für mehrere Variabeln beweisen. Satz 29. Es sei ein System von n unabhängigen Gleichungen Hi (x, YES * y Zn) =0,---, Hy (x, Y; 21, °°" Zn) = 0 gegeben, worin Hi... Hy ganzzahlige Polynome sind. Es sei für alle Paare (x, y) einer Klasse K mit den Eigenschaften 1) und 2) mindestens ein Wurzelsystem z,...24 ganzzahlig. Dann gibt es n Polynome P,(x,y), Ju, „Paz, y), sondaß a P5 y);.2 ea Pa (a, y) die: QE identisch befriedigen. Beweis: Die n Gleichungen bestimmen 724... zy als # Funktionen von x und y, für welche Reihenentwicklungen der im Satze 22 für f(z, y) an- gegebenen Form gelten. Da nur eine endliche Zahl von Wurzelsystemen Z1... Zn existieren, gibt es nach Satz 4 eine Unterklasse A’ von À, die wieder die Eigenschaften 1) und 2) hat, und für deren Paare (z,;) eben ein bestimmtes der Wurzelsysteme ganzzahlig ist. Nach 22 müssen aber dann die Zahlen 2,...2, dieses Wurzelsystems Polynome P(r, y), ..., P^ (2, y) mit rationalen Koeffizienten sein. Man kann auch den folgenden allgemeineren Satz aufstellen, dem Satze 16° entsprechend. Satz 29°. Es seien die m unabhängigen Gleichungen JEREZ re gegeben, worin Hy)... Hy ganze rationale Funktionen von 2... Zn sind, deren Koeffizienten eindeutige analytische Funktionen von x und y von der im Satze 24 erwähnten Art sind. Weiter sei für alle Paare x, y einer Klasse K von Paaren mit den Eigenschaften I) und 2) mindestens eine Wurzelkombination z,...2y ganzzahlig. Dann gibt es n Polynome mit rationalen Koeffizienten Py (x, y)... Pr, (x, y), welche bezw. statt 2; ... Zn eingesetzt die Gleichungen identisch befriedigen. IQ2I .No.1 7. VERTEILUNGEN GANZZAHLIGER LÓSUNGEN GEWISSER GLEICHUNGEN. 37 Der Beweis kann entweder analog dem Beweise für Satz 29 oder auch mit Hilfe des Satzes 16° analog dem zweiten Beweise des Satzes 24. Ich gebe hier kurz den letzteren. Beweis: Es sei 2 eine Zahl der Klasse À. Da k(x) eine Dichte > 0 hat, und mindestens eine Kombination 2; ... Zn ganzzahlig sein soll für das gewählte x und jedes y in (x), müssen nach Satz 16’ » Polynome P (y), .. Pr (y) existieren, deren Koeffizienten Funktionen von x sind, welche für jedes x in À rational sind, während sie bezw. statt 2; ... Zn eingesetzt alle n Gleichungen identisch in y befriedigen. Man kann folglich setzen Ey)—1.:y'3- y 4-4 13,7 Pa (y) = ton y ?4- ws y 271 + ++: + Ul, n? wo /,.../, durch die n Gleichungen bestimmte Zahlen sind. Da aie Klassen k (x) gleichmäßig Verteilungsdichten 7» 0 haben, bekommt man wie früher, daß to, ;, 15,5 .. ., 10,5 (1 — 1, 2,..., n) für alle x in À einen end- lichen Hauptnenner haben müssen. Durch Einsetzen von 2; = P (y)... Zn = Pn(y) in die Gleichungen HA, = 0,..., Hn = 0 bekommt man eine Reihe von Gleichungen zwischen x und den Größen «, und diese Glei- chungen sind ganz rational in bezug auf die uw. Nach 16° müssen folglich h+1+h+1+.---+/h +1 solche Polynome Qi(x),..., Q1,,1 (7), ..… DE... Qi. n (2) mit rationalen Koeffizienten existieren, daß sie bezw. statt 4o 1... Un eingesetzt alle zuletzt erwähnten Gleichungen identisch in x befriedigen. Es sind aber dann P, (x, y) = Que) y ++ Qual), Pa (2, Y)=Qony tts + Qu ar) Polynome mit rationalen Koeffizienten, welche statt 2,;...Z, in die Glei- chungen H, —0,..., Hn — eingesetzt diese identisch in bezug auf z und y befriedigen. Analoge Sätze können natürlich wieder für eine größere Zahl unab- hängiger Variabeln bewiesen werden. Satz 30. Es sei die Gleichung Hire) -& gegeben, wo H ein Polynom ist mit Koeffizienten in einem algebraischen Zahlkörper R. Es sei für jedes Paar (x, y) einer Klasse K von Paaren mit den Eigenschaften I) und 2) mindestens eine Wurzel z der Gleichung eine ganze Zahl in R. Dann gibt es ein Polynom P (z, y) mit Koef- fizienten in R, so daß H (a, y, P (x, y)) identisch Null ist. Beweis: Es sei wı,..., «& eine Basis der ganzen Zahlen in À. Für jedes Paar (7, y) in K ist dann mindestens eine Wurzel z von der Form 24 01 + 22 09 + +" + Zn Wn, WO Z1... Zn ganze rationale Zahlen sind. 38 TH. SKOLEM. M.-N. KI. x Wird dies in die Gleichung eingesetzt, spaltet sie sich bekanntlich in # simultane Gleichungen der Form H, (2, Un A OUT Zn) — 0, RE Jol p Y, Eu" En) = 0, wo H,,---, Hy, Polynome mit absolut rationalen Koeffizienten sind, und hier ist also ein Wurzelsystem 2,,..., 2, rational ganzzahlig, so oft x und y ein Paar in A bilden. Nach Satz 29 müssen deshalb » Polynome PX (x, y) ..., Pa(x, y) mit absolut rationalen Koeffizienten existieren, so daß die n Gleichungen zu Identitäten werden, wenn man 2, = /^(r, y), es £p = Py (2, Y) setzt. Das bedeutet aber augenscheinlich, daß die ge- gebene Gleichung H(z, y, :) = 0 identisch befriedigt wird, wenn man z= P (x, y) v, +: Pr (x, y) on setzt Eine Verallgemeinerung hiervon ist der folgende Satz: Satz 31. Es sei das System von m unabhängigen Gleichungen Hi (2, Up ye neues, 2m) = 0, ger His (x, Ys Aly? a5 Zm) = 0 gegeben, worin Hy... Hm Polynome sind mit Koeffizienten in einem a'gebraischen Zahlkörper R. Es bestehe für jedes Paar (x,y) in einer Klasse K mit den Eigenschaften 1) und 2) mindestens ein Wurzelsystem Étyeees 2m "ur aus ganzen Zahlen in R. Dann gibt es m Polynome P(&,Y),..,Pm(X,y) mit Koeffizienten in R so beschaffen, daß die m Gleichungen identisch in x und y befriedigt werden, wenn man à = EMO) en E [A setzt. Beweis: Es sei wy,..., Wn eine Basis der ganzen Zahlen in À. Wenn x und y ein Paar in Ä bilden, sollen die Gleichungen befriedigt werden, Wenn 2, — 2%, à @, + +++ + £n nn = 1,2,..., m) gesetzt wird, wobei alle mn Größen z,,, ganz rational sind. Werden diese Ausdrücke für 2, in die m Gleichungen eingesetzt, spaltet sich jede von diesen in # Glei- chungen, so daß man ein System von mn Gleichungen zwischen z, y und den mn Größen z,, erhält. Da nun für jedes Paar (7, y) in A minde- stens ein Wurzelsystem z;,, dieser Gleichungen nur aus ganzen rationalen Zahlen besteht, so gibt es nach Satz 29 mn Polynome P,,5 (x, y) mit ab- solut rationalen Koeffizienten, so daß das System der mn Gleichungen iden- tisch befriedigt wird, wenn man 2,3 — Pr s(r, y) setzt. Dann werden aber augenscheinlich die m gegebenen Gleichungen Identitäten in bezug auf x und, wenn er — LU) wy ae =>} PU) ca scd 22 gesetzt wird. | Ähnliche Sätze gelten für mehrere Variabeln. Satz 39. sise FL ne) = 2 AB y)e v tet Ale), 1921. No.1 7. VERTEILUNGEN GANZZAHLIGER LOSUNGEN GEWISSER GLEICHUNGEN. 39 wo n>1 und A,... 44 Polynome sind mit ganzen rationalen Koef- fizienten, eine irreduktible Funktion von z innerhalb des Körpers L, der aus allen rationalen Funktionen von x und y mit rationalen Koef- fizienten besteht. Die Klasse K der Paare ganzer rationaler Zahlen (x, y), für welche die übrig bleibende Funktion von z reduktibel im natür- lichen Rationalitätsbereich ist, kann dann keine Unterklasse mit den Eigenschaften I) und 2) haben. — Ich beweise die Behauptung in umge- kehrter Form: Falls eine solche Klasse A mit den Eigenschaften 1) und 2) existiert, muß F'(x,y,2) innerhalb / reduktibel sein. Beweis: Soll Fr, y, 2) für irgend ein Paar z, y reduktibel in bezug auf z werden, so muß eine Identität in z der Form 2 + 41 (7,9) 2" +: + An (7, 9) = (2 He 27 + + a) (0t == By gh—?—-1 + Au + Bn-») stattfinden. Da 4,... 4, immer ganze rationale Zahlen sind, wenn 7 und y ganz rational sind, müssen bekanntlich auch &;,..., av, 81, - -, Sn—» ganze rationale Zahlen sein. Gibt es nun eine Klasse A von Paaren (x, y) mit den Eigenschaften 1) und 2), so daß für jedes dieser Paare F (x, y, 2) reduktibel in bezug auf z ist, so muß (Satz 4), wenn Är(v=2,3,...,n—1) diejenige Unterklasse von Ä bezeichnet, für deren Zahlenpaare eben eine Reduktibilität in zwei Faktoren der Grade » und n — y stattfindet, minde- stens eine der Klassen Ky eine Unterklasse K, mit den Eigenschaften 1) und 2) haben. Weiter müssen die Gleichungen a, + Bi = 4i (2, y), e Bi + G2 + Ba Ao (7,9), ----- , ty fn» = Ay (7, y) bestehen. Sie sind von der im Satze 29 erwähnten Form und müssen für jedes Paar (x,7) in A, für ein System ganzer Zahlen a, ... «v B1... Bn— erfüllt sein. Nach Satz 29 gibt es dann n Polynome mit rationalen Koef- fizienten P, (x, y) ..., Pa(z,y), so daf die » Gleichungen identisch befrie- digt werden, wenn o, = P (z, y), ..., a» — P» (z, y) Bi = Prt (2, y)... Bu-v = Pr (.c, Y) gesetzt werden. Dadurch wird aber die Gleichung 24 A yz "+ e + An (y= (2 + Byz? ++ Prey) (TT + Po+i(a, y) £^ "^ 4-4 Pay) eine Identität in »,; und z; d.h. F(x,y,s) ist eine reduktible Funktion von Z innerhalb L. Satz 33. Es sei K die Klasse der Paare ganzer rationaler Zahlen m, y, für welche das Polynom 40 TH. SKOLEM. M. N. KI. 1 F(x,y,2)=2 + Ay (x,y) 2°” ++ + An (a, y), dessen Koeffizienten ganze Zahlen eines algebraischen Zahlkörpers R sind, reduktibel in bezug auf z im Körper R wird. Hat dann K, eine Unterklasse K mit den Eigenschaften 1) und 2), so muß F' (x, y, 2) eine reduktible Funktion von z sein innerhalb des Körpers L, der aus allen rationalen Funktionen von x und y mit Koeffizienten in R besteht, Beweis: Wenn /'(x, y, z) für ein Paar (x, y) reduktibel in bezug auf Z ist, gibt es eine Identität in 2 der Form — 1 v7 2 + Aix, yes +... + An (xy) = (27 + 2 pee rav) (2504 + Pi gow i E ... + Pn—»). Da A1... 4, immer ganze Zahlen in A sind, wenn x und y ganz ratio- nal sind, so müssen bekanntlich auch «4... «ay», B1... Pn-v ganze alge- braische Zahlen sein und folglich auch ganze Zahlen in À. Es sei Ay die Unterklasse von %k, für deren Paare (r, y) eine Reduktibilität mit den Graden v und » — v der Faktoren stattfindet. Nach Satz 4 muß dann mindestens eine der Klassen A» eine Unterklasse A/ mit den Eigenschaften 1) und 2) haben. Außerdem gelten die Gleichungen ay + Bi = Ay (7, y), ea B + eo + Ba — Ae (x, y), - +++, av Bn-v = An (x, y) welche von der im Satze 31 erwáhnten Form sind. Da sie für jedes Paar (x, y) in Ky erfüllt sind, wenn «4... a, pi... Pn-» gewisse ganze Zahlen in À sind, gibt es nach Satz 31 n Polynome P (x y),..., Pa (x. y) mit Koeffizienten in À, so daf die n Gleichungen identisch befriedigt werden, wenn man ey = P (2,9), - ar — Py(2, yh By = Poi, y) ca Py (x, y) setzt. Dadurch wird aber wieder F(x, y, 2) augenscheinlich re- duktibel im Körper /. In genau derselben Weise wie wir früher Satz 21 mit Hilfe von Satz 20 bewiesen haben, läßt sich hier der folgende Satz mit Hilfe von Satz 33 beweisen: Satz 34. Es set K, die Klasse der Paare ganzer rationaler Zahlen (x, y), für welche die ganze rationale Funktion F (x, y, 2) — Ao (5, ) £^ + Ay (a, y) +... + An (x, y) deren Koeffizienten ganze Zahlen eines Körpers R sind, reduktibel in bezug auf z im Körper R ist. Hat dann Ky eine Unterklasse K mit den Eigenschaften 1) und 2), so ist F(x, y, 2) reduktibel in bezug auf z im Körper L, der aus allen rationalen Funktionen von x und y mit Koeffizienten in R besteht. 1921 No. 17. VERTEILUNGEN GANZZAHLIGER LÖSUNGEN GEWISSER GLEICHUNGEN. 41 Analoge Sätze lassen sich natürlich für mehrere unabhängige Variabeln beweisen. Satz 35. Es sei K die Klasse der ganzen rationalen Zahlen x, für welche das Polynom F(a, y, 2), das ganze Koeffizienten in einem alge- braischen Körper R hat, eine reduktible Funktion von z ist im Körper L,, der aus allen rationalen Funktionen von y mit Koeffizienten in R besteht. Hat dann K eine Verteilungsdichte > 0, muß F(x, y, z) eine reduktible Funktion von z sein im Körper Ls y, der aus allen rationalen Funktionen von x und y besteht mit Koeffizienten in R. Beweis: Hat nämlich K eine Verteilungsdichte 7 0, so hat die Klasse K von Paaren, die aus allen Paaren (2, y), wo x eine Zahl in K und y eine beliebige ganze rationale Zahl ist, besteht, die Eigenschaften 1) und 2). Außerdem wird augenscheinlich F(x, y, z) eine reduktible Funktion von 2 im Körper A für jedes Paar (x,y) in K. Nach Satz 34 muß also F (r, y, 2) eine reduktible Funktion von z sein innerhalb L«x y. Auch dieser Satz läßt sich natürlich verallgemeinern. Der allgemeinste Satz über Reduktibilitäten, den man in dieser Weise gewinnen kann, lautet folgendermaßen: Es sei K eine Klasse von Komplexen ganzer rationaler Zahlen, jedes aus m Zahlen x4... xq bestehend. Es sei k die Klasse der in diesen Komplexen vorhandenen Zahlen xí, k(x) die Klasse der %s, welche mit a, zusammen in den Komplexen vorkommen, k (x1, 22) die Klasse der x3, welche mit x, und x, zusammen in den Komplexen vor- kommen, usw. Außerdem habe k eine Verteilungsdichte 70, die Klassen k (24) gleichmäßig Verteilungsdichten > 0, ebenso die k (x, x2) gleichmäßig Verteilungsdichten > 0, usw. Weiter sei F'(x1... Xm, Yı--- Yn-1, Yn) eine ganze rationale Funktion von m+n Variabeln mit Koeffizienten in einem algebraischen Zahlkörper R. Ist dann für jedes Zahlenkompler (21... Cm) in K die Funktion F reduktibel in bezug auf Yn im Körper L(y, «++. Jn), der aus allen rationalen Funktionen von yy... Yn-ı mit Koeffizienten in R besteht, so ist F eine reduktible Funktion von yy im Körper L(xq... Xm, Yı=---Yn-ı), der aus allen rationalen Funktionen VON Ty... Im Yieee Yn—1 mit Koeffizienten in R besteht. Der Satz ist in der Tat für n — 1 nur eine Verallgemeinerung des Satzes 34, und wenn soviel bewiesen ist, läßt sich der Fall n > ! darauf zurückführen mit Hilfe einer genau analogen Betrachtung wie die oben beim Beweise des Satzes 35 angestellte. 42 TH. SKOLEM. M.-N. Kl. a) - S 5: Uber einige Verschårfungen der im Vorhergehenden bewiesenen Såtze, u.a. eine Klasse von Gleichungen mit zwei Unbekannten, welche nur endlich viele Lösungen in ganzen rationalen Zahlen haben. Die in den vorhergehenden Paragraphen bewiesenen Sätze gestatten unzweifelhaft in ausgedehntem Maße Verschärfungen. Solche verschärften Sätze werden wohl aber größtenteils bedeutend schwerer zu beweisen sein. Es gibt aber einige ziemlich umfassende Fälle, da ein solche Verschärfung leicht gelingt. Ich will im folgenden ein Paar solche Fälle zeigen. Satz 36. Es sei die Reihe (lø D ON dean m konvergent, wenn |x| > HR, wührend nicht alle Koeffizienten a5, az, verschwinden. Falls y eine ganze Zahl ist für unendlich viele ganze Werte (die augenscheinlich alle positiv vorausgesetzt werden können) ay sa Az: von x, kónnen die Quotienten (£i — 2x3). (ire — 24) (tee — xt) X741 lr+2 nicht Null als Hüufungsstelle haben, oder m. a. W. für alle t 7 T sind sie > d, wo a eine positive von t unabhängige Zahl ist. Beweis: Aus den Gleichungen ( ) ( 2 2 ) =“ Ge fi; Tt Tori La E ee AN Yor — Yt — 09 (02a — Lt) + A 2 2 Jydt+1 I Xl ; 2 2 KK nn Yız2 — Yori = Ap (&tt2 — Xen) + m = eia 30 re) + : DX m 2 Ti to pp lt+2 bekommt man durch Elimination von Ay (ei — 26) (ete — Yeti) — Air — taa) (yes — Yt) = da Xs + 08 Xs +, 1921. No.r 7. VERTEILUNGEN GANZZAHLIGER LOSUNGEN GEWISSER GLEICHUNGEN. 43 wo m—1 m-—1 m -1 m-—1 X ® (241 — E12 ) | E (zt ee ARI ^m = (a in me 4x) D uen —1 (2 ta 4 £41) Deere ar d X Xt Lt+1 (Tt+2 == 41) (0441 RE Tt) m—1 m-Iı .m—2 m-2 m- 2 m—3 - Ee ee 5 (tte —— EP ) eat + (rt — dt Jerem X2 Tt Lt+1 It+2 ( ,D--2 m-—2 + +++ + (ee — 2x) dt Lt+2 | Hieraus r 7 rm [4 Aur 1 " T, + To 44 Tea + Tr A Ir Lt +1 Ti+2 Ni + N5 ++ Nm-1 ^C wo m—r-+1 DS np TI Inc pr fiae t+2 — XL mic: Lt+1 tre und Js m—r m—r r—1 m a i INSEE (Ce — Wt ) Pg t+1 X2 gesetzt ist. Es wird dann EE IN TE 1 T (aire eg =) Zum Ta M (isa T) gy reus Den t Bee r (tire + ito due usted ) m ES —9 i Crises Lans mt tar C D) vua [Corm JE Ne Kr SL Wu + X12 cea a (ems =F Lite SE Xt AR » — Lt12 Pal ! DE ar r—1 1 4 " = —r—3 = : (tte + DES Lt +: . + qe : ) T 4-2 Tt Tt+2 Ti > und weiter 1 Ts 1 < 1 ee New 4 SE i Tt Dal aber alle Größen Z5... T. Nr Nm-ı pesitivs sind, folgt^hieraus Amtı _ Ty + + Tasa ae Shir =Å n Lt Lti1 X42 (M + eee + Na) Ve Lt+1 Tt+2 (N +::+ NES) 2 1 3 em Xe — m : t Lt Es sei nun unter den Koeffizienten day Q3, *** 4.4. TH. SKOLEM. M.-N. KI. du der erste, welcher + 0 ist. Dann ist ØE (rt: 1 — 2X) Un po — Yeti) — UXt2 — Lets) (utei — yt) = r X y 1 Xu +2 | LI Xu Z + Au; — + “Aurea 2 zz «Leise, i X u X u und außerdem | X uaa | X ui 3 9 aa + SS] eg |p re] eg | + 0t RI | X u | ES Xu : Lt Zt | Da aber die Reihe 24,44 x" konvergent sein soll, wenn | x,» À, so bekommen wir für alle { > ein gewisses 7° 3 9 l race aa e ee aa, Lt 2e 2 so dafs 1 t 3 : FALL | DA T. Man erhält also auch, da z immer ganz sein soll 3 > 2 2 1 lu | Xu > 1 oder Xu > Gu Ln für alle {>T. Folglich kann Xu nicht Null als Häufungsstelle haben, | : : 7 N 3 \4—2 : und à fortiori gilt dies für Xs, da ja Y. E und 2 > 3 ist für alle < 2 vt hinreichend große f. Da also für alle ( T' (a Lt) (He42 — Lt) (Lt+2 — PH) a, Lt tri Lt+e wo a eine positive von £ unabhängige Größe ist, so bekommt man PRET AT ee e P TES Sa Lt+2 Sa Ty Lt+1 Lt+2 — Lt : oder Xt-po 41 Lt+2 — — — +1>a Xt Jt Lt+1 oder, da um «C 11 ty , Me 5 Sale lt TT IQ2I. No.ı 7. VERTEILUNGEN GANZZAHLIGER LÖSUNGEN GEWISSER GLEICHUNGEN. 45 Sowohl die « mit geradem als die « mit ungeradem Index müssen also am wenigsten so zerstreut liegen wie die Glieder einer geometrischen Reihe. Es ist klar, dafs dies weit mehr aussagt, als der Satz 9 nebst An- merkung, nach welchem man nur weiß, daß die x eine verschwindende Verteilungsdichte haben müssen. Satz 37. Es seien die Variabeln x und y durch eine Gleichung der Form wt U za ) y (ha? + beetbgt--)y + + (Ay x^ + hs gos ees )=0 verknüpft, wo die Reihen in x konvergent sind für hinreichend große x, während die Gleichung Pr ++. + —0 keine mehrfache Wurzel hat. Gibt es dann kein Polynom in x mit rationalen Koeffizienten, das statt y eingesetzt die Gleichung identisch befriedigt!, so müssen die ganzen Werte von x, für welche mindestens eine Wurzel y ganz ist, am wenigsten so zerstreut liegen wie die Glieder einer endlichen Zahl geometrischer Reihen. Beweis: Die Richtigkeit folgt sofort nach dem vorhergehenden Satze, wenn man bemerkt, daß jede Wurzelfunktion y der Gleichung eine Ent- wicklung nach fallenden ganzen Potenzen von x besitzt, welche mit der ersten positiven Potenz von % anfängt. Eine einfache Folgerung dieses Satzes ist, wie man sofort sieht, daß die Quotienten Te in mit wachsendem { über jede Grenze wachsen müssen für jeden positiven Wert von n. Satz 11 sagt dagegen nur aus, dafs die Quotienten Be t über alle Grenzen wachsen müssen. Man sieht hieraus, wie weit schärfer der Satz 37 ist. Auf algebraische Gleichungen angewandt bekommen wir den Satz: Satz 38. Ist H eine solche ganze rationale Funktion von x und y, daß die Gleichung h (1, 2) = 0, 1 Dies müßte natürlich vom ersten Grade sein. 46 TH. SKOLEM. M.-N. Kl. wo h(x, y) der höchste homogene Teil von H ist, mur einfache Wurzeln hat, und gibt es keine lineare Funktion von x mit rationalen Koef fi- zienten, welche statt y eingesetzt die Gleichung tdentisch befriedigt, so müssen die ganzen Zahlen x, für welche mindestens eine Wurzel y ganz ist, am wenigsten so zerstreut liegen wie die Glieder einer endlichen Zahl geometrischer leihen. Satz 39. Hat man n unabhängige Gleichungen zwischen den n +1 Variabeln &, y, ..., yg, ganz rational in qi ... Yn, 80 beschaffen, daß jede Wurzelkombination Yı...Ym dus n Reihen nach fallenden ganzen Potenzen von x besteht, während z. D. die Reihe für y; immer mit x! anfängt und sich nie auf eine lineare Funktion mit rationalen Koeffi- zienten reduziert, so müssen die ganzen Zahlen x, für welche mindestens eine Wurzelkombination ganzzahlig ist, am wenigsten so zerstreut liegen, wie die Glieder einer endlichen Zahl geometrischer Reihen. Beweis: Da die Zahl der Wurzelkombinationen endlich ist, und sie für hinreichend große || konsekvent unterschieden werden können, ist die Richtigkeit nach dem obigen sofort klar. Satz 40. Hat man eine irreduktible algebraische Gleichung mit rationalen Koeffizienten H (x, y) — y^ + A (ay? + + An (7) =0, wo A,(x) ein Polynom rten Grades ist, während h (1, z) = 0 nur einfache Wurzeln hat, und die Summe von nur einigen dieser Wurzeln nicht rational ist, indem h(a, y) der höchste homogene Teil von H (a, y) ist, so müssen die ganzen Zahlen x, für welche H(&,y) im natürlichen Ratio- nalitätsbereiche reduktibel wird, am wenigsten so zerstreut liegen, wie die Glieder einer endlichen Zahl geometrischer Reihen. Beweis: Setzt man y + Ay GQ) uy te As (7) = tat + @) tagt Bam) so bekommt man n Gleichungen zwischen 7, e... «v, B1... Bn—», nämlich a + Bi = Ale): a» Bay Anke). Diese Gleichungen sind sicher unabhängig; sie bestimmen nämlich a; . . fn-» (allerdings endlich vieldeutig) als Funktionen von #, indem ja q... «v elementarsymmetrische Funktionen von gewissen » der Wurzeln y der Gleichung A(x,y)=0 sind, während B;.../8n=» elementarsymmetrische Funktionen der # — » übrigen Wurzeln sind. Da alle Wurzeln der Glei- 1921. No. 17. VERTEILUNGEN GANZZAHLIGER LÖSUNGEN GEWISSER GLEICHUNGEN. 47 chung H(x,y) eine Entwicklung nach fallenden ganzen Potenzen haben, so besteht also auch jedes System zusammenhöriger Werte von cq... Bn—» aus n solchen Entwicklungen. Außerdem kann in den Reihen für e, und Bi kein höherer positiver Exponent als + 1 auftreten, da in den Entwick- lungen der Wurzeln y kein höherer Exponent auftritt, und weil c, und 9, nur Summen einiger dieser Wurzeln sind. Da die Summe von v der Wurzeln der Gleichung A (1,2) = 0 nie rational sein soll, so folgt, daß die Summe von » der Wurzeln y nicht ein Polynom mit rationalen Koeffi- zienten sein kann. Es kann also keiner der möglichen Werte von « (oder auch £,) ein Polynom mit rationalen Koeffizienten sein. Nach dem vorigen Satze, und weil y bloß ;» — 1 Werte haben kann, folgt dann die Richtigkeit der Behauptung. Es ist wiederum klar, daß entsprechende Sätze für andere Rationa- litätsbereiche als den natürlichen aufgestellt werden können. Ebenso kann man einen analogen Satz für Gleichungen zwischen x und y aufstellen, die ganz rational in bezug auf y sind; deren Koeffizienten 4,(x) aber be- liebige eindeutige analytische Funktionen von & sind, für welche x — x ein Pol st” Ordnung, s x7, ist — allerdings aber dann nur für Reduk- tibilitäten im natürlichen Rationalitätsbereich. (Siehe die beim Satze 17 gemachte Bemerkung). Satz 4l. Es sei die Gleichung gegeben ÿ = A (x) y" + + An (x), worin Ay,..., dn eindeutige analytische Funktionen von x sind, für welche x — e entweder eine reguläre Stelle oder ein Pol ist, und die Reihen nach fallenden ganzen Potenzen von x rationale Koeffizienten haben, während außerdem mindestens eine der Funktionen A,,..., An mindestens eine Singularität im Endlichen hat, so daß sie nicht alle bloße Polynome sind. Die Gleichung sei irreduktibel!. Unter diesen Voraussetzungen hat die Gleichung nur eine endliche Zahl von Lösungen in ganzen rationalen Zahlen x und y. Beweis: Da es höchstens n reelle unendliche Zweige der durch die gegebene Gleichung dargestellten Kurve gibt, genügt es zu zeigen, daß auf einem beliebigen dieser Zweige höchstens endlich viele Gitterpunkte existieren können. Auf einem solchen Zweige wird y sich wie eine Potenz von x mit rationalem Exponenten verhalten, d.h. es gibt eine solche ratio- Y Ju qa denen endlichen Grenzwert hat. Nun haben wir für x — & einen von Null verschie- nale Zahl FE daf der Quotient 1 Siehe die Erklårungen beim zweiten Beweis für Satz 11 oben, 48 TH. SKOLEM. M.-N. Kl = (t (lø, i Un , dan y = (2, (0 + T oe +++ Pa (ARRET : i x x? wo die Koeffizienten a alle rational sind, während P, (z),..., Pr (x) Poly- nome mit rationalen Koeffizienten sind. Hieraus bekommt man durch Multiplikation beiderseits mit ; und Elimination von y rechts eine Glei- chung der Form ho, n+1 l4, n—1 bin hon y (9 ba er Bel ++ Tale) + Zr J wo (1... Qu Polynome mit rationalen Koeffizienten und die ^ rational 2 sind. Durch Wiederholung dieser Operation bekommt man auch y"^* * pt... durch 1, y, y?, ..., y" ausgedrückt. Man kann deshalb so viele solche Gleichungen bilden, dafs die Quotienten eliminiert werden kónnen. Das Eliminationsresultat ist von der Form on nt — 7 C. y A m Cam UA M H (x, y) cis dis (7, y), wo die C' rationale Zahlen, die nicht alle verschwinden, und H'" ein Poly- nom mit rationalen Koeffizienten ist, während A’ (r, y) von der Form ist ze ks = D RR 9 = Wes 2 as Au 5i s E y xn—1 gent +1 u SÅ op n--2 yo n—2 +1 i‘ t ce, 4 wo lc. ki SR I, I y. Uy 51... rationale Zahlen sind und $,_- die kleinste ganze positive Zahl, die 2 (n — 7) ist. Die Zahlen C' und die Koef- fizienten von H' haben aber einen Hauptnenner N. Wird mit N multi- pliziert, bekommt man eine Gleichung CA ie == HE Chim CT — H (x, y) = R (x, y), wo jetzt H ein ganzzahliges Polynom ist, während die C ganz und R (x, y) ein Ausdruck derselben Form wie R’(x, y) ist. Augenscheinlich konver- giert R(x, y) gegen Null längs dem Zweige, wenn z ins Unendliche wächst. Gåbe es nun unendlich viele Gitterpunkte auf dem Zweige, so müfite für diese, wenn x > ein gewisses JM, R (x, y) = 0 sein, da ja À (x, y) nach der letzten Gleichung immer eine ganze Zahl sein muß, so oft x und y 1921. No.1 7. VERTEILUNGEN GANZZAHLIGER LOSUNGEN GEWISSER GLEICHUNGEN. 49 ce ganz sind. Da indessen y nach fallenden Potenzen von y x entwickelt werden kann, ist dies auch mit R(x,y) —C.y" + --- + my — H(x,y) der Fall. Sollte deshalb R(x, y) — 0 sein für unendlich viele ganze x, so müßte R(x, y) identisch — 0 sein. Da aber H höchstens vom Grade n — I in bezug auf y ist, würde die Gleichung CrhaW ++ Gy — H(zy)-—0 bedeuten, daß 7 eine ganze algebraische Funktion! von x wäre, was gegen die Voraussetzung streitet, daß die Koeffizienten 4,... An der gegebenen Gleichung nicht sämtlich Polynome sein sollten. Anmerkung: Man wird leicht einsehen, daß die Voraussetzung, daß die Koeffizienten rational sein sollen, durch die schwächere, daß sie alge- braische Zahlen sein sollen, die einem algebraischen Körper À angehören, ersetzt werden kann. Es sei zuerst À ein Normalkörper, L der Funktionenkórper, der aus allen eindeutigen Funktionen von 2 besteht, die nach fallenden Potenzen von æ mit rationalen Koeffizienten entwickelt werden können, und L(R) der entsprechende Funktionenkörper, wenn die Koeffizienten zu À gehören. Wenn f; (z, y) irreduktibel ist in L(A), so sind die konjugierten Funktionen fa (x, y). -.., faux, y), die auch alle Koeffizienten in A haben, irreduktibel in L(R). Das Produkt fi f2-.- f« gehört jedenfalls zu Z. Vielleicht ist das schon mit dem Produkte einer kleineren Anzahl unter ihnen der Fall. Es sei deshalb fi ff... = F(x,y) ein Produkt aus einer so kleinen Zahl dieser Funktionen als möglich, so daß F(r,y) zu L gehört. Ist dann Fi(r,y) ein irreduktibler Faktor von (zr, y) in L, so muß F| (7, y) das Produkt von einigen der Faktoren fi, f^, f^... sein. Weil aber Fy eine Funktion in L sein soll, und die Zahl der gewählten Faktoren f|, f*, f^, . so klein als möglich war, damit deren Produkt zu L gehören sollte, so muß Fy mit F identisch sein, d.h. F(r, y) ist irreduktibel in L. Außer- dem kann keine ganze algebraische Funktion von x die Gleichungen fo (x, y) — 0,..., ful’, y) =9 befriedigen, wenn keine solche fı (x, y) — 0 befriedigt. Deshalb kann auch keine solche Z'(z, y) = 0 befriedigen. Nach Satz 41 hat also die Gleichung F(x, y) — 0 bloß endlich viele Lösungen in ganzen rationalen Zahlen. Dies muf folglich auch mit jeder Faktor- gleichung f4 (x, y) — 0 usw. der Fall sein. 1 Eine ‚ganze algebraische‘ Funktion soll eine Funktion y von x bedeuten, welche eine Gleichung der Form V. + AY ++ fn (2) = 0 befriedigt, worin f1...fn Polynome sind. Vid.-Selsk. Skrifter, I. M.-N, Kl. 1921. No, 17. 4 TH. SKOLEM. M.-N. Kl. on e) Ist aber R kein Normalkórper, so ist /£ = (/%,..., Ru), wo By fi... Ru die sämtlichen mit J konjugierten Körper. bedeuten, ein Normalkórper. Eine Funktion f(z, y), die in L(A) irreduktibel ist, zerfällt im Körper L (K), der aus allen eindeutigen Funktionen besteht, welche nach fallenden ganzen Potenzen von & mit Koeffizienten in / entwickelt werden können, in eine gewisse Zahl (vielleicht nur eine) irreduktibler Funktionen fi... fr. Nun wird natürlich f(z,y)=0 bloß endlich viele Lösungen in ganzen Zahlen haben, wenn dies für jede der Gleichungen f; (x, y) — 0, ..., fr (x, y) — 0 der Fall ist. Da nach Voraussetzung keine ganze algebraische Funktion die Gleichung f(x, y) =0 befriedigen soll, so kann keine solche irgend eine der Gleichungen fi (7, y)=0... fv (x,y) =0 befriedigen. Da aber R ein Normalkörper ist, folgt aus dem obigen, daß die Gleichungen fy (x, y) =0... fr (x, y) = 0 bloß endlich viele ganzzahlige Lösungen haben. Falls die Koeffizienten wohl algebraisch sind, aber nicht demselben algebraischen Körper von endlichem Grade angehören, scheitert diese Zu- rückführung auf Satz 41. Auch scheint es im allgemeinen nicht mehr möglich mit Hilfe des im Beweise ebendiesen Satzes angewandten Elimi- nationsverfahrens zum Ziele zu gelangen. Ob der Satz noch materiell richtig bleibt, mag hier dahingestellt bleiben. Der Beweis mit Hilfe des Eliminationsverfahrens wird auch im allge- meinen nicht mehr gelingen, falls die Koeffizienten nicht sämtlich algebraisch sind. Denn kommt eine transcendente Zahl 7 vor in dem Ausdruck für : e cr 1 1-2 y, so kommen in den Ausdrücken für yee ye . nach und nach auch höhere Potenzen von t vor, und diese lassen sich nicht linear mit ganzen Koeffizienten durch eine endliche Anzahl unter ihnen ausdrücken. Die Zahl der Eliminanden wächst also mit der Zahl der Gleichungen. In speziellen Fallen gelingt natürlich noch der Beweis. Ein einfaches Beispiel darauf ist Tı T» 5 y=tr+bhb4+— LD + --+-, a und b ganz rational, x ES wo die unendliche Reihe für alle x absolut > À konvergiert. Es ist klar, dafs hier bloß endlich viele ganze rationale x existieren können, die so beschaffen sind, dafs zugleich y ganz rational wird, und dies ganz gleich- gültig was für Zahlen 74, m»... sind, wenn sie nur nicht alle Null sind. (Satz 8). Satz 49. Es sei die Gleichung gegeben y -—AQ()y" +++ + Ant), wo Ai... An nach fallenden ganzen Potenzen von x mit rationalen Koeffizienten entwickelt werden künnen, wobei diese Entwicklungen aber hier bloß als Elemente mehrdeutiger Funktionen vorausgesetzt werden. + 1921. No.1 7. VERTEILUNGEN GANZZAHLIGER LÖSUNGEN GEWISSER GLEICHUNGEN. SE Diesen Reihen haben dann einen gemeinsamen Konvergenzbereich xz | > M. Werden nur die Werte von x innerhalb dieses Bereiches betrachtet, kön- nen wir die durch die n Reihen gegebenen Zweige der Funktionen fest- halten. Werden diese Zweige festgehalten, so hat die Gleichung bloß endlich viele Lösungen in ganzen rationalen Zahlen x und y, falls keine ganze algebraische Funktion von x statt y eingesetzt die Gleichung befriedigt. In der Tat wird der Beweis für Satz 41 Wort für Wort auch hier gültig bleiben, wenn man bemerkt, daß höchstens n reelle Zweige der durch die Gleichung dargestellten Kurve existieren können, welche den betreffenden festgehaltenen n Zweigen der Koeffizientfunktionen À ent- sprechen. Bedeutet (A) der Funktionenkórper, der aus allen analytischen Funk- tionen besteht, die rational durch eindeutige Funktionen, welche nach fallen- den Potenzen von x mit rationalen Koeffizienten entwickelt werden können, und die betrachteten Zweige der Funktionen 4, ... An ausgedrückt werden können, so gilt auch innerhalb L(A) der Satz von der eindeutigen Dekom- position reduktibler ganzer Funktionen von % in irreduktible. Damit keine ganze algebraische Funktion der Gleichung Genüge leisten soll, wenn diese als irreduktibel vorausgesetzt wird, ist nun notwendig und hinreichend, daß mindestens eine der Funktionen A entweder mindestens eine nicht- algebraische Verzweigungstelle hat oder eine Singularität im Endlichen, die kein Verzweigungspunkt ist. Jede ganze algebraische Funktion befrie- digt ja auch in Z (4) eine irreduktible Gleichung, deren Koeffizienten eben- solche Funktionen sind, und die übrigen Wurzeln sind also auch ganz- algebraisch. Hat nun die gegebene Gleichung eine Wurzel y, die ganz- algebraisch ist, so müssen alle Wurzeln solche sein und folglich auch die Koeffizienten. Die erwähnte Bedingung ist also hinreichend; denn ist sie erfüllt, sind die Funktionen 4}, ..., 4, nicht alle ganz-algebraisch. Anderer- seits ist die Bedingung notwendig; denn ist sie nicht erfüllt, sind A,,.., An alle ganz algebraisch und folglich auch alle Wurzeln y. Die Voraussetzung in den Sätzen 41 und 42, daß die Funktionen 4,(7) Entwicklungen nach fallenden ganzen Potenzen von x besitzen, kann durch die schwächere, daß sie nach fallenden gebrochenen Potenzen entwickelt werden können, ersetzt werden, wenn nur die Koeffizienten rational! sind. Das rührt einfach davon her, daß eine Gleichung der Form 1 s (es y) = 0 1 Oder allgemeiner einem algebraischen Körper R angehören. TH. SKOLEM. M.-N. KI. Ul D nicht erfüllt sein kann, ohne daß gleichzeitig 1 1 1 F(a, y) — f (er y) f ( an, ») Far: f 5 rn y) 0 erfüllt ist, wo e eine primitive nte Wurzel der Einheit ist. Falls nun 1 re y) =0" + ay (x) 9° ++ am (7), I wobei «d, (x) (r — 1,..., m) nach fallenden Potenzen von «" mit Koeffi- zienten in À entwickelt werden kann, wird augenscheinlich F(z, y) eine Funktion der Form TER A la hen + Amn (x), worin A,(x) (r =1,..., mn) eine Entwicklung nach fallenden ganzen Potenzen von 4 mit Koeffizienten in Æ hat. Außerdem kann keine ganze algebraische Funktion y von x der Gleichung F'(x, y) = 0 Genüge leisten, ohne dafs mindestens eine der Gleichungen 1 1 1 16 » = 0, f ( en, „)= 0,:::, reum ») —10 dadurch befriedigt wird. Daß aber eine ganze algebraische Funktion 7 1 von « die Gleichung f 6 xm, » = 0 befriedigt, ist damit gleichbedeutend, 1 dafs eine ganze algebraische Funktion von x die Gleichung (en) = 0 befriedigt. Wenn also umgekehrt keine ganze algebraische Funktion 1 die Gleichung f (ov) — 0 befriedigt, so gilt dasselbe für die Gleichung F(x, y) — 0 i Da nun die letztere Gleichung nach den Sätzen 41 und 42 bloß end- lich viele Lösungen in ganzen Zahlen x und y hat, muß dies auch für die erstere gelten. Ich gebe zuletzt einige weitere Bemerkungen zu den früher bewiese- nen. Sätzen. Es sei f(x) eine Reihe der Form Qna + + asa e+ iy + OH + 1 1 Falls nåmlich rro. H (x) — 0 identisch ist, wobei (x) ganz alge- n braisch ist, so ist, wenn 72 — gesetzt wird, auch h (E) —.H (E) eme ganze aloes Funktion dud folglich eus h(e* &). Es ist aber FE h( (e-* 8) — 0 eine Identität, weil f EEE) Or est. I92I. No.ı 7. VERTEILUNGEN GANZZAHLIGER LÖSUNGEN GEWISSER GLEICHUNGEN. 53 worin die Koeffizienten An+i, An+2... nicht alle gleich Null sein sollen. (Vergl-- Satz 9). Es ist dann leicht zu sehen, daß man eine so große positive Zahl X angeben kann, dafs mindestens einer der Funktionswerte f (x + r;), wobei EEUU e Xe -— Fu wie früher, nieht eine »ganze Zahl sein kann, wenn |x| > X ist. Ist nàmlich die Konstante B (Seite 12 unten) eine ganze rationale Zahl und A — Max (A, 4,,..., Au), so braucht man nur X so groß zu wählen, daß X 7» rx und außerdem die Summe [ @n41 An+2 Est S14 pix (t + et + ) ann Z nie mehr Null für endliches x, wenn |2|>X ist (dies muß ja möglich sein, weil ein identisches Verschwinden dieser Summe nach Satz 6 bewir- ken würde, daß die Koeffizienten 4441, dn+2, ... alle Null sein müßten), und | An+1 | | An+2 | 1l an, Penn — Ne is (u 4-1) A wird, was offenbar stets móglich ist, da die Reihe für hinreichend große x konvergent sein soll. Hierdurch wird nämlich für alle z, für welche |z| — X ist, und für jedes 2 I (Ua 1 Fi (n+2 wt ny LIRE | | | An+1 An+2 | | An+2 i zx | Un: "t | (n 4-2 | pathos + (| EL. n? UP Ws E ar (X NL 12 d = A | und folglich wird (Seite 12 unten) o<|saf(e *tu)-B|« P. | 5 so daß 2 A,;f(x-+7;) nicht ganz ist. Da jede Zahl A, ganz ist, folgt hieraus, daf3 mindestens eine der Zahlen f(x + r,) nicht ganz ist. Ist dagegen D nicht ganz, so sei sie zuerst reel und B= D, + b, wo I D, die nächste ganze rationale Zahl bedeutet, so dafs |b! Si ist. Dann braucht man nur X so groß zu wählen, daß X 7 r4, und 54 TH. SKOLEM. M.-N. KI. Mie An+2 | = lj : + - = > Pa Pr << X ZU (X LT, JE iL (u —]) A wird. Dann bekommt man nämlich, wenn |x! > X ist | = Kol SA dm+1 An+2 me >> (x 3 | D (EL za [et 4 Ima E SAN +r,)-B|> X. Man hat ja nur X so groß zu wählen, daß die Reihen (fo (x), ..., Pal), un (x), ..., w«(x) (Seite 14 unten) alle hinreichend klein werden, wenn |x| > X ist. Ich glaube nicht, dafs es nötig sein kann dies näher auszuführen. Ebenso kann man X so grof positiv annehmen, daß wenn | > X, für mindestens einen der Werte x, x + 4, ..., © + ru von x keine Wurzel y einer Gleichung der im Satze 11 betrachteten Form ganz rational sein kann, falls nicht eine ganze rationale Funktion von x die Gleichung iden- tisch befriedigt. Ich will dies etwas näher zeigen. Die betrachtete Gleichung sei f{x, y) = 0. Die Zweige von y als Funktionen von x seien fi (X)... fn (x); sie können wie früher gezeigt für hinreichend große x konsekvent unterschieden werden. Weiter sei u eine ganze positive, Zahl, % 0, 0 e aet re m Tp» nd. ‘alle, yo sane rational. Gibt man %, à,..., tu beliebige (gleiche oder verschiedene) Werte unter den Zahlen 1,2,...;n, bekommt man n“+t! verschiedene Wertsy- steme. Für jedes dieser n“+! Wertsysteme besitzen die Funktionen fi, ( + 79 (£— 0, 1, 1% 4,44) Reihenentwicklungen nach fallenden (gebrochenen) 1921. No.17. VERTEILUNGEN GANZZAHLIGER LÜSUNGEN GEWISSER GLEICHUNGEN. D Potenzen von x. Mann kann u so groß wählen, daß in jedem der n“+1 Gleichungssysteme (nämlich Reihenentwicklungen) die Potenzen von .r mit positiven Exponenten eliminiert werden können (Vergl. Seite 15). Man erhält durch diese Eliminationen x“ *! Gleichungen der Form(Vergl.Seite 15) i“ u 0) - » (0) (0) (0) Or (0) N Hs fs, (x iB i — B JE q. (x) c > EN (y. (x) SØ D (x), t—0 <= (oc 2 aus À 0) UE ( A A : N ; : worin FOG oe, pe (7), wr (x)... Wy (x) ähnliche Reihen sind wie die Reihen p und w Seite 14 unten. In jeder dieser Gleichungen kann man . e = E en ees : ein so großes positives Xo wählen, daß X Ay’ f,, (x + i) nie mehr ganz sein kann, wenn |r| — Xo ist Setzt man X — Max (X,,..., Xqu41) ) wird also in allen «^ '! Gleichungen x AW Az +7.) nicht ganz, wenn |x| > X ist. Hieraus folgt aber, daß für mindestens ein t (i = 0, 1,. .., u) alle Funktionen fi (x + 7,),..., fa (+ + 74) nicht ganze Zahlen sind. Ähnliche Bemerkungen können zu den folgenden Sätzen gemacht werden. Betrachtet man z. B. das Gleichungssystem des Satzes 16’, so hat man: Falls nicht n Polynome / (x)... Pn (x) existieren, welche statt Y1-..Yn eingesetzt den Gleichungen identisch genügen, so gibt es, wenn |z| > ein gewisses X ist, unter den Zahlen x, x +r1,..,% + ru, wenn a hinreichend groß ist und 7,,...,r« eine beliebige Reihe wachsender ganzer rationaler Zahlen, mindestens eine, für welche die Gleichungen in bezug auf die y nicht ganzzahlig auflösbar sind. Man kan auch so sagen: Teilt man die Zahlenreihe in Intervalle einer hinreichend großen Länge /, so kann man in jedem Intervall Zahlen x, auch ganze rationale, wirklich angeben, für welche die gegebenen Glei- chungen kein ganzzahliges Wurzelsystem $4... %/n besitzen. Betrachtet man den Satz 21, so kann man in analoger Weise Zahlen x angeben, auch ganze rationale, für welche F' (x, y) eine irreduktible Funk- tion von y in À wird, wenn F(x,y) in Z irreduktibel ist. Es ist auch leicht zu sehen, daß die Zahlen x in R, für welche F (x, y) irreduktibel in R ist, überall dicht im Körper R liegen. Es sei nämlich der Körper R vom Grade g in einem g-dimensionalen Raume abgebildet; d.h. die Punkte dieses Raumes mit rationalen Koordinaten stellen dann die sämt- lichen Zahlen des Körpers A dar. Es seien nun « und b zwei beliebige Zahlen des Körpers À. Macht man jetzt die Transformation b— a Ty 4 x == a+ 56 TH. SKOLEM. M.-N. Kl. so sieht man, daß so oft %, eine absolut rationale Zahl zwischen 1 und + c ist, ist æ eine Zahl in R auf der Verbindungsstrecke zwischen den Punkten a und 5b, und umgekehrt. Durch diese Transformation geht F(r, y) in eine Funktion Fy (.,,y) über. Allerdings ist Fy (74, y) in bezug auf 7 ge- brochen, aber man kann mit einer solchen ganzen Funktion von %, allein multiplizieren, daß das Produkt eine primitive durchaus ganze Funktion G (21, y) wird, welche natürlich auch in JZ irreduktibel sein muß. Dann kann man aber in ebenso ausgedehntem Maße wie früher ganze Werte von #, angeben, für welche G (a, y) und also auch F, (r,, y) in FB irre- duktibel wird. Dies bedeutet, daß man auf der Verbindungsstrecke zwischen den Punkten @ und ^ unendlich viele Zahlen x in R finden kann, für welche F'(x, y) irreduktibel in À ist. Weiter muß folgender Satz gültig sein: Satz 21°. Es sei die Funktion F(x, y) Fx, Ay + Ay 4-4 worin Ay... An Polynome sind, deren Koeffizienten einem Körper R (Satz 21) angehören, das Produkt einer gewissen Zahl irreduktibler Faktoren Fey)—-RA&y) jhe im Körper L (Satz 21). Höchstens ausgenommen eine Klasse ganzer rattonaler Zahlen mit nur verschwindender Dichte muß für jede ganze rationale Zahl x die Funktion F(x,y) im Körper R genau in derselben Weise aus irreduktiblen Fuktoren zusammengesetzt sein, d. h. die Funk- tionen F(x, Yy),..., Fr(r, y) bleiben auch in R irreduktibel, und außer- dem bleiben ste von einander verschieden. Beweis: Nach Satz 21 kann die Klasse K, (r=1,2,...,v) ganzer rationaler Zahlen x, für welche F(z, y) reduktibel in A wird, nur die Dichte Null haben. Nach Satz 1 hat also die Klasse À aller ganzer ratio- naler x, für welche mindestens eine der Funktionen F (7, y),..., Fr (x, y) reduktibel in À ist, die Dichte Null. — Soll für ein x eine Gleichung der Form 8 Fei y) = Fale (res | = m = identisch in y stattfinden, so bekommt man hieraus, da dies jedenfalls keine Identität sowohl in x als y ist, gewisse Gleichungen in x allein, welche keine Identitäten sind. Also erhält man bloß endlich viele Werte von x, für welche irgend eine Gleichung der Form F, (x, y) = F (x, y) identisch in y gültig sein kann. I92I. No.r 7. VERTEILUNGEN GANZZAHLIGER LÖSUNGEN GEWISSER GLEICHUNGEN. 57 b—a Mit Hilfe einer Transformation der Form x = 4 + wird man 2 natürlich wieder beweisen können, daß die Zahlen in R, für welche eben die erwähnte Art der Reduktibilität stattfindet, überall dicht in A liegen. Auf dieser Grundlage kann man entsprechende gruppentheoretische Sätze aufstellen,! so z. B. den folgenden Satz: Es habe die Gleichung f (2, y) — 0, wo f(x,y) ein Polynom mit Koeffizienten in einem algebraischen Zahl- körper R ist, in dem Körper L aller rationaler Funktionen von x mit Koeffizienten in R eine Gruppe G. Dann hat für jede ganze rationale Zahl x, höchstens ausgenommen eine Klasse mit Dichte Null, die Glei- chung dieselbe Gruppe G in Körper R. Beweis: Man bilde eine Galoische Resolvente À (x, z) der Gleichung für den Körper L. Man kann z.B. 24 = u, :4 + W Ya + + ++ + Un ya setzen und 4... 4, als ganze rationale Zahlen so wählen, daß die n! Ausdrücke, welche durch alle möglichen Umstellungen der n Variablen y erhalten werden, alle innerhalb Z verschieden sind, d.h. keine zwei identisch gleich in bezug auf x. Bezeichnen 2 ...2n: diese n! Ausdrücke, so sind sie die Wurzeln einer Gleichung H (z, z) — 0, und A(z, z) = 0 ist eine Galoische Resolvente, wenn À (x, 2) ein irreduktibler Faktor von H (x, 2) ist. Die Funktion Z(z,z) zerfällt also in das Produkt einer gewissen Zahl irreduktibler Faktoren in /, und einem beliebigen dieser Faktoren ent- spricht in bekannter Weise die Gruppe G. Nach dem Satze 21’ bleibt aber die Art der Zusammensetzung von H (7, 2) aus irreduktiblen Faktoren genau dieselbe in À für jede ganze rationale Zahl x, wenn eventuell eine gewisse Menge solcher Zahlen der Dichte Null ausgenommen wird. Dies bedeutet aber, daf3 mit der erwähnten Ausnahme die Gruppe der Gleichung dieselbe bleibt. Natürlich wird man auch hier beweisen können, daß die Zahlen in À, für welche die Gruppe der Gleichung eben G ist, überall dicht in À liegen?. Mehrere interessante Bemerkungen ließen sich für den Fall einer größeren Zahl von Variabeln aufstellen; ich will aber hier nicht näher darauf eingehen. 1 Vergl. HizBerr 1. c. 2 Vergl auch H. WEBER, Lehrbuch der Algebra, Kl. Ausg., Braunschweig 1912, $ 83. pv Mæn 119 Donne arbe magia 5 n CUR. » Wr Weir Dre et pu À dm i. do mee ma jk Sy BERICHT UBER DIE NACHGELASSENEN SCHRIFTEN BE LOWS VON TH. SKOLEM (VIDENSKAPSSELSKAPETS SKRIFTER, I. Mar..Narurv. Krasse. 1921. No. 18) UTGIT FOR FRIDTJOF NANSENS FOND KRISTIANIA IN KOMMISSION BEI JACOB DYBWAD 1922 Fremlagt i fællesmøtet den 3dje mai 1921. x x SE einigen Monaten habe ich die nachgelassenen Schriften L. SyLows zum Durchsehen gehabt. Erstens habe ich untersucht, ob etwas auffallend neues darunter vorkomme; in dem Falle wäre eine sofortige Publikation wünschenswert gewesen. Es zeigte sich aber bald, daß das nicht der Fall war. Zweitens dachte ich ursprünglich alles zu kassieren, das nicht von mathematisch-wissenschaftlichem Werte war; da es aber oft schwer war diesen Wert zu beurteilen, und die Papiere vielleicht auch sonst (z. B. historisch, biographisch, pädagogisch) Interesse haben könnten, habe ich nur ganz wenige Papiere entfernt, nämlich solche, welche völlig wertlos oder über- flüssig waren. Drittens habe ich — und das ist meine wesentliche Arbeit gewesen — die (übrigen) Papiere katalogisiert und dem aufgestellten Ver- zeichnis entsprechend in Pakete verteilt. Nach dem Verzeichnis zerfallen die Papiere in 6 Abteilungen I—VI, wovon die erste wieder in Iı und Is geteilt wird. Diese Abteilungen enthalten bezw.: I. Originalarbeiten. A) Manuskripte früher publizierter Abhandlungen oder Studien, die dazu Anlafs gegeben haben. 9 Pakete. B) Andere Originalarbeiten oder Studien, welche nicht mit be- stimmten Abhandlungen anderer Mathematiker verknüpft zu sein scheinen. 20 Pakete. ll. Studien (zum Teil Kritik), welche Abhandlungen anderer Mathe- matiker betreffen. 22 Pakete. III. Vorlesungsmanuskripte. r9 Pakete. IV. Biographien, Urteile beim Besetzen von Professoraten und ähnliches. 4 Pakete. V. Papiere, welche die Herausgabe der Werke Abels und zum Teil auch die Sekulärfeier Abels betreffen. 6 Pakete. Vi. Briefe; 4 Pakete, Die Pakete sind dem Verzeichnis entsprechend numeriert worden. Sie enthalten zum Teil mehrere Manuskripte, welche dann mit Buchstaben ab, 2. versekien. sind. 4 TH. SKOLEM. M.-N. Kl. Von dem Verzeichnis habe ich einen Auszug gemacht, der die wichtig- sten Papiere aufzåhlt, nåmlich diejenigen, welche vielleicht neue mathe- matische Resultate enthalten. Dieser Auszug ist hier unten gedruckt worden. Die in eckigen Klammern hinzugefügten Zahlen beziehen sich auf die Paketennummer des vollen Verzeichnisses. Die in diesem Auszug-aufge- zählten Manuskripte sind alle auf norwegisch geschrieben. Die Papiere werden in der hiesigen Universitätsbibliothek aufbewahrt; ihre Nummern in dem Kataloge der Bibliothek sind unten mit Ms. Fol. bezeichnet, und diese Bezeichnung ist bei jeder Requisition zu benutzen. Auszug des Verzeichnisses der nachgelassenen Schriften. I. Über Gruppen vom Grade n3.1 Ms. Fol. 736. (74, 7e]. Mehrere Manuskripte mit einem von SyLow selbst verfaßten Inhalts- verzeichnis. Dies Verzeichnis ist folgendes: » £ | a. Dehandlung von Gruppen 8ten Grades u.a. 3 € 4b. Gruppen, deren Ordnung? eine Potenz einer Primzahl ist, hauptsächlich 9. an | c. Über Gruppen vom Grade ». |d. Etwas darüber, daß Dp und / hinreichend sind, so daß Do.. Dh-ı vernach- lissigt werden können, Mit roter Farbe von 12—21 numeriert. e. Die Gruppe A. + | f£ Anfang einer Behandlung der Frage, was für eine Form die Ordnung der a Gruppe G hat. Fälle, in welchen 2G — nv (n°p+1) ist. i g. Die Gruppe Ho; mit blauer Farbe von 1—57 numeriert. A h. Welche (transitive) /Gruppen künnen in mehreren verschiedenen Cauchy- = schen Gruppen (/-Gruppen) enthalten sein; mit roter Farbe von r— rr und 5 mit schwarzer von r—20 numeriert. i. Über Gruppen vom Grade #5. Auf Grundlage des Verhältnisses der Gruppen zur Causchyschen gegründet. Seitenzahlen von 1— 120 mit roter Farbe, blau unterstrichen. Einige Rechnungen beigelegt, die gemacht waren, da die Arbeit im Anfang 1885 zur Seite gelegt wurde. i Außerdem fügt Syrow folgende Bemerkung hinzu: »Die Pakete A und + sind die wichtigsten; 7 greift etwas zurück. Es kommen einige Resultate vor; vieles steht doch noch aus, und es scheint nicht leicht zu sein eine solche Arbeit zu liefern wie die über den Grad #?. Sollte aber das gelingen, wäre vielleicht weitere Verallgemeinerung möglich«. 2. Einige Papiere in einem Briefumschlag, auf welchem geschrieben ist: »Minimale unauflósbare Gruppen von Primzahlgrad (r—6); die Untergruppen der Cauchygruppe (1—9); Sätze, welche gebraucht werden können (nämlich beim Aufsuchen aller primitiven Gruppen gegebenen Grades) (4—C); nütz- licher Satz beim Aufsuchen aller primitiven Gruppen gegebenen Grades (1—3)«.. Ms Pol 742. Ty. 4]. 1 Syrow denkt sich immer die Gruppen als Substitutionsgruppen. Er unterscheidet des- halb ,Ordnung’ und ,Grad’; der Grad ist die Zahl der Dinge, welche untereinander vertauscht werden, während die Ordnung die Zahl der Substitutionen der Gruppe ist. 2 Es steht Ordnung, soll wohl aber Grad sein. 1921. No. 18. BERICHT ÜBER DIE NACHGELASSENEN SCHRIFTEN L.SYLOWS. 5 3. Die primitiven Gruppen niedrigsten Grades. Eine grofe Arbeit, 125 Seiten; enthält eine Untersuchung darüber, welche primitiven Gruppen von den niedrigsten Graden, nämlich von ı bis 15, vorhanden sind. Ms. Fol. 743. Is: 5]. 4. Umschlag mit dem Titel: »Spezielle Resultate über die Konstitution der Gruppen«. (Herbst ıgor). Enthält erstens 12 Seiten, welche davon handeln, wie viele Untergruppen der Ordnung pé die Gruppe I der Ord- nung p« enthält, wenn / Untergruppe einer Gruppe G der Ordnung per (np + 1) ist. Zweitens 17 Seiten, wesentlich über die Folgerungen aus der Voraussetzung, daß I zyklisch ist. Ms. Fol. 749. [Is, 11). 5. Umschlag mit dem Titel: »p und -—- Primzahlen«. Eine Unter- )—I suchung über die Gruppen vom Primzahlgrad p, wenn Ee - auch Primzahl D ist. Die letzten 7 Seiten scheinen die Resultate zu enthalten. Wahr- scheinlich von 1910. Ms. Fol. 750. [Jp, 12]. 6. Eine Verallgemeinerung eines Satzes von Mathieu. 8 Seiten. Der Hauptsatz, der hier bewiesen wird, ist: Wenn eine Gruppe G eine (kleinere) Untergruppe 4 enthält, welche nicht mit anderen Substitutionen in G als ihren eigenen permutabel ist, so gibt es unter den zu H konjugierten . Gruppen mindstens eine, welche mit /7 andere Substitutionen gemein hat als die identische. Ms. Fol. 753. [J5, 15]. 7. Ms. Fol. 754. a) r3 Seiten (die Paginanummer in roten Kreisen mit blauem Bleistift geschrieben). Handeln von der Cauchygruppe vom Grade p^. Es wird angefangen mit Betrachtungen über Einteilungen der p?" Elemente in p"-* Systeme mit je p* Elementen und entsprechende Einteilungen der Substi- tutionen in Klassen nach der Art, wie sie diese Systeme untereinander vertauschen. Nachher folgen »Untersuchungen über Gruppen vom Grade n? auf dem Verhältnis zur Cauchyschen Gruppe gegründet«. Diese letztere Untersuchung schließt sich an die oben unter 1. erwähnte Arbeit. Tp, 162]. b) Seiten @«—% (mit rotem Bleistift paginiert) nebst zwei beigelegten Blättern mit Rechnungen. Scheinen ähnliche Untersuchungen wie a) zu enthalten. Die letzten Seiten (h—A) enthalten etwas: über Kongruenzen mit mehreren Variabeln nach Primzahlmoduln. JB, 16e): 8. Einige Studien über Gruppen, deren Grad eine Primzahl oder das doppelte einer Primzahl ist. Ms. Fol. 755. a) Seiten 1—8 (mit Tinte paginiert). Scheinen wesentlich Unter- suchungen zu enthalten über Gruppen @ der Ordnung p*z (np + 1), innerhalb welcher eine Untergruppe / der Ordnung p* zyklisch ist. (Vergl. 4 oben). [Is, 17]. 6 TH. SKOLEM. M. N. Kl. b) 4 Seiten (mit Tinte paginiert). Eine Studie über Gruppen ( vom Primzahlgrad p und der Ordnung px (Np + 1). Scheint besonders den Fall zu betreffen, da @ einfach ist. [/p, 17.]. c) Seiten a—l (mit rotem Bleistift paginiert). Es wird eine Gruppe 6 von der Ordnung (Np + 1) px und dem Grade p (p Primzahl) betrachtet, wobei sie eine Untergruppe H der Ordnung (np + 1) pre enthält; H wird maximal angenommen, und A, H,... Hm-ı sind die sämtlichen zu H konjugierten Gruppen. Der Durchschnitt von Hy und H, wird J genannt. Für diese Gruppe I werden 3 Möglichkeiten angegeben, welche Gegen- stand weiterer Diskussion sind. [/p, 7e]. d) 5 Seiten (mit Tinte paginiert); außerdem 5 Blätter mit Rechnungen. Es werden Gruppen vom Primzahlgrade p und der Ordnung (np + 1) pre betrachtet, n wird > o angenommen. Die Untersuchung betrifft die Kon- stitution solcher Gruppen auf die Existenz einer Substitution von der Ord- nung p und einer anderen 2ter Ordnung basiert. |/p, 176. e) 11 Seiten (mit rotem Bleistift paginiert; vom Sommer 1909). Handeln von Gruppen der Ordnung p (np + 1)z. Der Fall » = r ist besonders studiert. [/p, 17g]. f) 11 Seiten (mit Tinte paginiert; Dez. 1912). Es werden transitive Gruppen vom Grade 2 yp, p Primzahl, und der Ordnung pz (np + 1) studiert. Von der Seite 2 an wird vorausgesetzt, dafs auch gt eine Prim- zahl ist. [Zp, 171]. g) 44 Seiten (mit Bleistift paginiert; Jan.—April 1913). Gruppen der Ordnung (np + xr) pz werden untersucht. Die Untersuchung betrifft, welche Substitutionen die np + 1 H-Gruppen der Ordnung pr enthalten und die größte gemeinsame Untergruppe dieser Gruppen usw. [/8, 171]. gu "Ms: Foltys6: a) 5 Seiten (mit Tinte paginiert; Weihnachtsferien 1913— 14) in einem Umschlag mit Titel: »Maximale, nicht-invariante Untergruppe; es wird angenommen, daß sie keine andere Substitution als die identische mit ihren konjugierten gemeinsam hat«. [/p, 182]. b) Seiten 1—3 (mit rotem Bleistift paginiert), a—g (mit rotem Bleistift), und 26 beigelegte Blätter. In einem Umschlag gelegt, worauf geschrieben ist: »Betrifft maximale, nicht-invariante Untergruppe«. [/p, 182]. c) Seiten 1—8 (mit blauem Bleistift, rot unterstrichen, paginiert). [/p, 18e]. Alle hier unter 9 aufgezählten Papiere enthalten ähnliche Unter- suchungen wie die oben unter 6 erwähnte. 1921. No. 18. BERICHT UBER DIE NACHGELASSENEN SCHRIFTEN L.SYLOWS. 7 10. Papiere in einem Umschlag, worauf geschrieben ist: »Uber maxi- male, nicht-invariante Untergruppe«. 47 Seiten. Enthält besonders Unter- suchungen über die Substitutionen der ganzen Gruppe, welche in keiner der mit der maximalen Untergruppe konjugierten Untergruppen vorkommen. Ms. Fol. 757. [Js, r9]. 11. Vorlesungen über »Composition und Auflósung« (1893). Ca. 120 Seiten mit Tinte und 19 Seiten mit rotem Bleistift paginiert. Außerdem sind 4 Seiten Umarbeitung der Seiten 41—44 und 19 Seiten Umarbeitung der Seiten 58—88 beigelegt. Weiter sind auch beigelegt 89 Seiten mit Rechnungen, die hierher zu gehóren scheinen. Handeln von der An- wendung der Substitutionstheorie auf algebraische Gleichungen. Ms.Fol. 783. [EFIE]. DIE STRUKTUR DES NORDLICHTS UND DIE ART DER KOSMISCHEN SER ARDEN VON LE VEGARD KRISTIANIA IN KOMMISSION BEI JACOB DYBWAD 1921 Fremlagt i den mat.-naturv. klasses mote den 23de september 1921. Die Lichtverteilung und ihre Deutung. Wir können es jetzt als festgestellt ansehen, dafs das Nordlicht dadurch gebildet wird, dafs elektrische Strahlen von der Sonne in die Atmosphäre der Erde hineindringen. BIRKELAND und STORMER haben zeigen können, daß diese Hypothese eine Reihe typischer Züge beim Nordlichte, wie die Nordlichtzone, das Auftreten des Nordlichts bei Nacht, sein Auftreten in langgestreckten Bogen und Banden, die den magnetischen Parallelen entlang annähernd gerichtet sind, und endlich die schnellen Änderungen des Nordlichts, erklären kann. Es gibt aber viele Eigentümlichkeiten, die eine nähere Aufklärung brauchen. Unter diesen Verhältnissen werde ich mich heute der Frage der Struktur des Nordlichts besonders widmen, einer Sache, mit welcher ich mich seit vielen Jahren beschäftige, und welche, in Verbindung mit der Frage von der Art der kosmischen Strahlen, die das Nordlicht hervorrufen, besonders großes Interesse hat. Bei diesen Untersuchungen ist es mir auch gelungen, über diese Verhältnisse neues Licht zu werfen. Wir können uns die verschiedensten Nordlichtformen aus Strahlen- bündeln gebildet denken, welche sich aneinander zusammenfügen. Diese Strahlenbündel sind, wie wir wissen, annähernd den magnetischen Kraft- linien entlang gerichtet. Wir sollen jetzt ein solches einfaches Strahlen- bündel (ein Nordlichtelement) betrachten, und besonders die Lichtverteilung einem solchen entlang ins Auge fassen. Diese Lichtverteilung muß teils für die Zusammensetzung der Atmo- sphäre Ausdruck geben, teils ist sie von der Natur der kosmischen Strahlen und teils von der Weise, in welcher diese absorbiert werden, bedingt. Das Studium dieser Lichtverteilung hat daher großes Interesse, beson- ders wenn sie mit der Bestimmung der Höhe des Nordlichts über der Ober- flache der Erde zusarmmengehalten wird. Mit Hülfe eines großen Materials Nordlichtphotographien, von Direktor Krocness an dem Haldde Observatorium aufgenommen, bin ich im Stande gewesen, die Frage der Lichtverteilung einer recht eingehenden Unter- suchung zu unterwerfen, und ist es von einem Teil der dabei gewonnenen Ergebnisse, daß ich hier eine kurze Mitteilung geben möchte. Anm. Vortrag bei der Sitzung der Wissenschaftgesellschaft (mat.-nat. Kl.) am 23. September 1921 gehalten. 4. L. VEGARD. M.-N. Kl. Eine kurze Ubersicht dieser Ergebnisse wurde auf dem Geophysiker- tage in Göteborg im Jahre 1918! gegeben, und eine ausführliche Dar- stellung findet man in einem Werke, das als Einleitung der Geophysikalischen Publikationen? erschien, sowie in einer Abhandlung in Phil. Mag., die am 8. Oktober 1920 eingesandt wurde.’ Eine genaue Bestimmung der Lichtverteilung würde eine genaue Photo- metrierung der Schwärzung mit Schwärzungskurven auf jeder Platte ver- langen. Das Material gestattete nicht eine solche Behandlungsweise, und ich mußte mir damit helfen, die Lichtverteilung durch Ausmessung der Entfernung von dem untersten Ende (Rand) bis zu gewissen charakteri- stischen Punkten B,, B, und B, (Fig. 1) in der Lichtverteilungskurve zu charakterisieren, nämlich: Die Länge 1, oder die Entfernung vom unteren Rand bis zum Maxi- mum des Leuchtens. Die Lange L, oder die Entfernung vom unteren Rand bis zu dem Punkte, wo das helle Leuchten aufhört. Die Länge 1,, oder die Entfernung vom unteren Rand bis zur oberen beobachtbaren Grenze. Es zeigte sich, daß die Größen 1,, L und 1l, ganz bedeutenden Änderungen unterworfen sind. Die Variation geht aus den Kurven Fig. 2 hervor. Die Ordinaten repräsentieren die Längen (1, 1, und lj. Diese |! L. VEcARD, Verhandlungen auf dem skandinavischen Physikertage in Göteborg den 28. August 1918, pag. 12. 2 L. Vecarp, & O. Krocness, The Position in Space of the Aura Borealis. Geophys. Publ; Vel.r, nr. 5 1920: 3 L. VEGARD, Phil. Mag. XLII, 1921, pag. 47. Distance from bottom edge Bottom Edge 1921. No. 10. DIE STRUKTUR DES NORDLICHTS. 5 sind in gleiche Intervalle geteilt, und als Abszisse dient die Anzahl Fälle, wo die betrachteten Größen zwischen zwei Ordinatintervallen fallen. Die Kurven repräsentieren mit anderen Worten die Häufigkeit als Funktion der Länge für die drei Größen 1,, L und L. Wir können sagen, dafs sich das Licht für Bogen und draperieförmige Bogen wesentlich in der Nähe des unteren Endes der Strahlen sammelt. 5 Number L, = Distance from bottom edge to maximum of light intensity —— Arcs lp ” " n » » the limit of strong luminosity —— —— Draperyshaped Arcs Ls ” ” ” ” " ” " n" feeble É RE Draperies Fig. 2. Für Draperien zieht sich das Licht weiter hinaut, und für Strahlen noch weiter. Besonders deutlich tritt dies hervor, wenn man l, (die ganze Aus- dehnung des Leuchtens) betrachtet. Für diese wurden die Durchschnitts- werte der beigefügten Tabelle gefunden: BS Bogen Qugtsugo Cr EC 14 Km. | 109,1 Km. Draperieförmige Bogen .......... AT: TOC 6, DrADETENN ae E 623m» 109,099 Strahlem ar mco eae ences Tee E37 = 1 I5 4 un 6 L. VEGARD. M.-N. KL In der Tabelle sind auch die Durchschnittshöhen (h) für die untere Grenze aufgeführt worden. Die diffusen Bogen zeigen wahrscheinlich, wegen systematischer Fehler bei der Bestimmung, eine zu große Höhe. Nimmt man dies in Betracht, zeigt die untere Grenze eine Verschiebung aufwärts, welche mit der Änderung der Strahlenlänge parallel geht. Gleichzeitig damit, daß sich die obere Grenze des Leuchtens aufwärts zieht, wird die Höhe der unteren Grenze des Nordlichts etwas vergrößert. Die Höhenänderung ist aber verhältnismäßig unbedeutend im Verhältnis zu der großen Änderung der Lichtverteilung. Und es verhält sich nicht so, daf die Lichtverteilung eine Funktion der Nordlichthöhe ist, denn man findet häufig, dafs Nordlichter, welche zu derselben Höhe hinunterreichen, eine ganz verschiedene Lichtverteilung zeigen. Variationen in der Lichtverteilung können also nicht davon herrühren, dafg die Nordlichter in verschiedener Höhe, also in verschiedenen Schichten der Atmosphäre, auftreten. Müssen wir auch mit der Möglichkeit rechnen, daß die kosmischen Strahlen nicht immer identisch sind, so werden die hier beobachteten Varia- tionen der Lichtverteilung doch nicht von einem Wechseln der Eigen- schaften der Strahlen herrühren können. Dies folgt daraus, daf Nordlichter in derselben Höhe verschiedene Lichtverteilung geben, und sogar dasselbe Nordlicht wird allmählich, oder sogar plötzlich, die Lichtverteilung ändern können. Eine Form wird nach und nach in eine andre Form mit verschie- dener Lichtverteilung übergehen können, ohne ihre Lage zu ändern, und man muf3 voraussetzen, daß ein gewisses Band durch homogene Strahlen gebildet wird. Wir werden also mit Notwendigkeit zu der Annahme geführt, daß Strahlen derselben Art je nach den Umständen eine verschiedene Lichtver- teilung geben können. Nun wissen wir indessen, dafs ein Strahlenbündel, das in einen gas- gefüllten kraftfreien Raum hineindringt, einem bestimmten Gesetze gemäß absorbiert wird und dementsprechend eine bestimmte Lichtverteilung geben muß. Die erwähnten Variationen müssen deshalb durch die Wirkung von Kraftfeldern verursacht werden. Unter der Voraussetzung, daß wir von der Wirkung von Kraftfeldern wegsehen können, habe ich früher die Lichtverteilung für %-Strahlen und Elektronenstrahlen, die in der Atmosphäre absorbiert werden, bestimmt.! Es zeigte sich, dafs die berechnete Lichtverteilung von «-Strahlen gewisse Formen, wo das Leuchten zu dem untersten Rand begrenzt ist, erklären konnte. Ich machte jedoch ausdrücklich darauf aufmerksam, dafs ınan in der Wirklichkeit mit einer Absorbtion in einem magnetischen Felde zu tun hat, und daß man dies in Betracht nehmen müsse. 1 L. Vecarp, Nordlichtuntersuchungen, Ann. d. Phys. 50, 853, 1916. L. VEGARD, Bericht über eine Expedition nach Finnmarken, Vid.-Selsk. Skr. Nr. 13, 1916. 1921. No. 10. DIE STRUKTUR DES NORDLICHTS. 7 Die erwähnten Ergebnisse der unternommenen Untersuchungen über die Lichtverteilung haben also in der Tat gezeigt, dafs Kraftfelder einen Einfluß auf das Absorbtionsgesetz ausüben. Das Kraftfeld, welches hier in erster Linie in Betracht kommt, ist das magnetische Feld der Erde, und die Frage wird dann, ob dieses Feld aut die Absorbtion einen solchen Einfluß ausüben kann, dafs dadurch die ge- fundenen Variationen der Lichtverteilung zustande kommen können. Wie ich schon auf dem Geophysikertage in Göteborg im Jahre 1918 klargelegt habe, ist das magnetische Feld der Erde im Stande, einen Einfluß dieser Art zu bewirken. | Wie es von den Untersuchungen von PoixcaRé, J. J. THomson und einer Reihe anderer Forscher, sowie durch die Arbeiten des Professors STORMER über die Theorie des Nordlichts wohlbekannt ist, werden elek- trische Strahlen, deren Richtung mit derjenigen der Kraftlinien nicht zu- sammenfällt, sich in Spiralen rings um diese bewegen. Die Anzahl Umdrehungen des Strahls für jede Längeneinheit in der Richtung der Kraftlinien wird mit dem Winkel, den der Strahl mit den magnetischen Kraftlinien bildet, wachsen. Da das Licht durch den Stoß des Strahls gegen die Gasmolekylen der Atmosphäre hervorgebracht wird, muf die Lichtintensität mit der Zahl von Umdrehungen per Längeneinheit proportional wachsen. Unter übrigens denselben Umständen wird die Lichtintensität ein Minimum sein, wenn sich die Strahlen den Kraftlinien entlang bewegen, und ein Maximum, wenn sie sich nähern senkrecht darauf zu werden. Eine Vergrößerung der Zahl von Umdrehungen per Längeneinheit würde also eine ähnliche Wirkung haben, als ob der Druck vergrößert wäre, indem die Zahl von Stößen per Längeneinheit (in der Richtung der Kraft- linien) zwischen dem Strahl und den Gasmolekylen in beiden Fällen ver- größert wird. Wie ich schon auf dem Geophysikertage in Göteborg klargelegt habe, kann man die Variationen der Lichtverteilung in folgender Weise erklären: Falls sich alle Strahlen durch die Atmosphäre mit den magnetischen Kraftlinien annähernd parallel bewegen, werden die Strahlen die oberste Schicht der Atmosphäre mit wenig möglichster Zahl von Stößen per Längen- einheit in der Richtung des Nordlichtstrahls durchdringen, und erst in der Nähe des unteren Rands wird die Stoßzahl per Längeneinheit wegen des vergrößerten Druckes so groß sein, da die Lichtintensität eine merkbare Größe erreicht. Wir bekommen dann die Formen, wo das Licht hauptsächlich an den untersten Rand begrenzt ist, und wo der untere Rand so nahe der Erd- oberfläche ist, wie es dieser bestimmten Art von Strahlen möglich ist. Denken wir uns dieselben Strahlen, daß aber diese in einer gegebenen Höhe alle denselben Winkel mit den magnetischen Kraftlinien bilden, so wird dies zur Folge haben, dafs der Strahl, um zu einer gegebenen Höhe 8 L. VEGARD. M.-N. Kl. hinabzureichen, einen viel größeren Weg zurückgelegt haben muß, und die Strahlen werden jetzt in einer größeren Höhe über der Erdoberfläche absorbiert werden. Eine Vergrößerung der Winkel zwischen dem Strahl und den magne- tischen Kraftlinien wird also zur Folge haben, daß die untere Grenze des Nordlichts weiter hinauf rückt. Falls aber alle Strahlen denselben Winkel mit den Kraftlinien bilden, wird sich auch in diesem Falle das Licht wesent- lich auf eine kurze Strecke in der Nähe des unteren Rands begrenzen. Kennt man das Gesetz für die Absorbtion der Strahlen und für die Ver- teilung der Gase in der Atmosphäre, kann man, wie ich in früheren Ab- handlungen! gezeigt habe, die Höhe und Lichtverteilung ohne Schwierigkeit auch für den Fall berechnen, dafs sich die Strahlen so bewegen, daf sie mit den Kraftlinien einen Winkel bilden. Falls man nun ein Strahlenbündel hat, wo die einzelnen Strahlen in einer gegebenen Höhe die verschiedensten Winkel mit den magnetischen Kraftlinien bilden, wird sich für jeden Winkel eine bestimmte untere Grenze mit relativ starker Lichtintensität bilden, und diese untere Grenze wird desto höher liegen, je mehr sich der Winkel, den die Strahlen mit den Kraftlinien bilden, 90° nähert.2 Der resultierende Nordlichtstrahl wird also durch die Superposition von Nordlichtstrahlen mit seinen lichtstarken unteren Grenzen in verschiedener Höhe gebildet. Das starke Leuchten wird sich also in die Höhe erstrecken. Es ist dieses Verhältnis, das wir bei den Draperien und in besonders ausgeprägtem Grade bei den isolierten Nordlichtstrahlen wiederfinden. Die Bogen und die draperieförmigen Bogen dagegen werden gewöhnlich durch elektrische Strahlen, welche in einem bestimmten Augenblick und einer gegebenen Höhe alle annäherend denselben Winkel mit den magnetischen Kraftlinien bilden, hervorgebracht. Die Lichtverteilung der Drapieren bildet eine Übergangsform zu derjenigen der typischen Strahlenform. Für die pulsierenden und diffusen Formen läßt sich die Lichtverteilung aufwärts | gewöhnlich nicht beobachten. Je nach der Weise, in welcher sich die Richtungen der elektrischen Strahlen relativ zu denjenigen der Kraftlinien beim Eintritt der Strahlen in die Atmosphäre verteilen, werden die Lichtverteilung und die Höhe des unteren Rands variieren können. Je nachdem man immer mehr Strahlen hat, die mit den magnetischen Kraftlinien große oder annähernd rechte |! L. VEGARD, Nordlichtuntersuchungen, Ann. d. Phys. 50, p. 853, 1916. — Berichte einer Exp. nach Finnmarken. — Chr. Vid.-Selsk. Skr. No. 13, 1916. — Recent Results of Northlight Investigations etc. — Phil. Mag. 42. P. 47. 2 Numerische Berechnungen einer Reihe Fälle sind auch von Professor STÖRMER in seinem soeben erschienenen Nordlichtwerke unternommen worden, Geoph. Publ. Vol. 1, Nr. 5. 2927. No: 19. DIE STRUKTUR DES NORDLICHTS. 9 Winkel bilden, wird die Lichtintensität nach oben zunehmen, die Länge des Nordlichtstrahls wächst. Falls es gleichzeitig relativ wenige Strahlen gibt, die in der Richtung der Kraftlinien in die Atmosphäre hineindringen, wird dies zur Folge haben, daß die untere Grenze des Nordlichts hinaut rückt, und wir sehen, daß unsere Erklärung der Struktur des Nordlichts das Verhältnis auch erklärt, daß die strahlenförmigen Nordlichter gewöhnlich einen größeren Wert für die Höhe des unteren Rands zeigen, mit anderen Worten: eine Verrückung der Lichtintensität nach oben ist von einer Hebung der unteren Grenze begleitet. Dies stimmt, wie wir gesehen haben, mit der Erfahrung. Wir haben früher stillschweigend vorausgesetzt, daß die magnetischen Kraftlinien miteinander parallel verlaufen, und da die Bewegung der Strahlen von der Atmosphäre nicht beeinflußt wird. : In der Tat konvergieren die Kraftlinien schwach gegen die Erde, und die Atmosphäre bewirkt Geschwindigkeitsverminderungen und Zerstreuung der Strahlen, und wir werden untersuchen, welchen Einfluß diese Verhält- nisse auf die Lichtverteilung haben können. Um die Wirkung der Konvergenz der Kraftlinien zu untersuchen kön- nen wir annehmen, daß die Kraftlinien innerhalb des Gebietes des betrach- teten Nordlichtelements gerade Linien sind, die alle gegen denselben Punkt konvergieren. Das Feld wird also dasselbe sein wie das Feld eines ein- zelnen Magnetpols, der sich im Konvergenzpunkte befände. Nach PoixcanÉ wird die Bahn eines elektrischen Strahls in einem solchen Felde eine geodätische Linie auf einem Umdrehungskegel mit Scheitelpunkt im Konvergenzpunkte sein. Oder im Falle wir uns die Bahn auf einer Ebene ausgewickelt denken, wird diese eine gerade Linie bilden, die den Kon- vergenzpunkt in einem gewissen Abstande d passiert. Die wirkliche Bahn im Raume wird eine Spirale, die in immer dichteren Windungen rings um die Kraftlinien läuft, bis sie in einer Entfernung d vom Konvergenzpunkte sich senkrecht auf diese bewegt, wonach der Strahl in einer ähnlichen Bahn gegen die Unendlichkeit zurückkehrt. Wie wir leicht bei Betrachtung der Bahn, wenn die Kegelfläche in der Ebene ausgefaltet ist, ersehen können, wird die Entfernung d, wo der Strahl zurückkehrt, nur von dem Winkel, den der Strahl mit den magnetischen Kraftlinien in einer bestimmten Entfernung des Konvergenzpunktes bildet, abhängig sein. Da uns nur die Strahlen, die in die Atmosphäre hinein- kommen, interessieren, könnten wir z. B. die Winkel, welche die Strahlen in einer Höhe von 500 Km. bilden, betrachten. Je größer der Winkel, den der Strahl in dieser Höhe mit den Kraftlinien bildet, desto ferner hinauf liegt der Umkehrpunkt. Strahlen sollten also allein durch die Wirkung des magnetischen Feldes aus der Atmosphäre hinausgeworfen werden können. Dieses Verhältnis, dafs der Strahl ohne absorbiert zu werden ausge- trieben werden kann, ändert nicht die schon gegebene Erklärung von IO L. VEGARD. M.-N. KI. der Änderung der Lichtverteilung und der unteren Grenze des Nordlichts. Denn wir bekommen in jedem Falle, daß die Höhe des niedrigsten Punktes, zu welchem der Strahl gelangt, mit dem Winkel wächst, den der Strahl mit den magnetischen Kraftlinien in dem Augenblicke, wo er in die Atmosphäre hineintritt, z. D. in einer Hóhe von 500 Km., bildet. Die Konvergenz der Kraftlinien wird sogar bewirken, dafs der Strahl nicht so weit hinabdringt, als er unter denselben Eintretungsbedingungen gekommen wäre, falls die Kraftlinien parallel gewesen wären. Mit anderen Worten: die Konvergenz des Kraftfeldes wird ein Verschieben der Lichtintensität nach oben dem Nord- lichtstrahl entlang begünstigen. Wenn es sich auch so verhält, daß die Konvergenz der Kraftlinien ein Verschieben des Nordlichts aufwärts begünstigt, so ist doch dieses Ver- hältnis für die Erklärung der Variationen der Lichtverteilung nicht von entscheidender Bedeutung. Dagegen ist die Tatsache, daf3 die Strahlen nach dem Raume zurück- getrieben werden können ohne gänzlich absorbiert zu werden, von Be- deutung für die Frage nach der Ursache der Farbenänderung des Nord- lichts. Wie ich schon auf dem Geophysikertage zu Göteborg bemerkt habe, und wie ich in späteren Arbeiten ausführlicher behandelt habe, kann man die Farbenänderungen erklären, wenn man annehmen darf, daf ein großer Teil der kosmischen Strahlen gewöhnlicherweise zum Raume zurück- kehrt, so daß nur ein Bruchteil absorbiert wird. Man weiß nämlich, daß im Stickstoff das Spektrum, welches durch Bom- bardement des Gases mit elektrischen Strahlen gebildet wird, durch die Strahlengeschwindigkeit im hohen Grade geändert wird. Falls ein großer Bruchteil der Strahlen mit einer bedeutenden Geschwin- digkeit zurückkehrt, sollten wir die gewöhnlichen grünlich-gelben Nordlichter bekommen. Der rote Farbenton sollte hervortreten, wenn eine große Anzahl Strahlen gänzlich oder annähernd absorbiert würde. Die Bestimmung des Herrn Poincare von den Bahnen eines konver- gierenden Feldes setzt voraus, daf sich der Strahl im luftleeren Raume bewegt. Wegen der Bedeutung, die das Zurückkehren der Strahlen nach dem Raume für die Erklärung der Farbenänderungen hat, wird es von Bedeu- tung sein, die Strahlenbahnen, unter der Voraussetzung, daf3 die Bewegung in einem absorbierenden Medium geschieht, zu untersuchen. Das Medium bewirkt eine Herabsetzung der Geschwindigkeit und eine Zerstreuung. Was die Zerstreuung betrifft, wird diese damit gleichbedeutend sein, dafs die Bahn auf eine ganz zufällige und unregelmäßige Weise ihre Richtung ändert, und genaue Vorausberechnungen der wirklichen Strahlenbahn sind des- wegen für Strahlen, die eine starke Zerstreuung zeigen, ganz ausgeschlossen. Wenn wir auch die Bahnen der zerstreuten Strahlen nicht berechnen können, so können wir jedoch den Schluß ziehen, daß die Zerstreuung das Zurückkehren der Strahlen in den Raum durchschnittlich begünstigen wird, in- dem ein Strahlenbündel, das unter einem kleinen Winkel mit den Kraftlinien 1921. No. I9. DIE STRUKTUR DES NORDLICHTS. TOT hineinkommt, durch die Zerstreuung durchschnittlich größere Winkel mit den Kraftlinien bilden wird. Einige Strahlen werden sogar durch Zerstreuung ihre Richtung so stark ändern, dafs der Winkel zwischen dem Strahl und dem nach unten gerichteten Ende der Kraftlinien größer als go’ wird. Die Strahlen werden also in den Raum zurückgetrieben als eine Wirkung der Zerstreuung. Falls es einen Sinn haben soll eine Gleichung für die Strahlenbahn eines absorbierenden Mediums zu suchen, müssen wir von der Zerstreuung wegsehen. Unter dieser Voraussetzung, welche für die «-Strahlen fast er- füllt ist, habe ich in einer vor kurzem herausgegebenen Abhandlung in der Phil. Mag. die allgemeine Differentialgleichung für die Bahnen der Strahlen in einem absorbierenden Medium aufgestellt, und ich habe gezeigt, wie die in die Differentialgleichung eingehenden Konstanten und Funktionen bestimmt werden kónnen. Die allgemeine Differentialgleichung ist sehr schwer zu lösen, ich habe aber einige wichtige Eigenschaften der Bahnen für den Fall herleiten kón- nen, daß die magnetischen Kraftlinien gerade Linien sind, welche gegen denselben Punkt konvergieren. Die Bahnen werden jetzt nicht mehr geodätische Linien einer Umdrehungs- kegelfläche, werden aber entstehen, wenn eine gerade Linie durch den Kon- vergenzpunkt sich so bewegt, daf3 sie immer eine gewisse Spirale berührt, oder der Offnungswinkel nimmt ab, je nachdem die Geschwindigkeit des Strahls durch die Einwirkung des Mediums immer kleiner wird. Man wird jetzt zeigen kónnen, dafs die kleinste Entfernung d vom Konvergenzpunkte, die der Strahl erreicht, von dem Medium unabhängig ist. Der Strahl kehrt also in derselben Entfernung von der Erde nach dem Raume zurück entweder das Medium anwesend ist oder nicht, selbst- verständlich vorausgesetzt, dafs der Strahl, ehe er den Wendepunkt erreicht hat, nicht zu Ruhe gebracht ist. Falls wir noch von der Zerstreuung wegsehen, sehen wir unmittelbar ein, daf Strahlen, die unter einem sehr kleinen Winkel mit den Kraftlinien in die Atmosphäre hineindringen, absorbiert werden, und sie kehren nicht nach dem Raume zurück. Wenn dagegen die Strahlen unter einem Winkel, der eine gewisse Größe überschreitet, hineintreten, werden dieselben nur eine gewisse Strecke in die Atmosphäre hineindringen, wonach sie nach dem Raume zurückkehren. Gleichzeitig ist zu bemerken, dafs die Wahrscheinlichkeit dafür, dafs die Strahlen in einer Höhe von etwa 500 Km. mit den Kraftlinien große Winkel bilden sollen, bei perturbierenden magnetischen Feldern vergrößert wird, indem diese Perturbation Änderungen in den Richtungen der Kraft- linien verursachen, welche in diesen Höhen, wo die elektrischen Ströme, die die Perturbation hervorrufen, wesentlich ihren Sitz haben, sehr grofs sein können. Dies stimmt mit dem Verhältnis, daß Strahlen und Draperien gewöhn- lich zu der Zeit, wo der magnetische Sturm am stärksten ist, auftreten. [2 L. VEGARD. M.-N. Kl. Wir können auch auf diese Weise erklären, daß die Nordlichtstrahlen, wie es von STÖRMER nachgewiesen ist, auf niedrigeren Breiten in die Atmosphäre durchschnittlich höher emporsteigen, denn, wie ich früher be- merkt habe, wird das Nordlicht von Stromsystemen, die während starken magnetischen Stürmen auftreten, nach dem Süden geführt. Wenn das Nordlicht auf niedrigen Breiten auftritt, sind folglich starke perturbierende Kräfte tätig, und diese werden also bewirken können, daß das Leuchten nach oben rückt, so daß die Strahlen länger werden. Die hier gegebene Erklärung der Variationen der Lichtverteilung und die Auffassung der Struktur des Nordlichts, worauf sie baut, müssen un- zweifelhaft im wesentlichen richtig sein, wenn es jedoch nicht ausgeschlossen ist, dafs auch elektrische Kräfte, die während der magnetischen Perturbationen ent- stehen, in gewissen Fällen auf die Lichtverteilung einen Einfluß ausüben können. Es darf in dieser Verbindung von Interesse sein zu bemerken, daß Professor STÖRMER in seinem soeben erschienenen Werke! sich meiner Auffassung gänzlich anschliefit. Er gibt hier auch einige numerische Be- rechnungen, die ihr wesentliches Interesse in Verbindung mit der hier gegebenen Erklärung der Lichtverteilung im Nordlicht bekommen. Die Natur der kosmischen Strahlen. Ein Nordlicht in der Form eines Strahls wird also von elektrischen Strahlen gebildet, welche an jedem Orte des Strahls alle möglichen Winkel mit den magnetischen Kraftlinien zwischen o und go. bilden. Da man also annehmen darf, daß sich die elektrischen Strahlen senk- recht auf die Kraftlinien bewegen, können wir davon eine untere Grenze für die Ablenkbarkeit der Strahlen berechnen? Da man die magnetische Feldstärke = !/2 Gauß setzen kann, bekommt man: — <{— , wo d der Querschnitt des Nordlichts, m, e und v Masse, e Ladung und Geschwindigkeit des kosmischen Strahls bedeuten. Von dem untersuchten Material aus dem Haldde Observatorium geht hervor, daß die Strahlendicke zuweilen kleiner als 1 Km. ist, also: Zr 104 2 mv 2 1 C. STöRMER, Geophys. Publ. Vol. 1, No. 5. 2 Schon unter seinen theoretischen Berechnungen der möglichen Strahlenbahnen hat Srón- MER darauf aufmerksam gemacht, daf man, falls sich die elektrischen Strahlen auf die Kraftlinien senkrecht bewegten, von dem Querschnitte eines Nordlichtstrahls eine untere Grenze für die Ablenkbarkeit der elektrischen Strahlen berechnen kann. STÖRMER erwähnt aber gleichzeitig die Möglichkeit, daß die kosmischen Strahlen sich annähernd in der Richtung der Kraftlinien bewegen, und dann kann man aus der Dicke eines Strahls keine Schlüsse betreffs der Ablenkbarkeit der Strahlen ziehen. Erst durch meine Untersuchungen über die Lichtverteilung ist es nachgewiesen worden, daß die kosmischen Strahlen sich in der Tat senkrecht auf die Kraftlinien bewegen, und erst dadurch ist es möglich gewesen, durch Messung des (Juerschnittes eines Nordlichtstrahls die untere Grenze der Ablenkbarkeit der kosmischen Strahlen zu bestimmen. 1921. No. 10. ' DIE STRUKTUR DES NORDLICHTS. I9 Dieses Resultat ist von aufserordentlich grofser Bedeutung für die Entscheidung der Frage von der Art der elektrischen Strahlen. Die Strahlen, die in Betracht kommen kónnen, sind entweder negative Elektronenstrahlen (B- oder Kathodenstrahlen) oder Strahlen, die eine Masse von atomistischer oder molekylärer Gréfsenordnung besitzen. Die letzteren werden gewöhnlich eine positive Ladung führen. Die Annahme von Strahlen, deren Träger als Staubkórnchen zu be- trachten sind, kann nicht in Betracht kommen, denn das Auftreten des Nord- lichts in scharf begrenzten Bogen und Banden läfit sich damit nicht vereini- gen, da solche Staubstrahlen notwendigerweise sehr heterogen sein müfiten. Für gewöhnliche «-Strahlen von radioaktiven Substanzen haben wir: < MV 3. 0. I0? < — < 4, 6. 105 e mv Der Wert von für diese Strahlen ist, wie wir ersehen, zu groß, 2 um die strahlenförmigen Nordlichter erklären zu können. Da viel darauf deutet, dafs sämtliche Nordlichttypen von wesentlich derselben Art von Strahlen hervorgebracht werden, können wohl überhaupt keine «- Strahlen dieser Geschwindigkeit als Ursache des Nordlichts in Betracht kommen. Dagegen würden «-Partikeln geringerer Geschwindigkeit wohl genügend mv weiche Strahlen geben können. (Kleine Werte von 2 Die Frage wird aber jetzt, 0b «-Partikeln oder andere Atomen- oder Molekiilenstrahlen mit der verlangten Ablenkbarkeit gleichzeitig eine genügende Durchdringlichkeit haben, um die Höhe des Nordlichts zu erklären. mv Für die Elektronenstrahlen variiert von o bis 4, 5. 10%, den durch- dringlichsten $-Strahlen entsprechend. Die Elektronenstrahlen vereinigen also eine genügende Durchdringlichkeit mit der genügenden Ablenkbarkeit, um die Höhe und Struktur des Nordlichts zu erklären, denn die schnellsten D-Strahlen würden bis zu einer Höhe von etwa 40 Km. hinabdringen. Um zu sehen, ob auch andere Strahlen als die negativen Elektronen- strahlen möglich sind, müßten wir die Zusammensetzung der höchsten Schicht der Atmosphäre sowie das Gesetz der Absorption der Atomen- und Molekülenstrahlen kennen. M Ist die Masse der Strahlenpartikel wv? wo N Avogadros Zahl ist, und i ist ihre Ladung ze, wo e die Ladung des Elementarquantums ist, bekommt man: mv Mv ys Nne und diese Größe soll kleiner als eine Größe a sein, also: na M na M v « Ne oder da Ne = 10%, so ist v < 104 14 L. VEGARD. M.-N. KI. Nun ist die Durchdringungsfähigkeit von v, n und M, sowie von der Dichte und dem Atomgewicht des absorbierenden Mediums abhängig. Für ein gegebenes Medium wird die Reichweite eine Funktion von v, » und M sein. Aus einer Theorie von Bour! für die Absorbtion von Atom- strahlen können wir für die Reichweite x im Stickstoff bei o? und 760 mm. Druck den folgenden Ausdruck herleiten: M x= 1o 2 —2 v9 cm. n " na Ist nun gleichzeitig v< 10? — i M i ; ER AS ETS so wird we nom TIC ME Setzen wir: a = 2, 5. 104, so bekommen wir: n —? X T 56.100 EI ‚> M? Bel a — 104 gibt x < 1073 — cm. M* Entsprechende Ausdrücke gelten für die Absorbtion in anderen Gasen, nur mit einem etwas verschiedenen Zahlenfaktor. M bedeutet das Atomgewicht (oder Mol.gewicht) der Partikel. Da die Zahl # die Atomnummer oder die Summe der Atom- nummer des Trägers nie überschreiten kann, so wissen wir, daf3 für alle Substanzen (der Wasserstoff ausgenommen) n- M sein wird, und die Reichweite wird mut wachsender Masse des Trägers sehr schnell abnehmen. Unter allen Atomen- (oder Molekülen-)strahlen, die gleichzeitig die Ab- lenkbarkeitsbedingung befriedigen, geben die Wasserstoffstrahlen die größte Durchdringlichkeit. | Nächst kommt die «-Partikel. (He-Atom mit 2 Elementarladungen). Sollte es sich dennoch zeigen, daß ein Wasserstoffstrahl, der die Bedingung für magnetische Ablenkbarkeit befriedigt, eine zu geringe Durchdringungs- fähigkeit besäße, um bis zu einer Höhe von 100 Km. herabzudringen, so würden auch keine anderen Materienstrahlen als Ursache derjenigen Nord- lichter, welche Strahlenstruktur besitzen, in Betracht kommen können. Die Zusammensetzung der Atmosphäre, die von WEGENER angegeben ist, würde dazu führen, daß Atomen- oder Molekülenstrahlen jeder Art eine gar zu geringe Durchdringlichkeit besitzen würden, um die Höhe des Nord- lichts erklären zu können. Die WEGEneER’sche Massenverteilung gibt für eine Höhe von 400 Km. eine Luftreichweite von 1,3 cm. Der Strahl müßte also, um zu dieser großen Höhe hinabzukommen, eine Reichweite x — 1,3 cm. besitzen. I N. Boum, Phil. Mag. 25, p. 10, 1913. 1921. No. IQ. DIE STRUKTUR DES NORDLICHTS. ES Ein Wasserstrahl, der die Ablenkbarkeitsbedingung befriedigen, soll wird laut der obigen Formel nur eine Reichweite von 0,16 Mm. haben, also nur 1/100 Teil der Reichweite, die erforderlich ist, um eine Höhe von 400 Km. zu erreichen. Nun zeigen indessen die Spektraluntersuchungen, dafs eine solche domi- nierende Wasserstoffatmosphäre, wie von WEGENER angenommen ist, nicht existieren kann. Sehen wir von der grünen Linie weg, dominieren im Nordlichtspektrum im allgemeinen die negativen Stickstoffbanden. Weder Wasserstoff noch Helium sollten in dem Höhenintervall (100 — 125), wovon die Hauptmasse des Nordlichtes ausgeht, in dominierenden Mengen existieren können. Wir haben also mit der Möglichkeit zu rechnen, daß der Stickstoff in der obersten Schicht der Atmosphäre über 100 Km. dominierend ist. Wird die Dichte des Stickstoffs in Übereinstimmung mit WEGENER berechnet, so würde ein Wasserstoffstrahl mit einer Ablenkbarkeit, die 4 entspricht, nur bis zu einer Höhe von 118 Km. gelangen. a= 2, 5. IO Wird a — ro* gesetzt, würde er nur zu einer Hóhe von r35 Km. gelangen. Alle anderen Materienstrahlen mit denselben Ablenkbarkeitsbedingungen würden noch größere Höhe geben. Nun müssen wir indessen damit rechnen, dafs die Verteilung des Stick- stoffdrucks, die durch die WEGENER'sche Formel gegeben ist, móglicherweise mit bedeutenden Fehlern behaftet sein kónne, welche u. a. einer mangelhaften Kenntnis der Temperatur der hóchsten Luftschichten zuzuschreiben sind. Der Druck müfite aber in der Tat beträchtlich kleiner sein, falls Materien- strahlen mit genügend großer Ablenkbarkeit zu einer Höhe von 90 —100 Km. gelangen sollten. Sollten die Wasserstoffstrahlen eine Hóhe von 95 Km. erreichen, müßte der Stickstoffdruck in dieser Höhe nur etwa !/25 Teil des von WEGENER berechneten Druckes besitzen. So große Fehler sind kaum wahrscheinlich, man muß aber eine genauere Bestimmung der Stoffverteilung der Atmospháre abwarten, ehe man mit voller Sicherheit die Frage erledigen kann. Im Falle die \WEGENER’sche Verteilung des Stickstoffs bis zm einer Höhe von roo Km. einigermaßen richtig ist, können wir den Schluß ziehen, daß jedenfalls die strahlenförmigen Nordlichter durch Elektronenstrahlen her- vorgebracht werden müssen.! I Diese Schlußfolgerung stützt sich darauf, daß, von Elektronen weggesehen, nur Atome, die in das periodische System hineingehen, als Strahlenträger möglich sind. Für die letzteren gilt das Rutherford-Borsche Konstitutions-Schema, nach welchem der Wasserstoff das leichteste aller Atome ist. Man wird jedoch nicht ohne weiteres die Möglichkeit ausschließen können, daß Atomionen existieren, für welche die spezifische Ladung zwischen derjenigen des Wasser- stoffkerns und derjenigen des Elektrons fällt. Die Nebelspektren, die Koronalinie, sowohl die grüne Linie im Nordlicht dürften auf die Existenz derartiger Atome deuten. Diese Frage hat hier ein besonderes 16 L. VEGARD: DIE STRUKTUR DES NORDLICHTS. M.-N. Kl. 1921. No. 19. Für die Bestimmung der Zusammensetzung der håheren Atmosphåren- schichten werden weitere Untersuchungen uber das Spektrum des Nordlichts uns eine wichtige Auskunft geben können. Die älteren Beobachtungen sind aber meistens zu ungenau. Ich habe aber schon seit vielen Jahren mit Präzisionsmessungen über das Nordlichtspektrum angefangen, und einige wichtigen Verhältnisse habe ich, wie erwähnt, schon durch meine Beobach- tungen in Finnmarken festsetzen können. Es steht aber noch viel übrig, und ich habe die Arbeit hier in Kristiania fortgesetzt. Ich habe hier zuerst einen Gitterapparat mit sehr großer Dispersion geprüft. Dieser zeigte sich aber zu lichtschwach. Jetzt habe ich einen lichtstärkeren Apparat anschaffen lassen, und hoffe ich, dafs dieser gute Ergebnisse geben wird.! Die durch das Studium der Lichtverteilung erhaltenen Ergebnisse ge- statten uns, auch andere wichtigen Schlüsse zu ziehen, und soll ich hier kurz die folgenden erwähnen: 1) Die Nordlichtstrahlen (die entweder isoliert sind oder als ein Teil einer Draperie auftreten) fallen immer mit den magnetischen Kraftlinien genau zusammen, und wir können die Richtung der magnetischen Kraftlinien in großen Höhen dadurch untersuchen, daß wir die Richtung der Nord- lichtstrahlen bestimmen. Die Richtung wird durch die Kronenbildung am besten bestimmt. 2) Das magnetische Feld der Erde in Entfernungen von der Größenordnung des Erddurchmessers muß sich ganz wesentlich von demjenigen eines Elementarmagnets unterscheiden. Es kann auch nicht angenommen werden, dafs das erdmagnetische Feld gänzlich von magnetischen Massen, welche innerhalb der Erdoberfläche liegen, seinen Ursprung hat. Um die Lage der Polarlichtzone mit der gefundenen großen Ab- lenkbarkeit der Strahlen zu erklären müssen wir annehmen dafs wenigstens während des Nordlichts elektrische Ströme oberhalb der Erdoberfläche, wahrscheinlich in der Nähe des magnetischen Äquatorplanes, existieren. 3) Da die Strahlen von der Sonne ausgehen, können wir den Schluß ziehen, dafs die Strahlenquelle (die Sonne) eine elektrische Potential größer als etwa 30000 Volt nicht besitzen kann. Interesse, denn es ist zu erwarten, daß solche Atomenstrahlen mit Träger, welche leichter als Wasserstoff sind, für die Erklärung der Nordlichtstruktur eine genügende Durchdringlichkeit sowie Ablenkbarkeit besitzen würden. ! Anmerkung bei der Korrektur. Mit diesem Apparat ist es mir gelungen, genaue Messungen der Wellenlànge der grünen Nordlichtlinie durchzuführen. Die Ergebnisse sind zur Veróffentlichung in den Geophys. Publikationen anfangs November 1921 ein- gesandt worden und werden hoffentlich bald in Druck erscheinen. Gedruckt 9. Februar 1922. TROMS FYLKE S ANTROPOLOGI AV HALFDAN BRYN MED 20 FIGURER OG KARTER I TEKSTEN (MED TYSK RESUME! (VIDENSKAPSSELSKAPETS SKRIFTER. I. MAT.-NATURV. KLASSE. ro2r. No. 20) UTGIT FOR FRIDTJOF NANSENS FOND KRISTIANIA I KOMMISSION. HOS JACOB DYBWAD 1922 II. II. VI. V. VIII. IX. Indhold. Side Indie 11 SS SEE ee nc re ERR RU : I Naar og hvor undersokelsen er foretat. De undersoktes alder og antal, s. r. E Pci Hehsgenhet.:ag sterfElse. stave Ain aed NU Cold I Indbyggerantal. Neeringsveier. Inddeling. Den første bebyggelse, s. 1. ARE LO TPT BOW apres se Sea one ie de Toro c ee caf 3 Norske, lapper, kvæner, s. 3. Naar de kom til Troms fylke, s. 5. Sjofinner og skridfinner, s. 9. 3. Tidligere antropologiske undersekelser ..:....... 1... ..... I1 ETS TENTE RE COM c OR tale ee 11 Bro mentere Does cU ORE AR nent RE Dee 18 A OE TIAL 00 à CO ae Eee 18 PREV AS AT AE Ven Ale ee US e Lr Tr E 21 SEHE mente. a Te, Cr pt pe oe 24 | 3 FA (5 EE PR e DR PRI S rU 25 ee Eiodctsssterste" Tangde. TS TR Lec ee SES DER 25 c ADS. sterste redde, ee c HM EN 28 cx Iudex. éephialieus Eee aie etta uu aeree eA E. o a 28 4. Legemsheidens forhold til hodets dimensioner ............... 37 AITUDuta MEER 2002: am Mi c a cma. JM que 39 I. Ansigtets heide, bredde og morfologiske index .............. 39 CA S s MEER e e e e ROS ar 43 a... Bredden, mellem” de mdre,;eenvinklerc: 25 92 0 E 45 E queodronpal index 22... 2 a ce c I M PE EE 45 5. Øvre gienlok (plica marginalis, epicanthus, mongolfold)............. 48 Om forholdet mellem ansigtets og hodets dimensioner ........ 49 Byer mindste pandebredde —— 222... Suis dt vue e ERES EE 49 2 Den transversale fronto-parietale Index. 7.1.39. peut ees 49 Kombination av eienfarven og haarfarven ................... 53 Den lyse og den mørke bloks størrelse, s. 56. Wltuiteftenndersskelsep- 2L Fc SES Be a Lue bad. 57 Resumé, s. 72. Hovedlinjene i befolkningens mosaikbillede .................. 72 Kombination av 6 træk, s. 72. Bastardene, s. 73. Dolichocephalenes kom- binationer svarer til mesocephalenes, s. 76. Brachycephalenes kombinationer, s. 78. Hyperbrachycephalenes kombinationer, s. 78. XI. XII. XIII. XIV. XV. Side Befolkningens væsentligste og mest karakteristiske bastarder... go 3 træks kombination: hodetype, ansigtstype, sientype, s. 90. Urtypene : homo nordicus, homo alpinus, homo palæoarcticus, s. 96. De 9 vigtigste bastarder, s. 90. Nogen spersmaal vedrørende arvelighetsforholdene, specielt an- gaaende hvilke karaktertræk som er eller har været domi- nerende a eee SENSE SER ES ee eee SELL cl 99 Resumé, s. 116. De fremmede elementer 0 m ee so 116 Es” Lappen $i buco xu uot RE er cache tions renee ER 117 SU NV ÆNOERS . ou ae et eee I E tes alerte o anni t MERI ERA Bae OC SEE 124 27 Bastardene RAT TR IN ee ve eter mio EE TNR RT IEEE EE 126 a. Norske X lapper, s. 126. b. Norske X kvæner, s. 128. De enkelte herreders antropologi .....-...... o... LTD 130 I. Gruppekarakteristik Rae a ee RE eet - 130 2: Inchvidwaltabellen, mm dae REI S CRETE 132 RÉSUMÉ AT oos. ob re bere de NE ee eu D NM 157 D INOFSEKS EA. RTE REUS Lc eL e E Lee lup avais VOS ORE c E TUNE 157 ZUM ly om Dr cr Ai: 165 Literatur I. Indledning. Med stipendium av Nansenfondet foretok jeg sommeren 1919 en reise til vort lands nordligste egne for at foreta antropologiske undersøkelser paa ekserserpladsene. Jeg opholdt mig da først paa Sætermoen, hvor jeg fik undersøkt 662 mænd fra Troms fylke. Det er det paa denne ekserserplads indsamlede materiale jeg i denne avhandling skal gi en fremstilling av. Undersøkelsene omfatter altsaa kun militært tjenestedygtige mænd i alderen 20—21 aar, samtlige fra Troms fylke. Det brogede menneske- materiale i dette fylke gir den antropologiske undersøkelse en særlig interesse. Ved siden av at gi en beskrivelse av Troms fylkes antropologi vil jeg 1 denne avhandling soke at gi en fremstilling av de forskjellige bastarders utbredelse. 1. Beliggenhet og størrelse. Troms fylke er Norges næst nordligste fylke. Det ligger i sin helhet nordenfor polarcirkelen. Det grænser mot nord til Nordishavet, mot syd til Haalogaland fylke, Sverige og Finland, mot øst til Finmark fylke. Det hadde ved sidste folketælling i 1910 81902 indbyggere. Da dets flateindhold er 26221" |km., blir det kun 3,19 indbyggere paa hver " | km. Til sammenligning vil jeg anføre at i Opland fylke er der 4,94 indbyggere pr. [ | km. Gjennemsnitlig er der i Norges landdistrikter 5,50 indbyggere pa hver | |km. Troms fylke staar altsaa ikke saa svært meget tilbake for hvad der er gjennemsnitlig i Norge. Befolkningens væsentligste næringsvei er fædrift, fiskeri og akerbruk. Der er kun lite bergverksdrift og skogbruk. Fylket er delt i 2 sorenskriverier, Senjen og Tromsø, og har i alt 25 herreder. Man har kun lite kjendskap til naar Troms fylke først blev bebygget. Med fuld sikkerhet kan man dog gaa ut fra at bebyggelsen hadde naadd selv til den nordligste del av Troms fylke i den yngre jernalder (800 til 1000 e. Kr). Det synes ogsaa temmelig sikkert at øene ute ved havet først blev bebygget. Om disse første bebyggere var nordmænd, er vel endnu et aapent spørsmaal. Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. 20. fi D Hier: M.-N. KI. HALFDAN BRYN. #65. 0 Ses x" 19444444 « d lod Det undersokte areal er merkt skrafert Kart over det undersokte omraade. 1022 No..20. TROMS FYLKES ANTROPOLOGI. 3 2. Befolkningen. Befolkningen i Troms fylke er og har i lange tider været overmaade uensartet. Stort set kan man jo si, at befolkningen i den del av Norge som ligger sondenfor Troms fylke, er en nogenlunde homogen masse. Rigtignok kan man ad antropologisk vei paavise at der indgaar ogsaa i denne befolkning vidt forskjellige raceelementer. Men disse forskjellige race- elementer har nu gjennem umindelige tider været saa intimt blandet at de ikke længer selv har opfatningen av raceforskjellighetene. Krydsningen er saa grundig gjennemfort at hver enkelt urraces eiendommelighet er fuldstændig splintret. Ganske anderledes er forholdet i denne henseende i Troms fylke. Tabel ı. Blandt de av mig 0/0 1891 undersokte var forholdet folgende SEERE TER ADD ERE er ee eis nee BZ 4,5 "usblandede lapper .—-- 623-9899. ee 3,6 1,2 Lene finlændere: tisse de moe see c'es eee 25 2,4 Gy Blandede-finlændere 0... LL 1 Her utgjer ganske vist ogsaa den norske befolkning grundstammen i den nuværende befolkning, og hovedmassen av befolkningen taler norsk. Men denne norske befolkning er i sterkere grad end i noget av landets syd- ligere fylker opblandet med 2 etnisk vidt forskjellige folkestammer, lapper og kvæner. Jeg gjør her med én gang opmerksom paa at dette er den norske befolknings navne paa disse fremmede elementer. Selv kalder de sig henholdsvis samer og finner. Hvis man for oversigtens skyld til at begynde med vil regne med runde tal, kan man vel si at omtrent go %0 regner sig selv for norske, 80/0 regner sig for lapper og 2/0 regner sig for finlændere. Nu er imidlertid disse 9o %/o norske aldeles ikke rent norske. En hel del av disse har enten finsk blød eller lappeblod i sine aarer. Ja, det er visselig vanskelig at si med bestemthet hvor stor del av befolkningen som er rent norsk. Om en bedstemor eller oldemor har været en lappepike, saa vil man helst la det bli glemt. Inden de lavere lag av befolkningen er indgifte mellem lapper, finner og norske saa almindelig at man bør være meget varsom med at tale om renracede folk heroppe. Man faar noie sig med at regne for rent norske dem som selv regner sig for saadanne, og som selv ikke vet om nogen fremmed indblanding. Likesaa faar man gjøre med lappene og finnene. Jeg har paa tabel 1 anført, hvordan befolkningen fordelte sig i 1891 naar de her nævnte principper lægges til grund. 4. HALFDAN BRYN. M.-N. KI. Av folketællingen synes at fremgaa at det norske element er i tilvekst i de senere aar. Dette er imidlertid ikke saa sikkert. Det kan bero paa at de fremmede elementer skjuler sig for folketællingen. Saafremt faren er norsk og moren finsk eller lappisk, saa vil vel folketællingen faa rede paa forholdet, og avkom av saadanne forældre vil bli opført som , blandet", Men saafremt barn av saadan blandet herkomst blir boende i en norsk bygd og gifter sig med norske, vil utvilsomt i de fleste tilfælder avkommet bli regnet som rent norsk. Selv ,rene" finner prøver nemlig at hemmeligholde sin her- komst. I anden generation vil man kun vanskelig komme efter det virkelige for- hold, og i tredje generation maa man ty til kirkeboken eller en antropo- logisk undersøkelse for at kunne paavise den fremmede avstamning. Men paa folketællingslisten vil saadant avkom bli opført som rent norsk. Dette kan ialfald være forklaringen til at folketællingen i de sidste 80 aar viser følgende tal: Tabel 2. £ x: Ubestemmelig Nordmænd Lapper Finner S blanding Som man vil se, er det siden 1865 at det norske element har vokset litt. Men jeg vil paany fremholde at dette efter al sandsynlighet kun er et selvbedrag. I virkeligheten er for- | holdet det, at flere og flere tidligere opblandede slegter gaar over til at regne sig for norske. Disse ,urene" La) elementer gifter sig atter ind i tid- ligere ,rene" norske familier. Og da TEN raceeiendommelighetene ikke derved for- svinder, vil dette 1 virkeligheten si at HERE den norske race 1 Troms fylke for hvert aar som gaar blir mere og mere | |- NORSKE forurenset med fremmede elementer. Hensigten med denne under- | sl nz sokelse er da at paavise dette antro- Il Zub APBER pologisk, at paavise at selv den saa- Fig. 2. Folkeblandingen i Troms fylke kaldte rene norske befolkning frem- ifølge folketællingen roro. byder” tegn paa at være uren, op- 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 5 blandet. De forskjellige herreder i Troms fylke viser en meget forskjellig- artet folkeblanding. Jeg anfører paa tabel 3, sidste 3 kolonner, hvorledes forholdet i denne henseende var i 1910. Kvænene indgaar hyppigst blandede egteskaper, snart med lapper, snart med norske. For nordmændenes vedkommende er det især mændene som indgaar blandede egteskaper, hyppigst med kvæner. Naar der i det foregaaende tales om ,rene" finner og rene lapper, saa er i grunden dette ganske misvisende. Gjennem aarhundreder har utvilsomt lappene blandet sig med andre folkeslag: russere, finner, svenske og norske. Og heller ikke finnene er nogen ,ren" race. Det skal jeg straks gjøre nærmere rede for. Hvor skriver de sig fra, disse fremmede elementer? Naar er de kommet til vort land, og hvad vei er de kommet? Jeg skal her kun ganske kortelig komme ind paa disse spørsmaal. Den almindelige benævnelse paa den finske befolkning i vort land er som bekjendt „kvaener“. Men spor man dem selv, faar man ofte det svar, at de ikke er kvæner. De er finlændere, sier de. Sammenhængen er utvilsomt den, åt den norske befolkning kun har lite kjendskap til de forskjellige finske folketyper. Usandsynlig er det vel ikke at de først indvandrede har været kvæner, siden har alle finske indflyttere her til landet blit kaldt ,kvæner“, og deres hjemsted kaldes i folkemunde „Kvaenland“. Men utvilsomt er det at der ialfald i den senere tid er indflyttet til Norge andre finlændere end de egentlige kvæner. Men vi kan vel gaa ut fra at kvænene utgjør hovedmassen av den i Norge bosatte finske befolkning. Angaaende de finske kvæners herkomst hersker der imidlertid endnu megen uklarhet. „Kvaenland“ kaldtes i gamle dage de egne som laa omkring den nordligste del av den Bottniske Bugt. Kvænene omtales ofte i de ældste historiske beretninger og sidste gang i 1271, da de sammen med karelene foretok et plyndringstog til Norge. WESTERLUND mener ogsaa at den nuværende befolkning i nordre Österbotten er ætlinger av disse gamle kvæner. Han mener at det nuværende Uleåborgs lån (den nordligste del av Osterbotten) er deres egentlige hjemsted i Finland. Disse kvæner har altid været urolige av sig. Fra denne sin faste boplads ved den Bottniske Bugt har de flakket viden om mot nordost til det Hvite Hav, som efter dem har været kaldt Kvænhavet, og mot nordvest til Norge. De er ikke i den grad nomadiserende som lappene, men i sin levevis fjerner de sig ikke meget fra nomadene, sier A. H. KEANE!. Den samme forfatter angir antallet av dem i vore dager til henimot 300,000. F. W. WESTERLUND beskriver dem saaledes: Legemshøiden er 164,5 cm. med 3 frekvensmaxima ved 163, 165 og 167 cm. Deres cephalindex er 82,1, 75°/0 av dem er brachycephaler, og ikke mindre end 23,5 /0 har en index paa 85 eller hoiere. 66 0/0 av dem I A. H. KEANE: Man, Past and Present (London 1920). 6 HALFDAN BRYN. M.-N. Kl. Tabel 3. J Rent norske fra " Lap Lap Kvæn BY lees 2 | x ERIZE A eu 5 norsk a | BU] 87 |<>2 Kvætjord lee sacha: 13 I - I Trond.— Harstad III . 50 2 - 2 Bjarkoyae ES 7 - E I Ibestad Ville nee 35 - - - Salangen VII ...... 20 - - r1 Bardu See. 0 5 7 I - Lavangen IV. 22.2 12 - - I HrAnSVAINEPE ER 36 I I I SOTTEIS A eee et ele 2 - - - Dyr or SEES = - 2 Bere sate ie slau - - I Horsken.: 2. ce ende - - I Fer ERR 31 I - - Hlillesay SETE ; 4 - - - Maalselvaler er et I5 2 4 - BalstjordilV m em 32 - I Malangen IV ....... 25 I - 2 Tromsoysund VI .... 45 - - - ilipomse T. ees sr 27 - - 3 SOTHord Mile. I2 - - - Eyngen XIE FETE 32 I - - KarnlsecysV S ooo oe aac 25 - - - LHelgoy S I2 - - - Skjervøy Ill. ais ae er. 30 - - - Nordreisa „0. ine: I - - - Kvænangen ..2..... 5 - - - A tale ee STI 16 6 17 ——— Procente- een. 83,35 1 Faren var fra Tyskland, moren fra Nordland. De ovenfor streken anførte herreder tilhører Senjen sorenskriveri, under streken Tromsø sorenskriveri. har lyst haar og blaa eller graa eine. Mørke eine og mørkt haar findes kun hos 9 0/0. 4699/0 er leptoprosope med index facial. totalis 55— 64 43 9/0 er mesoprosope — me MESS 65— 69 11 0/0 er chamæprosope Re S EE 70—8o 669/90 av dem er leptorhine. 459/0 har opstoppernæse, og 40/0 har ret næse. Sittehoiden er 88,7 cm. og favnevidden 176,1 cm., resp. 54 og 107 0/0 av legemsheiden. Vi skal senere se hvorledes disse tal svarer til de tilsvarende hos de norske kveener. 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 7 Label a. | Fordeling av folke- typer var i 1891 iflg. HELLAND — Ifølge folketælling av roro Kvæn | Norsk x De Sum svensk | svensk 0/0 0/0 Lapper 0 0 Folkemængde or. kv. km. a DSE I Norske Norske | Finner Lapper Finner I5 95,7 3,55 97,92 1,95 58 92,0 16,41 93,26 6,72 - 5 8 99,9 14,67 = 5 > - - 4I 86,3 6,65 89,82 9,77 - - 26 76,2 6,03 85,76 13,14 - = 13 95,5 0,69 98,21 7 0,62 x 2 17 5,78 91,37 8,43 : 1 41 96,3 3,92 97,99 2,85 - - 2 5,60 93,08 6,28 - I 23 8,21 96,36 C 2,67 = - 8 4,42 96,09 2,91 = 9 597 5,07 99,75 25 = Se > ee EC ee ee eS ee ee ee - - | 88,3 | 0,8 10,9 5469 | 8,04 | 93,39 | 0,50 | 6,11 = D 97,4 9,4 2,2 1990 4,17 99,51 9,10 0,39 - 2 94,4 2,7 2,9 3894 1,19 98,26 0,84 0,90 - = 82, 0,7 16,9 3420 2,89 91,93 0,36 7,71 = > 97,2 0,1 2,7 1686 5,15 96,35 | 0,35 | 3,30 = - 90,1 93 8,6 5691 3,69 98,41 0,23 1,36 = - - - = 7633 12115,87 99,84 0,13 0,03 = = - - - 229 2,20 42,22 1,20 | 56,58 - I 31,0 16,6 52,4 5260 LT: 57,07 | 11,821 3%ı1 - - 81,4 0,7 17,9 2143 2,88 87,19 0,47 | 12,34 5 = 85,2 9, 14,2 I444 2,24 92,46 0,27 1,27 = - 63,9 8,5 27,6 2987 | 88,14 4,78 7,68 7 2 56,7 | 28,4 | 14,9 1552 0,57 12,41 | 25,33| 2,26 D x 26,05| 15,8 | 57,7 1870 0,90 45,19 | 12,44 | 45,70 8 81902 3,13 88,77 2,29 8,94 E,2 Det synes temmelig sikkert at kvænene er kommet til Finland sammen med karelene, og de skiller sig i antropologisk henseende kun lite fra karelene. De er da kommet ind i Finland ostenfra over det karelske nes, har saa fulgt floden opover og er i de nordlige deler av Finland stett sam- men med lappene. De har utvilsomt paa et tidligt tidspunkt krydset sig med disse, og det som nu væsentlig skiller dem fra deres stamfrænder karelene, er netop dette lappiske element, som er mere fremtrædende hos dem end hos nogen anden finsk folkegruppe. Det er fra lappene de har faat sit ,mongolske“ præg. Alle nyere undersokelser synes tyde paa at kvænene likesom alle de ovrige finske folkegrupper oprindelig har været blonde og dolichocephale. Saavidt man nu kan forstaa, har finske folkeslag intet med Asia at bestille. Deres urhjem ligger i det centrale Rusland, antagelig 1 guvernementet Moskva. Imidlertid kan man ikke paa forhaand utelukke den mulighet, at de norske kvæner delvis ogsaa kan nedstamme fra andre finske folketyper end 8 HALFDAN BRYN. M.-N. Kl. de egentlige kvæner. Jeg skal derfor ganske kortelig gjøre rede for hvilke andre finske folketyper der i denne forbindelse kan bli tale om. Vestfinnene eller de egentlige finner bor i det sydvestlige hjørne av Finland. Blandt alle finlændere har disse den største legemshoide (168,6 cm.) og den laveste cephalindex (79,9); de er ogsaa de mest lyshaarede og blaa- øjede av alle finner. Tavastenes middelhoide er 167,8 cm. og deres cephalindex 80,9; de er litt højere end vestfinnene, men lysere end karelene. Og disse sidste staar igjen i enhver henseende midt mellem kvæner og tavaster. Vi finder altsaa her igjen den samme paralellisme som vi saa godt kjender fra Norge. Til stor legemsheide svarer relativt langt hode, lyst haar og lyse gine, til liten legemshoide kortskallethet, mørkere haar og mørkere eine. Den nuværende rent finske befolkning i Finland er altsaa opstaat ved at en lys blok paa ca. 80,6%/0 er blandet med en mørk blok paa 19,4 %0, sier WESTERLUND. Det lyse element tilhører efter WESTERLUNDS mening den nordiske race; det mørke element skyldes for en væsentlig del tilblanding av lapper, mener han. Men netop herfor har ogsaa sammenligningen mellem den finske og den vestnorske befolkning saa stor interesse. Ogsaa den vestnorske befolk- ning er jo tydeligvis opstaat ved at den nordiske race er blit blandet med et mørkt element, og blokkenes gjensidige størrelse er i Norge omtrent som i Finland. For kvænenes vedkommende er der ingen grund til at tvile paa at det mørke element hovedsagelig skriver sig fra lappene. Her i Norge er det betydelig vanskeligere at si noget bestemt herom. De hittidige undersøkelser har nærmest pekt i den retning, at det mørke element skriver sig fra den mellemeuropæiske alpine race, og derfor er det av stor interesse at foreta en sammenligning mellem den vestlandske brachy- cephale befolkning og den nordiske, hvor det brachycephale og mørke elements etniske oprindelse ialfald for en del kjendes. Naar begyndte, saa kvænene at komme til Norge? Amunp HELLAND mener at de første kvæner kom til Norge for noget over 200 aar siden. ANDREAS M. HANSEN mener de begyndte sin indvandring til Norge omkring aar 1600, altsaa for vel 300 aar siden. I hvert fald kan man vel anse det for utvilsomt at nogen nævneværdig indvandring av kvæner først er fore- gaat i de sidste 2 à 300 aar. Ganske anderledes vanskelig er det at bli klar over naar lappene kom til Norge. ANDREAS M. HANSEN mener at lappene første gang er kommet til Finmarken mellem 1100 og 1300 e. Kr. Og de skulde da neppe være kommet til Troms fylke for ca. roo aar senere. MANTEGAZZA og SOMMIER angir lappenes legemshoide for voksne mænd til 152,4 cm. og for kvinder til 145,0 cm, von DÜBEn og HuwBorpr angir 150,0 cm. Om deres an- tropologi foreligger der desværre kun meget mangelfulde oplysninger. Til- dels ogsaa meget motstridende. Enkelte angir cephalindex til 83,5 (von Düsen), andre til 85,2 (VircHow), atter andre til 86 à 88 (RırıEv, DENIKER). 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 9 MANTEGAZZA Og SOMMIER, hvis materiale er størst, angir deres cephalindex til 87 à 88. Karakteristisk er det meget brede ansigt, som smalner sterkt åv nedad. Haken er meget liten. Av de fleste skildres lappene som relativt blonde (VircHow). Hos Amunp HELLAND heter det, at ,oinenes farve er hos lappene den som er egen for den blonde race, blaa og graa". Haar- farven er brun, ofte lysebrun, meget sjelden sort. At lappene oprindelig har været nomader, og at de har sit hjem i det centrale Asia, derom hersker der vel for tiden enighet. Derimot er der vel endnu meget delte meninger om naar de kom til Europa, og især an- gaaende deres utbredningsomraade i tidligere tider. Der er vel endnu dem som mener at de gamle skridfinner er lapper. Hvis denne opfatning er rigtig, maa lappene tidligere ha hat en meget stor utbredelse i Norge. I Norge er nu lappene kun for en del nomader. I løpet av de sidste par hundrede aar er stadig flere og flere blit fastboende, fornemlig i Fin- mark og Troms fylker. Og vi har da nu paa øene og langs fjordene i Troms fylke en befolkning som almindelig benævnes ,sjøfinner". Selv kalder de sig lapper. Disse syofinner utgjor en ganske stor procent av den i denne avhandling beskrevne befolkning. Den almindelige opfatning er som bekjendt den, at disse sjøfinner er forarmede fjeldlapper som har søkt ned til kysten for at finde levebrød. Og at dette virkelig er tilfældet med endel av dem, derom kan der neppe være tvil. Her har de saa i tidens løp krydset sig dels med norske, dels med kvæner. Deres sprog er nu i almin- delighet lappisk eller norsk, og de fleste av dem er vistnok selv av den op- fatning, at de nedstammer fra lapper. Helt sikkert er imidlertid ikke dette. Anpr. M. Hansen mener at disse sjøfinner er ætlinger av de gamle skridfinner; han mener at man her har for sig de sidste rester av den anariske befolkning, som bebodde Norge før den , ariske" befolkning kom hit. Hans rike bevisrække herfor kan jeg ikke her referere; jeg maa noie mig med enkelte punkter. Han henter sine beviser baade fra det sprog- lige, arkæologiske og historiske omraade. Og han mener at det hittil fore- liggende ganske sparsomme antropologiske materiale ogsaa støtter hans op- fatning. Likeledes seder og skikker og aandelige eiendommeligheter hos den nulevende befolkning. At den urgamle befolkning ikke har kunnet sætte særlig mange merker efter sig i sproglig henseende, finder han ganske forklarlig. Men han mener dog at kunne paavise endel. En undersøkelse av norske stedsnavne viser at finner i urgammel tid har holdt til helt til Norges og Sveriges sydligste spidser, og netop i de strøk ute mot kysten og oppe i markebygdene hvor de sidste rester av urbefolkningen lettest kunde holde sig. Og at disse stedsnavne ikke skriver sig fra lappene, er klart allerede av den grund, sier han, at vi i en meget sen tid kan følge baade sproghistorisk og gjen- nem stedsnavne lappenes langsomme utbredelse utover Skandinavien. Et sproglig bevis for lappenes sene ankomst til Finmark og Troms, efterat nordmændene hadde bosat sig der, har man i den kjendsgjerning, IO HALFDAN BRYN. M.-N. KI. at alle ord i lappisk for sjobedrift og alle fremtraedende stedsnavne ved den norske kyst er norske laaneord. Har nu skridfinnenes sprog efterlatt sig nogen merker? Kan man i det norske sprog paavise forskandinaviske laaneord? Man kan dog ikke vente at finde mange saadanne, mener han. Ti der kan ikke være tvil om at ,arierne" fra første stund av stod paa et hoiere kulturtrin end ,skridfinnene"; derfor maatte det ariske sprog gi, ikke faa. Anpr. M. HANSEN mener dog, at al sandsynlighet taler for at en række stedsnavne langs kysten er saadanne laaneord fra skridfinnenes sprog. Som eksempler paa saadanne nævner han: Östr, Fistr, Sotr, Bökn, Sökn, Hitr, Titr, Matr, Fugl, Drafn, Vefsn. Ogsaa endel bygdenavne er efter ham slike laaneord: Pötn, Dofr, Fósn o. fl. Alle disse navne er énstavelsesord med enkel eller vokalisk fremlyd og en sammensat utlyd, hvor stadig en stængt medlyd smelder av i en aapen, og de skiller sig derved sterkt ifra de blote oldnordiske, germansk- ariske navne!. Men hvorledes kan man saa forklare sig at skridfinnenes sandsynlige mest direkte arvtakere, sjofinnene, nu taler lappisk. At de en gang i tiden har hat sit eiendommelige sprog, synes tydelig nok at fremgaa av PEDER Craussons skildring av dem: „Siofinnerne haffue dog deris eget Maal, som de bruge indbyrdis oc med Lappen; huilcket Norske Mend icke kand for- staae, oc det siges at de haffue flere Sprog end et; af deris Maal hafue de dog et andet at bruge indbyrdes, som ingen kand forstaae.“ Her har vi altsaa en samtidig paalidelig hjemmelsmand for at sjofinnene midt i 1500- aarene hadde sit eget sprog, samtidig med at de kunde tale norsk og lappisk. At det lappiske har kunnet holde sig, er helt naturlig av den grund, at der stadig er kommet nye indflyttere, bumænd, av lapper. Hvis det virkelig forholder sig saa, at sjofinnene er ætlinger av de gamle skridfinner, saa maa man vel kunne paavise dette antropologisk. Ti de antropologiske eiendommeligheter er ganske anderledes seiglivet end sproglige og kulturelle. De antropologiske eiendommeligheter løsner ganske vist fra sine op- rindelige forbindelser ved krydsning med fremmede racer; men de for- svinder ikke. Og hvis man saasandt kjendte skridfinnenes oprindelige an- tropologiske eiendommeligheter, og hvis man kjendte de antropologiske eien- dommeligheter hos de folketyper som de i Troms fylke har krydset sig med, saa skulde det vel ikke være saa vanskelig at paavise hos den nulevende befolkning antropologiske eiendommeligheter som skrev sig fra skridfinnene. Men ulykken er at man ikke kjender skridfinnenes oprindelige antro- pologiske eiendommeligheter og kun har et meget sparsomt kjendskap til lappenes. Det er heller ingen let sak at paavise hos den nulevende befolkning antropologiske træk som kunde tænkes at skrive sig fra skridfinnene. Men det blir dog en av opgavene for denne undersøkelse. 1 ANDREAS M. Hansen: Oldtidens Nordmænd, p. 97. 1921. No. 20. TROMS FYLKES ANTROPOLOGI: TET 3. Tidligere antropologiske undersekelser. Der er ikke tidligere foretat nogen samlet antropologisk undersokelse av Troms fylkes befolkning. Overlæge C. F. Larsen har i sin avhandling ,Nordlandsbefolkningen" git enkelte spredte meddelelser. Han finder at den norske befolkning i alt væsentlig har de samme træk som den trønderske befolkning. Han mener fremdeles at kunne paa- vise, at der med hensyn til pandebredden er en karakteristisk forskjel paa de brachycephale lappekranier og paa de brachycephale kranier som skriver sig fra „norske“ brachycephaler. Lappekraniene smalner hurtigt og sterkt til forover, saa at differensen mellem pandens bredde og hodets bredde blir betydelig større paa lappekranier end paa norske brachycephale kranier. Den samme forskjel mellem lapper og , norske brachycephaler" mener han ogsaa at kunne paavise inden den levende befolkning. Forøvrig er hans materiale fra Troms fylke altfor sparsomt (83 mand) til at man av dette kan opgjøre sig nogen mening om fylkets antropologiske forhold. Brigadelæge Gronn har ogsaa git endel mindre meddelelser om de antropologiske forhold. Han meddeler saaledes at lappenes middelheide var 159,5 cm., kvænenes 162,4, medens den norske befolknings middelhøide i Troms fylke var 169,9 cm. Han finder at der er meget stor forskjel paa „sjofinner“ og fjeldlapper. De førstnævnte er meget spinkle, har gjennem- gaaende en daarlig legemsbygning. Fjeldlappene er ganske anderledes kraftig bygget. Han finder blandt lappene forholdsvis mange av en særegen mørk type med brune øine og sort haar. ANDERS DAAE og Hans Daar meddeler i deres avhandling „Indlands- og kystbefolkningens legemshoide, favnevidde, siddehoide og brystomfang" folgende: ,Den yderste kyst mot Nordsjoen, Atlanterhavet og Nordishavet har en befolkning med for storste delen mindre legemshoide og saavel absolut som i forhold til legemshoiden kortere ben og storre brystomfang end det øvrige lands befolkning." II. Legemshgiden. Saavel i dette som i de folgende avsnit har jeg ved beregning av middelværdi (M), standardavvikelse (5), variationskoefficient (v), sandsynlige feil av middelværdi E (M), av standardavvikelse E (5) og variationskoefficient E (v) benyttet den vanlige beregningsmetode (se Martins haandbok p.67 — 92). Jeg har for legemshoidens vedkommende fundet folgende: Middelhoide (M) — 169,287 cm. Sandsynlig feil av middelhoiden E (M) = + 0,167. Standardavvikelse (c) — 6,78. 12 HALFDAN BRYN. M.-N. KL Sandsynlige feil av standardavvikelse E (5) + 0,177. Variationskoefficienten (v) 4,004. Sandsynlige feil av denne E (u) + 0,7004. Den gjennemsnitlige legemshoide for hele fylket, 169,287 cm., ligger ikke saa lite under gjennemsnittet for hele Norge, som nu er omkring 172 cm. Legemshoiden er imidlertid meget uensartet i fylkets forskjellige herreder. Mindst er legemshoiden i fylkets nordostligste herreder, i Nord- reisa saaledes kun 166,5 cm., i Lyngen og Karlsøy 167,6 og 167,7 cm. Andre herreder med særlig liten legemshoide er Sørfjord (168,3), Helgøy (168,7), Skjervøy (169,0) og Kvænangen (169,1). Av de 190 mand som blev undersokt fra disse distrikter, kunde imidlertid ikke mindre end 83 (= 43,7 9/0) opgi enten at de var rene lapper eller kvaener, eller at deres slegt var sterkt opblandet med lap eller kvæn. Det kan vel heller ikke være nogen grund til at tvile om at krydsning med lapper er den vigtigste aarsak til den ringe legemshoide 1 disse herreder. i Størst legemshoide har jeg fundet i følgende herreder: Tranøy (173,2), Bardu (172,8), Balsfjord (172,8), Salangen (172,7), Kvæfjord (171,2), Tronde- nes (171,2), Dyrøy (171,6) og Maalselv 171,7. I disse distrikter var der kun 2,6 %0 som hadde lappeblod eller kvænblod i sine aarer, medens der derimot var 11,7 0/0 som kunde meddele at de nedstammede fra indflyttede Østerdøler og Gudbrandsdøler. At dette er forklaringen til den store legems- heide i disse distrikter, er vel hoist sandsynlig. Ti hvis jeg særskilt under- soker legemsheiden for de forskjellige racer og raceblandinger som findes her i fylket, da finder jeg følgende: A0) SYS He ES p m DA nr 164,1 cm. DAR Vesnerto prium ERE 100,25 3aleapper, > Akyaenen na ve ee 105,4, — At Kappen; > Borske rar UE 106,0. SER Keren er = norcke em ee 168, 6:sNorskewtra Troms tiylke tr mere 170,9 ,— 7. Norske av gudbrandsdalsk herkomst.. 170,9 — 8. Norske av osterdalsk herkomst...... 17258 Jeg vil med en gang gjøre opmerksom paa, at de som her er opført som lapper, selvfolgelig ikke er rene lapper. Om man andre steder i Norge kan vaere i nogen tvil om hvilken betydning herkomsten spiller for distriktets gjennemsnitlige legemshoide, saa kan man dog neppe være i tvil her i Troms fylke. Nu er naturligvis ingen av de ovenfor anførte grupper ,rene" 1 an- tropologisk forstand. Lappene angav ganske vist at være rene lapper; men en nærmere undersøkelse viser dog at de er sterkt opblandet. Og det samme er utvilsomt tilfældet ogsaa med de øvrige grupper. Hvis jeg ordner de fundne legemshoider i serier for hver cm., saa faar kurven et helt andet 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 13 utseende end man er vant til at finde i den sydlige del av Norge. Kurven blir meget mere avlang end vanlig. Medens heidekurven i Trøndelagen som regel fremviser 3 tydelige spidser ved 172, 168 og 176 cm., finder man her, som det vil sees, ikke mindre end 6 vel markerte spidser. Den heieste av disse spidser tæller kun ca. 7/0 individer, medens den hoieste spids i Trøndelagen tæller om- kring det dobbelte antal individer (ca. r4 %0). Av de øvrige 5 spidser vil man se at de tre tæller fra 5!/2 til 61/20/o individer. De er altsaa kun litt mindre end den hoieste, og den ste spids tæller over 4 %0 individer. Hele kurven faar derved et betydelig mere avlangt forløp end man ellers vanlig finder i Norge. Det beror selvfølgelig paa at befolkningen her i Troms fylke er meget mere heterogen end sydpaa. Dune BERNER DSE Bar ee 138 140 142 146 .148 150 152 154 156 158 160 162 164 166 168 170 172 174 176 178 180 182 184 186 188 19d Fig. 3. Kurve for legemshoiden i Troms fylke. Jeg antar, at de tre spidser som findes ved 168, 173 og 175 Cm, svarer til de tre spidser som er de vanlige ellers. At de med hensyn til beliggenheten er blit noget forrykket, er kun en naturlig folge av opblan- dingen med andre typer med andre legemshoider!. Spidsen ved 170 cm. er kun en summeringsspids. De to spidser som findes paa kurvens opad- stigende ben, er fremkaldt av de to nye typer som er tilkommet i Troms fylke, og som ikke findes i de sydligere deler av Norge. Av spidsenes be- liggenhet kan man imidlertid i en saadan kurve som denne neppe dra nogen sikre slutninger angaaende disse typers virkelige middelheide. Blandt de av mig undersokte 662 maend var den hoieste 187 cm., den laveste 148 cm. Da imidlertid undersokelsen er foretat paa ekserserpladsene, er allerede be- folkningens laveste individer eliminert. Dette har selvfølgelig ikke saa ganske lite at si i disse distrikter. Jeg vil derfor anse det for hoist sand- synlig, at befolkningens virkelige middelhoide særlig i herreder med liten legemshoide er ikke saa lite mindre end av mig anført paa tabel 4. I et distrikt som Skjervøy til eks. har jeg fundet en middelhoide paa 169 cm.; kun halvparten av befolkningen her er av norsk herkomst. Her kan man 1 Se nærmere herom i ,More fylkes antropologi" og ,To grundracer i Norge", 14 HALFDAN BRYN. M.-N. Kl. Tabel 4. Legemsheiden i Troms Gj.snits- E 7 . højde |139 |145 |146 |147 148 |149 |150 |151 [152 |15: Kvæfjord ..... 171,2 - - . - - : : - : Harstad og Tron- denes...... [712 - - - - - - E E : Bjarkey 0:5 168,3 = > & 2 . " : , ] Ibestad =. 2... [70,2 - - - - - = - . £ Salangen ..... 172, - - - - - i 2 Bardu SSL 172, - = : - = = E å 7 Lavangen..... 170,6 - - - = - = = £ 2 Iranoya SS: 173,2 - - - = - = 1 3 i Sørrelisa a. 167,3 - = = ^ s : t 4 x Dyrayas nr 171,6 - 2 - - * : 2 x " Beust erg: 169,7 - - - : - i = z s lorsken,...". 166,8 - - - = = I a = = Penvik re 170,5 - = - = = = = 4 T Hillesey - 167,8 - - - - - - 2 = z Maalselv...... I^ I E - - = : = 2 Å " 3alsiord rn. 172,8 - - - - = : . I D Malangen ..... 170,7 = = = H = E = ; = Tromsoysund . . 169,5 = : - : : 2 2 Å J Tromsø ....... 169,3 - - - - = = I : 2 STONE 168,1 - = - B à I e a = [Sy meen. e 167,2 - = = I £ z = 3 2 Karlsey ...... 167,2 = = = z I = 1 E - Lleleey c. cc 167,8 - - - - = - = t SEIervey c. 168,4 I - = = = 2 E E d Nordreisa ..... 168,2 - = - = = = E 3 A Kvænangen ... 169,3 = I I = = = à P i ei: : Absolute Serier for de av ; taler - - - s n = 3 x : mig undersokte | 5. E soldater Procent . i i uentis à E = : Procent . - - - - = = a : 2 Tidl. kasserte mandskaper I I I I I 2 3 I 2 Serie for hele aarsklassen I I 1 I I 2 3 1 2 0,13|0,131l0,13|0,13!0,13|0,2610,39|0, 1 310,26|0,39l0,39|0,5310,80|2,0 |o,8 1,1 [5,5 |2,2 130 0,13| 0,26 0,26 0,65 0,39 0,78 1,33 2,8 da være sikker paa at der ved utskrivningsmotene er blit eliminert flere . mænd paa grund av for liten legemshoide. For at bringe dette paa det rene har jeg gjennemgaat utskrivnings- listene for det foregaaende aar, og jeg vil da faa med ialfald de allerfleste undermaalere. Jeg har samlet resultatet av denne undersøkelse paa tabel 4. Alle de individer som paa denne tabel er opført foran den tykke strek mellem 155 og 156 cm. (paa én mand nær), var ved utskrivningen blit kjendt udygtige. Jeg har opført disse distriktsvis. Selvfølgelig blev ved utskrivningen ogsaa en god del hoiere individer kassert. Disse er samlet paa 4de linje fra neden. Tar jeg alle disse med ved beregningen av legems- heiden i de forskjellige distrikter, blir resultatet det som er fremstillet paa det medfølgende kart fig. 4. Man vil av dette kart se at der helt ute ved wk 4 33 23|38|47|43|39|54|44|34|46|35|38|30|24 | 19/17/13] 9| 8 4,5 | 3,8 13,1 15,1 16,5 16,1 |5,3 17,3 [6,2 [4,6 16,3 14,7 15,7 [4,1 |3,2 |2,6 2,3 [1,7 [1,2 [1,1 8,1 12,6 12,6 10,8 Iro 9,1 5,8 4,0 2,3 8,3 28 kysten findes en række distrikter med en paafaldende liten legemshoide. Jeg nævner saaledes Berg, Torsken, Bjarkoy, Hillesoy, Helgoy, Karlsoy o. fl. Undertiden finder man en ganske paafaldende forskjel paa legems- heiden i 2 nabodistrikter, til eks. Tranøy 173,2 og Torsken 166,8. Det minder ikke saa lite om forholdene i Mere fylke. Blandt de av mig under- sokte fra Berg og Torsken sa alle sig fri for at være lapper eller nedstamme fra lapper. Det vilde jo ogsaa være noksaa paafaldende om fjeldlapper skulde ha slaat sig ned i nogen større mængde i slike distrikter. Men en hel mængde av disse distrikters mænd hadde dog et helt fremmed utseende. Der kan ikke være nogen tvil om at det norske element her var sterkt opblandet med et fremmed element, som vel ogsaa har forvoldt den ringe legemsheide. on on LI AHHNKNA H ' w D FWwWUWBO OWN H 1 © Qn OD ' oO D I92I. No. 20. TROMS FYLKES ANTROPOLOGI. 15 fylke for hver cm. «abel 4. 163|164 |165|166|167/168|169|170|171|172|1r73|174|175/1 76/1 77|178|170|180|181|182|183 |184 |185 |r86 | | | | | I re | = || pif EN HERE RE) | SK Se re reae 3 24m I | - I - - - - I Bi Sati TSA Ae eo | 2 An p] 3 4 a ear ih > 5 = = - = = [IE] EC NS ESC KEE I SE le || Fe - - - - - = I | Zu] yt HRG ri el eco TR EC Zell TA e I - I - - - I = Bl) SNS NS: SA SX) esd ii Nera - | - I I - - - - - - | all c c= EST ier a: Z5 ETE I I - - - - - - - E EIS EN | ga -] ı S» Ecce - - -| - - - - - I I - 3 2 3 2 I 2 I I 4 2 I 3 2 I 2 3 3 I - - - I - LE EIL sex ates elle y NE ES DES le Er =| =|) = - - - - I -| - re |) Sef ey ae) ers cet ee I i| ez] SI ae ||) es at S x - - - - - I mE e = - - =| - I 2 rus - - - - - - xS =| zul =) - -| -| - I - 1 - RE - | - - - - - - I | | 3 P| a) el sex | ey etl Tage ee |e - -| 1 - - - - 2 - IL =|) = ze Eur SÅ ANDS Ne a I - - | - - - - - I =.) = ||) ns] ats ar mel Ey my ae) a = ai) 2 - - - - I - - I = Sea - I e «5 I 2302 21 Ona - I 2 I - - - I - I 1 men - E SC DESI 2 ERR IS - I - 2 zb =) EX e E mE 5) 2) 3) 5] =|) 2) 2 Sa | ln I - 3 zl eleme e sel ec aa) ie 32722 - I - == = cele ors - Se SE | a 2| - - | - - = ler = 9 RS IN Or 381 3 7i 2) a3 ES - I I - I 2 - I I Risen 3: 2| 2| 4| 3) 2) - - ie ee SS -| - = I mE: Te Los etes Does nee e sat - I - -| e 3 RES s 2) GO} 6) 7 ZU em 2| 5 I - I - - - I =| = le -| 1| - An -| - - - = NS - I AIR = ess -| 4] - i eee ae |e a - - - Sk es 29| 28 | 21 | 38 | 44 | 42 | 39 | 48 | 47 | 34 | 42 | 30 | 38 [29 | 21 |ı8 | ı7 |ır | 9| 8 4,4 14,25|32 15,7 [6,6 16,4 15,9 17,3 16,2 15,1 16,4 14,5 [5,7 14,4 [3,2 12,7 [2,6 11,7 [1,3 11,2 8,6 9,1 12,9 13,2 11,3 IO, TO, I 5,9 4,3 2,5 IM scel s I ms SC CN HALFDAN BRYN. M.-N. Kl. MIDDELS LEGEMSH@IDE 166 cm 29 79 167 » 19 7 I6G8 ” 17 7 109 ” 11 33 17 0 ” T LE] 77 17 |» DR ge » 172% FRE a 3 ^^ 3? 17 3 » SAF? Be Fig. 4. Kart over legemshoiden. 1. Kveefjord. 9. Sorreisa. 18. Tromsoysund. 2. Trondenes og 10. Dyroy. 19. Tromsø. Harstad. 11. Berg. 20. Sørfjord. 3. Bjarkoy. 12. Torsken. 21. Lyngen. 4. Salangen. 13. Lenvik: 22. Karlsoy. 5. Bardu. 14. Hillesoy. 23. Helgoy. 6. Lavangen. 15. Maalselv. 24. Skjervoy. 7. Ibestad. 16. Balsfjord. 25. Nordreisa. 8. Tranoy. 17. Malangen. 26. Kvænangen. Tabelaz. Asiatiske folkeslag ! Troms fylke Lebediner Tubatarer Teleugeter Meget smaa 129,0— 147,9 cm.. Smaa 148,0 — 157,9 cm.. Undermiddels 158,0 — 16r,9 cm.. Middelshoi 162,0— 164,9 cm.. Overmiddels 165,0— 167,9 cm.. Hoie 168,0—177,9 cm.. Meget hole 178,0 — 190,0 Sammenligner vi denne befolkning med virkelig smaavoksne folkeslag (se tabel 5), saa vil man se at Troms fylkes befolkning naermest blir som kjæmper. | Efter KAARLo Hırven: Die Eingeborenen des russischen Altai. —— 9 ^e c m IO2I. No. 20. TROMS FYLKES ANTROPOLOGI. TT En sammenligning med finske folkegrupper gir følgende resultat: Tabel 6. Middels Meget Smaa Middels Hoie Meget legems- |smaa,under| 137,0 — 162,0 — 170,0— | høie, over hoide 157 cm. | 161,9 cm. | 169,9 cm. | 180,0 cm. | 180,0 cm. irons fylke = ......... 170,1 5,70 6,15 36,75 47:55 3,85 Weshimnen mr T2784. 168,6 2,29 8,83 44553 42,21 2,14 lavasten 2:0. 167,8 DE Ino 45,06 37,85 1,88 ‘SATIRE Se 165,4 7,30 18,56 48,76 24,65 0,73 GE STR nee 164,4 9,25 21,65 49,20 19,50 0,40 Som man vil se av denne tabel, har vi betydelig flere høie folk i Troms fylke end blandt nogen av de finske folkegrupper. Vi staar i denne henseende nærmest vestfinnene. Da det vel er hævet over tvil, at det er det nordiske element som gir begge disse folkegrupper deres store legems- heide, saa skulde Troms fylkes befolkning enten være mere rent nordisk end den mest nordisk rene av de finske folkegrupper. Eller ogsaa maa de finske folkegrupper være opblandet med en endnu mere lavvoksen type end tilfældet er i Norge. WESTERLUND kommer gjennem sine beregninger til det resultat, at der i den finske befolkning indgaar en nordisk blok paa 80 %0 og en fremmed paa 20 0/0. Utfores den samme beregning noiagtig likedan her + Troms fylke, blir resultatet at den nordiske bloks størrelse kun er paa 66/0. Da allikevel legemshoiden her er betydelig større, maa dette bero paa, at den fremmede blok her i Norge har hat en større legems- heide end den fremmede blok i Finland har hat. Men merkelig nok er ogsaa den lavvoksne befolkning hos os større end blandt vestfinnene. Det er kun blandt kareler og kvæner man finder flere smaavoksne folk end i Troms fylke. Den ringe legemshøide hos disse finske folketyper skyldes, mener WEsTERLUND, krydsning med lapper. Den frem- mede blok hos os kan da neppe ha været lapper. Da maatte selvsagt be- folkningen i Troms fylke været betydelig lavere end i Finland. Den eneste kjendte folketype med meget liten legemsheide 1 Nord- europa er som bekjendt lappene. MaxrEGazza fandt hos voksne lapper en gjennemsnitlig legemshoide paa 152,4 cm. Hos voksne lapper (mænd) varierer hoiden ifølge hans undersøkelse fra 138 til 161 cm. En mand paa 134 og to paa 168 og 170 cm. er ialfald saa tvilsomme at jeg tror det er rigtigst ikke at regne dem med. Inden en serie av fjeldlapper finder man derfor 50%0 av samtlige undersøkte under 152,3 cm. Inden en for lapper helt fri norsk indlands- befolkning finder man praktisk talt -ingen under denne legemshøide. Tar man derimot for sig den lavvoksne vestlandske brachycephale befolkning, saa finder man ganske vist en og anden under denne legemshoide. Men det blir dog ikke mere end ca. 4 promille under denne hoide. Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. 20. 2 18 HALFDAN BRYN. M.-N. Kl. I den her foreliggende serie fra Troms fylke kan man derfor med stor sikkerhet si, at de mænd hvis hoide ligger under 153 cm., i denne hen- seende bærer paa arv fra lapper. Dette er i alt 15 mænd. Da man maa regne med likesaa mange +-avvikere, skulde altsaa i alt 30 mænd i denne serie med hensyn til legemshoide være av lappisk avstamning. Dette utgjør omtrent 40/0. Efter den offentlige statistik skulde imidlertid i 1910 8,8 0/0 av befolkningen være av lappisk herkomst. Forholdet maa da enten være det, at der i statistikken er medregnet som lapper mange som ikke er det, eller som kun for en ringe del er av lappisk herkomst. Eller ogsaa maa det lappiske islæt ikke gi sig tilkjende ved den antropologiske undersøkelse av legemshoiden. III. Pigmentering. 1. Oienfarven. Oientypene er betegnet saaledes: 1 = blaa og graa (= MARTIN 13— 16), 2 = lyst melerte (M. 9—12), 3 = mørkt melerte (M. 6—8), 4 = lysebrune (M. 5), 5 mørkebrune (M. 4). abel. Oientyper | Procent av Antal under- søkte Herredets navn Index blaaoiede melerte brune I 233 Ar, Kvæfjord FREE 15 IO 2 - 2 I 1,80 66,4 13,6 20,0 Harstad og Trondenes ... 58 38 8 6 5 I 1,67 65,1 24,2 10,7 Bjarkayie ce. 8 6 - 2 - - 1,50 15,0 25,0 - Ipestad. oir sts 4I 26 1 2 1 3 1,82 62,3 34,1 4,6 Salangen FS. 26 18 I 3 2 2 | 1,80 69,2 15,4 15,4. arduo: inel 9 3 I 1,38 69,2 30,8 = Éavangen, 25: 17 II 3 I - 2 1,76 64,8 23,5 LI, Trangyi.. 2... =. 4I 29 [e - 2 I 1,46 70,8 21,9 13 Sorreisae oe er 2 I - - - I | 3,00 50,0 - 50,0 Dysser 23 15 5 I I I 1,60 58,0 333 8,7 [eno 00,00 8 4 I - 2 I 2,37 50,0 12,6 37,4 Forsker rese el 9 4 2 I 2 - SART 4445 29,15 22,25 PERMET 33 20 GAS 2 27] 1,78 60,8 27,1 LAST Elle Soares 5 2 I 2 - - 2,00 40,0 69,0 - Maalselver..... 23 I4 7 I I - E 61,8 34,9 4,35 Balshord o 2... 34 Bo) ax 2 - 1,58 58,0 36,2 5,8 Malangen ...... 28 22 4 I I - 1,32 78,0 17,9 3,9 Tromsoysund... 46 22| 16 6 2 - 1573 47,8 47,8 4,35 bao rie ORE 30 I4| Io I 3 2 1,96 53,6 36,9 16,7 SOC ac goood 14 6 4 3 I - 1,92 13,0 59,0 7,0 Éyngenreec na 72 33 | r2 5 i us 7 | 2331 4357 23,3 33,0 Korsør 30 13 8 6 I auos 43,5 46,5 10,0 IBIS? S 5 er 12 4 ans 2 = |) 2516 Bass 50,0 16,7 SEIenve vas s 55 37 6| 6 3 aA 170 67,3 27,8 10,9 Nordseisawar re 2 2 - - - - 1,0ol Er 6 B Kvænangen 17 8 Al 2 2 1 | 2,05) DEN eo 22 ANNEE re auto 388 | 133 | 57 | 52 Procent . aes. 58,5] 19,9| 8,9 | 7,8 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 19 Som det fremgaar av tabel 7, har jeg blandt samtlige undersøkte fundet 388 (58,5 %0) blaaoiede, 133 (19,9 %0) med lyst melerte oine, 57 (8,9 9/0) med mørkt melerte eine, 52 (7,8 %o) med lysebrune eine og 32 (4,9 Yo) med mørkebrune eine. Sammenholdt med hvad man finder andre steder i Skandinavien, maa altsaa denne befolkning kaldes morkeiet. Tabel 8. Troms Nidaros Møre Nordmør Søndre fylke fylke Søndmør 0/0 00 0/0 0/0 0/0 Blaaworesraataines. 6 s REE 58,5 69,5 67,2 69,4 55,7 EvyStmelestengines..-...... 0-7. 19,9 EA 13,7 14,4 12,1 Markismelertesame... sensor. 8,9 6,6 7,3 5,4 7,0 BEIMEFOME 25: ccc ee een ee 2,7 Bar hörte) 10,8 25,2 Endnu rikere materiale til sammenligning faar man hvis man noier sig med 2 grupper: 1. blaa- og graaoiede, 2. melerte og brune oine. Græn- sene mellem lyst melerte, mørkt melerte og brune @ine er ogsaa saa ube- stemte at man ved denne inddeling faar et sikrere grundlag at bygge paa. Tabel 9. Troms Søndre : e we Vester- : N Nidaros Sverige apple fylke Søndmør p: Mersey) DEN botten Blaa og graa oine .... 58,5 55,1 69,5 66,7 55,9 60,1 Melerte og brune oiue. 41,5 4453 30,5 33,3 44,1 39,9 Men som man vil se av begge de ovenstaaende tabeller, har vi baade i Norge og 1 Sverige distrikter med en mere merkoiet befolkning end denne. Specielt er det av interesse at lægge merke til at Søndre Sondmer, hvor der slet ikke findes og heller ikke i historisk tid har eksistert lapper, har en mere morkoiet befolkning end den med lapper sterkt opblandede befolkning i Troms fylke. Der er derimot med hensyn til oienfarven meget stor forskjel paa de forskjellige distrikter. De to lyseste herreder er Bardu og Maalselv og Malangen. I disse distrikter fandt jeg i alt 70,20/0 blaaøiede, 21,8 0/0 med lyst melerte eine, 4,8 0/0 med mørkt melerte eine og kun 3,29/0 med lysebrune oine. Disse tal svarer omtrent til hvad man finder i de lyseste distrikter i Norge og Sverige. Befolkningen i disse herreder er for en væsentlig del indvandret fra Østerdalen. Det har derfor en stor interesse at sammenligne disse tal med hvad man finder i Nordre Østerdalen. 20 HALFDAN BRYN. M.-N. Kl. Tabel ro. —————————D Bardu, Nord Blandt Nordre a; Maalselv, Södermanland | svensktalende Østerdalen age Malangen i Finland Blaa og graa gine ........... Lyst" melentemoine= nenn. Mørkt melerte eine........... TUNER cines oboe en: Det er et nyt bevis paa den seighet hvormed denne egenskap ned- arves. Man kan vel endvidere av disse tal dra den slutning, at den befolk- ning som fandtes i disse distrikter for, har været like saa lysoiet som ind- vandrerne. Hvis jeg saa derefter undersoker oienfarven i et av de mest morkoiede distrikter, da finder jeg folgende tal: Tabel rr. zt bp, | Reim y: = = v E Rs RE Te = D DER T nu 2e 2 © À. oD v Eo S EA © -4 = c Mico) m GH nla Au = > zs En KOEIRSE = Y ^, on ee tn es M eae = sess E 2 [o] E — c "M c o tz EX AES Bilan opera OMe i qe IE leystamelentezemes ke ne ele Mørkt melerte oine Brune gone treater MM SU 100,0 | 100,0 En saa morkeiet befolkning finder man ganske utvilsomt ikke i noget herred søndenfor Tromsø. Man maa gaa til østligere eller sydligere lande for at finde tilsvarende mørk befolkning. Vi har i Lyngen 2 fremmede elementer, nemlig lapper og kvæner. Det vil av denne tabel sees, at det er „lappene“ som tilfører befolkningen her dens store procenttal av mørk- oiede. Blandt samtlige lapper og lappebastarder i Troms fylke har jeg fundet kun 32,6 9/0 blaaoiede, altsaa endnu betydelig færre end i Lyngen. Blandt kvænene derimot har jeg fundet 53,5 /0 blaaøiede. Disses tilstede- væren i Lyngen herred bidrar altsaa kun til at forøke antallet av blaaøiede. Det fremgaar videre av samme tabel, at befolkningen i Lyngen herred har saa meget lappeblod i sig at der hvad oienfarven angaar, kun er en rent ubetydelig forskjel paa den del av befolkningen som kalder sig lapper, og paa den del som kalder sig norsk. Man kan vel herav dra den slut- ning, at de som kalder sig norske, har i tidligere slegtled været krydset med lapper. Det er kun de færreste som kjender sin avstamning mere end 2 generationer bakover. 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 21 Labelr2. Antal Herredets navn |under- sokte Procent av Haartyper lyshaarede morkhaarede Kyetord-- ..... QNS Harstad og Trondenes .... 58 3 I 22| 19 2,96 62,0 38,0 BAER OY: -....... 8 3 - I 4 - 215 50,0 50,0 Inestaderr ses 4I I2 I gl ES 4 ‚95 53,5 46,5 SELE er... 26 4 - OTT 2 - - Bard eee. I3 3| 2 5 3 11,0 23,0 IF iyaneen- --.... 17 5 5 7 - 59,0 1,0 ADD VE + ee 41 12 - 20 9 78,0 22,0 SPILEISA: 2....- 2 - 2 E IUS TOO TEE 23 6 9 AE tie SERGENT TE 8 3 4 37,5 62,5 Horskenn. =... ss 9 5 4 555 44,5 ILES 9... 33 6 4 48,5 55 Killesoye se... 5 I I 60,0 40,0 Maalselv. 2. ....:- 23 5 2 74,0 26,0 Balsfiord -.- ...... 34 7 I 64,5 355,5 Malansen..-..... 28 8 I 68,0 2,0 Tromsoysund.... 46 9 3 63,0 37,0 HRromsSg..". 2. 20% 30 8 4 60,0 40,0 ‘Siig Tea CR I4 2 = 43,0 57,0 LESE Nr 12 5 8 51,5 48,5 Kaulsay=........ 5. 30 7 4 53,5 46,5 Helsayen....... 12 5 - 83,4 16,6 SEJEEVØV = - - - -- - 55 5 5 5 45,5 Nordreisas- 04... 2 ae Kvænangen ..... 17 SER Ele nee ss. oe Procent .-...... En nærmere undersokelse viser at i følgende distrikter er der særlig faa blaaoiede: Helgoy, Berg, Torsken, Hillesey og Tromsoysund, Serfjord, Lyngen og Karlsoy. Det er med andre ord en række ø- og kystdistrikter. Gjennemsnitlig er der i de her nævnte distrikter kun 45,6 /0 med blaa eller graa eine uten spor av brunt pigment. For at dette forhold skal kunne komme istand, maa den blaaøiede norske befolkning her være blit opblandet i meget stor utstrækning med en sterkt brunøiet befolkning. Vore norske fjeldlapper er efter de sidste foreliggende oplysninger om dem neppe i nogen utpræget grad brunoiede. Nogen paalidelig statistik foreligger des- værre ikke. Den bedste jeg kjender skriver sig fra MANTEGAZZA og Sommier. De opgir følgende: D D HALFDAN BRYN. M.-N. KI. Her er altsaa ikke flere brunoiede end der nu findes blandt den blandede befolkning i Lyngen. Det synes da lite sandsynlig at befolkningen i Lyngen, hvorav ialfald hovedmassen tilhorer den nordiske race, kan ha faat sine sterkt pigmenterte eine fra lappene. Det synes ogsaa lite sandsynlig at det kan skyldes nogen indvandring fra Finland. Ti som det fremgaar av tabel rr, har selv det mest brunoiede landskap i Finland kun litt over 9 9/0 brunoiede. Og her har lappene i lange tider krydset sig med den finske befolkning, saa WESTERLUND mener, at det for en væsentlig del er gjennem denne krydsning at denne befolkning er blit saa brunoiet som den er. Men den er dog lite brunoiet 1 forhold til befolkningen i Lyngen. Hvorfra befolkningen i Lyngen og de øvrige morkoeiede herreder i Troms fylke har faat sine morke eine, faar da indtil videre bli et aapent sporsmaal. 2. Haarfarven. Jeg regner i det følgende med kun 5 typer av haar: Type wrériblondtuhaar ‘og svarerstil PiscHers S nen. ee Rocco DER LTOÄL FOR SVALeDEt WISCHPRSi shares. UE ee v 3 er lysebrunt og cendré og svarer til FiscHERS 7 samt 25 og 26 — o4 er morkebrunteog, svarer ts ER sS SEE 5 og 6 — s'epesort'oessvabem tS RISCHERS er PRE 4 og 27 Blandt samtlige undersokte fandtes 23,4 9/0 lyseblonde, 1,5 9/0 rod- haarede, 34,0°/0 lysebrune, 33,9 Ü/0 med mørkebrunt haar og 7,2 0/0 sort- haarede. Til sorthaarede er her medregnet baade de brunsorte og de blaa- sorte nuancer. Disse sidste forekommer dog her som ellers i Norge saa sparsomt at de omtrent kan sættes ut av betragtning. De allerfleste av de sorthaarede hører altsaa til FISCHERS type 4. Pabeltes 7 S > 2 © © UE 8 £e = : = d. oO ^ v oO n = n = = o 9 S Big did omni euro RETI S es ea | EG a ee HS "E "J £ = A ESS tle D T ECT 5 = ask nm" u os ec m © SR = ie er ae Ade DANS N S ZB m ie Hal. v r=) Im n un = mL sed RS wy Q ,0 m = >; EA > Blondt haare eter ee siete inne Rødt RAA meer are rear e ense Eysebsimtshaaner EEE CE ET Merkebruntihaars wo Sonate ne TT =e Ohi 30 ae leyshaared ela CREE = tet: ere FANS || ES RES Merkhaarede ee kicks nie 27,4 48,7 41,7 35,5 45,8 35,5 - 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 23 Der er dog med hensyn til haarfarven likesom med øienfarven stor forskjel paa de forskjellige herreder. Flest sorthaarede og morkhaarede findes i følgende herreder: Berg, Torsken, Skjervoy, Lyngen, Serfjord, Hillesøy, Lenvik, Salangen og Kveefjord. De 5 med hensyn til haar lyseste herreder er Bjarkøy, Bardu, Tranøy, Maalselv og Malangen. For- skjellen mellem de lyseste og mørkeste herreder er, som det vil sees av tabel 13, meget stor. Forholdet i de 3 lyseste herreder minder meget om forholdet i Nordre Østerdalen. Der er dog avgjort flere morkhaarede i Nordre Østerdalen. Lyngen har overordentlig mange sorthaarede. Rødhaarede mangler helt i Lyngen og findes i det hele tat meget sparsomt i de mørkeste herreder. I Maalselv og Bardu er 3/4 av befolkningen lyshaaret og kun !/4 mørk- haaret (FISCHERS 4, 5 og 6). Dette svarer temmelig præcis til hvad man finder i de lyseste herreder sydpaa, hvorfra befolkningen i disse herreder jo ogsaa er kommet for ca. 100 aar siden. De distrikter hvis befolkning har mørkest haar, er i alt væsentlig de samme som fremviste de største antal brunoiede. Og at det skriver sig fra de i disse distrikter boende , lapper", er sikkert nok. Det eiendomme- lige er blot at der blandt disse ,lapper“ er saa mange sorthaarede. Ti derom synes alle som har undersøkt fjeldlappene, at være enige, at hoved- massen av disse er brunhaarede; for en meget væsentlig del har de endog lysebrunt haar (og rent sorthaarede fjeldlapper er utvilsomt sjeldne). Hos voksne mænd over 13 aar opgir MANTEGAzza og SOMMIER føl- gende: Sort haar soon AS 3,40 | 0 RER * 18,7 /0 Morkebrunt haar... 15,3 — | Mellembrunt haar... 24,2 — | i PLU Lysebrunt haar .... 10,2 — | Merkeblondt haar... r5,3 — | Mellemblondt haar.. 20,4 — } 47,8 — Lyseblondt has... 125, — Sammenholder man disse tal med hvad jeg har fundet i de mørkeste herreder i Troms fylke, vil man straks forstaa at disse umulig kan ha faat sit mørke haar fra flytlappene. Og sammenholder man de samme tal med hvad WESTERLUND har fundet i de mørkeste landskap i Finland, blir det ogsaa klart at det heller ikke kan skyldes nogen invasion fra Finland. Ogsaa for haarfarvens vedkommende faar det da indtil videre bli et aapent spørsmaal hvor den mørke befolkning i Troms fylke har faat sit mørke haar fra. 24 HALFDAN BRYN. M.-N. KI. 3. Pigmentindex. For at faa et sikrere holdepunkt for bedømmelsen av pigmenterings- graden i de forskjellige herreder har jeg gaat frem saaledes: Jeg har i hvert enkelt herred multiplicert antallet av sorthaarede med 5, mørkebrunt- haarede med 4, lysebrunthaarede med 3, rødhaarede med 2 og blond- haarede med 1. De derved fremkomne tal er summert sammen og dividert med de samlede antal undersøkte i herredet. Det derved fremkomne tal har jeg kaldt haarfarveindex. lig; G 7 Sa Se GE | PIGMENTINDEX 2.00-2.19 ” 2,20-2,29 22 2,30-249 ap 2,50-2,59 ^ 260-269 22 270-279 Fig. 5. Kart over pigmentindex. I. Kvæfjord 2,46. 9. Sorreisa | m 18. Tromsoysund 2,38. 2. Trondenes og ro. Dyroy gus r9. Tromsø 2,46. Harstad 2,32. rr. Berg lis 20. Sorfjord 2,60. 3. Bjarkoy 2,12. r2. Torsken j 5 i an. Eyngen 2,75. 4. Salangen 2,47. 13. Lenvik 2,26. 22. Karlsoy 2,56. 5. Bardu 2,00. 14. Hillesoy 2,41. 23. Helgoy 2,25. 6. Lavangen 2,20. 15. Maalselv 2,19. 24. Skjervøy 2,35. 7. Ibestad 2,37. 16. Balsfjord 2,25. 25. Nordreisa le T 8. Traney 2,04. r7. Malangen 2,05. 26. Kvænangen ans Paa samme maate har jeg gaat frem for at finde oienfarveindex. Morke- bruneiet faar 5 point, lvsebrunoiet Joint, mørkt melerte eine faar oint, a à lyst melerte oine 2 point og blaa eller graa eine 1 point. Middeltallet av J o o den for herredet fundne haarfarveindex og eienfarveindex har jeg benævnt pigmentindex. I de lyseste herreder blir pigmentindex omkring 2,00, i de morkeste herreder omkring 2,80. 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 2 Or Det omstaaende kart gir en fremstilling av hvorledes pigmentindex forholder sig i hele fylket. Der er et lyst utstraalingscentrum i Bardu og Maalselv og et mørkt utstraalingscentrum i Lyngen. Pigmenteringsgraden synes hovedsagelig at være avhængig av om der i bygdens befolkning ind- gaar lapper. Jo flere lapper des sterkere pigmentering. Blandt de av mig undersekte fra Helgey var der angivelig ingen fremmed indblanding, hverken av lapper eller kvæner. Og som man vil se, er distriktet meget lyst til trods for at der paa de samme ger er andre meget mørke herreder beroende paa en relativ sterk lappeindblanding (Karlsøy). IV. Hodet. 1. Hodets største længde. Hodets længde varierer mellem 17,0 og 21,3 cm. Middellængden er 19,28 cm. Kurvens nedadgaaende ben er, som det vil sees, relativt jevnt, D à [TI : BEE DI ; LLL Le FE SNENRES RH azs EDS 170 180 190 200 210 = Kurven for hele Troms fylke. Kurven for de angivelig rene lapper. Fig. 6. Grafisk fremstilling av hodets største længde. medens det opadstigende ben er meget ujevnt. Kurven har ez tydelig spids ved 19,1 cm. I de enkelte herreder veksler middellængden fra 18,5 til 19,4 cm. Underseker jeg saa middellengden hos de forskjellige etniske grupper inden fylket, finder jeg følgende: 26 HALFDAN BRYN. M.-N. Kl. Tabel 14. Hodets største længde for Kvæfjord 1. - - - - - - - | I | I Harstad og Trondenes ... - - 2 I - - 2 3 3 16 Djarkey en... - - - I I - - - Salangen «n. - - - I - - 2 4 7 2 Banden ee - - - - - - - - I - 3 Ibestad ee" - E - - I - I r 5 2 6 Lavangen...... I - - I 2 2 - 3 3 Trancy os. eo - - - - 2 2 I 3 I 4 3 Serreisa ....... - - - - - - I - - - - Dyrøy ske - - I - - - 5 3 I 2 3 PÉTER eme - | - - - : I I I I - Torskenr....... - - . I - - I 2 I I PENTIER PERS - - - - - I I - 4 I 7 Hillesør 2. ... - - - = - - - - - I - Maalselv....... - - - - - - - ] 4 I 3 Balsfiord "7" - - - - - 2 I 3 3 4 Malangen...... - - I | | I - 3 4 I I 6 Tromsoysund .€. - I - - I - 2 8 6 I 5 roms ee ce - - - - I I - 3 3 I 4 Sortjordes «am ae: - - I - I - I - I 2 Lyngen - - - I - I - 3 - 5 9 Karlsoye 3-19: - = = = 2 I = + 3 5 3 Helene ce - - | : = : 2 1 : : 5 I Servo y i. - - I I - I I I 2 2 9 Nordrelsa. fie - - - - - - - - - I - Kvænangen - - - - - - I - - - I 5 7 4 9 13 28 40 | 52 44 80 ÉADpeR er - 4 - - 3 2 6 3 3 4 Kycenerex c - I - - I - I 2 I 2 3 Lap X kvæn ... - - - - - - 2 2 - I I Lap X norsk ... - - I - - I I 3 - 4 6 Kvæn X norsk . - - - - I I 3 I 3 - 4 Det er ikke mulig at faa istand nogen sikker kurve for lappenes ved- kommende. Dertil er de for faa i antal. Men saa meget kan man dog se av fig. 6, at lappenes kurve maa ligge ganske betydelig tilvenstre for nord- mændenes; tydelig fremgaar dette av tab. 15, kol. 7 og 8. Det fremgaar av denne tabel, at medens der blandt de rent norske er" 48,3 9/0 som har et hode længere end ror mm., saa er dette kun tilfældet med 16,5 %0 av de undersekte lapper. Hos de norske utgjor hodets længde 11,43 0/0 av legemshoiden, hos lappene 11,13. For den norske befolknings vedkommende stemmer dette tal nøiagtig med hvad jeg har fundet i Trønde- lagen (se Anthropologia nidarosiensis, pag. 84). Jeg har som sagt paavist at hos den norske befolkning er hodets længde i hoi grad avhængig av legemshoiden. 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 27 samtlige distrikter, ordnet i serier. 198 4 6 5 2 2 I - I - - - - - - I 2 - I I I - - - - - 3 3 2 - I - I - - - - - - - 6 5 2 I 2 I - 2 - - - | - - | - 2 I - - - - - - - - - S 5 5 2 5 = I > 5 i ; 2 : I - : - £ z 2 x s T 2 2 I I I - - - . - = - - I I I I - - - - - I 2 - - - - - - - - - EB 3 2 + 3 I = 5; : = r s = = 2 I - B = E - = = - 4 3 2 2 I I - I - - - - 9 4 2 2 2 I I - - - - 3 I | I | 2 2 I - - - - - - 6 6 4 3 - I - I - - - - 4 3 2 5 I I - I - - - - - I 3 I - I - - - - - - - - 3 5 3 I 2 I - - - - I - - - 3 = 3 = : 2 I 5 s = : = 7 3 I I - - I - = - - - - - 4 I 2 I 2 - 2 - - - = - - - 3 = 7 I = = 2 : = £ 67 60 46 31 30 | 15 II 6 3 I I - - = 559 I 3 I - | - - - - - - - - = 30 3 I - I I - - - - - - - - = 17 - 2 - - - - - - - - = 8 3 I 2 - - - I - - - - - - = 22 5 I 2 2 I - - I I - - - - 26 79 68 SI 34 32 15 12 7 4 | I I - - |= 662 Hos den norske befolkning av 164 cm. hoide er hodets største længde 19,19 cm. eller 11,71 0/0 av legemshoiden, idet hodets længde altid er relativt større hos smaa folk end hos høie folk. For de norske kvæners vedkommende vil det av tabel 15, kolonne 9 og ro sees, at der er fuld overensstemmelse med hvad WESTERLUND har fundet hos de finske kvæner. Hos 36,690 av de norske og 37,4 Yo av de finske kvæner ligger hodets længde mellem 18,6 og 19,1 cm. Hos 36,60 norske og 38,8 %0 finske kvæner er hodets længde større og hos 27,5 Yo norske og 33,8 %0 finske kvæner er hodets længde under 18,6 cm. De finske kvæner har litt længere hode end nordmændene, og det samme er tilfældet med de norske kvæner. 28 HALFDAN BRYN. M.-N. Kl. Tabel 15. Hodets største længde. BY D & o 2 D 8 o JA : V UM EEG E , D yv zx gaz 4 Om | 8% mi, a2 © 4 d cuim m- e qe v > Zen > 5 À © > m om a |fol£fal és] n | Po! go} *B | ag = bp E | we | wh 5 bo 8 | ws | we | be = ao - n = JA "iR =. = 27 2 p rra ees nos ES i BE LEE | SAME — "Sp DD + bp 5 — bp c bp + bp & DE c f: f n = = == M o ES < < < < Barden DIT - É Favansen een - > Ibestad m. neo - 3 Eben Coote wen co 2 SOLLLEISA t cS EE = = DYTOVEREE et - 3 SER dO d OD d.n 5 - - Moy «oveotutboDd5 uc - I Lenvik? SEES tee i - > Hillesgy 1-0 ep - _ Maalselv oo. ac. - : Balstiorder rer - I Malangen. cc. ai oie «one - 3 Tromseysund ....... - > roms rec Corne - I SOrljord copoanced 56 - R lyngenne s - 2 Keats] Soy e s S - 3 Eleleovic Er ERE - 2 SY de T ODE e toa - 3 Nordreisa 5-0: seis - - Kvænangen .2...... - = N 40 Pappese e E - I Keveene rig eee - I Lapper X kvæner ... E I Lapper X norske .... - I Kvæner X norske ... - . 44 T aibiel 77. Hodets sterste bredde. 0/0 Lapper Hodets største bredde db el loue ee 1:40 TA loge dre 0,3 - BA AS oie mofo a GLO OO De 0,4 - BAA AIS qo np So te SO ot 2,6 - BAD TAT 5,4 - izle). lon ub oes 6,5 SR SO ee ee: 14,5 : 12,9 eh Sq oO I4,7 22,5 (ei TAG o's 100 0000 2 16,8 12,9 ROSE eee mn 13,2 12,9 HSE Cod ooomcoccadde 11,0 9,7 TOO TOTEN OTO D OUS SE 6,4 97 BORE (O0 nn oo Jde 4,1 6,5 OAO SENE ae 22 6,5 n (S9) — S7 ac oopooooSouac I,2 3,2 108 Ns we oOo Oo DOU oo 0,6 - LOMME ST cire acm ae O, I = 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 31 Hodets bredde. I I 3 = 4 I - - - 8 6 8 TI 5 2 I - - I I I 2 I I - - 2 5 2 3 3 I I = a = ERS 3 4 I - when ve - I - - - 2 I 6 7 4 3 2 4 I - - 8 IO 4 3 3 3 2 2 - - - - I I - - - - - = = - - - 2 2 1 3 3 I - - - - - - I - 2 I I I I - - - - I I - 2 I SÅ - - - - 4 4 3 6 4 i 3 : z = - 2 I - I - - - - - x 2 6 5 2 2 2 I - - - - - 5 6 1 5 4 = I I 1 = 3 4 2 3 + 3 3 3 E 2 2 5 ; 8 4 IO 5 5 4 - I - - E 6 4 7 - 2 4 2 - I - - - 4 3 I I - - I - - 2 - - 3 3 4 8 8 3 2 = = I = 5 I 3 5 2 2 2 I - - - I 3 I I 3 - - - - - - - 4 6 9 I I I I - - - - - I = E = = = = = E = 2 - - I I - - - - = = 82 T 86 14 64 35 24 12 6 4 I - 4 jj 4 + 3 3 2 2 I 3 5 3 i 4 3 3 3 = = I E i 5 - 3 I I E - - - - - - 4 3 5 3 3 2 e F E E 5 5 4 7 3 2 I = I 5 " = 96 98 106 88 73 42 27 15 8 5 = * Hoiest index har jeg fundet 1 herredene Salangen, Lavangen, Lyngen, Serfjord og Tórsken. Hvad Torsken angaar, saa er de undersektes antal saa lite at jeg indtil videre vil sætte et sporsmaalstegn ved de for dette herred fundne middeltal. Det samme gjælder Berg herred. Men for de andre herreder er antallet saa stort at jeg ter anse de fundne middeltal for ialfald tilnærmelsesvis rigtige. I disse 4 herreder er middelvaerdien av cephalindex omkring 82. I alle disse herreder utgjør imidlertid lappene en ganske stor del av befolkningen. Og gjennem indgifte med den norske befolkning har ogsaa denne for en god del lappeblod i sine aarer. Dette er utvilsomt hovedaarsaken til den hoie cephalindex i disse 4 herreder. Nogen særlig liten index findes ikke i noget herred. I Østerdalen, Gudbrandsdalen og Trøndelagen vil man ialfald støte paa endel herreder med en saa liten index som 76 à 77. Dette er altsaa ikke tilfældet i Troms fylke. I saa henseende minder dette fylke om forholdene paa Vestlandet og Sørlandet. e» NJ HALFDAN BRYN. M.-N. KI. Tabel 18. Cephalindexene ordnet 67 | 68 78 IS voe f Once Boudin oOo - | - | : Harstad og Trondenes.... - - 3 Bjark AB ee en - | - [bestacd! EE Pr ere - - 5 Salangens.!. vss. sac - - - - - - - - I - - I BAEQU md. 00 Gia otro cue - - - - - = = z I 3 I 2 avian POM serbere - - - - - - - - I I - 2 Trang one I - - - - - - 2 - 5 2 5 SOTLEISAl ee ee - - - - - - - - - - - I DETTE Re RP ET EEE - - - - - - - - 2 I 4 3 ]jergi TEL ner - - - - - - - - I - - I kors Ken Mr er - - - - - - - - - I I I N a A - - - - - - E 3 2 3 2 ES NEED er - - - - - - - - - - I Maalselv: 0 een - - - - - - - I 2 e I 2 Baser ee Per en - - - - - - - - - 4 4 4 Malangen. Were nee - - - - - - I 2 - 2 | 2 2 Tromsoysunde essen: - - - - - - - 2 2 2 2 2 Tromsø sess ae et sve edere - - - - - - - 2 3 2 3 4 SOLL OTA sas ee ete che ar - - - - - - - - I - 2 - Lyngenij kg cer sister ee - - - - - - - I 3 3 6 Karlsoy en - - - - - - I - - - I 4 Helga ovn om. edere ess - - - - - - - - - - 3 I DRE Vie cesse rte. - - - - . - I I I I 7 7 INOXdreiSad eos ae Ies - - - - - - - - - - - - Kvænangen ce... - - - - - - - - - - - 2 Antal ne dece terere te eroe eee I - - = = = 3 r4 | 21 | 36, 538059 Procente-. een euere los, = E - - - |9,45| 1,66| 3,17| 5,43| 8,00| 8,91 Kurven for index cephalicus har, som det vil sees av fig. 9, en tydelig spids ved index 80. Paa det opadstigende ben finder man en liten knæk i kurven ved index 77. Paa det nedadgaaende ben finder man to tydelige spidser, en ved index 84 og en ved index 87. At denne sidste er frem- kaldt av lappene, behøver man her ikke at være i tvil om. Tar man ut av serien de rene lapper samt de som er av lappisk herkómst, forsvinder denne spids helt. Spidsen ved index 83 svarer helt til hvad man-ogsaa ofte ellers finder i Norge. Spidsen ved index 80 antar jeg er den samme som man ellers som regel finder ved index 78, men som her er trukket længere mot hoire paa grund av de mange brachycephale elementer som indgaar i denne befolkning. Den samme forrykning av denne spids finder man ogsaa i andre fylker med en sterkt brachycephal befolkning. Til sammenligning har jeg efter ARBO paa fig. 9 antegnet kurven for Jaederens sterkt brachycephale be- folkning. Sammenligner man de to kurver, vil man straks se at befolk- ningen i Troms fylke er ganske anderledes sterkt dolicho-mesocephal end Jæderens befolkning. Hele den befolkning, som befinder sig indenfor det omraade som markeres ved bogstavene a—b—c—d, mangler helt i Troms fylke. Middel- 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 33 i serier for hver hel index. I 7 2 3 = - I = = = z z | = k 5 6 6 6 3 I 3 2 I 3 3 I - - 58 I 3 I - - 2 - - - - - - - - - 8 4 5 5 2 6 6 - I 2 = 2 = - - - 41 5 4 I 2 4 3 2 | I - I | - I - - - 26 3 I 3 - - I - - - = - - - - - I3 2 2 I 2 - 2 2 - I I - - - - - I7 2 5 5 > 4 2 3 5 | = 2 E = = Y 7 41 - - - - I - - - - - - - - - - 2 I 5 2 - - 2 2 I - - - - - - - as 2 - I I - | I - - - - - - 8 - I 2 | | - I - 2 - I - I - I - - - - - a I 6 3 I I - I - - - - - - 33 2 - - - - - - - - - - - - 5 5 3 4 2 = = = - 2 =) = = - - - 23 5 - Ss maru xata atus eum vm ccs 34 4 I 3 3 2 2 4 - I - - - - - - 28 9 1 3 5 2 6 - I 2 I - - - - - 46 I 3 5 I 2 2 I - - - - I - - - 30 - 3 1 I 2 - - I I - I - - - - I4 5 Io [*] a II 5 I 4 2 = I = I = I 12 3 4 6 2 4 2 - I I I - - - - - 30 I 2 I 2 - - - I I - - - - - - 12 5 6 II 4 5 2 - 2 I I - - - - - 55 I I - - - - - - - - - - 2 4 3 2 2 2 - 2 - - - - - - - - 17 79 88 82 522 1,5541744 110247 iuo LET 9 7 2 2 - I 662 11,93] 13,29| 12,38| 7,85| 8,30] 6,64] 3,62| 2,41| 2,57| 1,36| 1,06] 0,30 0,15 indexen for disse er 77,7, og hovedmassen av dem tilhører utvilsomt den nordiske race. Disse er i Jæderens sorenskriveri erstattet med den befolk- ning som er markeret ved omraadet d—e—f, og hvis middelindex er 84,7. Allerede herav kan man slutte sig til at befolkningen i Troms fylke er en betydelig mere nordisk race end befolkningen paa Jæderen. Naar jeg beregner middelindexen særskilt for norske lapper og kvæner (finner), da finder jeg følgende middeltal: Lapper 439). 4.850 ae 84,3 Kvæner Orca: d rer 78,9 Norske fra Troms fylke (100).... 79,3 Lapper >< nerske 422) au... 81,1 Kvæner X norske (26) .......... 80,6 Eapper > Folketype storste storste 3: i 9/0 av 1 YO av hoide > cephalicus wiz à bredde længde legemshoiden | legemshoiden oT langer 5,5 9,90 11,44 157 Tronder .. „se 9,66 12,12 LOZ TEE YES sag r 84,7 | 9,61 11,28 162 79,58 9,38 11,81 09, Han ere 83,7 9,23 10,89 169 19,27 9,03 11,41 Ser man derefter paa hvorledes forholdet er hos lapper av 157 cm. heide, vil man se at hos disse har hodet gjennemsnitlig en længde av 17,97 cm. eller 11,44 %0 av legemshoiden. Jeg antar at lappenes gjennem- snitsheide er omkring 155 cm., og at den trønderske befolknings gjennem- snitshoide er omkring 172 cm. Ogsaa hos individer som har typens gjen- nemsnitshoide, er der altsaa en tydelig forskjel paa hodets længde regnet i 0/0 av legemshoiden. Den norske befolkning blir mere langhodet end den lappiske befolkning. Undersoker jeg saa forholdet mellem hodets bredde og legemshoiden, saa finder jeg at hodets bredde er endnu mindre avhængig av legemsheiden, baade hos lapper og hos norske. Hos lapper av 169 cm. høide er hodet gjen- nemsnitlig 15,60 cm. bredt. Hos en trender av samme hoide er hodet der- imot bare 15,28 cm. bredt. Hos en lap av 157 cm. heide er hodets bredde 15,55 cm., hos en tronder av samme hoide derimot betydelig smalere, kun 5,17 cm. Hos lapper av 155 cm. heide utgjer hodebredden temmelig nøi- agtig 9,72 0/0 av legemsheiden, hos trendere 9,6 0/0 av legemshoiden. Hvis jeg gaar ut fra at lappenes gjennemsnitshoide er 150—155 cm. saa utgjor hodets bredde hos disse „typiske lapper" ca. 9,72 9/0 av legems- hoiden. Den .typiske tronder har en legemshoide paa omtrent 172 cm. Den gjennemsnitlige hodebredde hos disse med hensyn til legemshoide typiske trondere er 15,33 cm. eller kun 8,91 %0 av legemshoiden. Hos lappene vokser index cephalicus meget raskt med en avtagende legemsheide. Hos 169 cm. høie lapper er index cephalicus 83,7. Hos 157 cm. høie lapper er index cephalicus 86,6 cm. Hos trondere tiltar ganske vist ogsaa index cephalicus naar legems- hoiden avtar, men i langt mindre grad. Hos en tronder av 169 cm. hoide 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 39 er index cephalicus 79,27. Hos en trender av 157 cm. heide er index cephalicus 79,69. Medens gjennemsnitsheiden for samtlige undersokte er 170,168, er den for dolichocephalene 168,856, for mesocephalene 170,561, for brachy- cephalene med index 81:—83 169,807 og for hyperbrachycephalene med index 84—93 169,622. V. Ansigtet. 1. Ansigtets heide, bredde og morfologiske index Ansigtshoiden, maalt fra næseroten til hakens underkant, varierer fra 10,1 til 14,2 cm., og dens gjennemsnitlige storrelse er 12,05 cm. Hos de undersokte lapper varierer ansigtsheiden fra 10,1—12,9 og er gjennemsnitlig 11,67 cm. Hos finnene varierer den fra 10,3 til 13,5 cm. og er gjennemsnitlig 11,82 cm. Hos den rent norske befolkning har jeg fundet at den varierer fra 10,4 til 14,2 cm., og at dens gjennemsnitlige storrelse er 12,41 cm. Ansigtsbredden (zy—zy) varierer inden samtlige undersokte fra 12,2 til 15,3 cm. og er gjennemsnitlig 14,14 cm. Hos lappene varierer den fra 13,0 til 15,0 cm. og er gjennemsnitlig 14,11 cm. Hos finnene varierer den fra 12,5 til 15,3 cm. og er gjennemsnitlig 14,04 cm. Hos den rent norske befolkning har jeg fundet som minimum 12,2 og som maximum 15,3 og middelbredde 13,97 cm. Den morfologiske ansigtsindex varierer fra 72—100. Dens gjennem- snitlige størrelse er 85,11. I de enkelte herreder varierer den fra 82,0 til 88,9. Det er altsaa en overmaade værdifuld index, naar det gjælder at karakterisere befolkningen. Av det medfelgende kart (fig. 10) vil man se at de smaleste ansigter findes i de to herreder Bardu og Maalselv, hvor man ogsaa finder den reneste norske befolkning. De bredeste ansigter finder man i Helgøy, Sorfjord, Kvaefjord, Bjarkoy og Nordreisa. For Nordreisas vedkommende har jeg paa kartet sat et spersmaalstegn, da jeg kun hadde 2 mand til undersokelse fra dette distrikt. Men de øvrige distrikter er sikre nok. Og som man vil se av kartet, er et odistrikt som Hélgoy et rent utstraalingscentrum for denne ansigtstype. Saa meget merkeligere er dette, som der blandt de av mig undersokte fra Helgoy ikke fandtes nogen som mente sig at nedstamme fra lapper. Det samme gjælder Kvæfjord og Bjarkoy. En befolkning som anser sig selv for rent norsk, har altsaa i disse distrikter en ansigtstype som er helt fremmed for den nordiske race. Paa fig. 11 har jeg nedtegnet kurven for ansigtsindex 1 Troms fylke. Den har, som man vil se, 3 spidser, en central spids ved index 85 og to perifere spidser ved indexene 83 og 88. Hos den brachycephale befolkning i Møre fylke fandt jeg at ansigtsindex var 83. 40 HALFDAN BRYN. M.-N. Kl. hy #7 OX 7, C, NA Yj Pts LAN VV NETS BEDER: INDEX 820-829 »» 830-839 7 84.0-849 ud 85,0-85,9 7 » 86,0- 86,9 ™ — 870-879 > » 880-889 Fig. ro. Kart over index facialis morphologicus. 1. Kvæfjord. 9. Sorreisa. 18. Tromsoysund. 2. Trondenes, ro. Dyroy. 19. Tromso. Harstad. 1I. Berg: 20. Sorfjord. 3. Bjarkoy. 12. Torsken. 21. Lyngen. 4. Salangen. 13. Lenvik. 22. Karlsoy. 5. Bardu. 14. Hillesoy. 23. Helgoy. 6. Lavangen. 15. Maalselv. 24. Skjervoy. 7. Ibestad. 16. Balsfjord. 25. Nordreisa. 8. Tranøy. 17. Malangen. 26. Kvænangen. | nn 8 79 gu AT AD 83 Aa 85 36 87 SR mM SO 91 92 9S 94 05 96 97 98 99 100 Fig. rr. Kurve for ansigtsindex (index morphologicus) i Troms fylke. 41 ;l. TROMS FYLKES ANTROPOLOC 1921. No. 20. St'o |Sı'o |o*o |c'1 16'0 |SL‘o |c'1 Ihe [o'€ |S'E |S'* |L** |e'g |1‘9 |L'L |S'or Jog |g'e |L*o | hq |*'S |1** ro KG] Ge | Srey msc 2 Dat rc UN force € I 122 rue) © le or es | Ee | of) re | PS Oo | tS | 89 | ES eS ERR EROS Leu mz lor bue E 1 aid NDS RAN LOC Oxo Sene misse PX EET IRE - - - - - - I c - [^ I I I 1 I € [2 - & - - - - - MIRE "*tt** uogsuvuwAN 1 N » E » 4 E 2 " ERO ome +++ +++ BSIOAPIONT - - - - I I - I & b - I L 1 E L L 9 b € + 1 - € - - - I | REN CE SEN ØRENE I " Z I [4 I I - = Z = ^ D [p st S CO DE CUT ove Tee. "Ao3ppH I pb c I in 5 E x = 5. ah: $t 819.276 4,9 QUE SIU.A .. Aosiey 8 o 9 m ll fe, 1 - c I 2 3 " REDDERE CS Ub CE peor I © 1 2 B I I bs 1 S = 2 récent ss... '* paofj10G - - - - E - - I € € c € I 1 £ & c & & I & £ 1 - - - - I - ros iul. C cic; amid °°°" ØSWOIT E - I - - - I I - I € I ca tero | ite} b Re 20 EC I b | - I I - - - BN ERROR " DUNSÅØUIOLT, I c I E € - I - - I - - -.| - SPAMMER SIRE! Si! Lal BD uoduv[e]y - - - I I I ut FF ES AE a e RC MSA - & ies eue N | I - - ll“ RE RE EEE p-1oljspeg] - 5 - I € - - I € I & I I [7 I e 1 [7] [7] I - - - - - - - - SM LE S900 SYN KERN ne SC ATOS RTA I 2 4 = - = = = = al = å væ = I I I = = = a = p I " = X w^ J| ' L9 $5 CO PAUL D AN eee . 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M.-N. Kl. Av tabel 22 fremgaar, at jeg hos lappene i Troms fylke har fundet at ansigtsindex er 83 (82,98). Det kan da heller ikke være tvil om at denne spids skyldes fylkets ,lappebefolkning". Tabel 22. Ansigtshoidez Ansigtsbredden Morfologisk ansigts- n— gn zy —zy index M. Min. Max. M. Min. | Med. | M. Min. Max. Ie Troms: fylkerne 14,2 | 14,14 12,2 15,3 | 85,11 72 100 Éappene rer ere E rer 72.9.1 Laer 13,0 I5, 82,98 72 92 Éinnene AGRE come 13,5. 74,04 | 912,5 15,3 | 84,29 - - Rent norske ss. 55 SETE 14,2 | 13,97 12,2 15,3 | 88,91 - - T abel 29: Ansigtstyper 1 Troms fylke. Antal Procent Antal Eury- | Meso- Lepto- prosoper | prosoper | prosoper M. IE 710 —83 84 —87 88 — 100 Kræ orde ERE re I5 8 4 3 53,4 26,6 20,0 Harstad og Trondenes.... 58 20 19 19 34,4 32,8 32,6 jaro e ECC Ce 8 5 2 I 62,5 25,0 12,5 SalanzenWer SER e 26 7 II 8 26,9 | 42,3 | 30,8 Bardem cesse 13 3 4 6 29,1 30,7 46,2 BAvansene leerer oe 17 3 8 6 17,6 47,1 35,3 Ibestade c ser see ee ere 41 ET II 19 26,8 26,8 46,4 EAN OVER rome ec 41 10 16 15 24,4 39,0 36,6 SOGREISA REN ee slat stele peste oe 2 - 2 ID Adonis ere. coche 23 9 5 36,0 SENS Ge OB atone Go ion E 8 3 2 315 Morsken ts eve ee 9 4 4 It,2 IL Ginnie cuo EA none co 38 8 14 29 ENNESS VE a ee ce 5 2 2 20,0 Maalselver SEERE 23 5 6 52,4 RÉIGIOUL emo 0 0000006 34 10 7 50,0 Malangen® 2... sskskere 28 8 To 35,7 Tromsaysund een. 46 24 I2 21,7 Uro mM SØ EE eee 20" 12 7 36,7 Sertjord/ seras eee save a I4 7i 6 ist ey M/S ene er SEE ENE 72 32 24 22,3 Wars aya arin ere sense: 30 I4 IO 20,0 Holzart I2 6 4 16,6 SK]eEVay EE ee isles 55 20 18 31,0 Neordreisa EEE CE 2 2 - Kvzenangense c e oe 17 8 4 26,3 Absolute tale tee ex 662 241 212 Procent 745.7 oo ERE E 36,8 32,6 Ansigtsindex hos den nordiske race er antagelig omkring 88 à go. Det er da sandsynlig at den anden perifere spids skyldes distriktets nordiske befolk- 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 43 ning. Hos de i Troms fylke boende kvæner har jeg fundet at ansigtsindex er 84,29. Det kunde da ligge nær at tro at den centrale spids ved index 85 skyldes den tilstedeværende kvænbefolkning. Denne er imidlertid saa liten at den kun kan yde et lite bidrag til denne spids. Det sandsynlige er vel at den for en meget stor del er et summationsfænomen. Hvis jeg noier mig med at inddele befolkningen efter ansigtsindex i 3 typer: euryprosoper (70—80), mesoprosoper (84—87) og leptoprosoper (88—100), da finder jeg inden hele fylket 36,8 %0 euryprosoper, 32,6 meso- prosoper og 30,6 leptoprosoper. Tabel27. Euryprosoper | Mesoprosoper | Leptoprosoper Nann AIS ARR A ENE EEE 36,8 32,6 30,6 Nadu arosSbispedomme. eee eee 15,8 24,2 60,0 Nordmot SOFenSkrlVerl. 4e. 8,3 28,4 63,3 XOU EGRSOndmmer-- A 6-0.» seele = cer ceca cee cic 27,4 30,7 41,9 Lebediner, efter KAARLO HILDÉN ........... 60,7 20,5 9,9 Tubularer, — — — an a 44,0 35,2 10,8 Telengeter — = —— OO TE 93,I 6,9 | : Som man vil forstaa av ovenstaaende tabel 24, er Troms fylke sterkt euryprosopt efter norske forhold. Man finder utvilsomt intet fylke langere syd i Norge som kan maale sig med det i denne henseende. Nordmer sorenskriveri, som paa en typisk maate repræsenterer den nordiske race, er en kras motsætning til Troms fylke. Gaar man derimot østover, finder man en jevn ekning av europros- opien. Sammenligner man Troms fylkes . befolkning med de typiske eury- prosope folk i Centralasien (Telengetene til eks.), da blir jo antallet av euryprosoper hos os ganske lite. Ser man saa paa forholdet i de enkelte distrikter, da falder det straks i øjnene, at euryprosopene findes i et overmaade stort antal i de samme kystdistrikter som har vist sig som repræsentanter for liten legemsheide, mørkt haar, mørke oine og brachycephali. Bjarkoy, Kvæfjord, Tromseysund, Helgoy og Kvænangen er saadanne sterkt euryprosope distrikter. 2. Nesen. Den gjennemsnitlige størrelse av index nasalis er 68,55. Vi har distrikter her i landet med betydelig hoiere næseindex, til eks. Jaederen med 72,1, Sondmor med 69,4, Vestagders kystbygder med 70,9. Men saa har vi ogsaa, især i de dolichocephale landsdeler, distrikter med langt lavere index, til eks. Nordmor med 65,4, Sortrondelagens dalforer med 66,9. 44 HALFDAN BRYN. M.-N. KI. Tabel 25. Neeseindex i Troms fylke, ordnet i 5-tals serier. 9 2 o 9 e|e|el|oe|e|oe|[o|el|ejle]|s]| ST ae Sl Ol el S| 2) Sle] S] se) | | se | | | ° o © © Se dee we a e a S1 ES in In ve) [2d > co co © mi „ + » Kvæfjord ...... E I 2 8 3 I - - - - E - : : Harstad og Trondenes ... I 6 I2 I5 I5 6 2 - I = = E - 2 3jarkoye must rene - - I 4 2 I - - - - = = = : Ibestad aia 22. - I 6 13 [1 7 3 = - E - - s zs Salangent re... - - 6 I 8 3 2 I - - = a = 1 BAT cerca I I 3 2 I 5 - = = = - = 3 " lLavangene «e. - - 3 8 4 I : - [ a 2 d 4 " lliranoya E I 3 8| 16 9| 3 - I - - - = : = SOLLOe!SaT e. - = I = = I 2 z B u : - L : Dyrøy SEERE - I 8 6 3 4 - I - - - = - = Bern eek I I 2 3 I - - - - å = E z E MOrskem ees sis - I - I 3 4 = = = A 5 E z Fenvik oo eo - I 6 12 7 5 I I - E - s = z Hillesay e - 1 I I I I - - - - - = t - Maalselv ..... I 5 7 4 5 I = - a = = = 2 Balstorder er 3 3 3 6) ert I I I - = = = = Malansgen...... - I 7 7 5 7 I af = = = = : 3 Tromsoysund... I 4 9| 15 9 5 I 2 = M à E d E Tromsø 7. 2 I 8 8 8 2 I = - = = 5 = SOTÉOnde ne. 2 I 6 I 3 I = - - = 2 - a Eyngen ns... T 5 re | sey ETS MEO 4 3 - - I - - - Karlsey ss se. I 2 5 7 7 5 3 = = : = z 3 - Heleoy tu - I - 4 3 2 I I a = 2 = : = Skjervey ...... - 5 Ol, 2n 76 I 2 - = - I - = : NOrdrelsæe ders - - I - I : = = = = = = 2 Kvænangen .... 3 2 2 5 2 3 = : - - - - a on 15 | 44) |) ran || 23/5549) 89) 22 ra 3 - 2 - - I Der er ogsaa i Troms fylke stor forskjel paa de forskjellige herreder. Højest index er der i Salangen (73,1), Torsken (71,8) og Helgey (72,5). I disse distrikter er altsaa index nasalis omtrent av samme storrelse som 1 de brachycephale distrikter paa Vestlandet: Jæderen og Sondmer. Det er vel sandsynlig at lappene bidrar til den høie næseindex. Hos 30 lappér fandt jeg nemlig at næseindex var 73,91, hos 17 kvæner derimot 67,35 og hos norske gjennemsnitlig 68,61. Av samtlige undersokte er 56,9 leptorhiner, 40,3 mesorhiner, 2,8 cha- mærhiner. Av lappene var 9 (30,0 0/0) leptorhiner, 19 (63,4 °/0) mesorhiner og 2 (6,6 %0) chamærhiner. Rette næser har jeg fundet hos 69/0 og konkave hos 24 0/0. Ti sammenligning meddeles at hos den trenderske befolkning fandt jeg 70%o rette og 28,69/o konkave. 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 45 Tabel 26. Næsetyper i Troms fylke. Antal Procent Herredets navn Antal i i Chan 2 8 Leptorhine| Mesorhine E sg o zi E TD META rhine aca diem SEE JL CX 33 23 x Mo erm : + 85—110 | 4 Fi oe IREENOrd fs eas ees 15 4 73 26,6 - Harstad og Trondenes.... 58 34 23 58 39,7 1,75 Bye en 8 5 3 62,5 | 37,5 - SE MESSE 26 II 13 42,3 50,0 77 BAFA uil M... I3 1 6 53,8 56,2 - Ba auscnéonciese eyes 17 II 5 64,7 29,4 | 5,9 DES RSR A 4I 20 21 48,8 57,2 - RARE ME res s fares ane de devas 41 28 12 68,3 | 29,3 2,44 SPEROlSd Was eue ende 2 I I \ [DEER (Em. a 23 15 7 pore Sl DEREN ETE 8 7 I 87,5 12,5 - BEES CI S. Lors Ie crie fe) 2 7 22,2 77,8 - Benz se 200 lern. 33 19 13 57,5 | 394 | 33 Elillesay an scie sm eme os 5 B 2 60,0 | 40,0 - Neisse Son. ae 2 13 10 56,5 43,5 = RAISON clle tre 34 15 17 44,1 50,0 | 5,9 Malangent se me oes ee 28 15 13 535 | 46,5 - siromsoysund °°... .. 46 20 15 63,0 EH 4,35 HC OUISG P4524 easet. arte 30 19 II 63,4 36,6 - UA fa 4: urs ele nie ee ects 14 9 5 64,3 35:7 = ILES ÉCART EE TEE 72 41 27 57,0 | 375 5,5 Barlsaya-. 222. 22.20.2020 cite de 30 15 15 50,0 | 50,0 - Bela ee tee ee en 12 5 6 41,7 50,0 8,35 SEN ON RS fars eee 55 35 19 63,6 | 34,6 1,82 Nordreissar SERENE 2 I I \ P + Kzenangen se ie 17 2 5 f 68,5 | 31,75 3 Absulutestale SETE SENERE 662 262 Broe SS 0 de mine Dev, - 40,3 | 3. Bredden mellem de indre gienvinkler. Som gjennemsnit for samtlige undersokte har jeg fundet 32,96 mm. av- stand mellem de indre eienvinkler. I distrikter med stor ansigtsbredde kan den gaa op til 34 à 35 mm. Paa den anden side har jeg i de mest typiske nordiske distrikter, som Bardu, fundet som middeltal kun 31,15 mm. 4. Jugo-frontal index, 2: Forholdet mellem pandebredde og kindbredde. En liten index kan bero paa særlig stor kindbredde eller særlig liten pandebredde. Da inden vor befolkning pandebredden er relativt lite variabel, medens kindbredden er sterkt variabel, vil en liten jugo-frontal index som regel bety at kindbredden er stor. BRYN. HALFDAN 46 ees b'et | E's LS ı Se Sto F'61 + £'go. | o'tz MO t n UM A TT SOITET S11 ELE gaı tot LLe Si ct LSt gsi BOO! aes POTS eye S >= i "e lobe à ern Seal essen EN AE NE > sso UOSUEUEA X : 2 : : 2 ; 1 E oben mener CA Pace ELEND Didone pe eio *ESIOIPION 11 ct cl ££ c I c 6€ £T Ye a Blend ALOE eer pale t € € t = D 6 £ ZI er Ot? 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CCC CE DAS dad o uoSuvAv] L [e I I I I 3 " _ RID OE BOO a E NOR» Mets ails ae etat ais ete usdurgeg b I I I 2 2 4 " Hd $^» eren RUE a ie eis T MOT TERES TTE TTE IDEE OU np.regq L c e z I " ; b: rå RS Es ETA Rene Beco On Eom x puisoq] I 1 E c = ^ " 1 CE RE FEE ao mL men. le Nr nations À am &oxvfq 8 € S c [V - € - - FRAME ET TR MELO FE souopuoi[ 30 PeJSICF] 2 c I D I " på 4 " AUR RO RL AA S PUR MEAE EEE + piofJæAN SER UNDER OL SL PEN Sb al eb FOR FO UABU SJ9POLO FH ———————————————————————————————————————————————————————————— E : x ( : z SSTTE onen 5 XOPUL [OU J9AU JO} AOLIIS T Joupso 'ox[Aj SWOAL, 1 JOXOpUIJUOIJ-O8N( “9s [age] 1921. No. 20. 48 HALFDAN BRYN. M.-N. Kl. En høi jugo-frontal index betyr av samme grund som regel at kind- bredden er liten; — Imidlertid varierer denne index fra 71 til 93 med to meget utprægede maxima ved index 78 og 80. Inden de enkelte herreder varierer denne index ikke særdeles meget. Naar jeg ser bort fra Hillesoy og Sorreisa (paa grund av det ringe antal undersokte), er den lavest i Tranøy, 77,8 (41 mand), hoiest i Kvæfjord. Hos finner og norske har denne index omtrent ens størrelse. Hos lapper er den noget mindre. 5. Øvre øienlok. (Plica marginalis, epicanthus, mongolfold). Øvre oienlok og især indre oienvinkel har hos den her beskrevne befolkning et meget vekslende utseende. Ved en mere overfladisk betragt- ning faar man det indtryk, at en stor del av befolkningen har skjæve øien- spalter. En nærmere undersøkelse bringer snart paa det rene at forskjel- lige foldedannelser er aarsak til denne tilsynelatende skjavhet.- Hos hoved- massen av befolkningen (87,2 0/0) finder man intet abnormt. Øvre gienlok og indre eienvinkel er saaledes som vanlig hos den nordiske race. Hos de øvrige 12,8 0/0 stoter man paa forskjellige avvikelser. Den hyppigst forekommende er en liten, men vel utviklet, stram, meget tynd hudfold, som begynder litt nedenfor nedre oienloks mediale del og herfra gaar skraat opover og utad og forsvinder saa i ovre oienlok, ikke saa ret langt fra indre øienvinkel (fig. 12 b). Denne uregelmæssighet har jeg fundet hos 0,5 0/0. Jeg kalder denne abnormitet for mongolfold nr. 1. Hos et betydelig mindre antal, 2,20/0, er denne fold saa stor at den strækker sig helt forbi eienspaltens midtparti. Jeg har ogsaa anset dette for en mere ekstrem form av foregaaende type og har kaldt den mongolfold nr. 2. Men mellem disse er overgangen saa umaadelig fin at man ikke kan trække nogen skarp grænse. Fælles for begge disse er at folden begynder nedenfor nedre oienlok og fortaper sig likesom i det øvre oienlok. Saa findes en tredje gruppe hvor hudfolden er tykkere, og som medialt ikke gaar nedenfor nedre oienlok. I dette tilfælde er cilierne ofte dækket av folden (se fig. 12d). Jeg har fundet denne type hos 0,9 %0. Enkelte (EuGEn FISCHER, Barz) skiller skarpt mellem 2 og 3 og regner denne sidste som egte mongolfold (plica marginalis) og de andre to som epicanthus. Saa finder man endelig endel individer, 0,2 0/0, hos hvem det ovre oienlok i midtpartiet danner en fold (fig. 12 e) som hænger nedenfor som et slags forhæng og derved kan dække cilierne paa øvre oienlok. FISCHER siger at han hos „die Rehobother Bastards“ aldrig fandt denne sidste abnormitet, som han kalder ,,dækfold", sammen med epicanthus, men nok sammen med egte mongolfold. Noget saadant har jeg ikke bemerket blandt HALFDAN BRYN: TROMS FYLKES ANTROPOLOGI. TI III E Fig: 12. 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 49 denne bastardbefolkning. Tvertimot forekommer det mig at de altid umerkelig gaar over i hinanden. Det egte mongoloie findes neppe blandt denne befolkning. Men heist sandsynlig er det vel at alle de her beskrevne „typer“ er remiscenser av det egte mongoloie. Dettes utstraalingscentrum er vel i Sydkina, hvor det findes hos 100 %0. Allerede naar man kommer til Japan, er antallet minsket til 70 %0, og jo længere man kommer vestover, des mere synker antallet av de egte mongol- oine. Men saa optrær til gjengjæld aile de her beskrevne typer, som jo hver for sig repræsenterer endel av de for det egte mongoleie karakte- ristiske træk. Angaaende utbredelsen skal jeg her kun bemerke at den synes at følge lappene. Paa hovedtabellen har jeg anført hvor mange mænd jeg har fundet denne eiendommelighet hos i hvert enkelt herred. Under avsnit VIII, Affinitetsundersøkelser, kommer jeg nærmere ind paa hvorfra vor befolkning har denne eiendommelighet. VI. Om forholdet mellem ansigtets og hodets dimensioner. 1. Den mindste pandebredde. Den mindste pandebredde varierer individuelt fra fra 10,0 til 12,3 med en gjennemsnitlig størrelse av 11,09. Dette er en meget stor pandebredde i forhold til hvad man finder hos andre folk. Det svarer temmelig præcis til hvad man finder hos lithauere. Den store pandebredde kunde tænkes at staa i forbindelse med befolkningens relative store legemshoide. Pande- bredden har imidlertid hos denne befolkning den samme gjennemsnitlige størrelse hos store som hos smaa mænd. Jeg finder saaledes hos de av mig undersøkte med legemshøide 157 en pandebredde paa 11,18 16S: c= — — 10,99 vp — 4 CERO 75 = ren 100 v ^st dd Ez rdg == = —— Ro Heller ikke staar pandebredden i et fikst forhold til hodets største bredde. Forholdet mellem disse to benævnes som bekjendt 2. Den transversale fronto-parietale index. Denne index varierer, som man vil se av tabel 29, inden den her beskrevne befolkning mellem 64 og 81. En liten index vil si at panden er Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. 20. 4 M.-N. Kl. HALFDAN BRYN. 50 A F = OI o o‘gs [bgt [t's I 1 o‘og |L‘zE |EL | SE | gt L*99 |£'‘e Jo'Se| 9g I 0'09 JESSE |L‘g | gr loi Sigt |o*£ € I6 Er | SE |Ze g‘at lo‘az |o'gz | o Le oot lo‘ot | Fer | F1 zı L*gS |o*c€ |L‘g | Le |Sı L*S€ [LICE |o'ge | o1 Ol 6'SS toe |L*L1 | 61 6 L*F€ |o'£* [Liz lg OI o*oc |o'ot |o'ot | 1 € CFC |F*o€ [16 | gi CA ‘az |g'SS |1fee | & c o'‘oS ISLE [Star | + £ t o 8 I git IS = €1 8 6‘ t o'ot OI Cte + oz + «ey e|a Sle 8 leg 2 GI =19 5 lo Silo = ‘à pad 1g—EL 1dojoui&imo 30 q pod cl + + +0 8 8e a rt € £a In ıdoyouu -OU9IS ıdopwuAıny IL ıdoypwosaw fe poA o1ouos sousajaq oL--£9 idojourouojG L OI | I I - - - t € € I - I - - 6 OI re] L I - [z - [z I I e I - - - € L & € - - I - 6 & t Z fa - - - € 9 I t 1 I z - I € S € c I - - 9 I € S - - - - I - I I I - - - D € & - € - - - e € I I - - - I z - 1 - - - 8 - - I I € I z - - OHHH MTD O NN VO HA ido3ourotn2]q 1do3ourouo1G “++ U9SUgUSAS DEN ESTS DION] Qro pa ' ÁoA49[xG CA CHIC Gan SOUS T) Ao8|2H e (98914999 . Kos[.ıe Deut iret wih etl uosuA'T eee lel rel nie del p-tofj.tøg DRE RTS OSWO1 [. **** punsÁosulo4 T. HO, on 0 " ussurfe '****** paofjspeg ett AJOS[ERN wkelle/ or DL AoSO]TUH Lotto tele yiaua’] Mogan +++ U9YSIO T. DONI OO: O .. BSI9.LIOG DOC ON OPE DD Aouri], ++ prJS0q] Qr go CET ES usduear] moo aos '* npaeq ss 9) elelshe ussurjeg UD DAD ORC .. Koy.ıelegg SIU9PUOA]L 30 PEJSIPH D COM O10 D plolja2ay UABU S}JIPITIOL "Xopur [oY A9AU JOF .I3LI9S I J9Up Jo xopur yejotied-ojyuo.y jesisasueif “6% [aqe |] 4 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 5I smal i forhold til hodets bredde, en hoi index vil si at enten er panden bred eller hodet relativt smalt. Hvis jeg for at faa rede paa korrelationsforholdet mellem hodets storste bredde og mindste pandebredde inddeler materialet efter hodebredden i 3 grupper og efter pandebredden i 4 grupper, da findes følgende naar jeg kun medtar den saakaldte norske befolkning: Tabel 30. Mindste pandebredde. 10,0 — 10,5 TO 6 E10 II,I—II,5 II,6 —I2,5 index — 71 index — 74 index — 78 index — 82 Lh D C! co 15,03—15,9 | 45 = 7,6 %0 |147 = 25,6 9/0|147 = 25,69/0| 54 = 9,4 0/0 | 393 = 68,2 index — 66 index — 70 index — 73 index — 77 Hodets bredde. 3 6 9 12 16,0 — 16,9 6 = 1,1 0/0 | 24 = 4,2 0/0 | 30 = 5,2 0/0 | 2x = 3,7 00 81 = 14,2 index — 62 index = 65 index — 68 index = 73 | 17 = 13,2 | 214 = 37,3 | 204 = 35,7 | 80 = 14,0 | 575 = 100,0 I 4 7 10 14,0—14,9 | 26 = 4,5 0/0 | 43 = 7,5 0/0 | 27 = 4,790 | 5 = 0,900 | ror = 17,6 Det fremgaar av denne tabel at liten pandebredde forekommer sammen med stor hodebredde hos 5,3 0/0. Stor pandebredde og meget stor hodebredde forekom hos 9,1: 0/0. Disse to grupper utgjor tilsammen befolkningens brachycephale halvdel. Stor pandebredde forekom, som rimelig kan være, sjelden sammen med liten hodebredde (5,6 0/0); hyppigere er kombinationen liten pandebredde og liten hodebredde, 12,1 %0. Muligens kan en korrelationsundersokelse bringe større klarhet i disse vanskelige sporsmaal. Man skulde efter hvad jeg her har utviklet, vente at finde en liten trans- versal fronto-parietal index fornemmelig i de mest brachycephale distrikter. Dette er imidlertid kun delvis tilfældet. I en del av de brachycephale distrikter er denne index tvertimot meget hoi. Brachycephale distrikter med liten transversal fronto-parietal index er føl- gende: Sørreisa 69,9, Hillesøy 70,3, Lavangen 71,3, Berg 71,4 og Torsken 71,4. De øvrige brachycephale distrikter har en endog meget høi transversal fronto-parietal index: Kvæfjord 73,3, Tromsøysundet 72,4, Karlsøy 72,4, Helgøy 73,0, Skjervøy 73,2, Nordreisa 73,0 og Kvænangen 72,4. Hvad dette beror paa, er det foreløbig umulig at si. Det kan, som allerede nævnt, bero paa at der er forskjelligartede brachycephale typer i Troms fylke. Av tabel 29 vil man se at av de forskjellige folketyper i Troms fylke har lappene den laveste transversale fronto-parientale index og finnene den heieste. Den norske befolkning staar midt imellem. HALFDAN BRYN. M.-N. Kl. Ian D Men en meget hoi index finder man merkelig nok hos enkelte bastarder. Særlig hei er den hos dem hvis forældre er lap og norsk. Disse bastarder har ogsaa en usedvanlig stor pandebredde. Pandebredden er storre end baade hos lapper og norske, mens derimot hodets bredde ligger midt imellem hvad den er hos norske og lapper. Det tor da hænde at en almindelig krydsningsundersokelse kan gi en forklaring paa den hoie transversale fronto-parietale index i endel brachy- cephale distrikter. Forholdet mellem cephalindex og pandebredde fremgaar av fel- gende tabel: , Tabel 31. Cephalindex. Under Mellem Mellem Over 75,9 78,0 og 79,9 | 82,0 og 84,9 85 Pandebreddetosssetslereete elei II,OI 10,82 II.IO II,04 Transversal fronto-parietal index 74,50 71,95 71,60 70,23 Det fremgaar herav, at pandebredden er paa det aller nærmeste av samme storrelse hvad enten index cephalicus er liten eller stor. En naturlig følge herav er da at en høi transversal fronto-parietal index hovedsakelig maa findes sammen med en lav index cephalicus og omvendt. Hvis jeg kun medtar alle mænd av middelheide (fra 169—171 cm.), da finder jeg følgende forhold mellem index cephalicus og den transversale fronto-parietale index. Tabel 32. Transversal fronto-parietal index. Dolichocephal Mesocephal Brachycephal 63— 69 - 29,2 70,8 Jo—7I 8,3 62,5 29,2 12— 74 13,3 59,0 377 15505 354 354 29,2 Den mulighet kan derfor ikke utelukkes, at der blandt til eks. brachy- cephalene kan være 2 typer hvad pandebredde angaar: én type med meget stor pandebredde og en med meget liten pandebredde. Hvis saa er tilfældet, blir det let at forstaa at pandebredden tilsyne- latende ikke staar i noget bestemt forhold til hodets bredde. Da blir det ogsaa forstaaelig at pandebredden tilsynelatende er like stor hos høie som hos lave folk. Ti man kan vel med sikkerhet gaa ut fra at forholdet her Éd. 1921. No. 20. TROMS FYLKES ANTROPOLOGI. So er som andensteds i Norge, at brachycephali hører sammen med liten legemshoide og dolichocephali med stor legemsheide. Og hvis man nu her har en brachycephal type med stor pandebredde, men liten legemshoide, saa er det klart at ogsaa pandebreddens avhængighet av legemshoiden maa bli utvisket. VII. Kombination av eienfarven og haarfarven. Paa tabel 33 og 34 har jeg utregnet hvor ofte de forskjellige farve- nuancer av haar og oine forekommer blandt samtlige undersokte og blandt hver av de 4 grupper av hodetyper. De to storste grupper er, som man vil se, blaa oine i forbindelse med brunt haar og blondt haar. Det er her værd at legge merke til at blandt hyperbrachycephalene forekommer blaa oine dobbelt saa hyppig sammen med blondt haar som sammen med brunt haar. Det er lappene som gir den hyperbrachycephale gruppe sit preg, og blandt disse forekommer den lyseste oientype relativt hyppigere end den lyseste haartype. Disse to første kombinationer er begge rent blonde. De tre neeste er ogsaa paa det nærmeste helt blonde. lalfald vil de vistnok bli regnet for helt blonde i Syd- eller Mellemeuropa. Tilsammen utgjer disse 5 relativt rene blonde kombinationer blandt dolichocephalene 72,50 %0, blandt mesocephalene 76,34 9/0, blandt brachy- cephalene 67,30 9/0 og blandt hyperbrachycephalene 64,90 9/0. Den meso- cephale gruppe er altsaa den største. De næste 3 grupper indeholder hovedmassen av de mørke kombina- tioner. Kombination nr. 8 er her av særlig interesse, da den jo er den for alle ikke-leucoderme racer vanlige kombination. Den forekommer, som det vil sees, hyppigst blandt brachycephalene. Man kan vel med temmelig stor sikkerhet gaa ut fra at de to første kombinationer i denne række er specifike for den blonde race. De øvrige kombinationer fjerner sig mer eller mindre fra denne type, idet de inde- holder mer pigment. Man kan til en viss grad gradere pigmentmængden og derigjennem gi et uttryk for i hvilken grad kombinationen fjerner sig fra det for den blonde race typiske forhold. Jeg maa da gi de forskjellige oientyper og haartyper en bestemt værdi i forhold til den pigmentmaengde typen indeholder. Jeg vil da i det følgende regne med 4 oientyper, som jeg gir føl- gende pigmentværdi : blaa og graa eine — o lyst melerte eine = I morkt melerte oine — 2 brune eine — 3 4 . M.-N. BRYN. HALFDAN uge I ‘Ivey 3108 30 savvy JIosunig 'S "ww junaqo».0]Ty b DIS: I — | JPAIBJ9IpU99 50 juniqos&T ‘€ ‘(8 9 "IBBU JPOY 'Z (em —6 ‘Ivey ypuolg ^1! (Q1 —€£1 NILAVM) -UDAIBJIUEU Jopue Jep 'uaasejualø JOUSo}JoOq [Vj 99810} Jag '9A1ejieeu So oAJvju3IO xLIqni JOAY I [er OF SL'g joS‘o1 | - o€'€ Joo‘L |SL‘g o'vc Cø'L |Sz'L |ot'o | og'e |oo'r |oo'£r oz 61 Sz'g |6c‘L - (ARS 09'023 |09'03 | 8 S'g | SL - cz Get |CC'L | Sr'o | 6e'€ |og'r |oo‘Lı |o0o'12 of of I Ic II ee NOE € + e "9490S.19pun IST Wes ypuelq snomeudoo Xoput 50 JAIEFIEEU ‘QAIe j ) outo aunig "P ) outo 2j19[our PIS ig ) oUulO oj1o[put JSÂT "2 ouio BVIS So BEI "I U91O Uuro[[2ut UOHBE[9.LI ON ap Jousozoq ofui[ : SUIUPAYOQ opuos[cj IE 975.19A0 Suo[[»q*1 BE -ydosA4qou1q1od4q ypurle +++ do[eudooKqov.tq 3PUETA 1 109/61} : : : : : 19[eudoboso ut JPUETA “++ Jo[eyda904t[op jpuv[H 9} {os.1lopun 23 NJ Wes ypurld ce 19487, 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 55 For haarets vedkommende regner jeg ogsaa med 4 typer, som jeg gir folgende pigmentveerdi: lyst haar (blondt, rødt) — o cendré og lysebrunt =I morkebrunt =2 sort = 3 Tabel 34 az 2 2 ES ES oi E E sv? © iuc | 1. Blaa—graa oine, lysebrunt haar .... 21,00 2. Blaa—graa oine, blondt haar....... 10,31 3. Blaa—graa oine, mørkebrunt haar... 17,00 4. Lyst melerte oine, lysebrunt haar... 1355 5. Lyst melerte oine, morkebrunt haar. 1555 6. Brune eine, mørkebrunt haar....... 5,45 7. Morkt melerte eine, morkebrunt haar 4,40 8, Brune eine. sort haar a........... 4,25 9. Lyst melerte oine, blondt haar ..... 3,29 10. Mørkt melerte oine, lysebrunt haar.. 3,02 rr. Brune gine, lysebrunt haar ........ 1,81 12. Blaa— graa gine, sort haar......... 1,66 13. Morkt melerte oine, sort haar ...... nr nae laa ome, rødt haar ANSER 0,91 75. [cyst melerte ome, sort haar....... 0,91 r6. Brune gine, blondt haar..........: 0,75 17. Mørkt melerte oine, blondt haar .... 0,45 18. Lyst melerte gine, rødt haar....... 0,15 29° prune eine, rødt haar... MELSE NER 0,15 20. Morkt melerte oine, rodt haar...... - Gruppenes størrelse blir da saaledes som anført paa tabel 35. Længst tilhoire paa denne tabel har jeg anført de forskjellige kombinationers pig- mentværdi. Paa tabel 36 har jeg saa summert sammen de grupper som har pig- mentværdi o, I, 2, 3, 4, 5 og 6. Nul betegner altsaa her den rene blonde types storrelse, 1, 2, 3, 4, 5, 6 indeholder jevnt ekende pigment, 6 er den helt morke type. Tilnærmelsesvis kan man da si at ıste gruppe indeholder 1 mørk kvantitet og 5 lyse. 2 gruppen indeholder 2 mørke og 4 lyse kvantiteter Se yn = 3 - he bx NE ^3 4 E; Tu ir "PP zx x "ee De OT | ON Ci | | [9] | | =6 HALFDAN BRYN. M.-N. Kl. Blandt meso- cephalene Blandt brachy- 1. Blaa—graa oine, lysebrunt haar... 21,00 | 30,00 | 20,60 | 19,20 o I I 2. Blaa—graa eine, blondt haar..... 20,22 | 22,50| 21,18] 20,40 [s] o o 3. Blaa— graa eine, mørkebrunt haar. 17,00 | 10,00 | 20,60 | 13,60 o 2 2 1. Lyst melerte oine, lysebrunt haar . 755 7,50 7,29 1,25 I I 2 5. Lyst melerte oine, morkebrunt haar 155 2,50 8,25 7,25 I 2 3 6. Brune oine, mørkebrunt haar..... 5,45 | 10,00 1,44 5,64 3 2 5 7. Mørkt melerte wine, mørkebrunt haar 4,40 7,50 3,16 5,21 2 2 4 srume wine, Sort AA... - 325 2,50 2,52 6,45 3 3 6 9. Lyst melerte oine, blondt haar ... 3,44 2,50 3,46 | .2,80 I +.0 I ro. Mørkt melerte oine, lysebrunt haar 3,02 2,50 3,16 3,20 1,75 | 2 I = 3 11. Brune gine, lysebrunt haar ...... 1,01 2,50 1,26 2,40 1,7503 I = 4 12. Blaa—graa gine, sort haar....... 1,66 - 0,95 1,60 7,00| o+ 3=3 I3. Mørkt melerte gine, sort haar .... 1,21 - 0,95 1,60 Og Fy 102 3 = 5 14. Lyst melerte gine, sort haar ..... 0,91 - 1,26 0,80 - I 3 4 v5. brune eine; blondt-haar... ....... 0,90 - 0,31 2,00 - 3tro=3 16. Mørkt melerte oine, blondt haar .. 0,45 - 0,63 - 1,75 | 2 a 0-02 Blaa— graa oine — o Blondt og rodt haar — o Lyst melerte oine = 1 Lysebrunt haar = I Mørkt melerte wine = 2 Mørkebrunt haar = 2 Brune øine = 3 Sort haar = 3 Mabel 26. Blandt samt- Blandt Blandt Blandt hyper- lige under- dolicho- uns brachy- brachy- sokte cephalene Son ens cephalene cephalene = 6,66 10,00 5,39 7,24 8,75 6 4,25 2,50 2,52 6,45 5,25 100,00 100,00 100,00 100,00 100,00 Beregner jeg paa denne maate værdien av hver pigmentgrad og samler de lyse kvantiteter for sig og de mørke for sig, blir resultatet som anført paa tabel 37. Jeg kommer da til det resultat, at den lyse blok i denne befolkning utgjor 66,05 9/0 og den mørke 33,95 Yo av den samlede befolkning. On MJ 1921. No. 20. TROMS FYLKES ANTROPOLOGI. Pabel 37. E samt- E e HE de a Bun. Blandt meso- Blandt brachy- Pau lige under- dolicho- : hyperbrachy- ME cephaler cephaler DT = sokte cephaler cephaler 0/0 0/0 0,0 0/0 0,0 mørke lyse mørke lyse | mørke 21,18 0,00 20,40 0,00 20,05 4,01 18,34 3,60 20,00 8,50 14,00 6,85 3 6,34 6,33 7,03 7,02 4 1,88 3,78 3,00 6,00 5 0,89 4,50 1,20 6,04 6 |. 0,00 2,52 0,90 6.45 70,34 | 29,66 | 63,97 | 36,03 Den lyse blok er avgjort størst blandt mesocephalene. Den er kun litt mindre blandt dolichocephalene. Blandt brachycephalene og hyperbrachy- cephalene er den derimot betydelig mindre, henholdsvis 6!/20/0 og 8 0/0 mindre end blandt mesocephalene. VIII. Affinitetsundersekelser. Den fremgangsmaate, som i de senere aar av antropologene har været anvendt for at finde hvilke træk som er biologisk samherige, er beregning av korrelationskoefficienten efter Bravaıs’ formel. Det forekommer mig imidlertid, at de resultater man har høstet, ikke egentlig frister til fortsat anvendelse av denne metode. Professor FiscHer kommer i sit verk „Die Rehobother Bastards“ til det resultat, at „in einer seit Generationen bestehenden Bastardpopulation zwischen den meisten Rassenmerkmalen keine feste Korrelation bezüglich der Vererbung besteht“. Dr. Kaarıo Hırpen har nylig utgit en større avhandling „Anthropo- logische Untersuchungen über die Eingeborenen des russischen Altai“. Han benytter sig ogsaa av Bravaıs’ formel i dette eiemed. Og resultatet er det samme: „jedoch läfst sich aus den Ziffern mit Bestimmtheit schließen, daß eine wirkliche Korrelation nicht existiert“ (side 79). Og i Meddelelser om Danmarks Antropologi, Bd. I, p. 275, har man av C. Burrau en meget detaljert matematisk granskning av det av den danske komité indsamlede materiale. Det synes mig at ogsaa hans vidt- løftige metode gir et noksaa magert resultat. I sin avhandling „To grund- racer i det danske folk" siger dr. Annr. M. Hansen om.denne metode: »Det viser sig ogsaa at den matematiske sikkerhet, den kvantitative nøiag- 58 HALFDAN BRYN. M.-N. Kl. tighet, som skulde vindes ved de overhaands moisommelige og haarfint beregnede størrelser, til syvende og sidst svigter. Det avløses i virkelig- heten av et temmelig løst skjøn, naar de begrepsuklare hjælpestørrelser endelig skal anvendes som grundlag for de slutninger som overhodet har nogen positiv værd for den antropologiske undersokelse." „Den uhyre besværlige og meget kostbare beregningsmetode svigter baade i begrepsmæssig klarhet og 1 kvantitativ precisjon. Den har videre endnu en avgørende mangel i praktisk bruk. Den gir vistnok et almindelig uttryk for hyppighetstabellernes samlede korrelasjonsforhold. Men den er fuld- stendig ute av stand til at gi overblik over kendsgerningernes vekslende forhold utover observasjonsfeltets forskellige deler. Det ubetingede maal for en virkelig biologisk analyse av de observerede antropologiske forhold som gjengis i tabellerne, er med lethet og sikkerhet at finde og skille ut hvor det særegne, det typiske optrær utskilt i kombinasjonerne, eller hvor den efter almindelig sandsynlighetsberegning givne regelmæssige fordeling av tallene avbrytes av kombinasjoner av bestemte karakterer, som optrær hyppigere end de efter sandsynlighetsberegningen skulde ventes mellem uavhængig variable, som altsaa maa være betinget av bestemte biologiske faktorer, av racebestemt korrelasjon.“ Jeg er tilboielig til at tro, at den skarpe dom som dr. ANDREAS M. Hansen her fælder over den vanlige korrelationsberegnings værdi, er fuldt berettiget. „Ved den superfine hoimatematiske beregningsteknik blir man efter et umaatelig vitloftig arbeide staaende ved tal hvis vegt eller logiske ind- hold er fuldstændig dunkelt, man har intet nærliggende forstaaelig middel til at avgere hvor stor affinitet 7 = + 0.09 svarer til, om det angir en reel rase-faktor eller ikke. Kvantiteten hos de rent abstrakte hjælpestørrelser gir som vist ikke engang grundlag for et blot nogenlunde sikkert skøn" (A MEL p.226). Den ovennævnte letvinte fremgangsmaate, efter den mest elementære sandsynlighetsberegning, som jeg i denne avhandling skal gjøre nærmere rede for, tillater os at overse med største lethet forholdene i det store og likeledes at skille ut og præcisere spørsmaalene i detalj, og gir os direkte aritmetiske maal til forstaaelse av koefficientenes logiske vegt. For 16 aar siden offentliggjorde dr. Anpr. M. Hansen i sin bok „Land- nåm i Norge", 1904, sin metode for denne slags undersøkelser. Senere har han i sin avhandling ,To grundracer i det danske folk"! nærmere gjort rede for denne sin metode. I denne avhandling paaviser han ogsaa den vanlige korrelations- beregnings mange mangler, dens ufuldkommenhet, dens besværlighet. | Trykt i Nyt Magazin for Naturvidenskaberne, bd. 53, 1915, s. 203—267. 7927. No. 20. TROMS FYLKES ANTROPOLOGI. 59 Man kan paa en langt enklere maate tilveiebringe langt klarere uttryk for korrelationsforholdene gjennem hans affinitetsmetode. Hvis en bestemt egenskap, til eks. dolichocephali, er fundet et bestemt antal gange (d) blandt et visst antal undersøkte (.S), saa er utsigten til at : Fe et es d.c stete paa denne egenskap inden befolkningen i sin almindelighet S Like- : i UN b ledes til eks. med blaaeiede individer S Det er nu umiddelbart logisk indlysende, at hvis der ikke er nogetsom- helst biologisk sammenhæng mellem disse to egenskaper, saa vil man ogsaa d b b 1 blandt de — blaaoiede finde kun en brøkdel © dolichocephaler, altsaa SxS S S a Be Er nu den brøkdel <, som undersokelsen gir til resultat, merkbart større S end — > b SS sammenhæng, for antropologisk ,affinitet"^ mellem disse to egenskaper. , saa taler dette for at der er et naturlig, biologisk, racebestemt Og et maal for styrken av denne affinitet faar man simpelthen ved at finde forholdet mellem den fundne brøkdel og den ved sandsynlighetsbe- regningen under forutsætning av fuldstændig uafhængighet mellem egen- skaperne givne brøkdel: Denne hans affinitetsformel er jo meget letvint og grei. Selv frem- hæver dr. Anpr. M. Hansen som en stor fordel ved formelen at den er fortrinlig logaritmisk. Men bruken av logaritmetabellen er jo aldeles ikke nogen abc for alle antropologer. Og man kan ogsaa finde de samme affinitetstal paa en efter min mening betydelig enklere maate end den av dr. Anpr. M. Hansen paaviste. Jeg sætter at jeg i en given befolkning har fundet til eks. 10,8 0/0 bruneiede individer. Hvis der nu ikke eksisterer nogen biologisk sammenhæng mellem brun- oiethet og kortskallethet, saa bør jeg ogsaa blandt de kortskallede finde ca. 10,8 9/0 brunoiede. Hvis jeg nu istedenfor 10,8 %/0 finder til eks. 17,0 %0 blandt de kortskallede, mens jeg kun finder til eks. 6,5 %o blandt de lang- skallede, og dette samme forhold gjentar sig flere steder og til flere tider, saa kan dette kun forklares gjennem en biologisk sammenhæng mellem disse to egenskaper. Hvis jeg nu dividerer det førstnævnte procenttal med det sidstnævnte, saa har jeg affinitetstallet. Og dette kan uten vanskelighet utføres av hver og en, simplest ved hjelp av en almindelig regnestok. 60 HALFDAN BRYN. M.-N. Kl. Min formel er altsaa, naar jeg anvender de samme bokstaver som ovenfor er anvendt i ANDREAS M. Hansens formel, folgende: a d hvilken brøk ved at multiplicere d blir as b baade tæller og nævner med s GET. s Der er altsaa i realiteten ingen forskjel paa dr. ANDREAS M. HANSENS metode og denne. Men mens han regner med absolute tal og logaritmer, regner jeg med to procenttal som divideres. Det er altsaa kun en for- enkling av hans metode jeg har benyttet i det folgende, ti procenttallene har man allerede av andre grunde utregnet. Det ved beregningen fundne affinitetstal kan defineres saaledes: Affinitetstallet er forholdet mellem den fundne brøkdel av undersokte hos hvem de to egenskaper findes kombinert, og det efter sandsynlighets- beregningen givne, naar de to egenskaper varierer uavhængig av hverandre. Hensigten med affinitetsundersøkelsen er altsaa at utpeke mellem hvilke antropologiske eiendommeligheter der kan antages at herske nogen biologisk sammenhæng. Denne biologiske sammenhæng gir sig paa affinitetstabellen tilkjende gjennem størrelsen av affinitetstallene. Et stort affinitetstal som støtter sig til store absolute tal, taler for en biologisk sammenhæng mellem de to træk som har det store tal. Omvendt tyder et litet tal paa at der ikke er noget biologisk sammenhæng. | Selv om et affinitetstal ikke er særlig stort (meget større end 1), kan det dog peke paa en biologisk sammenhæng, hvis det hviler paa meget store absolute tal. Endvidere vil jeg peke paa, at man maa gaa ut fra en biologisk sammenhæng naar der i flere undersøkelsesrækker fra forskjellige distrikter findes tilsvarende affinitetstal. Paa tabel 38 vil det sees at jeg har inddelt efter index cephalicus i 5 grupper. Jeg har saaledes opstykket brachycephalene i to grupper, en fra 81—84 og en anden fra 85—93. Det har jeg gjort, fordi den somatiske undersøkelse av befolkningen gjør det sandsynlig at der findes to genotyper av brachycephaler inden befolkningen. Det vil da være av stor betydning om affinitetsundersøkelsen støtter denne antagelse. Muligens kan ogsaa affinitetsundersøkelsen bidra til, at man faar rede paa hvilke eiendommeligheter som er særegne for hver av de to typer. Jeg har ogsaa samlet dolichocephalene i en gruppe for sig, fordi under- søkelser fra andre kanter av vort land tyder paa at der ogsaa indgaar en eller muligens to dolichocephale genotyper i vor befolkning, om end begge meget sparsomt. Saa har jeg ogsaa delt mesocephalene i to grupper. Denne gruppe er saa talrik at en saadan opstykning med lethet lar sig gjøre. (Grænsen mellem paa den ene side dolichocephaler og mesocephaler og paa den anden side mellem brachycephaler og mesocephaler er jo svævende. De 61 TROMS FYLKES ANTROPOLOGI. 1921. No. 20. <5 6 NT ie es « B UC NE B8. 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Derved .faar man fra 15 til 25 grupper med likesaa mange affinitetstal. Enkelte grupper kan derved bli meget smaa og affinitetstallene i samme grad usikre. Hvor dette viser sig at være tilfældet, har jeg sammendrat til større grupper, som paa tabel 39, hvor jeg samtidig har medtat alle de av mig undersøkte i Troms fylke. For derefter at belyse fremgangsmaaten ved et eksempel vil jeg hen- vise til tabel 38. Denne undersøkelse omfatter i alt 559 mand. Jeg vil undersøke affinitetsforholdene, idet jeg lægger index cephalicus til grund. Den av mig anvendte inddeling efter index cephalicus findes 1 øverste linje. I næste linje findes opført hvor mange individer der falder paa hver index cephalicus, først i absolute tal, dernæst i procent. Jeg har altsaa nu opdelt materialet i 5 grupper. Hver av disse 5 grupper opdeles saa videre efter legemshoiden i de 5 undergrupper som sees anført øverst tilvenstre paa tabellen. For hver enkelt indexgruppe tælles op hvor mange individer som findes i hver av de anførte hoidegrupper. Ogsaa dette omberegnes til procenttal. Disse findes opført i kolonnene A til m. I kolonne g og n findes opført hvor mange der blandt samtlige undersøkte falder paa hver av de anførte heidegrupper, i hele tal og i procent. Dermed har jeg alt hvad der behøves til beregning av affinitetstallene for legemshoide og cephalindex. Jeg vet nu at der blandt alle de av mig her undersokte findes 16,8 %0 med en legemshoide mellem 145 og 163 cm. Blandt dolichocephalene er der derimot 32,29/0 av denne legemshøide. Misforholdet er jo her rent iøjnefaldende. Men matematisk finder det klarest sit uttryk ved at dividere det sidstnævnte tal med det første, saaledes: 92,2 16,8 = 1,91 Paa samme maate gaaes saa frem med alle de andre fundne procenttal. Derved fremkommer de længst tilhoire paa tabellen anførte affinitetstal, hvorved man unegtelig faar et letvint og, efter min mening med visse for- behold, ogsaa meget paalidelig overblik over affinitetsforholdene inden en given befolkning. Jeg skal i det følgende gi en fremstilling av de resultater jeg er kommet til ved en affinitetsundersøkelse av en nordnorsk befolkning. Alle de undersøkte er mænd i 21-aarsalderen, bosat i Troms fylke 1i Nordnorge. Middelhoiden hos de undersokte var 170,168 cm. Den gjennemsnitlige størrelse av cephalindex var 80,77. Av de undersekte opgav 83,2 %0 at TROMS FYLKES ANTROPOLOGI. 1921. No. 20. 081 Li or £E 6€ 91 lan) = 10JSEE £e‘o 95 66 18 to F1 og gu == S[OPPIN "© 3 Lo'o ££ +6 EC er 6 | **LL—oL xaput [ejuo1j-o3nf uayrT ‘1 a DE g—€L i1dojyour&anq CE OO ET zL—-ıL ıdopwossy 'S ^I ES SEE FE L--89 1doppwousIg ce 3 idosoad Aung] Ian 6 lo RENE (Ud Mac ec EL OCUOPCCIRE CUORE DC oulo ounig + 11 DI VALL) [o ga tec cite. Coc US 23j1o[pour JHION ‘€ 63 ge Lj SE c] |e peo eo t ooo aUIø 2j1o[pur JSÂT "2 J OII 16 tc 9 OO ON OP i79 5) RIP PE set 10 oulo perl 7 9£‘o E 6z'o ss gc re 3 toto EI zó'o Oo. "x Besen 56. ls SUSCI EST RON ELSE = oos zg‘o co en CC | or, E = o xc TOT og'o px OUI SE fuh 363 27 9860 SERT SUE: oL1— 691 V g6'0 bi 7 ; D À LI NE ON Mauro sc 891—991 rrug 'c er Be 0 D sc ON Mee, | ER Co1—Sti veus 3989 "I SL—Lo £6— Sg Yg—198 og— 6L snogeudoo xopu snoyeydos xopu eu pu] eu pu] [eIsJOPWUY PY [ouv 'ojos1opun o3ipures Spusperwo 'snoeudoo xopur 1979 1os[oxos1opunsjoyugjyy ‘6€ [oqeve[ M.-N. Kl. BRYN. HALFDAN 64 QS'o glto oc*1 TO! Ore o'Li LS oc! 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(ae RO rn "wo oLr-—Sryr Aug “1 » £6—S9|*tg—1g|log —oL|SL—Lo| +++ snoyeydoo xopu z99 tL ££z 91€ BEL | Irre jeyuv ‘IH ‘a "N «I JE39:1 SEIS ET ‘a “IN Kal [EJO3ES I ESSEN ‘a "N «a "of [aq IL ro2r. No.20. TROMS FYLKES ANTROPOLOGI. 65 være rent norsk, 4,5 Vo opgav at være rene lapper, 2,4 Yo rene kvæner. Resten var av blandet norsk, lappisk-kvænsk herkomst. Jeg gaar derefter over til en nærmere gjennemgaaelse av de her utar- beidede affinitetstabeller og begynder da med tabel 39, som omfatter alle de av mig i Troms fylke undersøkte. Jeg vil her først se paa affinitets- tallene for den hyperbrachycephale gruppe længst tilhoire paa tabellen. Det vil da straks sees av denne tabel at der er en meget utpræget affinitet mellem denne index og meget liten legemshoide. Inden alle de øvrige høide- grupper er affiniteten negativ, og der er med engang et vældig sprang fra laveste til næstlaveste høidegruppe (1,63—0,96). Denne samme index viser ogsaa en utpræget affinitet til /vsedrunt haar (1,30), men negativ affinitet til alle de øvrige haartyper. Endvidere har samme index en meget sterk affinitet til ewryprosopri (1,31). Likeledes har den meget høie affinitetstal for stenometopi (2: en meget smal pande i forhold til hodets bredde) og ten jugo-frontal index. Dette betyr at denne type maa ha relativt meget /iten pandebredde. Endelig viser det sig at samme index har stort affinitetstal for brune oine, medens den heller ikke er uten affinitet til lyst melerte eine. Alle disse affinitetstal er saa store og hviler paa saavidt store tal, at man maa ha lov til at gaa ut fra at de kun kan tydes som bevis for en biologisk sammenhæng mellem denne index og de anførte eiendommeligheter. At denne index samtidig har et høit affinitetstal for brune øine og et lavere tal for lyst melerte øine, medens affinitetstallet for mørkt melerte øine er litet, kan bero paa vanske- ligheten eller umuligheten av at trække op skarpe grænser mellem de lyst og de mørkt melerte øine. Hvis der nu kun er en brachycephal genotype inden vor befolkning, saa maa man vente at finde ialfald tilnærmelsesvis lignende affinitetstal inden den ovennævnte brachycephale gruppe med index 81—84. Denne gruppes tal kan ikke ventes at være saa rene som den førstes. Den ligger nemlig klemt mellem 2 andre. Det er uundgaaelig at saavel endel +-avvikere av den mesocephale type som endel ~-avvikere av den hyperbrachycephale gruppe kommer med her, og begge vil de gjøre sit til at utviske affinitets- forholdene. En nærmere undersøkelse bringer dog straks paa det rene at denne index har sine egne affiniteter, helt uavhængig av begge nabotypenes. Særlig naar det gjælder legemshøiden, gjør nabotypenes indflydelse sig dog sterkt gjældende. Denne index viser 3 positive affinitetstal, 1,12, 1,04 og 1,25, for de 3 mellemhoie grupper. Det er da sandsynlig at dens affini- tetstal maa ligge indenfor dette omraade fra 166 til 176 cm. For at bringe dette nærmere paa det rene har jeg paa tabel 40 ind- delt efter hoiden i kun to grupper, 145 til 168 cm. og 169 til 200 cm., like- som jeg her kun har medtat de som selv regner sig for norske. Som man vil se, er der da et sikkert positivt affinitetstal for den mindste av disse legemsheider. Man kan da i hoiden slutte herav at typens hoide ligger mellem 145 og 168 cm.; men da det allerede før. er bragt paa det rene Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. 20. 5 66 HALFDAN BRYN. M.-N. Kl. at denne type ikke har affinitet til meget liten legemshoide (5: 145—165 cm.), er det sandsynlig at typens affinitet kan begrænses til højde 166 à 168 cm. Er denne index’s affinitetsforhold til legemsheiden litt uklar, saa er affinitetsforholdet til haarfarven saa meget desto tydeligere. Den har et meget høit affinitetstal til sort haar, 1,36, og her kan ikke nogen nabo- indflydelse ha gjort sig gjældende. Det er ogsaa den eneste index som viser affinitet til sort haar. Der er saa meget mindre grund til at tvile her som den samme index ogsaa paa Søndmør utvilsomt har affinitet til sort haar!. Den har fremdeles en tydelig affinitet til euryprosopi. Affinitetstallene er jevnt og typisk synkende mot leptoprosopi. Men det er dog tydelig at denne index ikke har saa sterk affinitet til euryprosopi som indexgruppe 85 93. Det samme er tilfældet med denne index's forhold til den transversale fronto-parietalindex og den jugo-frontale index. Alt dette staar i god sam- klang og finder sin forklaring deri, at den type som har denne cephalindex, labels ain Antal Afiinitetstal Index cephalicus 6780 | ST— O04 85—93 67—80 81—84 | 85—93 Te SMa ge pc 108 | 106 71 31 0,95 1,03 T,17 2. Føler 169 200.... | 206 123 22 | 1,03 0,98 0,91 I» 1Blaat eer. -...... | 203 108 33 . 1,06 o,91 I,OI 2. Melerte gine....... 85 59 ine 0,97 1,08 0,87 30 Brumesaimer. 2... | 24 2 9 0,74 1,28 7,27 maa ha en relativt større pandebredde end den anden lrachycephale type. Endelig viser denne index sig at ha tydelig affinitet til brune og mørkt melerte oine. Dens forhold til oientypene trær endnu tydeligere frem av tabel 41. Av denne tabel fremgaar nemlig at dens affinitet til brune og melerte eine er sterkere end den anden brachycephale gruppes. I det hele tat kan man vel si at affınitetsundersokelsene meget tydelig peker i den retning, at man her i Troms fylke har med to brachycephale typer at gjøre. Den ene, hvis index cephalicus ligger mellem 85 og 93, har meget liten legemshoide, lysebrunt haar, er meget sterkt euryprosop, har meget liten transversal fronto-parietalindex og meget liten jugo-frontal- index, altsaa en relativt smal pande. Typen synes at ha affinitet baade til brune og lyst melerte eine. At dette ikke kan være andet end de egte fjeldlapper, samene, derom kan heller ingen være i tvil. 1 Se herom More fylkes antropologi, Vid.-Selsk. Skrifter, Kristiania 1920, klasse I, nr. 7. I92I. No. 20. TROMS FYLKES ANTROPOLOGI. 67 Den anden brachycephale type er ogsaa liten av vekst, dog hoiere end foregaaende, har sort haar og brune oine, er euryprosop, men i mindre grad end foregaaende; den har en middels transversal fronto-parietalindex og en liten jugo-frontalindex, den sidste dog storre end hos foregaaende gruppe. Denne gruppe svarer i alle karaktertræk til den brachycephale type som jeg for har skildret fra Sondmor, og som jeg der har betegnet som en nordlig utloper av den centraleuropæiske alpine race. i Som man vil se, er den her i Troms fylke ganske talrik. Hvis samt- lige individer med index 81—84 tilhørte denne gruppe, saa skulde gruppen utgjore 34,8 0/0 av samtlige undersokte. Sandsynlig er det vel at den store mesocephale gruppe har endel +-avvikere med her, og sandsynligvis nogen flere end den anden har av ---avvikere i mesocephalenes rækker. Mesocephalenes gruppe er nemlig 50 0/0 større. Paa den anden side har selvfølgelig denne subbrachycephale gruppe avgit en god del +-avvikere til den hyperbrachycephale gruppe, som ogsaa derved er blit noget for stor. Men man er vel ialfald ikke meget langt fra det rigtige tal, naar man regner med at den lappoide gruppe utgjør henimot 49/0 og den alpine gruppe omkring 30%0 av den nuværende befolkning. Et blik paa indextallene for de to mesocephale grupper viser straks at der ikke er nogen væsensforskjel paa dem. De gaar i samme retning i begge grupper, men tegner sig dog tydeligst i gruppen 76—78. Gruppen 76—78 omfatter jo ogsaa netop kjernen av den nordiske race, medens gruppen 79—80 er dens +-avvikere, som selvfølgelig vil være forurenset med endel —-avvikere fra den alpine brachycephale gruppe. Fælles for begge disse grupper er at de har høie affinitetstal for meget stor legemsheide (177 —200). Men som det vil sees, har ogsaa index 76—78 meget høie affinitetstal for den middels legemshoide. Jeg har i Trøndelagens Antropologi fremholdt som sandsynlig at vi her i Trøndelagen har en type av denne legemshøide. Den er efter al sandsynlighet hvad tyskerne kalder en „Verschmelzungsgenotypus“. Den er en krydsningstype. For at bli klar over dens antropologiske eiendomme- ligheter forøvrig maa selvfølgelig legemsheiden lægges til grund for affini- tetsundersøkelsen. Denne tabel peker kun hen paa typens sandsynlige existens. Disse to mesocephale grupper har fremdeles høie indextal for blondt og rødt haar. Index 76—78 har meget høit affinitetstal for leptoprosopi, stor trans- versal fronto-pariental index og stor jugo-frontal index. Begge mesocephale grupper har høie indextal for blaa og for lyst melerte oine. Den laveste index omfatter kun 39 individer. Naar disse skal for- deles paa 5 grupper, blir tallene saa smaa at man maa være ytterst varsom med at dra slutninger av affinitetstallene. Tilfældighetene faar altfor rik anledning til at spille med. M.-N. Kl. BRYN. HALFDAN 68 Eto €s'1 I6'I oL'1 coco og'o get og'o og'o cO'I £o‘1 Loto Cat rS*o ot'ı a0‘o 66'o SII Loto LES FSU 9) )slopun osipures AV 0/9 Ser EST o‘o} Stes Se Seco Seo ]£3u2204q [pm e[osqy ‘wo Sti 1apun uoSur sojputj Jo([ | rr OE CC COUNCIL ET) "oulo oun. b Do Oeo BADE auto 3jlo[pour PHON ‘€ DUC ORG ER aus 3j19[our JSÂT "2 D CONO DAD OO 5*7 9uio ve[q ‘1 1075 u... : — SISPPIN "© Eos xopur [e3uoagg-oSnf uogr] ‘1 doo E 18—€L 1dopuk.ıng ‘€ er... zL—ıL 1doyuoso ‘2 GEO 20 oL— £9 idoyourouo1S CICR — gg 1odosoudojdoT STE Lg —Pg adosoidosom "2 '****£g —oL sadosoidAing "I DO D An 6 ENS CIT. Ivey j10G + DAS af o ponte Jeey JUnIQOYION ‘€ midi olo såe bes Ivey juniqosÁAT '& PIED ner Ivey 3puo[q ‘1 JESSE ooz — 1LI Høre Q O30 FE oLi—99I veus ‘& m [S91 —SPI veus 19394 ‘snoyeydes xopur 13492 'ox[Aj suro1i[, r.Surux[ojoq exsidde| usp av Aosjoyosıspunspnuyyvy “sh [aqer 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 69 Imidlertid er disse affinitetstal særdeles utprægede, og jeg vil tilfoie særdeles karakteristiske. Index 67—75 har nemlig et meget heit affinitetstal til en liten legemshøide. Fremdeles har den et meget høit affinitetstal for brune øine. Den har det hoieste affinitetstal som findes paa hele tabellen, for lepto- prosopi, eurymetopi og stor jugo-frontal index. Det er vanskelig at komme forbi disse tal. (Det synes som den betegner et utstraalingscentrum for smale ansigter med en relativt stor pandebredde). Naar hertil kommer at denne type maa være meget liten av vekst og har mørke øine, saa har man alle de træk som er karakteristiske for sydeuropæerne. Og at der findes isprængt vor befolkning ikke saa ganske faa elementer av sydeuropæiske racer, derom kan der ikke være tvil. Særlig er dette tilfældet langs kysten. Saa liten som den dolichocephale bløk er i Troms fylke, skal der selvfølgelig ikke saa ret mange typiske individer til før det kan merkes ved en under- søkelse som denne. Den befolkning som i Troms fylke benævnes lapper, er som allerede nævnt av en meget heterogen oprindelse. Der er blandt den samer som er krydset med russere, finner, svenske og norske. Kanske kommer der ind under denne gruppe endel individer av alpin race. Det vilde jo være av stor interesse om en affinitetsundersøkelse her kunde gi nogen veiledning. Blandt de av mig undersøkte var der kun 52 som mente sig helt eller delvis at være av lappisk herkomst. Det er et meget litet antal til denne slags undersøkelser. For at bringe det mest mulige ut av dette lille materiale har jeg her, som det vil sees av tabel 42, anvendt en anden gruppeinddeling. Det fremgaar av denne tabel, at affinitetstallene for lappenes vedkommende peker i ganske samme retning som de gjorde for den norske befolknings vedkommende. Index 85—93 viser høie affinitetstal for liten legemshoide, lysebrunt haar, mørkt melerte øine og liten tvansversal fronto-parietal index. Der er i denne gruppe tydelig nok affinitet baade til europrosopı og leptoprosopi. Den anden brachycephale gruppe med index 81—84 viser tilsvarende indextal til de som fandtes inden den norske befolkning, med særlig utprægede tal for sort haar og mesoprosopi. Den tredje gruppe av lapper med index 67—80 har høie indextal for alle de træk som særpræger den nordiske race: stor legemshøide, lyse- brunt haar, leptoprosopi, stor transversal fronto-parietal index og stor jugo- frontal index. Denne index har desuten et stort affinitetstal for brune øine, hvilket, som det vil erindres, ogsaa var tilfældet inden den norske befolk- nings dolichocephale gruppe. Dette viser tydelig nok at de saakaldte lapper er av meget heterogen oprindelse. De viser affinitet i 3 retninger: a. til de eiendommeligheter som maa antages at være særegne for de egentlige fjeldlapper (samene), 70 HALFDAN BRYN. M.-N. Kl. b. til de eiendommeligheter som er karakteristiske for den alpine race, c. til de eiendommeligheter som er karakteristiske for den nordiske race. Lappene er med andre ord utprægede bastarder. Og det er jo let for- staaelig. Ti historien fortæller os, at deres kvinder har krydset sig med andre folketyper hvor de har færdedes. Men avkommet har fulgt lappene (modrene). Der er en eiendommelighet som her i Norge er saa at si specifik for den nordnorske befolkning; den forekommer ialfald kun rent sporadisk hos voksne individer i de 5 sydligste bispedommer. Det er den eiendommelige foldedannelse mellem nedre og øvre øien- lok som findes i den indre oienvinkel, og som i almindelighet kaldes plica marginalis. Der har været megen strid om denne foldedannelse har noget at gjore med den saakaldte egte mongolfold. Jeg skal ikke komme naermere ind paa dette gamle stridssporsmaal her. Jeg vil blot si at hos den her omhandlede befolkning finder man alle overganger fra typisk epicanthus til vel utviklet plica marginalis. Og man vil utvilsomt mange ganger være i tvil om man skal henregne en folde- dannelse til førstnævnte eller til sidstnævnte gruppe. Nu er det jo sikkert nok at egte mongolfold, saadan som den findes hos sydkineserne, vel hører til de store sjeldenheter hos os. Men hvis man vil trække grænsen saaledes som prof. EUGEN FiscuER gjør i sit verk ,,Die Rehobother Bastards", da finder man i mange tilfælder en egte mongolfold hos denne befolkning. Han hævder at epicanthus griper over paa nedre øienlok, plica marginalis gjør det aldrig. Man finder denne eiendommelighet hos alle forskjellige folketyper i Troms fylke, hos nordmænd, lapper, kvæner og sjøfinner. Er det nu mulig gjennem en affinitetsundersøkelse at si noget om hvor dette karaktertræk har sine røtter, fra hvilken urtype vor befolkning har faat denne eiendommelighet ? Jeg har paa tabel 43 a inddelt alle de undersøkte efter index cephalicus i 4 grupper: dolichocephaler, mesocephaler, brachycephaler og hyperbrachy- cephaler. Jeg har for hver index opført hvor mange individer som har plica marginalis, hvor mange som mangler samme, og paa den foran be- skrevne maate utregnet procenttallene. Længst tilheire har jeg saa opført de fundne affinitetstal. Det vil da seés at affinitetstallet for hyperbrachycephali og plica mar- ginalis er overmaade stort, 1,48, medens alle andre indexer har negative tal. Der kan efter min mening ikke være tvil om, at dette beviser at der eksisterer en biologisk sammenhæng mellem plica marginalis og hyper- brachycephali. Jeg har i det foregaaende avsnit fremholdt at denne index er specifik for lappene, og man skulde da være berettiget til at gaa ut fra, at det er lappene som har tilført vor befolkning denne eiendommelighet. For at bringe dette endnu nærmere paa det rene har jeg paa tabel 43 b utregnet affinitetstallene for legemshoide og plica marginalis. Legemsheiden 3l. TROMS FYLKES ANTROPOLOC 1921. No. 20. LLS 98 [161 | LL | gor | £6 Fateh | ET CR soy .ojsuruı 1j Ce 8 £a OI | QI 61 6^ Te. RS ADELEN SOU sapuy SIJEBULSIBU BAIL zog p6 | Praz | Lg | vex | ort 1€ '*'[ejuy o]xX0s.ropun ae SOU -1 A : ei = o. o. o. P jus 1 [91] unie, -1 H o [on H on -wouualr) to - to H - - H M - Ô Oo © -1 -1 © on) lu o © © Ov © co oi [o] [PS9 HU} ju220.11 [n omposqy 'oprougsuroso7] 'q 90% soy .lo[duvul Ce La soy sapuy SIRPUISIEU Boll] u990.1d z09 al gez STE ge 94 teed adie dde we [UJu y Stylus Co -urouuofr) uns £6—Sg|ta— ıglog— 9L|SL— Sof : : :snoreuydos xopur [BISJOPUYPY ju2204q [m aynjosqy ———. eS norm. "er [Old eT 'snomeudoo xopu[ 'e v HALFDAN BRYN. M.-N. KI. kan jo umulig i og for sig ha nogen indflydelse paa tilstedeværelsen av plica marginalis. Hvis der derfor her findes nogen sammenhæng, maa den være beroende paa, at den bestemte legemshoide er knyttet til en bestemt folketype som igjen er beheftet med plica marginalis. Det vil da med én gang sees av tabellen at der er et meget heit affinitetstal for den mindste hoidegruppe (r45— 160). Men denne hoide- gruppe er netop den som er karakteristisk for lappene. Jeg kommer derfor gjennem denne affinitetsundersokelse til det resultat, at vor befolkning har faat den her omhandlede eiendommelighet fra kryds- ning med lappene. Resumé. Med en til visshet grænsende sandsynlighet tror jeg man kan si at der indgaar i den nulevende befolkning i Troms fylke mindst 3 forskjellig- artede raceelementer, som naermere kan karakteriseres saaledes: 1. En stor mesocephal blok, leptoprosop, av stor legemshoide, eury- metop, med stor jugo-frontal index, leptorhin, blond av haar og blaaoiet. 2. En mindre brachycephal blok, euryprosop, av liten legemsheide, mesometop, med liten jugo-frontal index, mesorhin, sorthaaret og brunoiet. 3. En endnu mindre, men hyperbrachycephal blok, sterkere eury- prosop og av endnu mindre legemsheide end foregaaende grupper, hei- gradig stenometop, chamærhin, brunhaaret og med lysere brune eine end foregaaende gruppe, samt med plica marginalis. Ved undersekelse av ,lappene" findes de samme 3 grupper igjen ogsaa hos dem, men 1 et andet blandingsforhold, idet det alpine raceelement blandt dem er det mest fremtrædende (40 9/0), medens hver av de to andre grupper er omtrent like sterkt repræsentert (med ca. 30 °/0 hver). IX. Hovedlinjene i befolkningens mosaikbillede. Jeg har i det foregaaende avsnit git en fremstilling av hvad der karak- teriserer Troms’ befolkning, trek for træk. Jeg skal her prøve at gi en fremstilling av hvorledes disse træk. er kombinert. Billedet blir da ganske overordentlig broget. Vi har av foregaaende avsnit set at der med hensyn til legemshoide sandsynligvis er mindst 3 genotyper. Foruten de meget smaa lapper og de meget hoie av nordisk race har vi muligens 1 eller 2 mellemtyper. Den alpine type er ialfald sikker nok. Med hensyn til cephalindex har vi ogsaa lært at kjende 3 sikre geno- typer; den 4de er mere tvilsom. Av ansigtstyper kan vi sikkert paavise 2 forskjellige. 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 73 Av næsetyper er der ogsaa mindst 2 utpræget forskjellige. Av eientyper er der vel i virkeligheten kun 2 genetisk forskjellige typer, de blaaeiede og de mer eller mindre brunoiede. De melerte oines forhold kan endnu ikke siges at være helt opklaret. Meget tyder paa at der i tidens lop virkelig er opstaat en melert oientype av genetisk art, „ein Verschmelzungsgenotypus". Man kan inden den her undersøkte befolkning ikke utelukke den mulig- het, at dette kan være tilfældet med lappenes lyse øine. Egte brunøiede, som man finder dem hos de xanthoderme og melanoderme racer, findes i det hele tat ikke hos os. Man maa derfor nødvendigvis regne med 3 eller 4 oientyper. Det samme gjælder haarfarven. Her har der vel oprindelig kun været 2 typer, blondt og sort. De brune og cendréfarvede typer er vel sand- synligvis krydsningsfarver. Men derés store utbredelse i den nuværende befolkning gjør at man ved en bastardundersekelse maa regne med mindst 4 haartyper. Men herved er ikke den nulevende befolknings karaktertræk medtat i sin helhet. Der er en hel mængde andre træk som skiller de enkelte individer fra hverandre. Men om jeg neier mig med at medta de her nævnte træk, saa vil allikevel bastardformenes antal bli altfor stort til at man med nogetsomhelst utbytte kan arbeide med dem. Da hvert av de her nævnte træk ved krydsning kan løsrives fra sine forbindelser, vil der nemlig være skapt mulighet for følgende antal bastarder: os quu cone ed SE BES SO: Skal man faa nogen oversigt, maa man noie sig med fzerre traek, ialfald til at begynde med. Jeg vil til at begynde med kun regne med 2 oien- typer, 2 haartyper, likesom jeg for legemshoidens vedkommende kun vil regne med hoie og lave. Jeg faar da 192 forskjellige typer, og jeg vil her prove at gi et lite billede av hvorledes disse 192 typer er fordelt inden denne befolkning. Et av de spersmaal som først melder sig, naar man vil prove at finde rede i en saadan broget menneskemasse som den jeg her har skildret, er karaktertrekkene hos de urtyper hvorav den nuværende befolkning er utgaat. Affinitetsundersokelsene har bragt endel klarhet over dette sporsmaal. Jeg vil her preve en anden fremgangsmaate. Der er vel ingen tvil om, at 2 av de træk som er mest konstante, er hodets og ansigtets form. I anden række kommer næsens form, einenes og haarets pigmentering. Alle de her nævnte træk er helt uavhængige av ydre forhold, livs- kaar o.l. Der er en viss likhet mellem dem indbyrdes; men denne deres 74 HALFDAN BRYN. M.-N. Kl. indre sammenhæng er dog ikke større end at de ved krydsning kan løses fra sine oprindelige forbindelser. Men det er dog hoist sandsynlig at man ved en detaljert undersokelse av en population kan finde de oprindelige forbindelseskjeder igjen som en kontinuerlig kjede av de samhørige træk. Jeg har da paa 4 tabeller (44-—47) ordnet samtlige av mig under- søkte individer gruppevis efter hver av de ovennævnte karaktertræk. Jeg lar i denne undersøkelse legemshoiden komme som sidste karakter- træk. Selv om nemlig ogsaa denne er konstant og uforanderlig, saa er den dog i højere grad end de øvrige træk foranderlig med livskaarene og derfor vanskeligere at benytte som racemerke. For tabellene 44—47 gjælder følgende: Ved inddeling efter hodetype, ansigtstype og næsetype er her fulgt samme princip som i hele avhandlingen forøvrig. Som /ysørede regnes alle med blaa, graa eller lyst melerte øine (type 1. 2). Som morkoiede regnes alle med mørkt melerte og brune eine (type 3.4.5). Som /vshaarede regnes alle med blondt, cendré, rødt og lysebrunt haan (type rt23): Som mørkhaarede regnes alle med mørkebrunt og sort haar (type 4. 5). Som /ave regnes alle med hoide 170 cm. eller mindre. Som høre regnes alle med hoide 171 cm. eller mere. Paa tabel 44 har jeg samlet alle de av mig undersøkte dolicho- cephaler. Jeg har saavel paa denne som paa de øvrige tabeller foretat ind- delingen saaledes: Jeg har efter index cephalicus’s størrelse inddelt samtlige 1 4 hode- grupper: dolichocephaler, mesocephaler, brachycephaler og hyperbrachy- cephaler. Hver av disse er saa igjen inddelt efter ansigtsformen 1 3 under- avdelinger: leptoprosoper, mesoprosoper og euryprosoper. Disse igjen efter næsens form i leptorhiner og meso-chamærhiner. Saa videre i lysoiede og morkoiede; disse igjen i lyshaarede og mørkhaarede og endelig til slut i lave og heie. Jeg har derved i alt 192 grupper. Man skulde jo tro at der ikke kunde findes nogen klare linjer gjennem denne brogede masse. Men det er ikke tilfældet. Man vil med én gang paa tabel 44 se at dolichocephalenes hoved- masse følger en meget markert linje, som er følgende: dolichocephali — leptoprosopi — leptorhini — lyse eine — lyst haar. Hele denne linje samler uforholdsmæssig mange individer, saa mange, at man ikke kan være i tvil om at der maa være en biologisk sammenhæng mellem disse træk. Under hvert av de absolute tal er anført affinitetstallene, som fortæller os hvor mange flere individer kombinationen samler om sig end den vilde gjøre hvis kun kombinationenes matematiske mængdeforhold var det avgjørende. Og denne linje samler til slut 6 høje, men hun 4 lave individer. Det lægger jeg mindre bret paa, da som nævnt livskaarene her kan veie be- tydelig mere end de øvrige karaktertræk. (Men da de tidligere refererte M In ANTROPOLOGI. TROMS FYLKES 1921.” N6. 20. € L SLO 980 STO 950 sro sro 980 ST'0 sro ST'0 RTO 8T'0 980 980 98°0 sro sr'o OF 0 20H 0 oAU'T 0 21H 0 Par] 0 eH | oAeT G oly I 9407 c SON I 9487 0 10 | DAPT 0 910H 0 oavT 0 oly I oav7 0 90H | one] 0 sød 0 oAry 0 otf | 9487 & OH | 9Av'T p 90H | »A07] 0 otøHq I 9487] '0 oH 0 o4r7 | eH G OAV'] 0 10H 0 Av 0 OH 0 oAuT 0 oH 0 oAwT & ow & 9407 I 910H I 9A] 0 otøH Q 9487 0 RI H { 9A] 9 91H + OA v7] ME 0 opone yoy 0 opøJveysA] nun I paiement". ( eco) - f oporesÁ'] Et OPAIBPUSAT {i opo4ueuN. 10 y ( GEG ) s ae FP OSpoto»xX40]q * | 2poierysAT i Q opor. + 1 apatos&7] *' Mu ] opaiuuysÂT >. LS | opoeeyy søn * ( 0€ 1 ) ve mu | 9potox10]y | 22-72 () 2poieuysÀT] qu Dd | opoamuux10]y ( T) f oporesá'7 FE { oporeeysÀ] Y (or | SEP IQ £ 9epole30]N \ o9peaenusÁ^T 2 () opogunuop "mn... ( LEO ) : apalasa’y T aporreysay 0 PP9ARRIDLON =» i PINON +. 0 9paloyion \ 0 opoireysAT """ t APAIUEUSAT 1G 9poto».10]N et) opoaeuus47] TOTIS) + 8 9poderuppulo]N =. ( PII ) Be a En a DI opaareysi] \ Q 9091010 x ( SFO ) ^ ^ lb JaulyJosoWN ( 89'0 ) 6 1odosoad Aang ( 180 ) © Jouty4101d9"T LJ L4 Ne (orat) ( 660) II Jodososdoson v r90) 9 9utt.10)do'T pri) 61 4adosoidojdary Jo[utjd a - 0q9 - [oq Dolichocephale bastarder. label 44. HALFDAN BRYN. M.-N. KI. SI ON affinitetsundersokelser tilfulde godtgjor at stor legemshoide har sterk affinitet til alle de her nævnte karaktertræk, er det ogsaa sandsynlig at denne linje med et endnu større materiale tydelig vilde ende i stor legemshoide). Der er paa denne tabel 46 andre bastardtyper, men ingen samler nær til saa mange individer som denne. 25 av dem ender ogsaa blindt, 2: uten en eneste repraesentant. Og av disse 46 er der heller ingen som markerer sig ved særlig mange individer. Det ser ut som dolichocephalene kun evner at samle individer paa denne ene linje. Paa tabel 45 har jeg samlet alle mesocephalene. Den linje som her samler de fleste individer, er noiagtig den samme: mesocephali — lepto- prosopi — leptorhini — lyse eine — lyst haar stor legemshoide. Der er blot den forskjel, at linjene er kraftigere tegnet blandt dolichocephalene end blandt mesocephalene. Dette fremgaar ogsaa av de i parentes anforte affinitetstal. Da dette blandt dolichocephalene var den. eneste linje som var markert og kontinuerlig, er der heller ingen grund til at tro at dolichocephalene inden denne befolkning repræsenterer nogen særskilt type. Forskjellen paa dolichocephalene og mesocephalene er kun den, at dolichocephalene repræ- senterer em renere linje; de er —-avvikere inden den store dolicho-meso- cephale gruppe. Da der ikke inden vor befolkning findes nogen ultra- dolichocephal gruppe, som kan utviske det av naturen selv istandbragte utvalg, vil de nødvendigvis holde sig mere typerene end mesocephalene. Der synes derfor heller ikke at være nogen anden grund til ved raceologiske undersøkelser inden denne befolkning at holde dem utskilt fra mesocephalene end den, at man derved lettere kan faa tak i de for den fælles dolicho-mesocephale gruppe karakteristiske træk, som ganske utvilsomt Synes. at Være:-leptoprosopi—— leptorhimi — lyse eimme — lyst haag stor legemshoide. Hvorledes forholder nu de mesoprosope mesocephaler sig? De for- holder sig stort set ganske paa samme maate som de mesoprosope dolicho- cephaler. I alt er 31 9/0 av mesocephalene mesoprosope. Blandt dolicho- cephalene findes 27 9/0 mesoprosope. Blandt mesoprosopene er der igjen flere leptorhiner end mesorhiner, flere lyseiede end morkoiede, flere lyshaarede end morkhaarede, flere høie end lave. Linjene er her fælles for dolichocephaler og mesocephaler, og de er fælles for leptoprosoper og mesoprosoper. Det er med andre ord ikke mulig at eine nogen særskilt mesoprosop gruppe. Mesoprosopene er kun at betragte som +-avvikere av den store leptoprosope gruppe. Hoved- massen av mesoprosopene har karaktertræk fælles med leptoprosopene, og det skal vi senere se vedvarer selv naar vi kommer over i brachycephalenes og hyperbrachycephalenes hovedgrupper. Jeg mener saaledes, at denne tabel taler for at den store dolicho- mesocephale gruppe har som karaktertræk: leptomesoprosopi, leptorhini, lyse oine, lyst haar og stor legemsheide. Naar vi derefter gaar over til = I» sl. ANTROPOLO( S TROMS FYLKE 1921. No. 20. © EE O00 © © n NA «aio © r- CO © © D DORE EE EE = r9 ‘OU paryseg 0c'0 99'T 88'0 9c'I GS'0 CGT GS'0 £8'0 00'T 98'0 GOT 0€'T 90'T 0€'1 I93153o3rugg V 86 I 97% F£'a 09'S 98'0 «L0 9€'0 ST'0 sto tT I S6 I 86'I ST'0 ST'0 8I O0 06'0 9c'I 91T 91% 40) STO 9£°0 FCO 86'I 861 97% OLS ZL ‘0 80'I ST'0 G9'T PPT rc'o PPT 980 pa'o 09'8 86'I 89°F Ors JU99014 914 0 oO X po Mae] > — opomepueW, — (reo ) 0 910H a5 > p ApaloxsoWy 0 OAR] RIT) opeaeeusá7]. «* Af 060 IT oH 09 A9uryJOSoW ro'r ) cl el 90 JAB'T 6 opoueeuxJ0] T 9potosÁ"T 0G 9AëT apareeysa’] & 90H . $ ore] 1179 —— apaaeeyyuoyy (690) c OH .., 2 se 9po9tOx.10 [A i i one] ...:=£ opou1euusá'] ,.*' ( €80 ) I OOH. S/O — sautysoydary g DABT ,..:% 6 oporeUqxioW-.. ( 88'0 ) EIUS! DAT TE 9P910SA’] OPAIBBUSÄT D e?vH. I daR] Bez aporeey yo (270 ) I 9107 e 9pot0x.10]q Q ar] ; G 9107 L ART ror) ; 6 EIC t£ opes] £l ae PO OH .. I DART ve UNION. (290) & eH. sy OL apaloyiow ENV TS NS PR Joulysoyda'y opaJeuux10[ v ^ * - EJUS I [4401 JIØH GP 3p9tos 7T GT .9^VT .-»-/!G opoieuusA7 t WW] . 0 SAUT |... o9 OPAIBBUNMION . ( t80 ) 0 Hs. nior t op9o10.10 X 0 DART »() 9po1euus47],.,-** Vf 090 ) 9 tod. S6 ~ Goutquosayy I 9po4p eu yo 6 - Fa OPalosAyy 8 2BUSA’] e loydarf 8 , opoautux40]y . (6l'I ) ve 9IOH | 7» 91. 9polOX40]N € DART ^. G opoaeeusá'] .« ** SS 0c AH. (rri) y II 93] TS I¢ 9po48eu».10 [N (931 ) ENT 9T'T ) p d 9L apalosary [a TE s GL 9487 Sgt opoieeysÀ7] leyuv 19|eud92 -USaN ırder. fa c ocephale bast = Me Tabel 45. 78 HALFDAN BRYN. M.-N. Kl. at se paa de mesocephale euryprosoper, moter os straks et nyt billede. Her er ingen sluttede linjer; affinitetstallene er gjennemgaaende under 1. Der er ingen biologisk sammenhæng mellem mesocephali og euryprosopi ; endnu mindre sammenhaeng er der mellem euryprosopi og leptorhini. Av euryprosopene er saaledes kun 40 0/0 leptorhiner, medens der var 77 Yo leptorhine leptoprosoper. Der er med andre ord ogsaa inden mesocephalenes store gruppe kun en linje som er biologisk fastbygget; det er den ovenfor nævnte. Av de i alt 96 kombinationer som findes opfort paa disse 2 tabeller, blir der kun en, som markerer sig ved det store antal individer den samler om sig. Vi gjenkjender straks alle disse træk som karakteristiske for den nordiske race. Jeg vil i det folgende benævne denne type homo nordicus. Der findes 32 høje og 23 lave individer av denne type. Da grænsen mellem høie og lave i dette tilfælde er sat til 170 cm., og da den nordiske races gjennemsnitsheide kun ligger lite over denne grænse, sier det sig selv at de lave individer i dette tilfælde hovedsagelig er —--avvikere for legemshoidens vedkommende. Der blir saaledes i alt 85 individer — 12,80/0 av samtlige undersøkte som samtidig er bærere av disse 6 for den nordiske race karakteristiske træk. Jeg gaar derefter over til den store brachycephale gruppe, hvis for- greninger findes opført paa tabel 46. Det falder her straks i einene at leptoprosopi og brachycephali gaar daarlig sammen. Brachycephalene har jo utvilsomt gammel hjemstavnsret her i fylket. De har ogsaa utvilsomt gjennem aarhundreder krydset sig med den norske leptoprosope befolkning. Men der er blit langt færre leptoprosope brachycephaler end det skulde blit efter den forholdsvise mængde av begge typer, hvis kun det mate- matiske mængdeforhold av disse træk gjorde sig gjældende. Vi tør derfor med tryghet gaa ut fra at der hersker et 610/0g1sk mot- sætningsforhold mellem leptoprosopi og brachycephah. Omvendt er der aabenbart en stor biologisk samhørighet mellem brachy- cephali og meso-euryprosopi (affinitetstal henholdsvis 1,13 og 1,12). Folger jeg nu linjene videre fremover, saa viser det sig at der er en sammenhængende biologisk velbegrundet række: brachycephali — mesoeury- prosopi — mesorhini — mørke oine — mørkt haar — liten legemsbygning. Brachymesoprosopene maa utvilsomt kun betragtes som —--avvikere av selve hovedgruppen. Der er paa alle punkter fuld overensstemmelse mellem disse linjer. De træk, som her findes forbundne ved tal som tyder paa biologisk samhørighet, gjenkjender vi som de for den alpine race karakteristiske træk. Jeg benævner i det følgende den type som homo alpinus. Der er i alt 10 av denne type, 2: 1,5 0/0 av samtlige undersokte, som er indehavere av alle de her nævnte 6 for den alpine race karakteristiske træk. Paa tabel 47 har jeg opført hyperbrachycephalene med deres for- greninger. Nederst paa denne tabel finder man en ved høie affinitetstal ANTROPOLOGI. TROMS FYLKES 1921. No. 20. ‘OU piujsug &6 0 Tc G9'I G8'0 80'I 0€*0 £9'0 sro 68'0 L8'0 [eSPOPLUP IV cL 0 PFT reo reo 96'0 80'1 80'T OL] Fe O0 br I 9£'0 06'0 980 98'0 980 980 Ah 06 0 re'c 6L 0 06'0 sro SI O0 9c'I GL'0 PEs OS'T 9£°0 9£'0 ST'0 ST'0 &L'0 re'o 96'0 GL'0 ro 98°0 £0 sr’o 80'I pc'o 887 &L'0 Ju99014 (ori) f Sl0H 8 AUT Te 9p9.IEE U.10 JA (ts | € 10H, L-* gr PPOION.ION ( 96'0 ) € 9AB'T - 9 epeuegeusá.«7 7 2 OOH. , Lp Jouryiosay 9 SAUT «008 5 OPAIBBUMION *.. ( 850 ) Á 9 — 9H... "s 68 9pareseT *" GT eAvI.-* gc opa1emgsape* (CE) 6 9H S OAT 0 BIOH., 2 OABT ts c [0 ØIØH. H EIN: pP £T owH DAT LG 910H II opoiveqyion 6 opouenux1o[p … o 9poteo».10]q " 9P9IBEUSAT ** (9€ I ) GP Jouryıoydar opoeeu QAU'T f opoateX.10 [y á 9I0H .. (t ) 0 9^*]..-' & opoaueys A] -*"” (151) 2 "mn er mern nam. E JOUITIOSO [N 6 OAB. II POPAIBRUMION **-.. ( CII ) [6] o10H CT - el DART SI b OOH s c DABT-. 6 I 9IOT +, I 9AUTS a. zZ ] oI0H . 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Kl. meget markert og biologisk set vel sammenhængende linje, som gaar gjennem euryprosopi mesorhini morke oine morkt haar til liten legems- bygning. Denne linje mangler helt repræsentanter for stør legemsheide. De 6 træk som er samlet paa denne linje, gjenkjender vi straks som karakteristiske for den mennesketype som av GiuFFRIDA-RUGERI er kaldt den palæoarktiske, og som omfatter de oprindelige lapper og samojedene. Denne ‘type har blandt de av mig undersøkte kun 5 repræsentanter, 2: 0,9%0. Det er vel hoist sandsynlig at man her har for sig den hyper- brachycephale urtype. Jeg vil i det følgende benævne denne type som homo palæoarcticus. Det er vel hævet over enhver tvil at lappene oprindelig har hat sort haar og brune øine. Linnés beskrivelse av dem synes jo at tyde paa at dette var tilfældet endog paa hans tid. Nu er som bekjendt dette ikke længer tilfældet. Paa tabel 47 finder vi at den bedst besatte linje gaar fra hyperbrachy- cephali gjennem euryprosopi — mesorhini — lyse oine — lyst haar til liten legemsbygning. Her har vi helt igjennem de nulevende norske lappers væsentligste træk. Type no. 185—187 tør vi vistnok betragte som repræsenterende de reneste lapper, som de der staar urtypen nærmest. Jeg betegner disse i det følgende som: homo lapponicus. Den har, som det vil sees, 23 repræsentanter, 2: 4,1 0/0 blandt samt- lige av mig undersøkte. Denne gruppe har, som det videre vil sees, ogsaa repræsentanter for stor legemshøide, men de er endnu i mindretal. Paa 18 lave kommer kun 5 høie. Disse ,rene" lapper har kun faat pigmenteringen fra den nordiske race. De har beholdt urtypens træk med hensyn til hodets, ansigtets og næsens form; og som man kan forstaa av det store antal lave, har den ogsaa be- holdt urtypens ringe legemshøide. Der findes som bekjendt en del lapper som er leptorhine. Men som det fremgaar av tabel 47, har de fleste av disse kun lite igjen av de for urtypen karakteristiske træk. Ti lappenes karakteristiske ansigtsform, eury- prosopien, gaar kun daarlig sammen med leptorhini. Der er derfor kun 8 av disse 2den grads bastarder mellem den nordiske race og lappene. Smal- næsede lapper har derfor i almindelighet ogsaa et betydelig mere avlangt ansigt. De har med andre ord kun beholdt et av urtypens træk, nemlig hyperbrachycephalien. De maa betegnes som zdje grads bastarder av homo paleoarcticus og homo nordicus. Inden denne bastardgruppe har, som det vil sees, de høie overtaket. Det er bastarden mellem lappen og norske, men hvor det norske element er helt dominerende. Disse bastarder findes hos mig repræsentert med i alt 24 individer, 9: 4,4 0/0 (type 161—176). Denne type har akkurat samme størrelse som den forrige ıste grads bastarder, de egentlige lapper. 81 me ANTROPOLOG TROMS FYLKES 1921. No. 20. 261 - - Eu. 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(«o ) t OGT 3 5 0 alo T pr | 9pote»10]N 5 6TI - - 0 9ART,...-» 2POIEEUSAT = ~~ €, ( LAV ) i? . aco) ; 6 4outt.ro)do'T STI THO sro Ton IBI E (ss LOT sro sro SAU area Spes EH, 2 OPT &ç‘0 #70 LL EUR LH M GFT 680 po'0 CT in opaarrusä7] A ou pawjseg |]1ejsjoyug] v 1U9901g eu y : i a 82 HALFDAN BRYN. M.-N. Kl. Tilbake staar nu kun at omtale de bastarder mellem lapper og norske som har lappenes hodeform, men den nordiske races ansigtsform. Disse findes paa tabel 47 opført som nr. 145—152. Man vil av denne tabel straks se at hyperbrachycephali gaar daarlig sammen med leptoprosopi. Affinitetstallene er for hele denne gruppe meget smaa. Hvis blandingen var skedd efter matematiske lover, vilde der været langt flere leptoprøsope hyperbrachycephaler end der er. Dette beror vel for en væsentlig del paa at den leptoprosope befolkning kun i ringe utstrækning indgaar forbindelse med den hyperbrachycephale. Tabel 48 Leptoprosoper 57 - Lyshaarede 5 115 Lyseiede 70 _ 26 114 "- Morkb. 20. Lave 8 115 Leptorhiner 94 Ten 12 116 ^ Lysh. 4." Lave 3. Ate Morkoiede 24 s. ' Hoie 1 = Brachy = X Mesoeuryprosoper "^ Morkh. 20.” Lave 13 119 233 ris * Hoie 1 120 cephaler Lysh. 28 121 Lysoiede 11 12 "Merkh. 19. Lave 15 123 ^ Hoie 4 124 2 . Lysh. g "Lave 5 125 N Morkoiede 24°” * Hoie 5 126 a Morkh. 16 Lave 10 497 -..Hoie 6 198 Men det faktiske forhold er altsaa at de /eptoprosope bastarder hører til de sjeldnest forekommende bastarder. De utgjor omtrent 2/0 av alle undersokte. Ganske anderledes talrike er den brachycephale gruppes bastarder. Ogsaa her viser det sig at med leptoprosoper har brachycephalene kun liten tendens til at danne bastarder. Hele den leptoprosope gruppe er svakt opbygget og meget lite talrik i betragtning av leptoprosopiens store ut- bredelse inden denne befolkning. Derimot har brachycephali omtrent like let for at forenes med mesoprosopi som med euryprosopi; der kan vel ikke være synderlig tvil om at type nr. 127 og type nr. 143 i alt væsentlig er ensartet. Den &ptrukne grænse mellem mesoprosopi og euryprosopi er for brachycephalenes vedkommende ikke hensigtsmæssig. Affinitetsunder- søkelsene synes at tyde paa at der inden vor befolkning kun er to ansigts- typer: leptomesoprosoper og mesoeuryprosoper. Gjennem arvelighetsundersøkelser kan muligens dette bringes helt paa det rene. Leptomesoprosopene skulde isaafald "genetisk høre sammen med dolicho-mesocephaler; brachycephalene og hyperbrachycephalene skulde der- imot begge være euryprosope. Tabellene 44—47 synes ogsaa at peke i den retning. 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 83 Brachycephalenes forgrening vil isaafald være saaledes som fremstillet paa tabel 48. Den alpine race er isaafald repræsentert gjennem de ro individer som har nr. 127. De 39 individer som har nr. 121 og 122, er bastarder av den alpine race, og lappene og de 50 individer som har nr. 113 og 114, er bastarder av den alpine race med den nordiske race. Alle disse linjer har høie affinitetstal. Alle de øvrige paa denne tabel opførte bastardformer er baade sparsomt repræsentert og har lave affinitetstal. Av type nr. 127 og 128 opgav 30 00 at være lapper eller finner, og av type nr. 121 og 122 opgav 30%0 at være enten lapper eller finner. Tilbake staar den dolichomesocephale gruppes bastarder. Som det vil sees, er der i alt rog dolichomesocephale euryprosoper. 31 0/0 av samtlige dolichomesocephaler er merkelig nok euryprosoper. Av disse euryprosoper er igjen 60%0 mesorhiner. At disse hovedsagelig er bastarder av den nordiske race med den store brachycephale (alpine) gruppe, synes utvilsomt. Hovedmassen (60 9/0) av disse bastarder er desuten lave av vekst. Der- -imot er de i utpræget grad lysoiede og lyshaarede. Lysoiede er 87 %0 og lyshaarede 58 0,0. Denne gruppes bastarder har med andre ord tat legemsproportionene fra den brachycephale type, men pigmenteringen fra den dolichomeso- cephale gruppe. Jeg har i et foregaaende avsnit paavist, at man gjennem affinitetsunder- sokelser kan finde frem de træk som biologisk hører sammen. Jeg paa- viste der at mesoce phali er sterkt knyttet til stor legemsheide, leptoprosopi, leptorhini, blondt haar og blaa eine. Dolichocephalenes ringe antal gjorde at det var vanskelig at bli helt klar over deres affinitetsforhold. Av tabellene 44 og 45 fremgaar imidlertid med stor tydelighet at der ikke er nogen merkbar forskjel paa dolichocephalene og mesocephalene. Blandt samtlige 662 finder jeg i alt 85 maend som endnu sitter inde med 5 av de for denne type særegne træk. Da jeg i alt har 355 dolicho- mesocephaler, vil det si at ikke mindre end 24/0 av disse endnu har den nordiske races eiendommelige træk. Av affinitetsundersokelsene fremgik videre, at der utvilsomt i vor be- folkning indgaar en type hvis egenskaper er: brachycephali, mesoeury- prosopi, mesorhini, mørke eine, mørkt haar, liten legemshoide. Og disse traek findes i biologisk sikkert paaviselig tilknytning til hverandre inden den nuværende befolkning. Men samtlige træk finder jeg kun hos ro individer. Da jeg i alt har 233 brachycephale blandt de av mig undersokte, vil det si at kun 4,30 0/0 av disse har bibeholdt typens oprindelige træk. 5 av typens oprindelige træk findes endnu hos 6,86 0/0 av befolkningen. Der er i denne henseende et paafaldende misforhold tilstede mellem denne type og den dolichocephale. Hos denne sidste fandtes, som det vil erindres, 24/0 som hadde bibeholdt den oprindelige types træk samlet. Dette kan 84 HALFDAN BRYN. M.-N. Kl. i eee — —"— ikke bare bero paa at den dolicho-mesocephale blok er litt større. Utreg- ningen er her for begge typers vedkommende foretat i procent av hver enkelt types antal inden den nulevende befolkning. Det er da tydelig at den brachycephale blok har faat en ganske anden voldsom medfart, er blit ganske anderledes sondersplittet end den dolichocephale blok. Det har sin naturlige og let forklarlige aarsak. Der kan vel ikke være nogen tvil om at det nordiske element inden vor befolkning fra forste stund har følt sig som det herskende, det overlegne element. Ogsaa nu vil det av den „norske“ befolkning ansees næsten som en nedværdigelse at indgaa egteskap med til eks. en lap. Hvor saadanne forbindelser kommer istand, vil repræsentanten for den nordiske parts vedkommende utvilsomt være hentet fra samfundets aller dypeste lag. De hoiere stillede klasser inden den nordiske race vil sikkerlig anse sig for god til saadan forbindelse. Men saa at si draapevis har det fremmede element flytt over i det nordiske. Først naar dette er skedd gjennem generationer og den fremmede indblanding er begyndt at gaa i glemmeboken, ialfald er blit mindre synlig paa. grund av opblanding med det norske element, først da har det fremmede element ogsaa kunnet trænge ind i den nordiske races hoiere stillede klasser. Derfor er den alpine blok blit saa sønderlemmet. Den kunde ikke paa anden maate optages i vor befolkning. Det maatte ske derigjennem, at der gjennem aarhundreder sagte og umerkelig fløt litt norsk blod over i den alpine blok. Først naar denne derved var blit passende fornorsket, kunde den vinde almindelig anerkjendelse og bli likestillet med den norske ved indgaaelse av egteskap. Derfor er det heller ikke saa rart at man blandt samtlige undersokte finder saa meget som 15,2 %0 ralativt rent nordiske individer. Endelig fremgik det ogsaa av affinitetsundersøkelsene, at der indgaar i vor befolkning en type hvis træk var hyperbrachycephali, euryprosopi, mesorhini, lyse eine, lyst haar, liten legemshoide; altsammen træk som vi gjenkjender som karakteristiske for lappene.' Paa tabel 47 findes typens vel markerte kjede som lopenr. 185. I alt fandtes rr individer som indehavere av disse træk. Da der i alt kun fandtes 74 hyperbrachycephaler, vil det si at 15/0 av hyperbrachycephalene har beholdt det for denne type karakteristiske træk. = Alle hensyn tat i betragtning vil det dog, som allerede for paapekt, vere mer korrekt at si at kombinationen nr. 191 er den nu forefindende levning av lappenes urtype. Av denne type fandtes kun 5 individer, hvilket svarer til 6,8 %0 av samtlige hyperbrachycephaler. Hvad som her er det rigtige kan man neppe bringe paa det rene uten gjennem arvelighetsunder- sokelser. Det er jo mulig, at lappene saa leenge har krydset sig med den blonde race at der nu har dannet sig en ny blond hyperbrachycephal genotype, en „Verschmelzungsgenotypus“. Anderledes kan man vanskelig forklare 1927. No. 20. TROMS FYLKES ANTROPOLOGI. 85 sig den eiendommelighet, at der blandt hyperbrachycephalene er flere lys- haarede end blandt samtlige undersokte. Blandt hyperbrachycephalene har jeg fundet 68,8 9/0 lyshaarede, medens jeg blandt samtlige undersokte i Troms fylke kun fandt 58,9 %0. Affinitets- tallet for hyperbrachycephali og lyst haar blir da 1,17. Med de meget store tal man her har at gjøre med, viser dette en meget sterk biologisk sam- menhæng mellem lyst haar og hyperbrachycephali. Indtil videre faar man derfor noie sig med at betegne som urlapper type nr. 191 og som nutidslapper type nr. 185. De mellemformer mellem disse som findes opført som lopenr. 186— 190, blir isaafald bastardformer mellem urlapper og nutidslapper. Det har nu interesse med éngang at se litt naermere paa hele denne gruppe. Av de 5 urlapper, kombination nr. 191, var 1 fra Trondenes, 1 fra Lyngen, 1 fra Skjervoy og 1 fra Salangen. Disses gjennemsnitlige legemshoide var 165,4 cm. Kun to av dem regnet sig selv for lapper, to kaldte sig for finlændere, 1 sa han var rent norsk; men jeg har for ham notert ,typisk lap av utseende*. Hos 3 av dem (60/0) fandtes en vel utviklet mongolfold. Deres gjennemsnitlige cephalindex var 86,9. Deres ansigtsindex var 80,7. Deres næseindex 82,2. 3 (60/0) av dem hadde kulsort haar. Blandt ,nutidslappene" (kombination no. 185) var 2 fra Tronde- nes, I fra Salangen, 1 fra Ibestad, 1 fra Dyroy, 1 fra Skjervey, ı fra Karlsey og 4 fra Lyngen. 6 av disse kaldte sig lapper, 5 regnet sig for norske. Deres gjennemsnitlige legemshoide var 164,3 cm. Deres cephal- index 87,3, ansigtsindex 80,3, næseindex 82,1. Mongolfold fandtes kun hos 3 av dem. Tilbake staar kun de r3 bastarder av ,anden grad". Av disse regnet kun 3 sig for lapper, de øvrige ansaa sig for helt norske. Av disse var I fra Lavangen, 1 fra Malangen, 2 fra Tromsoysund, 1 fra Salangen, I fra Ibestad, 2 fra Torsken og 2 fra Skjervey. Deres legemsheide var 168,1, deres cephalindex 86,8. Kun hos 2 av dem fandtes mongolfold. Gjennem alle sine karaktertræk viser saaledes disse sig virkelig at være mere ,utspaedd", mindre lappoide end de to førstnævnte grupper. Naar jeg i dette avsnit med tal har forsokt at illustrere i hvilken grad vor befolknings ,urtyper" er blit sonderlemmet, saa maa jeg gjøre en reservation. Man kan vel med en til visshet graensende sandsynlighet si at lappene oprindelig har vaeret hyperbrachycephale. Men det lar sig ikke gjore nu at trække op de noiagtige grænser for deres hyperbrachycephali. Like- ledes kan man vel med temmelig stor sikkerhet gaa ut fra at den nordiske race har været dolichomesocephal. Men heller ikke her kan man trække op de neiagtige grænser. Naar jeg nu i dette avsnit har prøvet at illustrere i hvilken grad de oprindelige typer i tidens lop er blit senderlemmet ved bastardering, saa 86 HALFDAN BRYN. M.-N. Kl, maa der selvfølgelig ikke lægges for meget i disse tal. De kan kun bli i hovedtrækkene rigtige. Men om de altsaa end ikke kan bli helt rigtige, saa har de dog sin interesse. Ti i det væsentlige er dog tallene rigtige nok. Og det væsentlige er i dette tilfælde paavisning av den alpine bloks totale sønderlemmelse og den nordiske bloks relative ubeskadigelse. Og i denne henseende er det ganske utænkelig at ikke resultatet er rigtig nok. Det kan være, at den alpine blok er blit mindre beskadiget end det efter mit regnestykke ser ut til, og det kan være at den nordiske blok er litt mere beskadiget. Men her blir der dog kun tale om en gradsforskjel. Men ogsaa i en anden henseende tror jeg at beregningen har sin interesse, nemlig for den sammenlignende antropologi. Ti her spiller det selvfølgelig en mindre rolle Avor grænsene trækkes, naar de blot altid trækkes ens. Man har ved undersøkelsen av disse 4 tabeller (44, 45, 46 og 47) faat et meget sterkt indtryk av samhørigheten av visse træk. Et fremmed træk svækker linjene merkbart. Jeg skal først følge linjene paa tabel 44. Man ser her straks det intense biologiske sammenhæng mellem dolichocephali og leptoprosopi. Dolichocephali kan ganske vist ogsaa inden denne befolkning knyttes sam- men med euryprosopi; men affinitetstallet viser at denne forbindelse har vanskelig for at komme istand. Leptorhini har sterk affinitet til leptoprosopi, men den har ogsaa meget sterk affinitet til dolichocephali. Indskydes der et mellemled av en anden biogenetisk type, svækkes straks linjen. Indskydes 2 fremmede led, er svækkelsen endnu alvor- ligere. Medens" linjen dolichocephali, leptoprosopi, leptorhini, lyse oine er repræsentert av henholdsvis 39, 19, 15 og 13 individer, er sidegrenen meso- rhini, mørke øine repræsentert av henholdsvis 4 og o individer. 2 fremmede mellemled taaler altsaa ikke denne linje (se øverst paa tabel 44). Ett fremmed mellemled gjør mindre. Saaledes fortsætter den dolichocephale, leptopros- ope, mesorhine linje med relativt stor kraft gjennem lyse oine til lyst haar, medens den ikke har nogen repræsentant for mørkt haar. Om man undersøker en saa talrik gruppe som brachycephalenes, saa gjentar dog det samme sig. Brachycephali har sterk tilknytning til mesoprosopi, mesorhini, mørke eine og mørkt haar. Et fremmed element virker straks betydelig svækkende paa kjeden. Brachycephali, leptoprosopi, leptorhini, lyse eine viser jevnt avtagende affinitetstal. Derimot tiltar affinitetstallene igjen jevnt og sikkert om kjeden faar fortsætte sig gjennem leptoprosopi til mesorhini (0,84), mørke oine (1,73) til mørkt haar (1,86). Av stor interesse i denne henseende er de to typer 127 og 129. Phænotypisk arter jo disse sig som rene kontraster. Den ene type morkhaaret, morkoiet, mesorhin og mesoprosop, den anden lys- haaret, lysoiet, leptorhin og euryprosop; men allikevel har, som det vil 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 87 sees, begge kjeder høie affinitetstal. Det eneste fælles tilknytningspunkt er brachycephalien. I den første kjede hører alle led genotypisk sammen. Derfor er affinitetstallene her saa høie. I den anden kjede er alle led hentet fra den hyperbrachycephale genotype (lappene). Derfor er affinitetstallene her saa høie. Tabel 49: Hoie 45 Lyshaarede 85 Lave 40 Leptorhiner 172 Leptomesoprosoper 246 Lyshaarede 23 Dolichomesocephaler 35: Lysoiede 32 Leptorhiner 45 Lyshaarede 36 Euryprosoper 109 Lyseiede 60 Lave 21 Mesorhiner 64 Lyshaarede 20 Lyseiede 29 Hoie 16 Leptorhiner 38 Leptoprosoper 57 Lyshaarede-50 Brachycephaler 233 Lyseiede 70 Leptorhiner 94 Lave 28 Mesoeuryprosoper 176 Lyshaarede 39 Lyseiede 58 Mesorhiner 8? Merkoiede 24 Morkhaarede 16 Lave Lyshaarede 10 Hoie 6 Lysøiede 12 Leptorhiner Mesoprosoper 24 Hyperbrachycephaler 74 Lyshaarede Lave 15 Hoie Euryprosoper 37 Lysoiede 25 Morkhaarede 8 Lave Mesorhiner .29 Merkeiede 6 Morkhaarede 5 Lave 5 Type nr. 129 har med andre ord alle træk for lappene med undtagelse av brachycephali. Men som jeg paaviste ved affinitetsundersokelsene, hersker der intet motszetningsforhold mellem brachycephali og euryprosopi. Det blir da let forstaaelig at disse to phaenotypisk saa forskjellige typer begge to kan ha høie affinitetstal. Derfor kan man ogsaa straks slutte sig til at type nr. 129 maatte være en bastard av den alpine race og lappene. Brachycephali har derimot meget liten tilknytning til leptoprosopi. Her finder vi derfor meget svake affinitetstal for den alpine races bastarder med 88 HALFDAN BRYN. M.-N. Kl. den nordiske race. Bastardene er der, noksaa talrike endog; men overalt viser de smaa affinitetstal at de to typers karaktertræk gaar daarlig i samme spand. Jeg har i dette avsnit prøvet om det er mulig at finde frem hvilke typer det er som gir denne befolkning sit præg. Og jeg mener dette til en vis grad har lykkes. Jeg har noiet mig med herunder at holde mig til 6 av de for menneskeracene mest karakteristiske træk. Men hvert av disse træk er igjen avhængig av ikke ett, men mange faktorpar. Jeg har saaledes i en anden avhandling søkt at bevise at bare for hodeformens vedkom- mende har vi med mindst 5 faktorpar at gjøre. For legemshoidens ved- kommende sandsynligvis likesaa mange. Hvor mange faktorpar oienfarve, haarfarve, ansigtsindex og næseindex er avhængig av, derom vet vi endnu intet. Men sikkert er det ialfald at vi blot for disse 6 træks vedkommende har med overordentlig mange faktorpar at gjøre. Naar man nu erindrer at de mulige kombinationers antal ved 10 faktorpar er 1048576, saa kan man tænke sig til hvilke svimlende tal man vil komme op i her, hvor man har med mindst det dobbelte antal faktorpar at gjøre. Man kommer op i milliarder av kombinationer. Man skulde da tro, at man vilde komme op i et saadant virvar av kombinationer at det ikke længer blir mulig at finde nogen orden i dette kaos. Av saa meget større intéresse er det at se at hovedlinjene trær ganske skarpt frem. Der er endel kombinationer som optrær med en saa stor hyppighet, og som synes at være saa fastbygget at de derigjennem præger hele populationen. Sammenhængen herved er overordentlig klart frem- stillet av dr. phil. Oscar HAGEM i hans bok Arvelighetsforskning, pag. 268: »Hver enkelt linnéisk art bestaar av mange forskjellige genotyper som i sin sammensætning kan være en mere eller mindre fast gruppering av artens gener. Genene følger i ‘sine arveforhold MenDers regel, med den variation herav som mulige koblings- og frastøtningsforhold bevirker; kryss- ning mellem artens mange genotyper gir derfor ved spaltning og rekom- bination grundlag for en kaleidoskopisk variation av genotyper og fæno- typer. Kryssning, spaltning og rekombination er hovedgrundlaget for alle fremmedbefrugtende arters variation og danner en rik samling av genotyper. Inden denne artens genotypsamling er det selektionen — det naturlige utvalg — har virket og fremdeles virker. En stor del av de teoretisk mulige genotyper er antagelig relativt litet levedygtige og gaar tilgrunde i kampen for tilværelsen allerede paa et tidlig tidspunkt av sit liv. Antar man f. eks. ro faktorpar inden en art, saa vil dette muliggjore 210 = 1024 kon- stante kombinationer (homozygoter). Men antallet av mulige kombinationer er 410 1048576 + 1024 — 1047552. Heterozygotene er altsaa teoretisk 1000 eller 1048576, og de heterozygotiske kombinationers antal er ganger saa talrike som homozygotene, og disse sidste krysses stadig med heterozygoter og gir heterozygotisk avkom. Inden fremmedbefrugtende X921. No. 20. TROMS FYLKES ANTROPOLOGI. 89 arter er derfor en mængde av genotypene heterozygoter, og muligheten for en saadan arts variation er derfor overordentlig stor. En stor del av disse mulige genotyper er imidlertid sikkert mindre levedygtige, og i kampen for tilværelsen skjæres de bort før de har naadd fuld utvikling og for- plantning. De linnéiske arters karakteristiske og ofte temmelig ensartede utseende skyldes temmelig sikkert, at meget av den variation som er mulig paa grundlag av artens gener, stadig holdes nede i kampen for tilværelsen. Disse mindre levedygtige genotyper dannes selvfølgelig for en del auto- matisk og nødvendig ved spaltning av bedre heterozygotiske genotyper, men naar ikke i sin utvikling saa langt at de blir med i prægningen av artens utseende. Det naturlige utvalg virker derfor kun sorterende i en variation som beror paa bestemte allerede eksisterende genotyper." Jeg har i dette avsnit paavist-hvilke kombinationer som synes at være levedygtige. Det fremgaar av undersøkelsen, at disses antal ikke er større end at de kan skrives om ikke med ensifrede tal, saa ialfald med meget lave tosifrede tal. Det vil derfor gaa an inden enhver befolkning at skaffe sig en let overskuelig oversigt over dem. Og da faar man ogsaa her- igjennem et meget klart billede av angjældende befolknings sammensætning. Av dette avsnits indhold fremgaar følgende (se tabel 49): 1. Der er ingen væsensforskjel paa dolichocephaler og mesocephaler med hensyn til disse typers forhold til ansigtstype, næsetype, oienfarve, haarfarve og legemshøide. 2. Begge disse hodetyper er sterkt knyttet til leptomesoprosopi, lepto- rhini, lyse eine, lyst haar og stor legemsheide. 3. Disse træk findes blandt de av mig undersøkte dolichomesocephaler samlet hos 85 = 24 %0. Hos 12,89/0 av samtlige undersøkte. 4. Brachycephalene har biologisk sterk tilknytning til meso-euryprosopi, mesorhini, mørke oine, mørkt haar og liten legemshoide. 5. Disse karaktertræk findes blandt de av mig undersøkte brachy- cephaler samlet hos ro = 4,30 0/0. Hos 1,5°/o0 av samtlige undersokte. 6. Hyperbrachycephali synes at være sterkt knyttet til euryprosopi, mesorhini, lyse øine, lyst haar og liten legemshøide. 7. Disse træk findes blandt de av mig undersøkte hyperbrachycephaler samlet hos rr = 15 %0. Hos 1,6 %0 av samtlige undersokte. 8. Hyperbrachycephalien har dog ogsaa en fast tilknytning til eury- prosopi, mesorhini, mørke eine, mørkt haar og liten legemsheide. Disse træk, som antagelig er lappenes oprindelige træk, findes blandt de av mig undersøkte hyperbrachycephaler samlet hos 5 mand = 6,8 0/0, hvilket svarer til 0,75 9/0 av samtlige undersokte. 9. Ved krydsning av de her nævnte urtyper er opstaat en række bastarder, hvorav de hyppigst forekommende er folgende: a. Dolichomesocephali, euryprosopi, leptorhini, lyse eine, lyst haar, liten legemsheide hos 12 = 1,8 0/0. 90 HALFDAN BRYN. M.-N. Kl. b. Dolichomesocephali, euryprosopi, mesorhini, lyse gine, lyst haar, liten legemshoide hos 21 3,2 9/0. c. Brachycephali, leptoprosopi, leptorhini, lyse oine, lyst haar, stor legemsheide hos 16 = 2,4 0/0. d. Brachycephali, mesoeuryprosopi, leptorhini, lyse oine, lyst haar, x. liten legemshoide hos 24 = 3,6 9/0. [j. stor legemshoide hos 26 = 3,9 0/0. e. Brachycephali, mesoeuryprosopi, mesorhini, lyse oine, lyst haar, liten legemshoide hos 28 4,2 0/0. f. Hyperbrachycephali, mesoprosopi, leptorhini, lyse eine, lyst haar, 0/ stor legemsheide hos 6 = 0,9 "/0. X. Befolkningens væsentligste og mest karakteristiske bastarder. Det billede som jeg i det foregaaende avsnit har git av denne befolk- ning, kan nærmest karakteriseres som et uhyre komplicert mosaikbillede. Ved en detaljert undersøkelse av dette mosaikbillede lyktes det dog at faa nogen klarhet over hvorledes mosaikbilledet er kommet istand. Jeg vil nu prøve at forenkle dette billede ved at utelukke alle mindre væsent- lige træk og ved at slaa sammen de træk som vi nu vet er samhørige. Men jeg tror desuten at man gjennem kun nogle faa træk kan paa en fuldt tilfredsstillende maate karakterisere en befolkning. Det er det jeg vil forsøke at gjøre i dette avsnit. Til dette oiemed vil jeg kun bruke den del av befolkningen som regner sig for norske. Jeg vil saa til slut sammenligne dette rene norske billede med det billede som kommer istand naar jeg tar med ogsaa alle fremmede elementer, lapper og kvæner. I mit materiale har jeg i alt 559 ,norske individer", De træk som jeg vil anvende for at karakterisere dem, er hodeform, ansigtsform og øienfarve. Ogsaa de 3 urtyper som indgaar i vor nuværende befolkning, kan paa en helt tilfredsstillende maate karakteriseres gjennem disse 3 træk saaledes: a. Det nordiske element: mesocephalt, leptomesoprosopisk, blaaøiet. b. Det alpine element: brachycephalt, meso-euryprosopisk, brunoiet. c, Det lappoide element: hyperbrachycephalt, euryprosopisk, lyst melerte oine. I mesocephalenes gruppe vil der selvsagt indgaa et ganske betydelig antal ---avvikere fra den meget store brachycephale gruppe. Og da denne 1921. No. 20. TROMS FYLKES ANTROPOLOGI. QI er saa sterkt avvikende fra mesocephalene i alle henseender, vil den ogsaa bidra ikke saa lite til at forkludre mesocephalgruppen, saa at det blir vanskelig at se hvad der er særegent for den. Dolichocephalene repræ- senterer derimot —-avvikerne av den mesocephale gruppe, og da der ikke her er anledning til nogen væsentlig opblanding med andre grupper, kan man her vente at finde de mest typiske repræsentanter for den store meso- cephale gruppe. Jeg har paa tabel 50 i alt 48 kombinationer. Hodets form er lagt til grund for den videre inddeling. Rækkefølgen svarer til den hyppighet hvormed de forskjellige kom- binationer findes inden hver enkelt hodetype. Det er jo nemlig av liten relativ interesse ved en saadan undersokelse at faa rede paa hvor ofte hver enkelt kombination forekommer blandt samtlige undersekte. Det sier sig jo nemlig selv, at den kombination maa forutsættes at bli den hyppigst forekommende som repræsenterer de inden den samlede masse hyppigst forekommende enkelttræk. Da saaledes mesocephali, leptoprosopi og blaa eine er de hyppigst forekommende enkelttræk, er det ogsaa at vente at disse træk hyppigst maa forekomme kombinert. Av betydelig større interesse er det at bemerke at dolichocephali, leptoprosopi og blaa øine er den bedst besatte kombination inden de enkelte hodetyper. Men for den videre beregnings skyld har jeg i sidste kolonne ogsaa anført kombinationens hyppighet blandt samtlige undersøkte i pro mille. Saa har jeg endelig i kolonne 6 anført affinitetstallet. Paa samme maate som Ü/o-tallene i kolonne 5 tar hensyn til den relative hyppighet av det ene karaktertræk — hodetypen — tar affinitetstallet hensyn til den relative hyppighet av alle 3 karaktertræk. Derfor er ogsaa dette tal av meget stor interesse naar det bygges paa et tilstrækkelig stort antal individer. Det er nu ikke min mening detaljert at gjennemgaa alle de 48 her anførte kombinationers forekomst. Jeg vil kun ta med hvad der forekommer mig at være av særlig interesse. Av aller størst interesse mener jeg det er at se hvilke kombinationer det er som har det største affinitetstal. Det er da meget bemærknings- værdig, at de 3 eneste kombinationer som har høie affinitetstal, er følgende: Nr. 17. Brachycephali, euryprosopi, brune eine 1,75. 2. Hyperbrachycephali, euryprosopi, blaa eine 1,34. „ I. Dolichocephali, leptoprosopi, blaa oine 1,28. De er ogsaa de 3 kombinationer som vi for har erkjendt som karak- teristiske for denne befolknings urtyper. Den tredje største i antal er mesocephali, leptoprosopi og blaa oine. Jeg kom i forrige avsnit til det resultat, at ogsaa disse træk tilhører den nordiske race. Naar saa allikevel affinitetstallet er saa meget mindré end det er for den tilsvarende dolicho- cephale kombination, saa kan vel grunden hertil kun være den, at en stor 92 HALFDAN BRYN. M.-N. Kl. Label 50, Ansigts- type i91] 6 | 7 | 8 Antal indi-| Pro mille vider med | blandt alle Affinitets- tal 0/0 inden Nr. Hodetype ^ hodetypen komb. undersokte I 38,0 1,28 14 25,1 2 34,0 1,34 18 32,2 3 24,8 I.OT 68 I21,5 4 20,8 0,99 II 19,8 5 20,6 0,99 40 71,6 6 20,2 1,10 56 100,2 7 20,0 III 55 99,4 8 18,6 0,77 36 64,4 9 16,2 1,21 6 10,7 10 16,0 0,97 31 55,5 II 9,5 0,75 5 8,9 12 9,5 2,23 5 8,9 13 6,8 1,08 24 42,9 I4 8,8 I,12 17 30,5 15 8,1 2,91 3 54 16 8,1 0,70 3 554 17 7,8 1,75 15 26,8 18 1754 1,08 18 32,2 19 7,4 0,99 + 7,2 20 6,7 0,09 13 23,2 2 RII 355 3 5u 22 5,5 0,90 15 26,8 23 . 54 9,55 2 3,6 24 D 152 L. m. © 5,4 1,42 2 3,6 25 D. 12% Br. ø 5,4 2,52 2 3,6 26 M. 1% Br. ø. 4,3 0,90 12 21,0 27 B. E: M.m. 9. 4,1 1,22 8 14,3 28 HP: M. M. m. o. 3.8 1,16 2 3,6 29 HB. FE? I5 mo 3,9 0,45 2 3,6 30 HB: E. Br. ø. 3,8 0,81 2 3,6 31 B. ES L.m. e. 3,6 0,75 7 12,5 32 B. IE. M.m.o. 3,6 1,74 7 12,5 33 B: E Br. ø. 3,6 1,10 7 12,5 34 B. M. M. m. o. 3,6 0,95 7 12,5 35 B. M. Br. o. 31 0,82 6 10,7 36 D: E: Br. o. 2,7 0,45 I 1,8 37 D. M. L. m. 6. 2,7 0,42 I 1,8 38 D. M. Br. o. 2,7 0,74 I 1,8 39 D. [Eg M.m.ø. 2,7 0,65 I 1,8 40 M. M. M. m.o. 2,5 0,64 7 12,5 41 M. Je M.m.ø. 2,5 0,08 7 12,5 42 EB. 1ER Br. 9. 1,9 o,81 I 1,8 43 M. M. Pr. o. 1,8 0,54 5 8,9 44 M. E. M.m.ø. 1,8 0,70 5 8,9 45 M. 1% Br. ø. I,4 0,43 4 ke 46 D. E. M. m.0o. o o o 0,0 47 HEB: Ie M. m. o. o o o 0,0 48 Lip. E: M. m. o. o o o 0,0 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 93 del av mesocephalene kun er phænotypiske mesocephaler. Genotypisk til- hører de den brachycephale gruppe. Gruppe 4 har lappenes hodeform, den nordiske races ansigtsform og øjenfarve. Denne kombination forekommer, som det vil sees, meget sjelden, kun hos 11 individer av 559, det vil si hos 1,9 9/0 av samtlige undersøkte. Men den forekommer hos 20,80 av samtlige hyperbrachycephaler. Den er selvfølgelig et krydsningsprodukt av lapper med individer som tilhører den nordiske race. Det samme er tilfældet med løpenr. 11. Denne gruppe har ogsaa lappenes hodeform, den nordiske races ansigtsform og øjenfarve. Av denne kategori findes i alt 5 individer, hvilket svarer til 0,89 9/0 av samtlige undersokte, men 9,5 9/0 av samtlige hyperbrachycephaler. I alt er der altsaa 16 individer som har lappenes hodeform, men den nordiske races ansigtsform og oienfarve. Dette svarer til 30,3 %0 av alle hyperbrachycephaler. Hos løpenr. 3 er hodeformen hentet fra den brachycephale gruppe, ansigtsformen og eienfarven fra den nordiske. Affinitetstallet tyder paa at der ikke her er noget affinitetsforhold tilstede; men der synes heller ikke at være noget motsætningsforhold tilstede. Kombinationen forekommer hos 20 0/0 av samtlige brachycephaler, og hos 7,2 %0 av samtlige undersøkte. Den næst største gruppe blandt samtlige undersøkte er mesocephali, mesoprosopi og blaa oine. Den tæller 56 individer og utgjor 100,2 9/00 av samtlige undersøkte. Den har ogsaa et heit affinitetstal, 1,10, og dette faler jo for at der kan være en biologisk sammenhæng tilstede ogsaa her. Det er der ogsaa utvilsomt. Nogen særskilt mesoprosop type findes neppe inden vor befolkning. Mesoprosopene er dels +-avvikere av leptoprosopene, dels —-avvikere av euryprosopene. Den lille gruppe blaaøiede dolichocephale mesoprosoper (nr. 9) har ogsaa et saa høit affinitetstal, at man med én gang kan være sikker paa at der her har gjort sig gjældende meget sterke kræfter, at der med andre ord er biologiske forhold som er grund til den hyppig forekommende kombination av disse 3 træk. Affinitetstallene løper ogsaa helt paralelt med den foregaaende gruppes, størst for den dolichocephale gruppe, mindst for den brachycephale. Utvil- somt har man heller ikke her med bastarder at gjore; det er kun +- og --.avvikere fra den nordiske race. Disse 3 grupper tæller hen- holdsvis 56, 40 og 6 individer og utgjor altsaa 18,4 %0 av samtlige undersokte. Antallet av dem som har beholdt disse 3 trek fra den nordiske race samlet, forokes derved til 33,2 9/0. Den tredje største gruppe, lopenr. 7, er mesocephali, euryprosopi og blaa oine. Det er en utvilsom bastard, et krydsningsprodukt av det nordiske element med det alpine. ; Løpenr. 8 er ogsaa et typisk krydsningsprodukt av det nordiske element med det alpine. Det alpine element gir sig tilkjende i hodeformen 94 HALFDAN BRYN. M.-N. Kl. og ansigtsformen, det nordiske element i eienfarven. Man skulde vente at denne bastard var meget talrikere, da den er et krydsningsprodukt av de to hovedtyper. De repræsenterer imidlertid diametrale motsaetninger baade med hensyn til hodeform, ansigtsform og oienfarve. Disse træk som her findes kombinert: brachycephali, euryprosopi og blaa eine, hører biologisk ikke sammen; affinitetstallet peker i samme retning. Gruppe 13 svarer til gruppe 3, blot med den forskjel, at øjnene er blit lyst melert. Baade hodets og ansigtets form har denne gruppe fælles Homo nordicus. Homo nordicus var. fuscus. Homo nordicus var. euryprosopicus. Homo alpinus var. dolichocephalicus. Homo nordicus var. brachycephalicus. Homo alpinus var. nordicus. Homo alpinus lividus s. coeruleus. Homo alpinus. Homo lapponicus var. nordicus. Homo lapponicus var. alpinus. Homo lapponicus. Homo palæoarcticus. Fig. 13. Grafisk fremstilling av tabel 51. Bastardernes forgreningsnet i henhold til tabel 51. Strekenes tykkelse illustrerer samtidig mængdeforholdet. Skraveringen har følgende betydninger: Vandret betegner den nordiske race. Lodret -- — alpine race. Sort = — palæoarktiske race. med den nordiske race. De melerte eine maa den ha faat fra en av de 2 andre urtyper. Denne bastard findes overalt hvor den nordiske race findes, og dens store utbredelse overalt i Norge taler for at den hoved- sagelig maa betragtes som et krydsningsprodukt av den nordiske race med den alpine race. At de melerte eine kun er en modifikation av de brune eine, er vel ganske utvilsomt. Gjennem lange tiders krydsning med den nordiske race er det brune pigment blit utspædd; men ved krydsning med blaasiede forholder disse melerte eine sig ganske som de brune og domi- 1921. No. 20: TROMS FYLKES ANTROPOLOGI. 95 nerer over dem. Genetisk set blir derfor denne gruppe at slaa sammen med de tilsvarende kombinationer av mesocephale og leptoprosope med merkt melerte eine og brune øine. Der er mellem disse grupper kun en gradsforskjel tilstede. De lyst melerte eine er resultatet av en længere fortsat krydsning end de mørkt melerte eine, og disse tyder igjen paa en længere fortsat krydsning end de lysebrune gine o. s. v. Naar det gjælder en bastardundersøkelse, gjør man derfor rettest i at regne med disse som ensartede bastarder. Paa tabel 50 findes disse 3 grupper opført som nr. 13, 15, 22, 23, 26, 36, 37, 38, 39, 40, 41 og 43. Fælles for alle disse grupper er det altsaa at de har tat hodeformen og ansigtsformen fra den nordiske race, medens de med hensyn til oien- TL d = E: : Procent ™ © © Ansigts- "EX uot Hodetype "E = Oienfarve Antal av alle x E SP | undersøkte r | D.M L. M l. o. Dolichomesocephali 63 — 80 2 B. LME l. e. 9r 16,4 Brachycephali 81 — 85 3 DM. E: l. 9. 18 I4,0 Hyperbrachycephali 86 — 93 4 | B. E: l. o. 53 9,5 5 D. M. IM: m. © 31 6,6 Euryprosopi 70—83 6 B. EM: m. o 2] 4,8 Leptomesoprosopi 84— 100 1 HB: EM: l. 9. 25 4,5 8 B. E m. ø. 23 4,0 9 EYE: E l. ø 20 3,6 10 D. M. 12% m. 9. ET 2,0 II H. B. L.M m 6 If 12 HB: E. m 2 0,3 farve har faat et større eller mindre stænk fra den alpine race. Tilsammen tæller disse grupper 79 individer, hvilket svarer til 140/0 av samtlige undersøkte. Ier no. 18, 44 Og 45 finder vi mesocephali sammen med euryprosopi og henholdsvis lyst melerte, morkt melerte og brune eine. Disse grupper har altsaa hodeform efter den nordiske race, men ansigtsform og eienfarve efter den alpine race. Disse bastarder er saaledes sterkere alpint markert end foregaaende gruppe. Under samme kategori kommer ogsaa lopenr. 24, 25 og 46. Tilsammen har disse 6 grupper 31 individer og utgjor saa- ledes 4,7 9/0 av samtlige undersokte. Fælles for alle disse er altsaa at de har to trek fra den alpine race og ett fra den nordiske. Bastarder mellem det lappoide og det nordiske element finder man i no. 4, II, I2 og 19. I alt finder man 43 bastarder mellem det lappoide og det nordiske element, svarende til 6,59/0 av samtlige undersekte. Der 96 HALFDAN BRYN. M.-N. Kl. findes ogsaa en del grupper som nærmest maa antages at ha tat et træk fra hver av urtypene. Dette er saaledes tilfældet med nr. 42. Saa broget som dette bastardbillede av befolkningen til en begyndelse ser ut, saa kan man altsaa dog reducere det til at omfatte folgende grupper (se tabel 51). 1. En ren nordisk gruppe: dolichomesocephal, leptomesoprosopisk, lys- olet. 33,2 9/0 av befolkningen tilhører denne gruppe, som jeg vil benævne homo nordicus. 2. En ren alpin gruppe: brachycephal, euryprosopisk, brunoiet. 49/0 av befolkningen tilhører denne gruppe, som jeg vil benævne homo alpınus. 3. En ren hyperbrachycephal gruppe: hyperbrachycephal, eurypros- opisk, brunoiet: kun 0,3 %0 av befolkningen tilhører denne gruppe, som jeg vil benævne homo palæoarcticus. Ved krydsning av disse 3 typer er opstaat felgende hybride varieteter: 4. En dolichomesocephal, leptomesoprosopisk, brunoiet. Denne har altsaa to træk fra den nordiske race og ett træk som for den aller væsent- ligste del maa skrive sig fra den alpine race. 6,6 0/0 av befolkningen til- hører denne varietet, som jeg benævner homo nordicus fuscus. 5. En dolichomesocephal, euryprosopisk, lysoiet varietet. Denne har ogsaa to træk fra den nordiske race og ett træk fra den alpine race. Den er i flere henseender en meget eiendommelig bastard. For det forste er de brede ansigter i forbindelse med et avlangt hode en eiendommelig kom- bination. Dernæst er ogsaa de lyse oine 1 et bredt ansigt et meget ioine- faldende fænomen. Ikke mindre end r4/o av befolkningen tilhører denne varietet, som jeg benævner homo nordicus var. euryprosopicus. 6. Saa har vi en liten gruppe dolichomesocephaler som er eury- prosope og har mørke øine. Den har altsaa to træk fra den alpine race, ett træk fra fra den nordiske race. Da de to mest iøinefaldende træk skriver sig fra den alpine race, vil denne varietet tilsynelatende staa den alpine race meget nær. Jeg har ogsaa benævnt den homo alpinus var. dolicho- cephalicus. Den forekommer kun hos 2/0 av befolkningen. Den har disse 3 træk tilfælles med den av mig andensteds beskrevne Tydals-type (Cro-Magnon). Men den adskiller sig fra den gjennem sin ringe legemsheide. Den har tydeligvis intet med denne at gjøre. Som jeg i næste avsnit skal paavise, maatte vi vente at støte paa en saadan type som denne. Og den forekommer ogsaa i det antal som mån teoretisk kan beregne sig til bør være det rigtige. 7. Jeg kommer saa til den mest utbredte av alle hybride former, nemlig de brachycephale leptomesoprosoper med lyse eine. Av saadanne findes i alt 16,4 %0. Disse har altsaa 2 træk fra den nordiske race og ett fra den alpine race. Jeg benævner derfor denne varietet homo nordicus var. brachycephalicus, idet det kun er dette sidste træk som adskiller den fra den nordiske race. QCTPEPCTPUCOORIEPS 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 97 8. En gruppe brachycephale leptomesoprosoper med mørke øine staar den alpine race saa nær at jeg har benævnt dem homo alpinus var. nordicus. 4,8 0/0 tilhører denne varietet. 9. Saa møter vi en gruppe euryprosope brachycephaler med lyse eine. Denne gruppe har altsaa sine to væsentligste træk fra den alpine race. Den har kun laant haarfarve fra den nordiske race. 9,5 %0 tilhører denne varietet. Jeg har benævnt den homo alpinus lividus. 1o. Jeg kommer derefter over til de 3 varieteter som man hos os finder av den palæoarktiske race. Den største av disse er opstaat ved krydsning med den nordiske race. Den er hyperbrachycephal, men lepto- mesoprosopisk og har lyse eine. 4,59/0 av befolkningen tilhører denne varietet, som jeg har benævnt homo lapponicus var. nordicus. De fleste av disse vil utvilsomt enten regne sig for lapper eller ialfald finde lapper i de nærmeste slegtled. 11. Den næste varietet er sandsynligvis opstaat ved krydsning dels av homo alpinus og homo palæoarcticus, dels av homo palæoarcticus og homo nordicus. Jeg har benævnt denne varietet homo lapponicus var. alpinus, idet jeg derved faar forbundet at der indgaar i denne varietet litt fra alle de nævnte urtyper. 1,1 0/0 av befolkningen tilhører denne varietet. 12. Som sidste varietet har jeg opført de egentlige lapper, 9: hyper- brachycephale euryprosoper med lyse øine. 3,6%0 av de undersøkte til- hører denne varietet, som jeg har benævnt homo lapponicus. Jeg skal i det følgende avsnit se paa hvorledes de her opstillede hybride former, hvad antal angaar, stemmer overens med hvad man maa vente at finde, hvis krydsningen er foregaat mellem de av mig forut- satte urtyper og er skedd overensstemmende med de Mendelske arvelig- hetslover. Paa den rite almindelige antropologiske kongres i Moskva i 1892 uttalte KoLLMANN følgende: ,,Paa hele det store europæiske kontinent, som siden den neolitiske periode har været befolket av flere forskjellige racer, varierer indenfor de mindre gebeter stadig paany verdensdelens alminde- lige tema, paa grund av at disse samme 5 racer har trængt ind paa alle omraader, og det allerede før Kurganernes tid. Den allikevel overalt merk- bare forskjel mellem de ulike folkeslag beror ikke paa optræden av nye racer, ti disse er overalt de samme, men paa det relative antal av hver races repræsentanter; ti disse veksler indenfor hver folkegruppe og be- tinger det ulike fysiognomi." De 5 racer som KOLLMANN mente hadde bebodd Europa siden den neolitiske tid, var følgende: 1. Dolichocephale leptoprosoper. Dolichocephale chamæprosoper. Brachycephale leptoprosoper. HS. us = Brachycephale chamaeprosoper. 5. Mesocephale chamæprosoper. Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. 20. 7 98 HALFDAN BRYN. M.-N. Kl. Hvad det altsaa gjælder om, mener KOLLMANN, er at bringe paa det rene hvor mange repræsentanter hver av ovenstaaende 5 racer har inden et visst omraade. Har man det paa det rene, saa er dermed ogsaa distriktets antropologiske fysiognomi tegnet. Jeg har i denne avhandling paavist at disse 5 ,racer" ogsaa findes i Troms fylke, og jeg har paavist hvor mange repræsentanter hver enkelt av disse 5 ,racer" har inden fylket. Jeg har endvidere fremholdt betyd- ningen av at man ogsaa medtar oienfarven. Da Korrmann formulerte sin opfatning, var arvelighetslæren endnu i sin barndom. Man hadde paa den tid ingen idé om, hvorledes det gik naar to uensartede racer krydsedes med hinanden. Med vort nuværende kjendskap til disse ting vet vi ogsaa at ved krydsning av fo racer: en brachycephal euryprosop med en dolichomesocephal leptoprosop, saa vil inden avkommet i F,-generationen samtlige KOLLMANNS 5 racer være repræ- sentert. Hvis de to ,urracer“ findes i samme mængde alle steder, vil ogsaa de 5 „racer“ bli like talrikt repræsentert overalt. Naar dette ikke er til- fældet, beror det paa at snart den ene, snart den anden av .urracene fra første stund av har været tilstede i større antal end den anden. Her i Troms fylke er forholdene blit yderligere komplicert ved at der ogsaa er kommet til en hyperbrachycephal type. Denne hyperbrachycephale type har imidlertid ikke været medtat av Korımann, fordi den slet ikke forekom i de deler av Europa hvorfra han hadde hentet sit materiale. Jeg tror ikke længer, der kan være tvil om at den av mig her givne forklaring paa raceblandingen i Troms fylke er den rigtige. Jeg tror heller ikke, der kan være tvil om at krydsningen av de to racer for en meget væsentlig del maa være foregaat inden selve fylket. Dette forutsætter, at fylket har været bebodd av en brachycephal type før den nordiske race kom hit. Det kan vel være sandsynlig, at heller ingen av disse to racer har været helt rene da krydsningen foregik. Fremfor alt maa man vel gaa ut fra at det sidst indflyttede raceelement, den nordiske race, har været opblandet endel med alpine raceelementer tidligere. Det kunde neppe naa saa langt nord i Skandinavien uten at det vilde ske. Men det behøver dog ikke at ha været sterkere opblandet end tilfældet har været med de i de senere aar indflyttede østerdølinger. Og vi ser nu, hvorledes race- blandingen er blit i de bygder hvortil disse østerdølinger og gudbrands- dolinger er flyttet. Disse bygder (Bardu, Maalselv o. fl.) har et helt av- vikende præg. Disse bygder har da indflytningen foregik, omtrent ikke været bebodd. Dette er store indlandsbygder, som har virket særlig dragende paa de nordiske raceelementer. Enkelte lappefamilier har vistnok holdt til i disse indlandsbygder; men det alpine raceelement har ikke følt sig til- trukket av denne natur. Det er i kyst- og fjorddistriktene det alpine race- element har holdt sig. Derfor har ogsaa saa mange av kystdistriktene og fjorddistriktene et eiendommelig præg. Ikke alle. Der er ogsaa en forskjel paa disse. Men netop dette gjør, at man nødes til at gaa ut fra at kryds- 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 99 ningen er foregaat paa stedet. Hvis nemlig ikke det var tilfældet, hvis krydsningen hadde foregaat til eks. i Sydnorge, blev det aldeles umulig at forklare sig hvorledes distriktene nu kan ha et i raceantropologisk hen- seende saa forskjelligartet præg. Det maatte da kun bli i højden nuancerings- forskjelligheter. Men som det fremgaar av denne avhandling, er dette ikke tilfældet. At dette fremmede element ikke skyldes tidligere indflyttede lapper, tør ogsaa være sikkert nok. Det er tydelig nok et brachycephalt, ikke et hyper- brachycephalt element. Det fremmede elements utbredningsomraade netop i kystdistriktene taler ogsaa herimot. Det fremmede element har helt igjennem det samme præg som i Søndmør og som paa Jæderen. Og det samme, for den nordiske race fremmede element er jo ogsaa paavist i Sverige, hvor det ogsaa overalt holder sig til kystdistriktene. Professor C. M. First er ogsaa av den overbevisning, at ,vi i Sverige i stenalderen ikke bare har to forskjellige folkestammer eller kaster, men mindst 2 forskjellige racer. Den ene race har den nordiske langskalleform og tilhører særskilt de store stengraver, den anden race — eller muligens den ene av de andre — er kortskallet og sikkert ogsaa den ældre 1 landet". Just saaledes maa vi ogsaa tænke os forholdene her i landet. Og vi skal nu se litt nærmere paa til hvilket resultat krydsningen av de 2 for- skjellige racer har ført. XI. Nogen spørsmaal vedrørende arvelighetsforholdene specielt angaaende hvilke karaktertræk som er eller har været dominerende. Jeg har i de foregaaende avsnit gjort rede for utbredelsen av de væsentligste antropologiske karaktertræk inden den nulevende befolkning i Troms fylke. Den senere tids arvelighetsundersøkelser har bragt paa det rene at flere av disse karaktertræk er overmaade stabile. De nedarves uforandret fra generation til generation. De kan derunder indgaa nye forbindelser, men de blir ellers uforanderlige. Dette gjælder i særlig grad index cephalicus, index facialis morphologicus og index nasalis. Relativt uforanderlig nedarves ogsaa øienfarven. Nogen undersøkelser synes at tale for at de her nævnte træk her- under følger de Mendelske lover, saaledes at enkelte træk er dominerende, andre recessive. Meget sparsomme er imidlertid de undersøkelser som fore- ligger over disse spørsmaal for menneskenes vedkommende. Av de av professor EuGEn FiscuER angaaende disse spørsmaal fore- tagne undersøkelser blandt ,,die Rehobother Bastards" fremgaar, at ialfald 100 HALFDAN BRYN. M.-N. Kl. index cephalicus med stor sandsynlighet nedarves overensstemmende med Mendels lover, og saaledes, at den hoiere index dominerer over den lavere. Hvorvidt dette altid er tilfældet, er et andet sporsmaal. Ved de av mig foretagne undersøkelser i Tydalen og Selbu fandt ogsaa jeg at brachycephali synes ubetinget at dominere over mesocephali. I Tydalen kunde jeg imidlertid paavise en dolichocephal type som i alle henseender mindet sterkt om Cro-Magnon-typen. Denne dolichocephale type synes at eie dominans over den meso- cephale type. Rigtignok er dette materiale sparsomt, men det er dog stort nok til at man kan si at sandsynligheten taler for denne dolichocephale types dominans over den mesocephale. For ansigtsindeks's vedkommende mener FiscHer at kunne fastslaa at ogsaa denne nedarves alternativt, ikke intermediært. For oienfarvens vedkommende foreligger en række undersøkelser, som alle gaar i den retning, at oienfarven nedarves Mendelsk, og at brune eine dominerer over blaa øine. De fleste forskere er ogsaa av den mening, at melerte wine dominerer over blaa. Men paa hele dette omraade er under- søkelsene meget sparsomme. Det vilde være altfor dristig allerede nu at fastslaa som en almindelig regel at brachycephali i alle tilfælder dominerer over mesocephali, eller at brune oine altid dominerer over blaa oine o.s. v. Der kan vel her spille faktorer med som vi endnu kun har litet kjendskap til. Vort kjendskap til de faktorer som fremkalder de her omhandlede karaktertræk, er jo endnu lik nul. Det er i den senere tid av flere forskere fremholdt, at de her om- handlede træk, sp. index cephalicus er beroende paa flere faktorer. I en undersøkelse som den her foreliggende vil det imidlertid være mest praktisk at betragte index cephalicus som en enhet. For denne under- søkelse vil nemlig resultatet bli det samme, og materialet blir derved mere oversigtlig og haandterlig. Ved den taksinometriske undersøkelse av denne befolkning er jeg i de foregaaende avsnit kommet til det resultat, at befolkningen er av en meget heterogen beskaffenhet. Hovedmassen av den tilhører den nordiske race. Jeg kom til det resultat at denne blok maa utgjore omtrent 66/0 av befolkningen. En anden, ogsaa ganske stor blok tilhører den alpine race. Jeg kom til det resultat, at denne blok har utgjort omtrent 30 9/0 av befolkningen. Endelig indgaar der ogsaa i befolkningen en ganske liten blok av lappoid herkomst. Jeg har gaat ut fra at denne blok neppe utgjør mere end 40/0 av befolkningen. Disse tal kan naturligvis ikke gjøre krav paa nogen matematisk nøiag- tighet. Det kan saaledes være at den sidstnævnte blok er noget større, skjønt sandsynligheten herfor er meget liten. Det kan ogsaa være at den 1921. No. 20. TROMS FYLKES ANTROPOLOGI. IOI er mindre end 4 %o. Likeledes kan det være at den alpine blok er nogen procent mindre eller større end av mig beregnet. Hvad der i hvert fald er sikkert, er at den nordiske blok maa ha været mindst dobbelt saa stor som den alpine, og den igjen mange ganger større end den lappoide. Og sikkert er det ogsaa, at naar man anvender alle de hjælpemidler som for tiden staar til vor raadighet, saa kommer man til det resultat, at inden den nulevende befolkning indgaar de nævnte blokker paa det aller nærmeste i det forhold som ovenfor er anført. Og jeg vil indtil videre gaa ut fra at dette er rigtig. Nu er det ganske vist saa, at man ikke kan være viss paa at dette forhold altid har været det samme. Heller ikke har man visshet for, at de anførte ,urracer" var rene dengang de støtte sammen i Norge. For lappenes vedkommende kan man jo endog med sikkerhet gaa ut fra at det motsatte har været tilfældet. Men for det første er denne blok meget liten. Dertil kommer at affinitetsundersøkelsene peker paa, at hvis de har været opblandet før de kom hertil, saa har dette hovedsagelig været med elementer tilhørende der nordiske „race“. Dette spiller derfor ved den undersøkelse som her skal foretages, en mindre rolle. Det samme kan siges om de to andre blokker. Det kan være, at den alpine race har været litt opblandet før den kom til Troms fylke. Men isaafald har det hovedsagelig været med de samme to elementer hvormed den senere er blit krydset 1 Troms fylke. Jeg vil ved slutten av dette avsnit komme nærmere tilbake til hvilken vegt man bør tillægge de momenter, som svækker rigtigheten av de forut- sætninger hvorpaa hele denne undersøkelse hviler. Jeg vil her gaa ut fra, at disse 3 blokker har været rene dengang krydsningen foregik. Om krydsningen muligens for en del er foregaat et andet sted end i Troms fylke, spiller jo i denne forbindelse ingensom- helst rolle. : De tre trek som jeg her vil ta med, er index ‘cephalicus, index facialis morphologicus og eienfarven. Jeg har i et foregaaende avsnit noiagtig gjort rede for bastardenes fordeling med hensyn til disse 3 træk i Troms fylke. Hvorledes svarer nu denne fordeling til det man vil faa, om urtypene har krydset sig i det mængdeforhold som jeg ovenfor har forutsat. Resultatet av denne krydsning vil naturligvis helt avhænge av hvilke træk som er dominerende og hvilke recessive. Om jeg tænker mig at 2 ,rene“ racer krydses, saa vil selvfølgelig i F,-generationen de recessive karaktertræk helt forsvinde, saafremt de to blokker som krydses, har noiagtig samme størrelse. I F,-generationen vil de igjen komme frem, men i mindre antal end før krydsningen, medens de dominerende træk har øket i tilsvarende grad. Ved den fortsatte pan- 102 HALFDAN BRYN. M.-N. Kl. miksi vil de procentforhold som fandtes i F,-generationen, forbli uforandret. Og om den ene blok fra første stund av har været meget større end den anden, saa vil selvfølgelig ogsaa dette medføre at dennes karaktertræk fore- kommer i et større procenttal i F,-generationen. Men ogsaa i dette tilfælde vil det samme procenttal som findes i F,-generationen, fortsætte uforandret i de senere generationer!. I sin bok: Anthropologische Untersuchungen über die Eingeborenen des Russischen Altai fremholder ogsaa Kaar1o Hirpén den store betydning herav for raceantropologien. I den nævnte boks side 106 siger han saa- ledes: „Es sei hinzugefügt, dafs genau die gleichen Gesetze gelten auch wenn wir Rassen kreuzen, die sich in mehreren Merkmalen unterscheiden, wenn wir also Polyhybriden haben. Wir können demnach generell sagen: eine Bastardpopulation, die sich panmiktisch fortpflanzt, behält ihre nach der ersten Bastardierung erworbene Zusammensetzung durch sämtliche fol- gende Generationen bei." Vi har jo ingen grund til at tro at ikke ogsaa den samme lov gjelder for en menneskelig bastardpopulation. Og hvis denne regel gjælder et menneskesamfund, saa har vi derigjennem et udmerket middel til at utdype vor forstaaelse av dette menneskesamfunds raceologiske oprindelse. Jeg vil i dette avsnit bringe denne regel i anvendelse paa det her foreliggende materiale. Jeg vil til at begynde med gaa ut fra at hyperbrachycephali dominerer baade over brachycephali og dolichomesocephali, og at brachycephali domi- nerer over dolichomesocephali; fremdeles at euryprosopi dominerer over leptoprosopi og brune eine over blaa eine. Kan man nu gjøre sig op nogen mening om, hvorledes det vil gaa naar 2 saadanne typer krydses ? Hvor mange synlig forskjellige grupper vil der komme istand, og hvor stort antal kombinationer vil der være? Jeg tar altsaa her kun hensyn til disse 3 karaktertræk. Jeg tar først for mig forholdet ved krydsning av den nordiske race med den alpine race. Jeg vil i det følgende gaa ut fra, at brachy- cephali fremkaldes ved en faktor som jeg benævner 5. Mesocephali kommer istand hvor denne faktor mangler, og denne manglende faktor betegner jeg med 6. Paa samme maate fremkaldes euryprosopi ved en faktor som jeg benævner Æ, og leptoprosopi ved manglen av denne faktor e. Brune eine fremkaldes av en faktor P, og blaa eine ved manglen av denne faktor f. F,-generationens formel blir da B6. Ec. Pp. Denne vil danne 8 slags kjenscelleg > BAER PX DEP, Be Pb ED Bieb OE pi be 2:02 beg: Man vil da ved krydsning av disse 2 typer faa 64 kombinationsmulig- heter og i alt 8 synlig forskjellige grupper, som vil fordele sig saaledes: 1 Nits von Horsten: Ärftlighetslära, Upsala roro. 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 103 ı med 3 dominerende” faktorer BEP= 27 DN FE? = c3 Beto UE 5 —— cce» >= 9 Mage 2 — — CEP iE B RT = sage Ben 3 Or c M Bt, 3 jJ CN : UN NOC 3 TS CL —= bep I Tilsammen, 64 Saaledes vil fordelingen bli hvis begge typer fra første stund av har været tilstede i samme mængde, og under forutsætning av at der fra første stund av har hersket panmiksi. Hvis derimot den ene type er tilstede i dobbelt saa stort antal som den anden, vil forholdet selvfølgelig bli et andet. Om jeg forutsætter at den dolichomesocephale type fra første stund av har været dobbelt saa talrik som den brachycephale, saa vil altsaa halvparten av den dolicho- mesocephale blok komme til at krydses indbyrdes. Dette avkom har formelen bep, og man faar altsaa da i tillæg til ovenstaaende 32 bep. Nu vet vi, som allerede nævnt, at en bastard- population som forplanter sig panmiktisk, gjennem samtlige senere genera- tioner beholder den sammensætning som den fik efter første bastardering. For disse 2 typers vedkommende skulde altsaa typegrupperingen bli som paa tabel 52 anført, med den forandring, at 1 bep blir forandret So b’ep. Tabe] 52: Brachycephali euryprosopi brune eine 14 X 27 = 378 Brachycephali euryprosopi DIE er 9 = 126 Brachycephali leptoprosopi brune — 14 9 = 126 Dolichocephali euryprosopi brune 7, — 14 9 = 126 Brachycephali leptoprosopi blaa — 14 3 — 42 Dolichocephali — euryprosopi blaa ATH 3 2 Dolichocephali leptoprosopi brune — 14 3 — 42 Dolichocephali leptoprosopi blaa ner I 14 Jeg sætter nu at der ogsaa kommer til en anden type: hyperbrachy- cephal, euryprosopisk og bruneiet. Jeg vil forst se, hvorledes det gaar naar denne type krydses med den dolichomesocephale type. Den har en faktor for hyperbrachycephali som jeg vil benævne /7, og manglen av denne faktor / (= dolichomesocephali). Den har en faktor for euryprosopi som jeg benævner Æ, og manglen av denne faktor e = leptoprosopi). Dens formel blir altsaa /7 E P. F,-generationens formel 10. HALFDAN BRYN. M.-N. KL I blir /74 Ee Pp, og denne vil igjen danne folgende kjensceller: HEP, HEp, hEP, HeP, Hep, h Ep, heP, hep. Ved krydsning av disse to typer vil man derfor faa 64 kombinationsmuligheter og i alt 8 synlig forskjellige grupper: Med 3 dominerende faktorer HE P = 27 2 HED 9 2 Eid 9 2 hEP 9 I AXE D 3 I heP 2 I Hep 3 ingen hep I Tua elu Hyperbrachycephali euryprosopi brune eine — 27 Hyperbrachycephali euryprosopi blaa — = 9 Hyperbrachycephali — leptoprosopi brune 9 Dolichocephali euryprosopi brune — — 9 Dolichocephali euryprosopi blaa — = 3 Dolichocephali leptoprosopi brune — - 3 Hyperbrachycephali — leptoprosopi blaa -— 3 Dolichocephali leptoprosopi blaa I Ved krydsning av den hyperbrachycephale type med den brachycephale vil utfaldet bli anderledes. Den brachycephale type hadde, som det vil erindres, formlen 5 E P. Den hyperbrachycephale type hadde formlen HE P. FiscHERS undersekelser tyder paa at hyperbrachycephali dominerer over brachycephali, og jeg vil i det felgende gaa ut fra at saa er tilfzeldet. F,-generationens formel blir da 7 BE E P P. Denne vil danne følgende slags kjensceller: HE P og BEP. Vi faar altsaa 4 mulige kombinationer, som imidlertid vil fordele sig paa felgende 2 grupper: abe les 4 H EP Hyperbrachycephali euryprosopi bruneiet 48 BEP Brachycephali euryprosopi bruneiet 16 Ved den ovenfor av mig forutsatte størrelse av de forskjellige grupper vil der under forutsætning av panmiksi bli tilbake 36 dolichomesocephale som ikke blir krydset med nogen av de øvrige. Disse 36 krydses ind- byrdes, og deres avkom faar formelen dep. Den ved krydsning frembragte population skulde isaafald faa følgende sammensætning: 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 105 a. Bastarder av hyperbrachycephaler og brachycephaler......... 4 9/o b. Bastarder av hyperbrachycephaler og dolichomesocephaler..... 4: 0/0 c. Bastarder av brachycephaler og dolichomesocephaler.......... 56 %0 EErydsede xlaliehomesocephaler:? 25:4 c ee ere erus 36 9/0 Tilsammen 100 ? 0 Anbringer jeg nu de her fundne tal paa de for for hver kombination fundne gruppetal, finder jeg følgende (se tabel 55) som slutresultat for krydsningen. Tabelsss: MEE I E | | | Ved krydsning av nedenstaaende typer i det anforte mængdeforhold skulde Fe-generationen faa neden- Éode- An- Øjen: anførte sammensætning H. B. betyr Hyperbrachycephali. m.o. betyr mørke øine. B. — Brachycephali. H. B. dominerer over B. og D. IDE — Dolichocephali. B. = D. os — Euryprosopi. 192 — I. IU — Leptoprosopi. m. ©. l. o. l. o. — lyse eine. Flere end disse 12 bastarder kan heller ikke forekomme i de senere generationer, saafremt der ikke paa en eller anden maate sker et utvalg, naturlig eller kunstig. I kolonne 5 har jeg utregnet resultatet av krydsningen for brachy- cephalenes og hyperbrachycephalenes vedkommende. I kolonne 6 findes utregnet resultatet for hyperbrachycephalene og dolichocephalene, og 1 kolonne 8 er anfort det tilsvarende resultat av de resterende dolicho- cephalers indbyrdes krydsning. 106 HALFDAN BRYN. M.-N. Kl. | kolonne 9 og 10 er opsummert antal og procent av hver bastard- type. Endelig har jeg i kolonne 11 anført i hvilket antal hver av de samme bastardtyper av mig er fundet inden denne befolkning, naar type- grænsene er de i denne avhandling anvendte. Det. er da med engang iøjnefaldende, at der hersker en gjennemgaaende uoverensstemmelse mel- lem det teoretisk beregnede resultat og det av mig fundne. Ved det teoretisk beregnede er der saaledes 24,69/0 morkoiede euryprosope brachy- cephaler, mens der i virkeligheten kun findes 4,0 0 av dem. Omvendt finder jeg ved den teoretiske beregning kun 2,90 %/0 lysoiede euryprosope dolichocephaler, mens virkeligheten fortæller os at der er 14 /o saadanne. Og av lysoiede leptoprosope brachycephaler har jeg fundet 16,4 90 inden den nulevende befolkning, mens jeg ved den teoretiske beregning finder at der kun burde været 2,9 9/0. Er det teorien som er feil, eller er det mit fund som er feilagtig? | I dette sidste kan der vel være feil av flere grunde. Mine observationer fortæller mig jo kun antallet av fænotypiske brachycephaler, dolichocephaler, leptoprosoper o. s. v. Og det er jo klart at endel av de fzenotypiske brachy- cephaler i virkeligheten er +-avvikere av de genotypiske dolichomeso- cephaler. Dette kan imidlertid ikke volde nogen nævneværdig forstyrrelse. Ti paa tilsvarende maate vil jo omtrent like mange av de fænotypiske dolichomesocephaler i virkeligheten være —-avvikere av den brachycephale type. Da imidlertid denne sidste gruppe er litt mindre end den første, vil der ogsaa blandt de fænotypiske dolichomesocephaler være litt færre geno- typiske brachycephaler end omvendt. Men dette har jeg ogsaa tat hensyn til ved beregning av de genotypiske gruppers gjensidige størrelse, saa den herved fremkaldte feil maa bli ganske minimal. Vanskeligere er det unegtelig at trække grænsene rigtig mellem brun- oiede og blaaoiede inden den nulevende befolkning. Jeg har ved den teoretiske beregning gaat ut fra at disse to oientyper ved krydsning bibe- holdes uforandret. Undersekelsene viser at dette ikke holder stik. Oien- farvene er ikke saa stabile og uforanderlige som hodeformen. Det synes som de brune øine har mistet adskillig av sit pigment og har fordelt dette paa et relativt stort antal blaaøiede. Det tor ogsaa være at F,-generationen ved krydsning av en bruneiet og blaaøiet type ikke faar utelukkende brunøiede og blaaøiede, men at den ogsaa faar endel med melerte oine. Herom vet vi endnu saare lite. Jeg har av den grund fordelt de melerte eine saaledes, at jeg har henført de lyst melerte oine til den lyseste øiengruppe og de mørkt melerte oine til den merkoiede oientype. Her er altsaa plads for mindre feil. Men da antallet av melerte oine i det hele tat ikke er stort, blir det heller ikke paa dette omraade tale om at en forandret beregning kan gi noget syn- derlig andet resultat ved beregningen av den relative størrelse av de i kolonne 11 opførte bastardtyper. 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 107 Jeg kommer saaledes til det resultat, at uoverensstemmelsene mellem de to resultater maa bero paa at den teoretiske beregning hviler paa feil- agtige forutsætninger. Jeg .gik, som det vil erindres, ved den teoretiske beregning ut fra at euryprosopi dominerer over leptoprosopi. Der fore- ligger selvfelgelig ingen grund til at gaa ut fra at dette er rigtig. Der kan derfor være al grund til at se hvorledes resultatet vil bli, om jeg for- utsætter at leptoprosopi dominerer over euryprosopi. Likesaa har jeg forutsat som givet at brune eine dominerer over blaa eine. Dette har jeg jo hat god grund til, al den stund der foreligger en række undersøkelser som peker hen paa at saa er tilfældet inden den nu- levende befolkning paa flere steder baade i Amerika og i Norge. Men derfor behøver selvfølgelig ikke dette at være saa altid og alle stedér. Tabel 56. | | 2 | | = | a. DE: E. | m. © 48 35 b. . B. E: l. o - 0,19 2,1 c. : E. m. o 16 - > 8,8 ST d. | Es : x 42 2,6 | 3,8 ex PEEL B. 182 l.o - 9 - - 9 0,6 5,9 f D. E. l.o - I I4 - 15 0,9 5,7 g. B. p m. 6 - - 31 - 378 | 23,6 6,1 h. D. E. m. o - 3 42 - 45 2,8 0,5 i B. I lo - - 126 - 126 7:9 22,8 k D. p- m. 9 - 9 126 - 135 8,5 8,0 l D. qz lo - 2: 42 576 621 | 38,7 41,6 m^ H-B 152 m. o - 21 - - 21 1.7 1,2 64 64 896 576 1600 Sammendrag: | Teoretisk | Av mig | beregnet | fundet Dohchocephaler.......... 51,3 | 55,8 Brachycephaler 2... 2.2... 43,0 34,7 Hyperbrachycephaler ..... d 9,5 LeptoprosopeEc-: ez 88,9 66,5 Euryprosopers 2"... 19,1 33,5 EySen ame SE SKS aes 54.9 81,2 Morke- ES ne see | 45,1 18,8 H. B. dominerer over B. og D. 108 HALFDAN BRYN. M.-N. Kl. Tabella QNEM T ONES Ved krydsning av nedenstaaende typer i det av mig anførte maengdeforhold skulde F;-generationen faa Q ee) "n Ne) - 5 © — - - Av mig : er 1 Hode- nedenstaaende sammensætning an She Troms sigts- ; type fylke fundet b. forutsættes at dominere over D. FEB: — - = — B.og D. Ie — - — — E. I. ©. — - - — m.ø. H. B. betyr Hyperbrachycephali. L. betyr Leptoprosopi. B: — Brachycephali. l. o. — ]yse oine. D. — Dolichomesocephali. m. 09. — morke gine. Toe - . Euryprosopi. Paa tabel 56 har jeg utregnet, hvorledes forholdet skulde været om leptoprosopi dominerersover euryprosopi. Som man vil se, er overens- stemmelsen mellem teori og virkelighet her betydelig større. Men der mangler dog endnu meget paa at der er fuld overensstemmelse. Under disse omstændigheter fandt jeg, at der kunde være al grund til at undersøke hvorledes forholdet vilde arte sig, om jeg ogsaa gik ut fra at lyse eine dominerer over merke gine. Dette er gjort paa tabel 57. Og som man vil se, er resultatet helt forbløffende. Den eneste nævneværdige uoverensstemmelse mellem teori og virkelighet er her den, at de eury- prosope grupper er uforholdsmæssig smaa og de leptoprosope for store. Ved den av mig foretagne gruppeinddeling har jeg anvendt de van- lige grænser for ansigtstypene: euryprosopi 70—83, mesoprosopi 84—87, leptoprosopi 88—100. Nogen rationel grund for denne inddeling eksisterer neppe. Den genotypisk rigtige inddeling kjender vi desværre endnu lite til. Euryprosopenes gruppe blir paa denne maate meget stor. Da jeg hadde I92I. No. 20. TROMS FYLKES ANTROPOLOGI. 109 grund til at tro at dette kunde være aarsaken til den ovenfor nævnte uoverensstemmelse mellem teori og virkelighet, tok jeg mig for at om- arbeide mit materiale saaledes, at graensen mellem mesoprosopi og eury- prosopi flyttedes nedover. Paa tabel 58 er dette gjort i 2 alternativer. Tabel 58. I kolonne 6 er anført resultatet hvis jeg regner som euryprosoper alle med index 70—81, og i kolonne 7 er anført resultatet hvis jeg regner som euryprosoper alle med index 70—82. Som man vil se, blir overensstemmelsen mellem teori og virkelighet nu saa stor som man overhodet kunde vente at finde den under et saa heterogent materiale som denne befolkning er. Paa tabel 59 har jeg sammenstillet de teoretisk beregnede tal med de av mig fundne tal, naar jeg regner som euryprosoper alle med index 70—81. Det er vel heist sandsynlig at man ved at flytte litt paa grænsene mellem mesocephali og brachycephali vil kunne opnaa en endnu større overensstemmelse mellem teori og virkelighet. Dette er efter min mening helt overflødig. Enhver som har arbeidet med antropologi, vil indrømme at oven- staaende talrække er overensstemmende nok allikevel. At der paa index 79 og 80 for cephalindexens vedkommende vil være individer baade fra den brachycephale og fra den mesocephale genotype, er jo ingen tvil om. Det er ogsaa hoist sandsynlig at der ikke inden Troms fylke hersker en komplet panmiksi. Saaledes er der endnu kun et faatal av lappene som krydses med den norske befolkning. De to første bastardgrupper paa tabel 59 vil dermed bli større end av mig beregnet. Og dette vil igjen føre til at gruppe 10, 6 og 5 blir endel mindre. 110 HALFDAN BRYN. M.-N. Kl. Tabel ‘59. I henhold til den Ansigts- . teoretiske beregning Øientype AJ cc Av mig er fundet Antal Procent Bastard no. ! Hodetype k type Antal Procent I l. o. 114 44,5 232 41,6 | L: m. o. 12 2,8 45 8,0 IDE l. e. 46 2,8 32 5,7 E. m. ø. 14 0,9 3 0,5 IL 1. e. 378 23,6 123 22,0 [7 m. o. 126 7,9 34 6,1 He 1. ø. 138 1,9 24 4,3 E. m.o. 46 3,6 16 2 L. l. o. 36 37 30 5,4 [es m. o. - 5 7 1,2 E 1. o. 48 0,5 12 2,1 Ex: m. ø. 12 2 I 0,2 1600 559 Endvidere maa man ta i betragtning at den av mig beregnede størrelse av de forskjellige genotypiske grupper selvfølgelig ikke kan gjøre krav paa matematisk nøiagtighet. Jeg har, som det vil erindres, regnet med at den hyperbrachycephale gruppe utgjorde 4/0, den brachycephale 30 9/0 og den dolichomesocephale gruppe 66 9/0 inden den nulevende befolkning. Det tor hænde at det hadde været rigtigere at beregne méd henholdsvis 6, 32 og " 62/0. Men dette betragter jeg her som finesser av underordnet interesse. Naar overensstemmelsen mellem det teoretisk beregnede forhold mel- lem bastardtypene og det i virkelig- heten fundne er saa uttalt som den i dette tilfælde er, saa kan man herav slutte sig til, at den i Troms fylke nu eksisterende befolkning i alt væsent- lig er kommet istand paa den maate som den teoretiske beregning er ba- M sert paa. Dolichoceph. MM Hyperbr.ceph. Man maa ha lov til at Sl, at der bast. bast. bast. = x er en aldeles forbløffende overens- Fig. 14. Grafisk fremstilling av tabel 59. — stemmelse ialfald mellem en flerhet av — Bastardenes antal i henhold til mine de tal som findes i kolonne 6 og 8 2o aa tabelss Saaledes er det meget ke Basile ele et de = 59: S . . ) teoretiske beregning. bemerkningsværdig at hos 41,6 %0 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 103 090 av de undersokte findes kombinert den nordiske races 3 vigtige træk: dolichocephali, leptoprosopi, blaa oine, medens man efter den teoretiske beregning skulde vente at finde 44,5 Yo. Dette taler i hoi grad for at disse 3 træk ved krydsning har forholdt sig overensstemmende med de Mendelske lover. Der kan ikke her bli tale om intermediær arv. Den paafaldende over- ensstemmelse i talrækkene taler endvidere for, at de forutsætninger hvorpaa den teoretiske beregning hviler, i alt væsentlig maa være rigtig. Ialfald maa beregningens forutsætning angaaende hvilke træk som er dominante, og hvilke som er recessive, være rigtig. At brachycephali dominerer over dolichocephali, er jo ikke noget nyt. At leptoprosopi dominerer over eury- prosopi, fremgaar tydelig nok ved at sammenligne de av mig fundne procenttal med de teoretisk beregnede paa tabel 59. Med hensyn til øienfarven var jeg paa forhaand overbevist om at de brune eine dominerer over de blaa. Dette fremgaar av DavENPORTS og Hunts undersøkelser, og jeg har ogsaa selv paavist fra en anden norsk befolkning (Selbu og Tydalen) at dette ogsaa forholder sig saa her i Norge. Ved alle de teoretiske beregninger som jeg først foretok, gik jeg derfor ut fra som selvsagt, at jeg maatte regne med at de mørke øine dominerer over de lyse. Men som det vil sees av alle disse tabeller (56 til 58), blir der i alle disse tilfælder en paafaldende og aldeles ufor- klarlig uoverensstemmelse mellem teori og virkelighet. Først da jeg tok mig for at beregne, hvorledes typeforholdene vilde arte sig under forutsætning av at lyse øine dominerte over mørke øine, fik jeg overensstemmelse mellem teori og virkelighet. Og overensstemmelsen var saa stor, at jeg ikke kunde være i tvil om at jeg her var inde paa den rigtige vei. Men hvorledes skulde jeg saa kunne forklare mig dette resultat ? Brune eine kan ikke være dominerende i Selbu og Tydalen, men recessive i Tromsø. Kan det være tænkelig at baade Davenports, Hunts og mine egne slutninger om de brune øines dominans er feilagtig? Har den nyere tids arvelighetsforskning eksempel paa noget lignende paa andre omraader? Er muligens læren om en egenskaps dominans ikke saa absolut sikker ? SIX sm: bok „Einführung in die experimentelle Vererbungslehre" sier professor E. BAUER herom følgende paa side 70: „Man hat dieser Dominanserscheinung, die durchaus keine allgemeine Regel ist, vielfach übertrieben große Bedeutung zugeschrieben, von einer „Dominansregel“ gesprochen. Das ist ganz verkehrt. Eine irgendwie allgemein gültige Dominansregel gibt es nicht, und sehr häufig ist eine Dominanz nur scheinbar. Es kann, darauf hat zuerst Correns hingewiesen, für unser Auge ein Bastard völlige Dominanz, etwa in der Blütenfarbe eines Elters zeigen, aber wenn wir die Farbe des Bastards kolorimetrisch untersuchen, dann sehen wir, daß er, im Grunde genommen, sich so verhält wie der 112 HALFDAN BRYN. M.-N. KL Bastard zwischen dem roten und dem elfenbeinfärbigen Antirrhinum, d. h. dafs die Färbung des Heterozygoten viel schwächer ist als die der Homo- zygoten, dafs also die völlige Dominanz nur eine scheinbare ist. Ob überhaupt völlige Dominanz häufig vorkommt, ist mir fraglich. Scheinbar völlige Dominanz beruht eben wohl oft nur auf unserem mangel- haften Unterscheidungsvermógen. Hat man durch langes Arbeiten mit einem bestimmten Versuchstier oder eine Versuchspflanze seinen Blick geschärft, dann wird man wohl meistens Unterschiede zwischen den Homozygoten und den Heterozygoten erkennen." Heterozygotene er i virkeligheten altid litt mindre pigmentert end den brunoiede av forældrene. Har til eks. den brunoiede av forældrene brune oine som svarer til MARTINS no. I, vil den homozygotiske part av avkommet ogsaa ha like brune oine, medens den heterozygote del av avkommet har eine som svarer til MARTIN 2 og 3 til eks. For undersokeren vil det da fortone sig som baade homozygoter og heterozygoter er like bruneiet, og man vil drage den slutning, at brune eine dominerer over blaa. Hos en mindre bruneiet race (som til eks. den norske), hvor den brun- oiede av forældrene har en eienfarve som svarer til MARTIN no. 6, vil ogsaa den homozygotiske del av avkommet faa denne oienfarve, medens heterozygotenes oienfarve svarer til Martin 7, 8 og 9. Ogsaa i dette til- fælde ligger det heterozygote avkoms oienfarve saa nar op til det homo- zygotes, at man vil si at ogsaa denne type av brune eine dominerer over de blaa. Der er altsaa blot en tilsynelatende dominans tilstede. I virkeligheten er forholdet det, at eienfarven ikke nedarves efter „Pisum- typen" men efter ,Zeatypen". Men forskjellen paa de heterozygotiske og de homozygotiske brunoiede er saa liten at den kun kan erkjendes gjennem lang øvelse eller en meget detaljert undersokelse. Naar en saadan sondring mellem mere og mindre sterkt pigmenterte oine ikke gjøres, vil nødvendigvis resultatet bli, at man tillægger de brune gine en dominans som de i virkeligheten ikke eier. Ti det maa jo fast- holdes, at virkelig dominans kun foreligger hvor heterozygotene har noiagtig samme utseende som den ene av forældrene (BAUER pag 70). Brune eine i egentlig forstand (Martins tavle r— 4) findes praktisk talt ikke inden denne befolkning. Man finder i heiden hos 1 av hundrede brune eine som svarer til Martins tavle 4 à s. Hos de fleste brunoiede svarer farven omtrent til MARTINS tavle no. 6—8. Det blir altsaa nærmest at regne for mørkt melerte øine. Naar jeg i denne undersøkelse har delt efter oienfarven i 2 grupper: lyse og mørke oine, saa vil den første gruppe omfatte alle blaa, graa og lyst melerte øine (Martins 8—16). Den anden gruppe, de mørke øine, vil hovedsagelig komme til at omfatte alle de mørkt melerte oine samt desuten de meget sparsomt forekommende rent brune eine. 1921. No. 20. TROMS FYLKES ANTROPOLOGI. RIS Hovedmassen av heterozygotene vil da selvfølgelig komme med i den forste gruppe. Den for den nordiske race genotypiske eienfarve er utvil- somt 6/aa. I distrikter hvor den nordiske race findes særlig ren, der er ogsaa de blaaoïedes antal meget stort. Alle graa, grønne og lyst melerte eine er resultater av krydsning. Men hvis denne min forutsætning er rigtig: at oienfarven nedarves Mendelsk efter Zeatypen og heterozygotene inden vor befolkning svarer til de graa, grønne og lyst melerte eine, da blir alt forstaaelig. Ti da vil jo tallene bli de samme som om blaa øine eide dominans over brune, 1:2:1 — blaaeiede homozygoter (1), lyst melerte heterozygoter (2), mørkt melerte homozygoter (1), idet vi, som jeg allerede har nævnt, ikke har virkelig bruneiede inden vor befolkning. Her vil forholdet mellem lyse eine og mørke eine bli som 3:1, eller de lyse oine eier en falsk, en tilsyne- latende dominans over de brune øine. I virkeligheten blir der heller ikke nogen uoverensstemmelse mellem det resultat som de foran refererte arvelighetsundersøkelser har git, og det resultat som denne bastardundersøkelse har git. Men den absolute dominans for de brune øine maa opgives. Ialfald mener jeg at man av denne under- søkelse kan dra den slutning, at: I. Oienfarven nedarves Mendelsk. 2. Heterozygotenes eine er svakere pigmentert end den bruneiede av forældrene. Hvis man deler vor befolkning i en lysoiet og en merkeiet befolkning, vil heterozygotene for en væsentlig del være at finde inden den lysoiede gruppe. Før jeg avslutter disse betragtninger, maa jeg endnu engang komme tilbake til de forutsætninger som ligger til grund for denne bastardunder- søkelse. Disse er følgende: 1. Den av mig undersøkte befolkning er opstaat ved krydsning av 3 forskjellige typer: en dolichomesocephal, en brachycephal og en hyper- brachycephal, i forholdet 66 : 30 : 4. 2. Krydsningen er foregaat i alt væsentlig overensstemmende med de Mendelske lover og saaledes, at hyperbrachycephali dominerer over brachy- cephali og dolichomesocephali, brachycephali dominerer over dolichomeso- cephali, leptoprosopi dominerer over euryprosopi. De brune og mørkt melerte eine eier ikke fuld dominans over blaa oine, idet heterozygotene har mellemfarvede øine. Hvis alt dette forholder sig saaledes, vil resultatet bli som fremstillet paa fig. 13 a. Nu er resultatet av min undersøkelse saaledes som fremstillet paa fig. 15 b. Uoverensstemmelsene er, som man vil se, ganske smaa og uvæsentlige og er hovedsagelig begrænset til den hyperbrachycephale gruppe. Jeg maa herav kunne dra den slutning, at mine forutsætninger 7 a/f væsentlig er rigtige. Uoverensstemmelsene kan ha flere aarsaker: Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. 20. 8 114 HALFDAN BRYN. M.-N. Kl. 1. Den relative størrelse av de 3 urtyper kan være noget anderledes end av mig forutsat. Resultatet tyder dog paa at min forutsætning i denne henseende ikke kan ligge saa særdeles langt fra det rigtige forhold. 2. Mine forutsætninger kan være feilagtige med hensyn til hvilke træk som er dominante og hvilke recessive. Jeg har, som det vil erindres, i denne avhandling gaat ut fra at index cephalicus er en enkel arvelig eiendommelighet. Om den beror paa et enkelt faktorpar eller flere faktorpar, om disse er like- værdige eller ikke, er spors- maal som jeg her har sat ut av betragtning av den simple ESAE au grund, at den her fremlagte FOR KRYDSNINGEN KRYDS= NINGEN. undersekelse ikke i ringeste maate kan bidra til losningen av dette vanskelige spersmaal. Det kan ogsaa i denne forbindelse være likegyldig om man har med ett eller flere faktorpar at gjøre. Det som er uomstetelig sikkert er, at index cephalicus er en overmaade arvefast eien- dommelighet. Hvad jeg gjennem denne undersokelse har villet for- soke at bringe paa det rene er, hvorledes dette arvefaste Fig. 15 a. Bastardenes fordeling efter den teoretiske beregning. træk forholder sig ved kryds- Le ning: Og da mener jeg, at denne undersokelse tyder paa at hvis man her har med flere faktorpar at gjøre, saa forholder dog disse sig ganske saaledes som om der var en enkelt faktor for brachycephali med dominans over en tilsvarende faktor for dolichomesocephali. Om hvorledes hyperbrachycephali forholder sig ved krydsning, fore- ligger der for tiden ingen undersekelse, og derom kan man heller ikke av denne undersokelse drage nogen slutninger. Hvis det skal være tillatt av denne undersøkelse at dra nogen slut- ning, saa maatte det for hyperbrachycephalenes vedkommende først og fremst være den, at den hyperbrachycephale gruppe muligens oprindelig har været litt større end av mig forutsat. (Den maa efter al sandsynlighet ha utgjort ca. 6%0 av urtypene.) En anden uoverensstemmelse angaar ogsaa den hyperbrachycephale gruppe. Min opfatning var at den oprindelig har været brunøiet. Som man vil se av fig. 15 a og b, kan dette ikke 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 115 holde stik. Den tredje forutsætning var at den oprindelig har været eury- prosopisk. Antallet av lyseiede, leptoprosope hyperbrachycephaler inden den nulevende befolkning er imidlertid saa stort, at man saa at si nodes til at gaa ut fra at den hyperbrachycephale type maa vaere indgaat i vor befolkning som delvis lysøiede leptoprosoper. I motsat fald skulde hyper- brachycephalenes bastarder ha været som paa fig. 15 a. De er altsaa som paa fig. r5 b. Den logiske slutning herav maa da bli den, at den hyperbrachycephale blok som indgaar i vor befolk- ning, ikke har vaeret ublandet euryprosopisk; den har ogsaa omfattet lepto- og mesopros- oper. Heller ikke kan den ha været rent brunoiet; den har ogsaa hat individer med * NORDISK ELEMENT = ALPINT LAPPOID lysere øine, blaa og melerte, saaledes som tilfældet er nu. NE Dette kan vel igjen forklares saaledes, at hyperbrachycepha- lien ved krydsning med andre racer har en sterre evne til at holde sig end ansigtsformen og oienfarven. Jeg kommer da til at DE SUPPONERTE URTYPER maatte gjere den forandring i min forutsætning, at den hyperbrachycephale blok sand- synligvis har været noget over 4 9/0, samt at denne blok ikke Fig. 15 b. Bastardenes fordeling som de er fundet av mig. har været euryprosopisk og bruneiet, men hat repræsen- tanter for alle 3 ansigtstyper og for alle nuancer av eienfarve. Dette med- ferer atter endel yderligere forandringer paa fig. 15 a. Gruppe H. B. har i henhold til hvad jeg her har fremholdt, ikke vaeret helt brunoiet og eury- prosop. Den kan altsaa ikke ved krydsningen ha tilfert den brachycephale og den dolichocephale gruppe saa mange brunoiede euryprosope individer som beregnet paa fig. 15 a. De leptoprosope og lyseiede grupper vil altsaa bli litt storre end beregnet, og uoverensstemmelsene mellem fig. 15 a og b vil bli endnu mindre end de er. Men de reservationer som jeg her har maattet ta med hensyn til mine forutsætningers rigtighet, er dog ganske smaa og uvæsentlige. I det hele og store tat mener jeg, at denne undersokelse av de nu eksisterende bastarder taler for at mine forutseetninger er rigtige, og at bastardene ogsaa er kommet i stand i alt væsentlig saaledes som av mig forutsat. ®=DE NU EKSISTEREHDE BASTARDEI I TROMS FYLKE. 116 HALFDAN BRYN. M.-N. Kl. Resumé. Av det i dette avsnit meddelte fremgaar følgende: i. Den i Troms fylke nu boende befolkning er sandsynligvis kommet i stand ved en krydsning av 3 genotypisk forskjellige folketyper: a. en dolichomesocephal, leptomesoprosopisk, blaaøiet blok, b. en brachycephal, euryprosopisk, brungiet blok, c. en hyperbrachycephal blok med meget stor variationsvidde for ansigtsindex og oienfarve. to Den relative størrelse av disse 3 blokker har ialfald tilnærmelsesvis været som 66: 30:4. Muligens har de to første været litt mindre end anført og den sidste litt større. 3. Ved krydsning nedarves de 3 her nævnte karaktertræk overensstem- mende med de Mendelske lover, saaledes at: a. hyperbrachycephali dominerer tilsyneladende over brachycephali og dolichocephali, b. brachycephali dominerer tilsyneladende over dolichomesocephali, e leptoprosopi dominerer tilsyneladende over euryprosopi, d. eienfarven nedarves overensstemmende med Zeatypen og saaledes, at heterozygotene har noget lysere eine end den brunaiede av forældrene. XII. De fremmede elementer. Jeg har i de foregaaende avsnit saavidt mulig søkt at holde den norske fastboende befolkning ut fra de mere tilfældige fremmede elementer. Der er nemlig ikke saa ganske liten bevægelse i befolkningen i Troms fylke. De fremmede elementer utgjøres hovedsagelig av lapper og kvæner. Saafremt den undersøkte mand har kunnet meddele at han var av lappoid eller kvænsk eller av - anden fremmed avstamning, har jeg selv- følgelig notert dette paa hans individualseddel. For 559 mænds vedkommende kunde ingen oplysning erholdes om fremmed herkomst. Jeg har allikevel i de foregaaende avsnit kunnet paa- vise at der ogsaa i denne "befolkning indgaar omtrent 34 %0 fremmede elementer; men herom vet de undersøkte altsaa intet selv. 103 av de undersokte var selv vidende om at de ikke var rent norske. Jeg skal i dette avsnit gi en ganske kort fremstilling av de væsent- ligste antropologiske eiendommeligheter hos disse. 1921. No. 20. TROMS FYLKES ANTROPOLOGI. ua 1. Lapper. Det er ikke min mening her at gi nogen uttommende skildring av lappenes antropologi. Dertil er mit.materiale altfor litet. Jeg vil her kun omtale de træk hos lappene som jeg foran har skildret hos den norske befolkning. Det er umulig av det her foreliggende materiale at gjere sig nogen mening om de norske lappers legemsheide. Alle de mindste lapper blir jo ved utskrivningen kassert som udygtige til militærtjeneste. Ved at gjen- nemgaa utskrivningslistene viste det sig at ikke mindre end 23 mænd med en heide under 155 cm. var kassert ved utskrivningen. Hvor mange av disse som var lapper, fremgaar ikke av utskrivningslistene. Men at ialfald størsteparten av disse var av lappisk herkomst, derom kan der neppe være tvil. Blandt de av mig undersokte lapper var gjennemsnitsheiden 164,1 cm.; regner jeg med at alle de ved utskrivningen kasserte var lapper, vil middel- heiden bli 158,1 cm. Blandt de av mig undersøkte var 18 meget smaa (under 164,1 cm.), 5 var 166—168 cm., 6 var 169—170 cm., og I var 171 cm. At ogsaa disse lappers forfædre gjennem generationer har krydset sig med nord- mænd, svensker, finner og andre hoivoksne folkeslag, er jo hævet over en- hver tvil. Det maa da forbause at ikke en eneste av disse er heiere end 171 cm. Den nordiske races gjennemsnitsheide ligger adskillig over 171 cm. Ved krydsningen skulde man jo vente at endel av lappene skulde ha faat den nordiske races legemshoide, likesaavel som de har faat den nordiske races haarfarve og eienfarve. Den almindelige opfatning er jo ogsaa den, at stor legemsheide dominerer over liten legemsheide. Ved krydsning mellem en lap og et individ av ren nordisk herkomst skulde da alt avkom faa den nordiske races legemsheide. Nu er det vel saa, at der ikke saa særdeles ofte indgaaes egteskap mellem rene lapper og rene norske. For lappenes vedkommende er vel forholdet det, at av og til en lappepike har faat et uegte barn med en norsk, svensk eller en anden person av nordisk race. Dette barn har saa fulgt sin mor og er blit lap. Men denne lappebastard vil efter al sand- synlighet komme til at gifte sig med en lap. Hvis det nu er saa, at stor legemsheide dominerer over liten legems- højde, saa skulde dog halvparten av de barn som resulterer av dette egteskap, faa den nordiske races heide. Og dette skulde vedblivende fort- sætte gjennem de følgende generationer. Man burde derfor, hvis forutsætningen om den store legemshøides dominans er rigtig, vente at finde ialfald endel lapper med stor legems- heide, likesom man finder endel lapper med blaa eine. Naar man nu ikke gjør det, saa synes det mig at den logiske slutning maa bli enten den, M.-N. Ki. BRYN. HALFDAN xapul -juaurstq Aulo SEEN auio asa] -OJUO. >d youn m 1} UD auto oun. 3un.qos.rout = = 3 = epu E U d + a © oulo oulo Ivey ee ION evIg Mop 7547 2j. SE'gg | 6g'* CEE 16'æL | gL't oS'€ "p ouniqosA] '£ oyro[|our jour 'z ouo ‘jou ISA] *I = QI C1 LI Y 8 £1 6 € pb t b I L 8 6 Y 6 Ci Ci 1p'£ La | 26‘'+ SE€'€ or‘E > ” un o 3 e S cupa Misses icem t sta a 8 o © m3 cA + B dq = L4 n -— vU Jour à [a DES a No ue u 5 eue ES D “ns =) ler oF mir EMA Q S 5 : n Qu. = gg A — CI @ a) auto SJ2POH vulg 30 BUI u ect S am | GE o © 8,09 fu =. om Io H ct (>) on [77] [o D cu a) DO OXSION x OUUrg ED DYSION xX — DA DEAR Jouul] x Jodde Fe ER oc ** jouurg 97 9.2/9, 1919191 9119 Lv Q9 19) plie odde Doe ero Ug d n CIC DHSION Zur mk OMSTON x TOUT OxSION x sos: TOUTE Jodden sie ee ee ee 2o n drei gos Rss pog 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 119 1) at stor legemshoide 7kke dominerer over liten legemshoide ved kryds- ning av lapper og norske, eller den 2) at heterozygotene har en inter- mediær heide. De heieste blandt disse lapper naar kun op til at bli —-avvikere av den nordiske races legemsheide. Nu foregaar jo, som allerede nævnt, krydsningen av lapper og norske saagodtsom udelukkende mellem kvinde- lige lapper og norske maend. Det kan jo vaere at dette spiller nogen rolle, at med andre ord den kvindelige part har en meget vasentlig ind- flydelse paa avkommets legemshoide. Herom foreligger der mig bekjendt ingen arvelighetsundersokelse. Men det her paapekte forhold peker ialfald i den retning. Hodets bredde er hos disse lapper meget stor (15,63 cm.) og hodets længde meget liten (18,54 cm.) Bredden svarer altsaa til 9,50 9/0 av legemshøiden og længden til 11,82 0,0. Hos nordmænd av samme hoide er hodets bredde og længde hen- holdsvis 15,22 og 19,20 cm. Hos nordmænd er hodets bredde gjennem- snitlig 8,91 9/0 og hodets længde 11,17 V/o av legemshøiden. Hodets pro- portioner er saaledes helt forrykket hos lappene. Hodets oreheide er hos lappene gjennemsnitlig 12,56 cm., hos nord- mænd 13,11 cm. Beregnet ad modum Welcker blir da lappekraniets kapacitet 1444 cm, mens nordmændenes blir 1468 cm. Noget materiale til sammenligning med andre folk har desværre ikke staat til min raadighet. Skal sammenligningen kunne foretages, maa jo beregningen være utført paa ensartet maate. Og der foreligger desværre kun sparsomme beregninger efter denne metode. Den gjennemsnitlige størrelse av index cephalicus var 84,29. Serien for index cephalicus ser saaledes ut: Bannere t Hiyperbrach....... D m 3. 30179937 MET: n I Braehyeeph.- .. .. Mesoceph =. At de laveste indexer her ikke er +-avvikere av den genotypiske hyperbrachycephale type, er vel sikkert nok. De markerer disse lapper som utpraegede bastarder. Der er blandt disse lapper bastarder baade med den brachycephale type og med den nordiske. Det er vel ikke usandsynlig at serien er sammensat saaledes som an- fort paa tabellens nederste linjer, 2: 15 genotypiske hyperbrachycephaler, 8 brachycephaler og 7 mesocephaler. [20 HALFDAN BRYN. M.-N. Kl. Jeg kommer nedenfor nærmere tilbake hertil. Faenotypisk er 8 av lappene mesocephaler, ro er brachycephaler, 11 hyperbrachycephaler, og ı er ultrabrachycephal. Fænotypiske dolichocephaler findes ikke blandt lappene. Man skulde dog ha ventet at der blandt lappene ogsaa kunde findes dolichocephaler. Ti blandt norske forældre har der vel været baade fænotypiske dolichocephaler og mesocephaler. Men det er vel hoist sand- synlig at den sterke hyperbrachycephali hos den ene av forældrene vil ha nogen virkning ogsaa paa den del av avkommet som blir avspaltet. At hyperbrachycephalien hos den ene av forældrene med andre ord vil gjøre at det dolicho-mesocephale avkom væsentlig vil bli mesocephalt. Jeg har heller aldrig hos andre undersøkere fundet dolichocephale lapper, men nok av mesocephale. Nogen anden plausibel forklaring herpaa end den anførte kan jeg vanskelig tænke mig. Som allerede nævnt var jo dette samme forhold mindst like saa uttalt for legemshoidens vedkom- mende. Aldrig finder man rigtig høie lapper. Det kan ikke være livs- kaarene som gjør at lappebastardene aldrig faar den nordiske races legems- hoide og hodeform. For legemsheidens vedkommende har man jo altid ogsaa gaat ut fra at stor legemshoide dominerer over liten legemsheide. Dette skulde jo føre til at der blev relativt mange høie lappebastarder. Og hvorfor skulde der ikke ogsaa blandt lappene like saa vel bli +-avvikere som ~-avvikere av den nordiske races gjennemsnitsheide. Jeg kan kun forklare mig dette saaledes, at det spiller en væsentlig rolle at den kvindelige part av forældre- parret er en lap. Det er kvindens evne til at holde fast ved det genotypiske som har gjort sig gjældende. Avkommet faar ganske vist fra den mandlige part av forældrene en faktor for stor legemshoide eller liten cephalindex. Men morens indflydelse gjør sig saa sterkt gjældende i motsat retning, virker saa sterkt svækkende paa den fra faren mottagne faktor at avkommet baade for legemshoidens og hodeindexens vedkommende blir avvikere av den anden type, og avvikelsen gaar 1 alle tilfelder i mortypens favor. Hvis nogen vil si at den her meddelte serie for cephalindex ikke viser tegn paa avspaltning av en anden genotype, vil jeg henvise til den av MANTEGAZZA meddelte serie for index cephalicus. Den har følgende utseende : 82.183, 04. .85. 80.87.1080. 00.100 OI. 92.293.904. G5 2M or. rig M OSes tks di: Se ee eter Son ie I denne serie findes ikke en eneste fænotypisk mesocephal. Disse lapper var dog aabenbart adskillig opblandet med den nordiske race. Det fremgaar av haarfarven og oienfarven hos de av ham undersokte lapper. Der var vistnok ikke mange blondhaarede og blaaoiede. Men et ganske stort antal hadde mellemfarve baade med hensyn til oine og haar. I9Q2I. No. 20. TROMS FYLKES ANTROPOLOGI. I2I Hvis det forholder sig saaledes som jeg har gaat ut fra 1 et fore- gaaende avsnit, at der ikke eksisterer nogen absolut dominans for brune eine og mørkt haar, men at heterozygotene kun utpræger sig med lysere haar og eine end den mørke forældrepart har, saa kan jo dette fuldt for- klare MawrEGAzzas fund. Isaafald kan man hos F,-generationen kun vente at finde mellemfarver. Og da der vel ogsaa blandt nordmænd og svenske kun er et faatal homozygotisk blonde, er det jo let forstaaelig, at der vil gaa en rum tid hen og kræves adskillige krydsninger fer man faar virkelig blonde lapper. Men MaNwrEGazzas serie for cephalindex synes at tyde paa at der for denne karakters vedkommende eksisterer en absolut dominans for hyper- brachycephali. Der maa mange generationers krydsninger til før man kan vente at finde dolicho-mesocephale lapper; ti ogsaa her foregaar kryds- ningen med folk som selv for en meget væsentlig del er heterozygoter. I den av mig optagne serie indgaar derfor utvilsomt et ganske be- tydelig nordisk element. I hans store serie har ingen lap en index under 82, og kun 9 %0 har index under 85. Lægger jeg denne maalestok paa den av mig leverte serie, saa maa mindst 23 9/0 være homozygoter av den dolicho-mesocephale type, 23 90 maa tilhøre den alpine race, og i heiden 50 %0 er dels homo- dels heterozygoter av den hyperbrachycephale genotype. Jeg kommer saaledes til det resultat, at selv disse lapper, som dog regnet sig selv for rene lapper, kun har omtrent 50 %o lappeblod i sine aarer. Men da man paa dette omraade endnu ikke har anledning til at regne med matematisk sikre tal, vil jeg noie mig med at si at de er meget sterkt opblandet med fremmede elementer. Ansigtsindex var hos de av mig undersøkte lapper 82,98. Hos de av MANTEGAZZA undersøkte lapper var den 82,34. I denne henseende har altsaa lappene undergaat endnu mindre forandring. Blandt de av mig undersøkte var der 4 (13,5 0/0) leptoprosoper, 7 (23 0/0) mesoprosoper og 19 (63,5 9/0) euryprosoper. | Med hensyn til ansigtsindex adskiller altsaa ikke lappene sig fra den vestlandske brachycephale type. Ogsaa hos dem er ansigtsindex 83. Hos de 4 leptoprosope var leptoprosopien kun litet uttalt (fra 88,2— 92,8). Underansigtet (n—gn) er overordentlig kort hos lappene, 11,67 cm., mens det er 12,4 cm. hos nordmænd. Der er betydelig mindre forskjel paa ansigtsbredden hos lappene og norske, henholdsvis 14,1 cm. og 13,9 cm. Index nasalis var 73,91. 30 9/0 var leptorhiner, 63,4 %0 mesorhiner og 6,6 9/0. chamzrhiner. MANTEGAZZA har desværre intet herom. Heller ikke har jeg fundet lappens næseindex angit hos andre forskere. 122 HALFDAN BRYN. M.-N. Kl. Den størrelse av næseindex som jeg har fundet hos disse lapper, svarer til hvad der er angit for ostjaker og kalmücker. 21 av disse hadde en retbygget næse, og g hadde konkav næse eller rettere sagt tupnæse. Oien- farven var hos 9 (30 V/o blaagraa, hos 15 (so %0) melert og hos 6 (20 9/0) brun. MANTEGAZZA fandt hos 20 (30 9/0) blaagraa, hos 19 (29 0/0) melerte og hos 27 (41 9/0) brune eine. De helt brune eine har altsaa avtat ganske betydelig i antal. For haarets vedkommende fandt jeg følgende: Tabel 62. MANTEGAZZA Antal 0/0 Antal 00 Eysebruntshaarer. er sn un YW S + ho o © Rø En are EC EC hoa E | Begge tabeller viser at de nulevende lapper er relativt lyshaarede. At MANTEGAZZA har saa mange blonde og lyshaarede, beror paa to ting. For det første at alle de av mig undersøkte er 21 og 22 aar gamle, mens MawrEGAZZas er av alle aldersklasser. Dernæst har MANTEGAZZA som italiener været langt snarere end jeg til at betegne et haar som lyst og langt strengere end jeg i sine for- dringer til sort haar. Det som her i landet kaldes sort haar, er MARTINS tavle no. 4, mens MANTEGAZZA med sort haar utvilsomt mener MARTINS tavle no. 27. Derfor gaar det ikke an at dra nogen sammenligning her. Derimot kan jeg nok sammenligne mit eget fund med hvad jeg har fundet andre steder i Norge. Og det er da vel værd at lægge merke til at disse lapper har /vsere haar end mænd av samme alder 1 Sondre Sondmor: Ulstein, Hero og Sando. Mongolfold (plica marginalis og epicantus) fandtes hos 13 (44 0/0) av dem. Jeg har før beskrevet deres utseende og paavist at mongolfold er genotypisk for lappene. Naar den findes hos den nordiske befolkning, be- viser dette kun en tidligere foregaat krydsning med lappene. Pandebredden maa nærmest karakteriseres som stor hos lappene, 11,14 cm. Men den er meget liten i forhold til lappenes store hodebredde og store ansigtsbredde. Pandebredden utgjor hos lappene 6,81 %0 av legemshoiden, hos nordmænd derimot kun 6,33 %0 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 123 Hvilke breddedimensioner man end tar for sig hos lappene, saa faar man det indtryk, at deres legeme har været under pres ovenfra nedad. Sidetrykket er derved øket og breddedimensionene har tiltat, men i for- skjellig grad. Baade pandebredde, ansigtsbredde og hodebredde er relativt store hos lappene. Men av disse 3 har dog pandebredden tiltat mindst i forhold til legemshoiden. Lappene har derfor ogsaa en meget liten transversal fronto-parietal- index, 71,15. De er stenometope. Blandt samtlige av mig undersokte var der 14,0 9/0 stenometope, 37,5 9/0 metriometope og 49,5 %0 eurymetope. Blandt lappene derimot er forholdet folgende: 50 9/0 stenometope, 20 0/0 metriometope og 30 0/0 eur ymetope. Dette er med andre ord et for lappene meget karakteristisk træk. _ Sammenholder man derimot pandebredden med ansigtsbredden, saa viser det sig at disse to dimensioner loper mere paralelt sammen. Til en større pandebredde svarer ogsaa en relativt større kindbredde. Forholdet mellem pandebredden og kindbredden er derfor omtrent ens hos nordmænd og lapper, en liten grand mindre (78,7) hos lappene end hos nordmæn- dene (79,2). Nordmænd Lapper Liten jugo-frontal index (7o—77)........ SAT 30,0 Middels »— ago) 19,1 43,5 Stor »— (IT 95) ERE 22,8 16,5 Indenfor vor befolkning har derfor den transversale fronto-parietale index betydelig større interesse end jugo-frontal-indexen. Man kan gjennem den første tydelig utskille 3 antropologisk forskjel- lige typer inden vor befolkning. 1. Den dolicho-mesocephale med hoi transversal parieto-frontal index, eurymetopisk, affinitetstal 1,94. 2. Den brachycephale, ogsaa med hei transversal parieto-frontal index, metriometopisk, affinitetstal 1,16. 3. Den hyperbrachycephale med liten transversal parieto-frontal index, stenometopisk, affinitetstal 1,61. [24 HALFDAN BRYN. M.-N. Kl. 2. Kvænene. De finlændere som bor i Troms fylke, er utvilsomt fra flere forskjel- lige finske lån. Men selv kalder de sig i almindelighet kvæner, og denne benævnelse brukes ogsaa i almindelighet av den norske befolkning paa alle finlændere. Derfor benytter jeg ogsaa i det følgende denne benævnelse paa alle finlændere. Blandt de 662 mænd som jeg undersøkte, var der kun 17 som mente at de var av ren finsk herkomst. Men jeg hadde ikke mindre end 26 som var av blandet norsk og finsk herkomst, og 8 som var av blandet finsk og lappisk herkomst. Jeg vil foreløbig holde mig til de 17 som mente at de var av ren finsk herkomst. Legemshøiden hos disse var 166,2 cm. WESTERLUND op- gir for de naturlige finske folkegrupper folgende legemshoider : Vestinner seere 168,6 shavastengs wer er 167,8 Kan eler d uot RENE 165,4 Kræ ner ae mE 164,4 Index cephalicus’ gjennemsnitlige størrelse var 82,06. Middeltallet for hodets storste lengde var 18,75. Bredden var gjennemsnitlig r5,4 cm. Hodet er altsaa samtidig litt kortere og litt bredere end nordmændenes. 1 var dolichocephal, 6 mesocephale og 1 hyperbrachycephal. Middeltallet for hodets orehoide var 13,06 cm., en liten grand mindre end hos nordmændene altsaa. Hjernekraniets kubikindhold beregnet ad modum WELCckER blir da 1432 cm.3, litt mindre altsaa end baade hos lapper og hos nordmænd. Ansigtsmaalene var for bredden 14,00 cm. og for højden 11,82 cm. Ansigt-index blir saaledes 84,29. Pandebredden er 11,10 cm., litt mindre end hos lappene, litt større end hos nordmeendene. Den transversale fronto-parietal-index er 72,08 og jugo-frontal-index 79,29. I begge disse henseender staar de den norske befolkning meget nær. Indre oienvinkel-bredde 3,26 cm., litt mindre end hos lappene, litt storre end hos nordmændene. Mongolfold fandtes hos 4 (23,5 9/0) altsaa meget sjeldnere end hos lappene. Ansigtet er relativt firkantet at se til, idet kjaevebredden er meget stor. Næsens heide er 4,92 cm. og bredden 3,35 cm. Index nasalis altsaa 67,35. De er mere leptorhine end nordmændene. De er meget lyse baade av haar og oine, men de naar dog i denne henseende paa langt nar op mot den indfødte norske befolkning. Med hensyn til oienfarve fandt jeg folgende: 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 125 Ne 40 Blaa og graa eine........ 41,4 %/o le PD 5 ; yse eine 64,9 /0 Lyst melerte eine ........ oe stall DE Merkt melerte eine ....... De Eysebrimereme «s. 0... E 5 mørke oine 35,1 %0 Mørkebrune eine (MARTIN 4) 5,9 , Blondt og redt haar ...... | T lyst haar 53,0 Mys eh mn El ha are 29,00, Morkebrunt haar... 2... 23,5 n 39 | mørkt haar 47,0 0 Brunsort og sort haar..... oc De r7 ,rene" kvæner skrev sig fra følgende herreder 6 fra Lyngen. 6 fra Kvænangen. lj fra Karlsoy. I fra Skjervey. 1 fra Tromsoysund. 1 fra Tromso. Paa 2 undtagelser nær skriver de sig altsaa alle sammen fra fylkets aller nordligste herreder. I sin beskrivelse av de finske folkestammer har dr. F. W. WESTER- LUND kun delvis anvendt de samme karaktertræk som jeg har benyttet. Han har saaledes brukt andre ansigtsmaal end jeg. Han har ogsaa en helt anden gruppe-inddeling end jeg. Det viser sig derfor her, som saa ofte ellers 1 antropologien, meget vanskelig at dra sammenligninger. I en- kelte henseender lar det sig dog gjøre. Han deler finlanderne i 4 naturlige folkegrupper, og jeg skal her an- fore de for hver av disse grupper eiendommelige træk. Tabel 62. Norske Vestfinner Tavaster Kareler Kvæner kvæner Legemshgide........ 5 57: ; 166,2 Index cephalieus..... 19,4 82,06 Eyserainer... #0... 83,0 64,9 0/0 Mørke oine ......... 17,0 35,1 0/0 D:ySbutia21520,5 5545. 2: 65,0 53,0 0/0 Mørkt haare 35,0 47,0 0/0 Jeg kan noie mig med at anfore disse 4 karaktertræk. 126 HALFDAN BRYN. M.-N. KI. Som det vil sees av denne tabel, staar de norske kvæner med hen- syn til legemshoide og cephalindex nærmest karelene, mens de med hensyn til haarfarve og oienfarve har mest tilfælles med de finske kvæner. De finske kvæner repræsenterer det mørke element i den finske be- folkning; de repræsenterer endvidere det brachycephale og lavvoksne ele- ment. De repræsenterer altsaa i alle disse henseender de samme eien- dommeligheter som den vestlandske brachycephale type gjør i Norge. Det er 1 WESTERLUNDS beskrivelse av dem vanskelig at se nogen- somhelst forskjel paa dem og den vestlandske brachycephal. Og likesom den alpine urtype i Nord-Norge har krydset sig med lap- pene, saa har ogsaa de finske kvæner krydset sig med de finske lapper. „Den relativt mörkare typen i norra Österbotten, Kvänerna, som i många antropologiska hånseenden intager en sjålfståndig plats, skild från karelarne, har vål af dessa trångts mot våster och norr, och dårunder mot- tagit intryck från de af dem sjålfa undantrångda lapparne, såsom vi redan tidigare, med anledning af kvånernas betydande brakycefali, framhållit", sier WESTERLUND |. Men som allerede for nævnt, de norske kvæner repræsenterer ikke nogen bestemt finsk type. De er for det forste absolut ikke 1 antropologisk henseende analoge med de finske kvæner. En hel masse av vore norske kvæner har helt igjennem træk som svarer til tavastenes. Og de finske kareler svarer jo stort set til den type som vi her i Norge kalder Vestlandstypen. Der er i somatisk henseende neppe nogen forskjel paa disse to typer. Begge to er vel ætlinger av den alpine race. 3. Bastardene. a. Norske >< lapper. 22 mænd opgav at den ene av forældrene var norsk, den anden lap. 18 av disse hadde norsk far og lappisk mor. 4 meddelte at faren var lap og moren norsk. Jeg har ikke fundet nogen grund til at skille denne sidste gruppe fra den første. I alle de tilfælder hvor faren var lap, var han av de fastboende sjølapper i Lyngen eller Kvænangen. Jeg kunde ikke hos de 4 opdage noget som skilte dem fra de andre 18. Fælles for alle disse 22 var at de hadde et utpræget mongolsk utseende. Gjennemgaaende var de mindre av vekst end den norske befolkning. Dette sammen med det brede ansigt, de fremstaaende kindben, den ringe avstand mellem øienlokene, de ofte skjæve eienspalter og den spinkle underkjæve gav dem et fremmedartet utseende. En neiere undersøkelse bragte dog for dagen at disse bastarder var mere | Fennia, 21,5 pag. 40. 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 127 nordiske end de saakaldte rene lapper. Dette fremgaar allerede av gjen- nemsnitstallene paa tabel 61. Deres middelheide var saaledes 166,8 cm., deres cephalindex 81,05, deres ansigtsindex 83,2, deres index nasalis 68,35, altsammen tal som ligger betydelig nærmere den norske befolknings middeltal end lappenes. Tabel 64. a. Serie for legemshoiden. Blandt alle Blandt Blandt undersokte lapper lapper X norske 0/0 | Antal | 0/0 Dome TS Se ee BH5—Sn60... 2.00... 4,5 uen [rp e 41,0 HOO TO ee - ee 22,7 un DS es ces ee 22,7 MO —=e 8X0 ic ce le SEDs 9,0 TOR OS. ce eee es ce I86—I90...2--2 e b. Blandt alle Blandt Blandt undersokte lapper lapper ^ norske 0/0 ER 688 seis a ey ays, alia 4,55 Boys SEES ENE ER 31,50 Me FR OU 55,00 e SS DESI BE. 9,00 For legemsheidens vedkommende vil jeg, idet jeg henviser til tabel 64, særlig bemerke følgende: Av de 22 var der kun én som var under 160 cm. hei. Og der var kun 2 som var over 175 cm. Der er altsaa blandt disse bastarder langt færre smaa end blandt lappene og langt færre høie end blandt den norske befolkning. Mellemklassen var derimot godt besat, og særlig godt besat var heidegruppen 161—165. Dette støtter ialfald den opfatning, at heterozygotene har en inter- mediær heide. Ganske likedan er forholdet med index cephalicus. Av de 128 HALFDAN BRYN. M.-N. KL 22 var der kun 2 som hadde en index 86 eller derover, og der var kun r som hadde en index under 76. 55 9/0 hadde derimot en index mellem 81-83; blandt lappene talte denne gruppe kun 33,4 9/0 og blandt nordmændene 38,9 0/0. Det ser herav ut som index cephalicus blir mer og mer intermediær jo hyppigere kryds- ningen gjentages. Gaar jeg derefter over til ansigtsindex, gjentar ogsaa her det samme forhold sig. Blandt samtlige undersokte fandt jeg 36,8 9/0 euryprosope, 32,6 %0 mesoprosope og 30,6 0/0 leptoprosope. Blandt lappene var tallene hen- holdsvis 63,5, 23,0 og 13,5. Blandt disse bastarder var tallene 50,0, 27 og 23. De ligger altsaa saa præcist midt mellem forholdstallene hos de „rene“ lapper og de ,rene” norske som det vel er mulig. Ansigtsindex synes derfor ogsaa at bli intermediær ved hyppig gjentat krydsning. Anderledes med næseindex. Av den norske befolkning er 57 %0 leptorhiner og 43 9/0 meso- chamærhiner. Blandt lappene fandtes 30 %0 leptorhiner og 70 °/0 mesochameerhiner. Av de 22 bastarder var 14 (63 9/0) leptorhine og 8 (37 %0) meso- chamærhine. Dette synes mig at tale for at leptorhini fuldstændig dominerer over mesochamærhini. Med hensyn til bastardenes oienfarve og haarfarve er intet av interesse at meddele. De staar baade med hensyn til haarfarve og oienfarve nær- mere til lappene end til de norske. Hos 5 (23 9/0) av disse bastarder fandtes en meget tydelig mongolfold. Gjennemgaaende maa man veere berettiget til at si, at disse bastarder mellem norske og lapper i somatisk henseende indtar et mellemstandpunkt mellem de to typer hvortil forældrene hører. b. Norske X kvæner. Av saadanne bastarder har jeg 1 alt 26. Av tabel'61 fremgaar, at deres middeltal for legemshøide og cephalindex ligger midt imellem hvad jeg har fundet hos norske og hos kvæner. Bastardenes ansigtsindex svarer derimot neiagtig til hvad den er hos den mest bredansigtede av forældrene, nemlig 84,4. Av bastardene var 1 dolichocephal, 17 mesocephale, 5 brachycephale og 2 hyperbrachycephale. Der er altsaa blandt bastardene et betydelig større antal -mesocephale end blandt dem som regnet sig for rene kvæner. En nærmere undersøkelse av disse bastarder frembyr litet av interesse av den grund, at forældreparrene utvilsomt selv for en meget stor del har været meget litet racerene. 129 S ANTROPOLOGI. TROMS FYLKE 1921. 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CCE DS a | & cmo : 5 uaru SPPA.LIOH Dm BS) © 3 od | 023! $3 (=e 3| 95 =. 3 zB EE ime Bra i MM EE RM a3 NES à. SO Lm 1o ls Sal &à le — dl ga sn Su] oa |SPol zu AD Tal Bu om sm 0 Saal se WS la28| 5 Ie Pe! Ag RB mS gs | e. B] B.ES| SES [e Se Ses CI BUE aloe m Den ez LE EL Es B E GO) ics Q. E 4 EE ® c ere PE = E Es E NÉE S à Fler S D = CE a = i E o E = LIÉ = -_ en == = = ES = - BE 08 ET o 09| oa |^ = di og dq dq dq de | ER ® gq [T dq qa qa a D A - ? D oc | 61 | g1 | L1 | 91 | ST | PI | ET | 21 | II OI | 6 | 8 | L | 9 | S | t | £ | c 1 a No. 20. 1921. dk Vid.-Selsk. Skrifter. I. M.-N. 130 HALFDAN BRYN. M.-N. KL XIIL De enkelte herreders antropologi. 1. Gruppekarakteristik. Naar jeg nu til slutning skal gi en fremstilling av de enkelte herreders antropologi, kan jeg fatte mig i stor korthet. Det falder da naturlig at samle flere eller færre herreder hvor for- holdene i antropologisk henseende er ensartet, i større grupper. Den første av disse vil jeg kalde Bardu-gruppen. Den bestaar av følgende herreder: Bardu, Maalselv, Balsfjord, Malangen, Dyrøy, Lenvik, Sørreisa og Hillesøy. Fra de to sidstnævnte distrikter er mit materiale vistnok meget sparsomt. Jeg kan derfor intet sikkert si om disse to her- reders antropologi. Men jeg tror dog nærmest at de hører hjemme under denne gruppe. Hele denne gruppe har faat sit antropologiske præg derigjennem, at dens befolkning for en meget væsentlig del nedstammer fra de indflyttede Østerdøler og tildels Gudbrandsdøler. Likesom Østerdølene er ogsaa befolk- ningen i disse bygder meget hoivoksen (omkring 172 cm.), lysoiet og lys- haaret, har en relativ lav cephalindex (mellem 79 og 80) samt en høi ansigtsindex (omkring 88). Næsen er som regel meget smal og retbygget, og avstanden mellem de indre oienvinkler er mindre end i de øvrige her- reder. Paa tabel 66 har jeg anført størrelsen av de forskjellige karakte- ristiske typer. Ved beregningen av disses størrelse har jeg benyttet de i denne avhandlings specialavsnit optrukne typegrænser. Det er den samme inddeling som blev anvendt paa tabel 51 (fig. 13). Det fremgaar av tabel 66 at den rent nordiske type er overordentlig utbredt i disse herreder. Den utgjor 38,4 %0 av samtlige undersekte. Til sammenligning henvises til gruppe 5, hvor den nordiske type kun utgjør 22,0 0/0. Tilsammen utgjør de 5 første typer, som jo i det hele tat har et sterkt nordisk præg, 85/0 i disse herreder. Bemerkningsværdig er det ogsaa, at de bastardtyper som jeg har benævnt homo alpinus, er yderst sjeldne i disse herreder (1,8 9/0). Bastardtype 9 og 12 (homo palæoarcticus) mangler helt. Den anden gruppe omfatter en række øer og fjorddistrikter: Kvæ- fjord, Trondenes, Bjarkøy, Ibestad, Tranøy, Lavangen og Salangen. I disse herreder er befolkningen litt lavere av vekst, ca. 171 cm., litt mere brachycephal, litt mørkere av haar og øine end i foregaaende gruppe. Den rent nordiske type utgjor ogsaa her ca. 34%0 av samtlige undersokte. Til den tredje gruppe hører Tromsø, Tromsøysund, Berg og Torsken. Her er befolkningen endnu lavere av vekst, 169 à 170 cm., endnu mere brachycephal, samt mørkere av haar og øine end i de foregaaende grupper. Den rent nordiske type utgjør kun 269/o. Den 4de gruppe omfatter Skjervøy, Helgøy og Karlsoy med en meget lavvoksen befolkning, ca. 168 cm., meget morkhaaret og morkoiet. Den nordiske type er mindsket til 25,3 %o. 131 TROMS FYLKES ANTROPOLOGI. 1921. No. 20. 'snonoaeoa qud OUIOFLT OULD O3.10]J eI 'snoruoddv[. oworf JUIØ ISA” idosoad Ain 11 'snurdpe ‘A snoruoddyy owoyy OUIO OX.IO]A tt O1 'snorp.rou "A snoruodcdv[ oo} outo osÁ'] idosoadosouiogdo7q ipeudoo &qov.rq.iod Arq 6 ‘snuidje oworf 2s bo gt g'1 OUIO OYAO IA, ee i 8 'snpyjed ‘A snurdpe outo[] e'ıı ofS] 9'6 SL oulo ISA idosoad &anz^ L 'snorp.rou-ourd[e. OWoH er, alg 6'E e£ OULD O3.10]N 9 'snoeudoo&qoeaq "A snorpou. owo o'og ous ISA] ıdoso.1dossuoydo7] € 'snogeudoooqorop ‘A snurde outo[q Se 9‘o OUIO OION i b 'snordosoadA&ano "A snotpiou owojj ‘6 outo ISA idoso.d Many £ 'snosnj "A SN)IPDIOU Outo[] ES OUIO 92.1OJA 2d z 'snorp.ou OWoH ouo ISA idosordosouwoydo"] quydososowouyoroq I "JU uoneu -IQuo 81 dig £ oddn.te) "durpugqAg ouuop I od ÁA1uorg OSPUABUOG suouornrutquio»p.mgsue , od Ays}31suy ad Ajopoyy oddnar) | oddn.ary MM——9000RFPPEPtPecBRVrerr————————————————————————————————————————————————————————————————áÓ— 'piofjrogG *uoSuA] *esroipaoN ‘uosueuwas +S oddnair) '"Aospimw. *Kospp *AoAaobps :+ oddnair) ‘U9MSIOT, ‘dog 'punsAosuro.g[ 'osurog] :£ oddnir) "uoguv|eG 'uoduvAv ‘Aouvit, 'pujsoq] ‘Aoyivle 'souopuoap pioljæas se oddnir) 'Aoso]npp 'Ao4A(qp aus srouaoc 'uosuv[epy ‘paoljspeeg *Apospeepy paeep : 1 oddnas IH I Al I I S IPN progs'egq AJOSICEN np.ree E) oyyrysp osnpb[stoy op uopur zængdo aopaejseq osipb[si0] op pourioAtQ joysiddÅy usp SIA ‘99 [oqv [ 132 HALFDAN BRYN. M.-N. Kl. Den ste og sidste distriktsgruppe omfatter Kvænangen, Nordreisa, À D 5 5 Lyngen og Sorfjord. MS) B Her finder man den laveste befolkning og samtidig den sterkest brachycephale befolkning i hele Troms fylke. Paa fig. 16 —20 har jeg illustrert disse distrikters antropologi. Meget tydelig fremgaar det av disse figurer hvorledes type 1, 3 og 5 mindsker jevnt og sikkert i størrelse fra gruppe 1 til gruppe 5. Type 4, Fig. 16. Bastarder i distriktsgruppe r. Fig. 17. Bastarder 1 distriktsgruppe 2. (Tabel 66.) (Tabel 66.) som næsten ikke findes i ,Dardu"-bygdene, er blit ganske stor i sidste distriktsgruppe. Men det fremgaar ogsaa av disse figurer og tabellen, at bastarderingen er ikke mere broget end at linjene er ganske klare naar man blot har saapas som roo mand til behandling. Man ser hvorledes hver enkelt bastard- type enten okes eller mindskes, alt eftersom man gaar den ene eller den anden vei. Linjene er overalt klare. Disse figurer gir os et helt klart billede av folketypene 1 disse distrikter. 2. Individualtabeller. Det værdifuldeste antropologiske billede av de enkelte herreders an- tropologi har man dog i individualtabellene. Derfor medtar jeg her disse. Fra Norge er der hittil kun offentliggjort meget litet av saadanne. Det er 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 133 væsentlig forfatternes bearbeidelse av individualtabellene som er offentlig- gjort. Og hver forfatter og hver tidsperiode har sin egen metode, som snart gaar i glemmeboken. Meget av det arbeide som er nedlagt paa det antropologiske omraade, blir derfor efter kortere eller længere tid noksaa værdiløst. Men for efterslegten vil det utvilsomt være av stor interesse at ha de enkelte individers nøiagtige maal til sammenligning. Disse tabeller behøver kun i et par henseender litt nærmere for- klaring. Alle enkelte maal er tat helt overensstemmende med nu gjældende Fig. 18. Bastarder i distrikts- Fig. 19. Bastarder i distrikts- Fig. 20. Bastarder i distrikts- gruppe 3. (Tabel 66). gruppe 4. (Tabel 66). gruppe 5. (Tabel 66). regler, og saaledes som det nærmere findes beskrevet i professor RUDOLF Martins store haandbok. Betydningen av de tal som er anført under rubrikkene oienfarve og haarfarve, findes angit ved indledningen av hvert av disse avsnit. Længst tilhoire findes en rubrik som har til oversigt „formel“. Bokstavene eller tabellene her angir til hvilken type individet horer med hensyn til de 6 vigtigste træk: 1) legemshoide, 2) index cephalicus, 3) index facialis mor- phologicus, 4) index nasalis, 5) oienfarve, 6) haarfarve. Legemshoiden be- tegnes med tal, saaledes at I betyr meget smaa 145165 cm: 2 betyr smaa ROO 100" — 3 betyr middels 209- Ug == 4 betyr høie 77-206 134 HALFDAN BRYN. M.-N. Kl. Derefter kommer et bokstav som angir hodetypen saaledes: D betyr index cephalicus 07-75: M betyr index cephalicus 10==80; B betyr index cephalicus 81-85, H D betyr index cephalicus 9695; Saa kommer et bokstav som angir ansigtstypen saaledes: E betyr index facialis morpholog. 70— 83. M betyr index facialis morpholog. 84— 87. L betyr index facialis morpholog. | 88— t 1o. Derefter kommer et bokstav som angir til hvilken neesetype individet hører, saaledes: L betyr index nasalis Ai, 69: Ch betyr index nasalis "70-120: Derefter kommer et litet bokstav som angir pigmenteringsgraden saa- ledes: ] betyr at baade eine og haar er lysfarvet, m betyr at baade eine og haar er mørke, x betyr at der er motsaetningsforhold tilstede med hensyn til oinenes og haarets farve. Hvis oinene er lyse, er haaret mørkt, og omvendt. GÅ ae g'19 a'Lg QiSo She £ I of'E bor gts bE 681 L'g1 g'S1 691 'N be E. 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Kl. BRYN. HALFDAN IW NN SCT SIS IN xy I xy ^ iQ nn JO = uw INN X Q5 N 4 9poH 3ptoH ISBN ISUV Ju udg [eu ^4 61 ett + +t + + - a itc s^ MTM rr mi Ot ~ > UC nm mo + mın ” Y; - o 1 ” 0) — Lot Fl ha ^ $6 qo row o SONETTER OOS C= NO NO) NOM) Fb KO H T "a To re) = [o He by = — os So 5 3 ct je] om » A ES = © 7 p Ar = E = u EB PUEISABTONUIA > app2qIpPUr a w À + 10 Le) H+ONTO0rO nn + 10 9pIoqQ SUISÆN = oO ‘(‘suoy) Lo [aqey c= wu) Q t «x Qos Orc Errem om C C AN m m m co nm — eee o'ti o'ti g'£1 ori z'S1 ‘ti DEC BG [5e o‘pi Ci ofti De Ci 6'€1 v'E 1 6:ET Stem CET o'tr SV oftr Ci 2PP214SJ8ISUY r- aploys}sisuy Sgı PVT 8:08 | LIST g‘g1 Lx 9'61 9'Sı L'61 6'°S1 261 EET 6'g1 eS s'gı L*Y1 o'6I Steyr Shy gti L'gi | o'gI z'61 o'€1 E'gI oS toa 9‘Sı g'61 SST 9'61 e'S1 z‘61 e'Gr 1‘Q1 o‘Ci g'gı Er 9‘61 ‘OI 6°L1 EST c'ór S‘Sı 1'g1 SS gn | om JE ES 23 | ao ov Pu @ gli "N ££c £L1 'N cte CLI "N 16% gli "N of 9L1 'N 625 6Lı "N gcc 9L1 'N ee £91 "N ele oor [lNx' Sac pli "N oS ILT "N zz 'puzur gg ‘AgiÂG eL1 ó ToS EQI "N 155 'puaui 7 'esioJ10S oli "N 025 891 "N 615 691 "N gla 891 °N Liz ıLı "N 91c 691 "N Cis oL1 'N bia 891 "N £reg ıLı "N SIG SLı "N Tis 3 jan E 5 3 20 ea Ey 2. à c a (9 I q 143 N WO PREY — — -— Al => 9 ) \ TROMS FYLKES ANTROPOLOGI. 1921. No. 20. qe LSogr 79:55 of 6:69 | Eıg ¢ I % 6*01 LÆS o'E Seen S'ET z‘61 of€1 991 'N | 992 aq F "Etre 9*£9 6'gg Lek £'1g t € TSG Lfri SEG SE PFI g'ci 8'61 1*91 oli "N Coa qe z'zg Czg tbe eL E'Cg € Z IE nen gr o'E SET Peder E'giI 9‘Cr Loi "N +oz Wt c'rg g'z9 $99 z'gl aol I I OLE STI DEG CAS) ger zíz1 £*6r L'v1 Ler N £oz "puæw gg *xrauaT q e LCL o‘SL 9'08 £'Lo | o‘gg € t e£ 6°01 ++ EIE PFI 9‘11 P'gI z‘oI gor "N 295 q e VLL fe £*og £*69 | o‘og t I EME 9°01 et SEE L*£1 o‘11 g‘Li EfCr tor "N 195 W 2 L'eg 1*9L C‘og EL I'LL t 1 (SUIS o‘11 oft SEE GET Sr z'6I g'tI 991 "N 095 I: 9*og SL 6'bg L*gL gol € z T'E d'TI LSp HE GET g'rr 0:61 Cha: ocr "N 6°5 W I g'tL Sq | #06 L'69 | o'gL t € g'c 1*01 Ses HE SE cal 9'gI Spi S91 N gSc qe £‘oL SPL g'Lg 8'g9 619g € I SEG 9°01 L+ Sie 6'£1 cal gig LAS 991 N LSz q e L'QL of'gL AA 6'oL +18 S e£ CE SAT oS g'E o'tı o'zı r°61 g'S1 QQI "N o£z q + PILL E'gl cíeg z‘oL o'Eg 1 I pe TI 9‘+ 9'€ CHA o'zı +61 1'91 9L1 'N Ga q #? o‘1g CH o‘Lge g'69 G(Co E t CS TOT r8 off L'£1 ofz1 991 6*€1 tLı N tSc 'pugur 6 '*uaxsJo] (a 2 o'og ‘69 | ofgL SSL ce'*g v S as ol 6't HE o'i o'11 r'gı ST gol "N £€c qi! tgl E'6S £‘og L‘zl of'CL € I i XS, 6*01 FS Ze 6‘£1 o'z1 o‘oz o‘Sı £or "N Ss N + g‘oL L'og | g'26 I'eL o‘6L t t gic g‘oi gS r'€ g'£1 g‘z1 9'gI Lx 6L1 "N 1Se N + £‘og z‘69 | 9'Sg z‘LL z’gl € I FE oat 2s OE ofS) o'£1 zor g'SI 6L1 'N ofc q Lrg 9‘+S €'96 069 z‘Sg Y I o‘E L*o1 SS o‘E e'€1 o'£1 s'gı Seca 091 "N 6tc W i Fol o'aL 6‘18 Sol 9*6L t c nds o‘11 ofS oe FFI giri 9'61 o‘C1 Fol "N etz a + o'gL 0'09 z'E6 L‘Lo z'Lg © I FE Tom SS €'€ CHA 9‘£1 g'gı t*o1 LLi "N Lrz q + g‘LL of99 | Erg | 069 | o'eg S LZ ae SEIT ofS BI #1 Lx C61 1'gI SL1 'N 9tc 'pugur g ‘8194 W + CCL o‘oL 1:26 o‘oL ELL b I oft Sor ofS CE 6‘£1 g'zı +‘61 o'€1 ıLı "N Stc MS 6'og | o'oo ‘Lg E'pL SEGL € € off o'r! ofS off 9*£1 6'TI 9'61 gi oL1 'N the W © 8g'gL 0'99 6'06 LfxL bel Y e off For ofS ats e'£1 Tor fer Cp oli "N. £te N © E'6L 6'gg r‘Lg gel g'og I I CH L‘oi + oft SEJ g'ir z'gı L'px oL1 "N etc CRE ‘19 969 6°Ce g'€L 619 € I LA o‘11 oth oe GET 911 cgi 6*1 601 "N Ita q v Levey 10:89) 79:06 || etr o'SL I I gic L‘or BS PE DS 6'11 z'ô1 bh eL1 'N otc Sn z‘6L +‘So £‘o6 EST L sig + S bE Pala as vs bh o'£1 €*61 6'ST SLi "N 68 ap bå: Stel o'*SL g'ig GEL 8'Sg € I 9'€ 9'r1 gt robo gti [or £'g1 L‘'Sı 191 "N gta (ap at o'eg | 9°89 21g | o'£L L‘tg I ] pE v'r1 gt ESO g'eı e'I1 eig SGT 991 "N LEz q + b'æg Sfg t'eg aol t'og € I EIE SSI g'S CE gti oS LATE 6*€ 1 SLI "N otc W * 9'08 009 S'g6 r'oL o'LL I I EE Q*or SES BLE r:£1 CALE: o‘oz pci CLI "N S£c W + £‘og L'g9 L'gg o‘oL o‘6L t I Le a PS gE or 9'z1 0*61 ofCT LLi "N res M.-N. Kl. BRYN. HALFDAN 144 ————— = — SÉ UNUM UUIUISUURHE ur "roy Ww aol ESQ ool o‘£L 9'rg r I or e'£ 1'81 ost lom be a s a‘ol L'oo bog bol S‘6L I I LÆS 9'£ L'v1 SI X TWH ! 618g L'oo 1'098 LVL g‘6L ! € LÆS 9'€ bhi SI (ee aes ON r'ag ‘609 P10 BEL 1'zg ie ] etg 9'€ o'ti Q'er IDwa À 3'6L ool o‘Le ool o'PL { I ofS ge v'v1 9‘z1 Sys) oo t g‘ol L'gL 1*€g oil £'eg i 1 LS De oF girl hw a q.s o'cg PTE 9'ag s'6L PSL I I er cts Q'£1 r‘ıı Iu Ww t S'el L'Sg z'Cg 9'1L 9'‘6L € c e OE SET STA Il Taq es t'eg L'oo g'Eg g'ıl 6'Eg e I gt AAS 9'£I rrr wud Wa t t'eg 9'SL e'Sg CFL e'Lg t t Cth FE orl TGI I TNN ! ool 1‘19 o'og eh o'6L c Z 1283 Cu VÆGT Q'TI l rc a Ne 60g e'€9 L'6g 6'1L SLE I I 9't off ‘OE 1 SSI fo ch oct. Pr o'gl +‘Co Q'16 L'eL b'6L € I as ve ori of€1 SET TAT TALE g'ol £:€9 r'tg z'ol CL rt I 6't e'€ gel 9'r1 Mon. nen o'gl o'og £'6g9 SSL 6'rL S I o'€ o'r o'bI Sem [UD WN I o'og gi LL L'og o'&L SEE € I Scy SE SET LET ee, £'1g 9'69 Ca orl PEL E e ott oe VET a uns ON v t‘ıg e'rh £‘r6 mee 9'6L S E e LSE o'tı c'£1 ur a 7 a # 60g £'e9 c'c6 o‘CL CPL ig < Es Ets ı°bı o'*£1 I C'og g'EL g'SL S S LY Pac SLET 9 ‘SQ L'69 £*og t I [0157 2.5 o'tı IST g'Eg bel o'6L 1 I oF EE g't1 ber 6‘og Pol L'gL t I g't g'E CAST £'e1 6'89 I'eL 61g t 1 git Vie SKET o'c1 e'Sg 6*Lo L'eg Y I 6't ge Spi I'dI ofS 9'€ CET GSI ; j gr BEG CHA ‘SI BZ Ss RE; 3 B w 09 8 | 6 = 2 ® SEG dy P qm cuo > B: Eno ©. 5 o 8 (pa de - Ais NI SEC GE 2 eg CE B En a zm o à 3 S S e. S u =o [210 4 = 2 B: À = re Le Se ($10) L9 [9qe] AN AD A NAN are ARE EN AN A A = Ke} = SjopoH 2pPIOUSW9S9"T jsutox.I9Tq ise) q H 145 mM + M M +H In q \ N a ' eq + ' — EB Mo bd AA H nn ' ' Rl SoSe Se SP Se Sar yore} TROMS FYLKES ANTROPOLOGI. + HM MM nm IN SE MM IN +H 4 = r 1021. No: 20. + 1 = eI oth SAS, PT girl 6'gI g'Si 191 [NX | 92€ L‘o1 gt 9'€ 9'£1 ‘aI s'61 e'S1 991 'N Sct IT LÆS CE LA 2: PET toe | g'Si CLI "N VER ue puzw pg (piofjspeg ~ O'ZI Sc ee gir g'e1 toe | z'o1 rL1 'N £ct O11 ofS E56 9'£1 ezı zoe | 6'S1 gol "N cct 901 ofS PE oft 1 CAE L‘61 SI SLI |Nox«'s| Des sry gr 9€ pipi o'z1 g'61 g'ST 691 "N ozE SII ofS CE EVI L*xx S'61 LSST ıLı "N 61€ OTI or ge bh o'c1 o‘g1 PCy ıLı NT gıe 6:01 CAN g'E Sen I'21 L'g1 LAS ıLı "N LIE tor gt z'£ Cr o'zı 9'61 oti g91 "N 91€ £«01 ott ESS o'ti 6‘11 €*61 o‘Cr 691 "N cre Ort off oe o'r O11 9'gI e'S1 IL1 'N Là 4 OfII CAS re FET S'g1 1‘61 a'ST ELI N S18 c1 os zs o't1 o'z1 t'6r1 L*v1 £91 "N Tie tari ofS p'E SET c'c1 6'gI g'tr 991 'N 11€ 901 ofS gt 9'€1 9‘z1 1‘61 r‘Sı 991 N o1€ [o] 6:01 PS LIE 9'£1 d'€I g‘oz 0'91 ogi N 60€ à sc as ot EI c'£1 t'61 LAC: SLı "N got 2 Péri off ce OFT CST 6'61 z'C1 6Lı "N LOE . IST I off CE PPI g'zı o‘oz | O91 goLı |'N x 'S| 90€ a 6:01 oft c*€ ott 1 (ST 9'61 z'S1 9L1 'N Sof 2 Q'oT ofS git o*t1 9*11 1‘0Z e(S1 tLı "N tot — 901 e CE o't1 gai o'6I PCr Lol "N £o£ : OTI LARS LAS e'v1 ‘SI 9'g1 z'S1 Cor "N cot 4 L*o1 Sp Se g'E1 o‘11 S'g1 o'CI 091 "N 106 = "pueur ep 'A[es|eew ^" L boy ESS ge fer PET +61 SES 6L1 'N 00€ E 8'o1 LA PE o*t 1 o'zı gig oS ELI "N 665% 1.077 ot ec otı £'II ber obi 6S1 |"[x'M| g6e n bor bib z‘E o'E1 gol r'61 USE 6°1 "N L6s % o‘11 gr LIE PPI SSI 961 g'S1 991 'N 965 2 -puæu g ‘ÂOSAIIH + L‘oi Lp EE 961 £'ri c'61 otc] IL1 'N S6c = 9f11 e'S a eSI ger 6'61 | £'or | cL1 | "N r65 ———— ——————— @ . M.-N. HALFDAN BRYN. 146 Ia) TN 8 L°6L bL S66 | €'6L LILL I I a ort 6‘+ HS g'£t "N ESE Du VISITS GEL g'oL 1‘L6 1*L9 ce I I e(t aor gr bE g'eı "N SSE Iu A W t 6'LL c'oL ó'eg sel 6'gL 1 rz SE 6*01 Lp ge oF i "N 1SE xem ab e e AL t'ig oto g't6 LL o'6L t I as 6'ol ofS c(t per "N oSE I TT TT KN ! £'1g boo 1°99 LL L‘og € I eie 6°01 6th PE Ate "N 6re [UD NN = o‘LL o'SL ó'tg gical ool € c ge L‘oı gt oft 6'1 "N gre ron = Wh g‘ol o'ol L'6g ofEL 9'‘LL [5 e ge STI ofS S:E Spa "N LYE Xe m TAL rig gts zoo gol z'gl + I cae CHE: (SÅS oft £'v1 'N ore NO Ee SAB eng s'gl g' rS t*16 ELL z'gl b c SSE OI ‘9 LAS TEST "N Cre > Mia] CAES Peer CES à £‘og g‘19 <‘16 1 EL 6‘oL t c DSE y‘ıı SS LÆS roa "N rr& CUS Www t sol Eigl e'Lg | g'€L o'gL e I oe +'or 9't ge EET "N Ere Xu) NN 3 z'ıg o‘zg SÅS ‘al £‘og + I r£ STI o't git g'£1 "N ove SET TON CE £L 0'909 6'gg c'go €*6L € ts ot L'or ofS bE y*v1 "N ive 10 NP £‘eL CFL z'eg £'eL 6*6L I 1 1*€ SII Lt** SEE Er "N ove [ao nw 6'EL ELS £‘og | 9'89 1'og € c o'E C‘or oth gic CA "N 6t€ Iu5 3 W + o‘oL t*og L‘gL CORE o'gL I I LÆS STET ytv g'E o'ST1 'N gee DESI NS qe: Fol o'og t'Sg | 9'69 c'£g € c ake o‘11 9S gia PFI "N LEE SUT AN = t'gL IIı o'Eg 9'go 6'gL F I SE S*or Sp c£ Tats "N Otte Tyson Ou EFL of FL o'tg 6'oL Szg € I IC L‘ol ofS LSE VI "N SEE Duy mW F tgl o'zL 6'tg +69 o'tg € I SE 6'o1 ofS 9'€ GET "N VEE D per ger g'tg c'69 | 9'06 1‘oL og & e 6'€ L'11 eS 9'€ GET "N EEE ^ lem RBB = 3 5 E 2 T = > 5 > 5 " Ho d a e s [m © E zl MEC > = an 2 i 52] d o. | gu | mm 3 E à £ jg BR à | as + A o 5 El B 3 D. d m 3 a 8 = dg So a © = ai D 5 097 0 G dg $ id SS | po es = a u 7 an u 7 od | oo D © ? == Br fo D’ zu zu = = un 7 > g-9 5 [p a © gg E 3 5 e v Boso SES 2 < SB & S o à a s | oF | oe | s 2 e eu |E OR REIR || | + (Be) a | 8 = | # an 61 | 91 | L1 | OI | €1 | Fi | ET | oI | II | O1 | 6 | 8 | L 9 S | v | € z | I ($40j Lg JoqeL 147 TROMS FYLKES ANTROPOLOGI. 1921. No. 20. A nn 1) d € +++ b6L 6'gL EGL Phe L‘99 o'£9 1°89 099 £‘Co 1°39 o'oL o'og 9'gL +‘69 o'go SSL 6SEL SEG o'tL +e CD oH m MH 2 tH +H H q € E + m (ap) r e wu) “+ w)u) _ +: c5 c5 qe ^ nn O 0 + 120 mm m giri 611 Iti o'gI T'QI +‘Ci eL1 'N 99€ olı "N Lee 891 N 98€ 'puzur gp ‘PunsÂgSWOIL oL1 'N SgE ıLı 'N tgE& 691 IN Ege 691 "N age oli "N 19€ oli "N og£ 691 "N 6LE 991 "N gLE FLI "N LLE 9L1 'N 9L£ £91 'N SLE oL1 'N FLE ogi "N ELE tol °N aLE £L1 'N DES Co "N oLE SLı "N 69€ 901 "N 998 Lor "N LOE 91 "N 99€ PLY "N Coe Loi "N tof oLlı "N £o£ Loi "N cot FL "N 10€ 991 "N 298 SLT "N SS 76SE oli "N gSE "puæw gz ‘usduejew oli "N LSE 1L1 "N 9SE zlı "N sse TUA 'N rS€ M.-N. Kl. HALFDAN BRYN. 148 I^ rere l'eg | o'£9 Doom SE Sol € I Te L‘ı1 BS WE c'Y1 girl 8'61 DGI gli 'N Siv Duc c'og Sel g'Eg bel g'6L € I PE 6*01 Lp HE 981 pri g‘g1 SCT £91 'N [rw s'ol 0'c9 L‘€g L*eL g'el 9 I gfe c'11 ofS De gf Sar g'61 HS ELI "N Su Ton Fe ool o*oL t'£g ESTL o*6L 1 I obra 6*o1 ofS GE g'eı GUYS 1*61 CS: 9L1 'N Ina F* 9'08 r'So g'lg o'69 1'og € c se S'11 aS LA 661 aol L'gı 1*91 tg 'N SUD Hier 1 g'Eg 0‘zg s'LL o'gL s'Lg t e r*€ y 511 IP PE 9'£1 Sor CA o'€1 191 "N X The on 2 o'gl 0'809 +‘og bL 9'08 + & Ij OMI ofS PE o'ti I'c1 1*61 LAC: Soi "N [09 N «€ I L‘Cg g‘LL L'Sg ool £'FL € € off r'ıı ety SIG EET y‘ıı Zou o'Sı £91 "N le ore OU CF o‘og o‘o9 o'o6 L PL g'SL € I os ori cc SE o'tı 9'c1 9'61 o'CT £L1 "N Veith: 2 S*£g Etes L‘£6 1'EL LL € c Se ool gt gta ‘SI 611 r°61 Sty1 091 "N KT es o'Eg o‘oL o*6g el SSL g e SEG SI ofS SRE GO o'c1 z‘61 Ca 991 "N xa sel kt Dog CP L'og ofS 9'g6 PEL r'6L S I Es SII rs o'E oF) g'eı FOL LAS gli "N IE le St AIR SEQ Lo z'g8 L*SL 6‘og I I GE fol or es ‘SI Ear CLI o't1 LS “J u I NW ! L'gL o'go 6'Lg e'1L 9‘6L Y © 6'c iua ofS bE 1'vi "c1 9‘61 9fS1 gli "N xu) IN ST € £'FL o‘&L Srg o‘1L c'tg t e GE o‘11 ofS 9'€ gti Sa r'gı S67 oL1 'N leo Tg e o'gl E'L9 0'06 9‘69 8'88 9 ra gta OST as Ste o'tı 9‘z1 gil g'SI 991 'N Tat d es o'og 8'g9 1°Lg LL o'tg S Z e'€ STI gr GE o't1 ool o‘gI aon oL1 "N ug q $e | Sel 0'g9 L‘18 Erk 6‘rg LA € LÆS orl ofS HE ahi 9‘11 Sgı L°S1 691 "N ae Ge Kern, a‘og 9‘69 g'Sg t'go C'+g 1 € MS g'o1 9°S 6'€ LÆS: Sıı L*g1 g'S1 eL1 'N I INN = SLL L'og | o'og EEL z‘og I I SE or! 9S HE ov a1 L*g1 of'C1 891 "N On sp We z'gl L*oo L*16 £‘oL o*6L t t nts; tol ofS TAG te teal oo o'gI gti 991 "N U 4) T ga it 1°6L 9*oL L*o6 SSEL cıg t € e£ o‘11 9'z1 F'gi ofr 1L1 "N SU NON S a‘og 1°Cg CaL C‘og t I *eg gto LA Soi 6‘pi1 oL1 'N 14 AW ? 138 z'gL S‘6L I 1 evs ori Sign S'gI L*v1 1LI "N D CRC MN eS £'£g 6‘69 | tog v 1 ee 6*o1 S'zı +61 9'S1 oL1 'N [UD 3N + o‘6L GEL o‘6L I I g'E CR: o's1 6'053 C‘or oli N pus UNE 6'Eg ‘SL g'gl c I ote e'II OSI 9*6r FST 691 "N rg : A pe eee EE NC "es ; ANN ce eue Rio nenn, op | 55 S © 3 Kl dQ” 3 = D 8m & 8 Sels LE d Ug LONE E [ouL1o J > a 2 5; = À = S = | 61 | QI | Li | Ql | CI | tr | €1 | GI | II | OI | 6 | 8 | L 9 S, | r | € Iz | 1 '("suoj L9 JogeL 149 [£2 — TROMS FYLKES ANTROPOLOGI. as = ——— — c^ t ^^ = ' = wn + = fy 3 +e qu x 1921. 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LIST o'og o'og 0'909 o'og t S a 9o*or os ob o't1 CI C61 o‘S1 oLı |:1 X '7| Sho AUS) ST ST Ur SOL Sol o'£g oil o'og t I Xe O'II L*v SS o't1 sl L*g1 2'901 oli "N cto I egt ASE OS o*og 9‘£9 e‘og g vL o'ıg I 1 Sis Quit: L*v o'E V1 Ca o‘61 SIG 691 "N rto Pons SF o'og L‘oa o‘og g‘1L L*1g I I 6e e'11 g't a o'tı ort 1‘61 | OST GLU NX sa] to ei ee gol o'gg 1‘+g o'gg 1'eg iS I gta 9*or ofS HE g'eı o‘11 o‘61 OCT 991 "N 689 nk: LSLE C‘r9o 6'tg g‘oL BEL I I Ba, gol oS se 6'£1 QUIT L*61 | EST oL1 "N 989 See 3 MS. 3 B B. w o9 S | d > d. s FA Tz dei RB, mm | ee ES G 2 gy À 2 == " x o3 5 o 8 5 gg 53 © AS 3 Be Wes M PE EE MES 2138 3 a © = Z |a8 | eo | E Ss 2 Sch Bona E: s | oa Jos | s [QUO J = = E 2 = = Cu 3 61 91 | L1 | OI | €1 | [9 | 8 | L | 9 | S | r | € | ‘(suor) Lo [9qe] O1 —| 1921. No. 20. TROMS FYLKES ANTROPOLOGI. I XIV. Resume. 1. Norsk. I. Undersokelsen omfatter 662 mænd i alderen 20— 21 aar, samtlige fra Troms fylke i det nordlige Norge. Man gaar nu ut fra at bebyggelsen hadde naadd hitop 1000 aar f. Kr. Befolkningen her er meget uensartet. Grundstammen er utvilsomt norsk. Ca. 90%0 regner sig som norske, 8 0/0 regner sig for lapper, og ca. 20/0 regner sig for finlændere. Gjennem mange generationer har dog norske, lapper og finner krydset indbyrdes. Man bør derfor være varsom med at tale om racerenhet heroppe. Av tabel 2 ser det ut som det norske element er i jevn vekst. Det er dog kun et selvbedrag. Bastardene regner sig nemlig som norske i 2den og 3dje generation. Og da raceeiendomme- lighetene ikke forsvinder, vil dette i virkeligheten si at den norske race i Troms fylke for hvert aar som gaar blir mere og mere forurenset med fremmede elementer. Langs fjordene og paa øene i Troms fylke bor en befolkning som vanlig benævnes ,sjofinner". Disse utgjør en ganske stor procent av den nuværende befolkning. Om disse sjøfinners herkomst er der endnu ikke enighet. Nogen mener at det kun er forarmede fjeld- lapper. Andre mener at disse sjøfinner for en del er resten av en gammel »anarisk" befolkning, som har bodd heroppe før nordmændene kom hit. Il. Legemsheiden (M) er 169,28; cm. Standardavvikelsen (6) er 6,78. Variationskoefficienten (v) = 4,004. Legemshoiden er meget uensartet i de forskjellige herreder (se tabel 4). Mindst er den i de distrikter hvor der er mange lapper eller sjøfinner (Lyngen og Karlsøy). Størst er den i de distrikter hvor der er mange indflyttere fra det sydlige Norges største dal- fører, Østerdalen og Gudbrandsdalen. Kurven for legemsheiden (fig. 3) har 6 vel markerte spidser og har et betydelig mere avlangt forløp end man ellers vanlig finder i Norge. III. Pigmentering. Blaa-graa oine har 38,5 %0, lyst melerte eine 19,9 %0, mørkt melerte eine 8,9 0/0, brune eine 12,7 0/0. Brune eine svarer til Martins tavle 4 og s. Flest brunoiede finder man i Lyngen herred (30,6 %0), se tabel rr. Det er lappene og de saakaldte sjøfinner som til- fører befolkningen saa mange brunøiede individer. Hos de egte fjeldlapper har MANTEGAZZA fundet folgende tal: blaaoiede 30 Vo, melerte oine 40 Wo, brune eine 30%0. De egte fjeldlapper har med andre ord ikke mørkere gine end befolkningen i Lyngen. Da nu mindst 30/0 av befolkningen i 158 HALFDAN BRYN. M.-N. Kl. Lyngen er av ren nordisk herkomst og altsaa har hat blaa oine, synes det lite sandsynlig at befolkningen i Lyngen kan være blit saa sterkt brunoiet ved krydsning med fjeldlapper. Dette taler for at det maa være sjøfinnene som har tilført befolkningen i Lyngen saa mange brunøiede, og sjøfinnene maa da ha været mere brunoiet end lappene. Det største antal blaaøiede individer findes i Bardu og Maalselv. Befolkningen her er for en meget stor del indflyttet hit for ca. 100 aar siden fra Østerdalen og Gudbrandsdalen. Av tabel 10 fremgaar ogsaa at oienfarven i Bardu og Maalselv paa det nærmeste svarer til hvad der nu er i Nordre Østerdalen. Det er et nyt bevis paa den seighet hvormed denne egenskap nedarves. Haarfarven. Blandt samtlige undersokte fandtes 23,4 ?/0 lyseblonde, 1,5 0/0 rodhaarede, 34,0 % med lysebrunt haar, 33,9 0/0 med mørkebrunt haar og 7,2 %0 sorthaarede. De fleste sorthaarede svarer til FiscHERS type nr. 4. De distrikter som har flest mørkhaarede, er de samme som hadde flest brunoiede og flest smaa folk. Det synes sikkert, at det er sjø- finnene som har tilført befolkningen saa mange sorthaarede. Hvis man sammenholder haarfarven hos befolkningen til eks. i Lyngen med hvad MANTEGAZZA har fundet blandt fjeldlapper, blir det klart, at det ikke er lappene som har tilført denne befolkning dens mørke haar. Der er færre sorthaarede blandt lappene end blandt denne befolkning. Paa fig. 5 er frem- stillet pigmenteringsgraden i de forskjellige distrikter, naar haarfarve og øjenfarve regnes under ett (pigmentindex). IV. Hodet. Middellængden er 19,28 cm. blandt samtlige. Hos de norske er den 19,4 cm., hos lappene 18,5 cm. Middelbredden er 15,41 cm., hos lappene 15,6 cm. Index cephalicus's gjennemsnitlige størrelse ér 80,77. Lavest index findes i Bardu (79,3) og Maalselv (79,1). Forøvrig kan jeg henvise til indexkartet (fig. 8). Kurven for index cephalicus (se fig. 9) har en tydelig spids ved index 80, desuten to tydelige spidser ved index 83 og 87. Den sidste antages at skyldes lappene. Spidsen ved index 83 svarer helt til hvad man ogsaa ofte ellers finder 1 Norge, specielt paa Vestlandet. Paa tabel 20 er fremstillet forholdet mellem hodets længde og bredde samt legemshoiden hos norske og hos lapper. Hos lappene utgjør hodets bredde ca 15,6 0/0 av lagemshoiden, hvad enten denne sidste er stor eller liten. Hos norske derimot kun 15,2 %o. Hodets længde utgjor hos lappene 18,0—18,4 %0 av legemshoiden, hos norske derimot fra 19,0—19,3 9/0. Jeg fandt 6 %o dolichocephaler, 47 %0 mesocephaler, 39 %0 brachycephaler, 8 0/0 hyperbrachycephaler. V. Ansigtets middelhoide er 12,05, dets middelbredde er 14,14. Index facialis morphologicus er 85,1. Denne sidste varierer sterkt i de for- skjellige herreder (se kartet fig. 10). De smaleste ansigter findes i Bardu og Maalselv, hvor man ogsaa finder den største legemshoide, den mindste index cephalicus, det største antal lyshaarede og lysøiede. 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 159 De bredeste ansigter findes i Helgøy (nr. 23 paa fig. 10). Dette er ganske paafaldende. Ti blandt de av mig undersøkte fra Helgøy var ingen av lappisk herkomst, og det er jo i det hele lite sandsynlig, at lappene nogen gang skal ha bodd ute paa en o ved Nordishavet i en saadan mængde at de kunde paatrykke befolkningen sit stempel. Den nulevende befolkning maa derfor ha faat sit brede ansigt i arv fra en anden folketype end lappene. Kurven for ansigtsindex (index facialis morphologicus) er ned- tegnet paa fig. 11 og har, som det vil sees, 3 spidser: ved index 83, 83 og 88. I hele fylket har jeg fundet 37 %0 euryprosoper, 33 %0 mesoprosoper og 30 0/0 leptoprosoper. Index nasalis er 68,55. I kystdistriktene Helgøy, Torsken og Salangen findes en betydelig heiere index, omkring 73, hvilket svarer til dens størrelse i de vestlandske brachycephale distrikter. Av samtlige undersøkte var 57 %0 leptorhine, 40 0/0 mesorhine og 3%0 chamærhine. Av lappene var 30 0/0 leptorhine, 63 9/0 mesorhine og 7/0 chamærhine. Den gjennemsnitlige avstand mellem de indre oienvinkler var 32,96 mm. VI. Plica marginalis fandtes hos 12,8 %/0 (se fig. 12). Den findes hos saavel norske som hos lapper og kvæner og i alle fylkets herreder. Men som jeg i et senere avsnit skal paavise, er denne eiendommelighet tilført befolkningen ved krydsning med lappene. Den gjennemsnitlige størelse av mindste pandebredde er 11,09 cm. Den transversale fronto-parietale index (se tabel 29) er mindst hos lappene og størst hos kvænene. Forholdet mellem cephalindex og pande- bredde fremgaar av tabel 31. Blandt samtlige undersokte er der 14 /o stenometope, 37,5 9/0 metrio- metope og 49,5 9/0 eurymetope. VII. Paa tabellene 33 til 37 er anfort de forskjellige kombinationer av haarfarver og eientyper. Det sees av tabel 34 at de lyse kombinationer, blaagraa eine med blondt og lysebrunt haar, forekommer hyppigst blandt doli- chocephalene. Den mørkeste kombination (nr. 8), brune eine og sort haar, forekommer hyppigst blandt brachycephalene. Hvis jeg summerer sammen særskilt alle lyse træk og alle mørke træk og gir dem værdi efter pigmen- teringsgrad, finder jeg at den lyse blok inden denne befolkning utgjer 66 1/0 og den mørke blok 349/o. Hvis jeg gjør det samme for hver hode- type, finder jeg at den lyse blok har felgende sterrelse: blandt dolicho- cephaler 68,7 9/0, blandt mesocephaler 70,3? 0, blandt brachycephaler 63,9 0/0, blandt hyperbrachycephaler 62,3 %0. VII. Affinitetsundersekelser. Disse er utfort efter AnpReas M. Hansens metode, idet jeg mener at denne er at foretrække for beregning av korrelationskoefficienten efter Bravaıs’ formel. Affinitetstallet er forholdet mellem den fundne brøkdel av undersekte hos hvem de to egenskaper findes kombinert, og det efter sandsynlighets- 160 HALFDAN BRYN. M.-N. Kl. beregningen givne, naar de to egenskaper varierer uavhaengig av hver- andre. Et affinitetstal som er stort, tyder altsaa i almindelighet paa biologisk sammenhæng, medens et litet affinitetstal taler mot biologisk sammenhæng. Resultatet av disse undersøkelser findes paa tabellene 38 til 43. Av disse undersøkelser fremgaar følgende: I. At der indgaar i vor befolkning en stor mesocephal blok, lepto- prosop, av stor legemshoide, eurymetop, med stor jugofrontal index, lepto- rhin, blond av haar og blaaøiet, 2. samt en mindre blok, brachycephal, euryprosop, av liten legems- heide, mesometop, med liten jugofrontal index, mesorhin, sorthaaret og brunoiet. Endelig indgaar der ogsaa 3. en endnu mindre, men hyperbrachycephal blok, sterkt eurypros- opisk og av endnu mindre legemshoide end foregaaende gruppe, heigradig stenometop, chamærhin, brunhaaret og med lysere brune eine end fore- gaaende gruppe, samt med plica marginalis. 4. Ved affinitetsundersokelse av lappene findes der ogsaa at irdgaa i dem de samme 3 raceelementer. Lappene er derfor ingenlunde renracede. De er i hoi grad præget av at være bastarder. IX. Befolkningens mosaikbillede ved kombination av de enkelte trek. Jeg skal her gi en fremstilling av hvorledes de 6 vigtigste traek er kombinert, og jeg maa da indskrænke mig til det mindst mulige antal typer for hvert træk. Naar jeg regner med 4 hodetyper, 3 ansigtstyper, 2 næse- typer, 2 oientyper, 2 haartyper og 2 hoidetyper, faar jeg i alt 192 mulige kombinationer. Av ‘disse 192 tænkelige kombinationer blir dog en hel del ganske ubesat eller saa tyndt besat at man med én gang kan sætte dem ut av betragtning. Til gjengjæld samler andre linjer saa mange individer at man tydelig kan utpeke dem, og disse ,linjer" gir saa at si befolkningen sit preg. For dolichocephalenes vedkommende er den mest markerte linje: dolichocephali — leptoprosopi — leptorhini — lyse oine — lyst haar (tab. 44). Mesocephali følger noiagtig den samme linje, nemlig: mesocephali — leptoprosopi — leptorhini — lyse oine — lyst haar, og man kan her med større sikkerhet tilføje at linjen ender i stor legemshoide. Da denne linje inden dolichocephalenes gruppe er den eneste som er markert og kontinuerlig, og som samtidig har hoie affinitetstal, er det heller ingen grund til at tro at dolichocephalene inden denne befolkning repræsenterer nogen særskilt type. Dolichocephalene utgjer bare en renere linje, de er +-avvikere inden den store dolicho-mesocephale gruppe. Heller ikke er det inden disse to grupper mulig at oine nogen forskjel paa leptoprosoper og mesoprosoper. Leptoprosopene er kun at betragte som ---avvikere av den store lepto- mesoprosope gruppe. Jeg mener saaledes, at disse tabeller taler for at der i vor befolkning indgaar e» stor dolichomesocephal gruppe med følgende træk: leptomesoprosopi — leptorhini — lyse oine — lyst haar — stor legemsheide. Denne type benævner jeg i det følgende homo nordicus. 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 161 Brachycephalene findes paa tabel 46. Av denne fremgaar at der hersker et biologisk motsaetningsforhold mellem leptoprosopi og brachycephali, medens der utvilsomt er sterke biologiske baand som knytter brachycephali til meso- euryprosopi. Følger man denne linje videre, vil man se, at der er en sam- menhaengende biologisk velbegrundet række som gaar gjennem mesoeury- prosopi — mesorhini — mørke oine — mørkt haar til liten legemsbygning. Man gjenfinder altsaa her en række træk som samtlige er karakteristiske for homo alpinus. Hyperbrachycephalene findes paa tabel 47. Nederst paa denne tabel finder man en ved høie affinitetstal sterkt markert og biologisk set vel sam- menhængende linje som gaar gjennem euryprosopi — mesorhint — mørke ome — mørkt haar til liten legemsbygning. Vi gjenkjender straks disse træk som karakteristiske for den-mennesketype som av GIUFFRIDA-RUGGERI er kaldt den palæoarktiske, og som omfatter samojeder og lapper. Jeg vil i det følgende benævne denne type homo paleoarcticus. Fandtes hos 6,8 %0 hyperbrachycephale = 0,75 %0 av samtlige. Paa tabel 47 finder vi at den bedst besatte linje gaar gjennem hyperbrachycephali — euryprosopi — mesorhini — lyse oine — lyst haar til liten legemsbygning. Hele denne linje har ogsaa høie affinitetstal, og trækkene svarer helt igjennem til hvad vi nu finder hos lappene. Antropologisk set markerer denne bastard nr. 185 sig som en ıste grads bastard av homo paleoarcticus og homo nordicus. Herhen kan ogsaa regnes bastard nr. 186—189. Jeg benævner i det folgende disse bastarder som homo lapponicus. Som 2den grads bastarder av homo nordicus og homo palæoarcticus maa bastardene nr. 177 —184 betegnes. Disse er leptorhine; de karakteristiske lappetræk er sterkt utvandet i denne gruppe, som ogsaa er meget sparsom i antal. 3dje grads bastarder er type nr. 161—176. Her har det norske element overtaket. De har kun hodeformen fra homo palæoarcticus. Betegnende er det ogsaa at inden denne gruppe er de høie i majoritet, medens ved ıste og 2den grads bastarder de lave var i majoritet. Hvad ansigtsform angaar, maa hele denne gruppe nærmest betegnes som -+--avvikere av den nordiske race. Ti leptoprosopi gaar meget daarlig sammen med hyperbrachycephali. Denne kombination forekommer kun hos 13 blandt samtlige undersøkte. Brachycephalenes bastarder findes paa tabel 48. Den brachycephale urtypes oprindelige træk findes samlet kun kos ro individer (type nr. 127) = 4,300. Den dolichocephale urtypes oprindelige træk fandtes samlet hos 24 %0. Utregningen er da for begge typers vedkommende foretat i procent av hver enkelt types antal inden den nulevende befolkning. Det er da tydelig at den brachycephale blok har faat en ganske anderledes voldsom medfart, er blit ganske anderledes søndersplittet end den dolichocephale blok. Dette kan tænkes at bero paa at det nordiske element altid har følt sig som det overlegne. Draapevis, saa at si, har derfor det brachycephale element flytt ind i det nordiske element. Først naar dette har gaat for sig gjennem generationer, og den fremmede indblanding er begyndt at gaa i Vid.-Selsk. Skrifter. I. M.-N. Kl. 1921. No. 20. 11 162 HALFDAN BRYN. M.-N. Kl. glemmeboken, har de bedre "elementer av den nordiske race blandet sig med det fremmede element. Derfor er det brachycephale element blit saa sønderlemmet, medens det nordiske har holdt sig mere ubeskadiget. En anden forklaring er dog tænkelig, og den skal jeg komme tilbake til i et følgende avsnit. Jeg har i dette.avsnit prøvet, om der kan paavises typer som gir be- folkningen sit præg. Jeg har hertil valgt 6 av de for menneskeracene mest karakteristiske træk. Hvert av disse træk er sandsynligvis avhængig av flere faktorpar. Da nu bare to faktorpar gir 1,048,576 mulige kombina- tioner, skulde man tro, at man inden en saa heterogen befolkning som denne vilde finde saa mange kombinationer at det ikke længer blev mulig at finde nogen orden i dette kaos. Av saa meget større interesse er det at se at en række hovedlinjer trær meget skarpt frem. Sammenhængen hermed er sandsynligvis følgende: Hver enkelt linnéisk art bestaar av mange forskjellige genotyper, som i sin sammensætning kan være en mere eller mindre fast gruppering av artens gener. En stor del av de teoretisk mulige genotyper er antagelig relativt lite levedygtige og gaar til grunde i kampen for tilværelsen allerede paa et tidlig stadium av sit liv. De linnéiske arters karakteristiske og ofte temmelig ensartede utseende skyldes temmelig sikkert, at mange av de krydsningsvarieteter som er mulige paa grund av artens gener, stadig holdes nede i kampen for tilværelsen. Paa tabel 49 er anført, hvilke varieteter det er som i særlig grad præger den her beskrevne befolkning. De tykke streker antyder urtypenes træk, og de tynde streker er de hybride varieteters træk. X. I dette avsnit sokes befolkningens mosaikbillede yderligere for- enklet, idet her kun medtages 3 træk: 1. Index cephalicus, 2. Index facialis morphologicus, 3. Qienfarve. Jeg mener at man herved kan faa et meget sxarpt og værdifuldt billede av en befolknings antropologiske sammensætning. Inden denne befolkning finder jeg følgende 12 grupper (se fig. 13): 1. En dolichomesocephal, leptomesoprosopisk, lysoiet, 33,2 %0, homo nordicus. En brachycephal, euryprosopisk, brunøiet, 4,0 0/0, homo alpinus. En hyperbrachycephal, euryprosopisk, brunoiet, 0,3 0/0, homo palæo- arcticus. 4. En dolichomesocephal, leptomesoprosopisk, brunoiet, 6,6 9/0, homo nor- dicus fuscus. s. En dolichomesocephal, euryprosopisk, lysoiet, 14,0 0/0, homo nordicus var. euryprosopicus. 6. En dolichomesocephal, euryprosopisk, brunoiet, 2,0 0/0, homo alpinus var. dolichocephalicus. 7. En brachycephal, leptomesoprosopisk, bruneiet, 16,4 0/0, homo nordicus var. brachycephalicus. 8. En brachycephal, leptomesoprosopisk, bruneiet, 4,8 %0, homo alpinus var. nordicus. — Yr — 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 163 9. En brachycephal, euryprosopisk, lysoiet, 9,5 9/0, homo alpinus lividus. 10. En hyperbrachycephal, leptomesoprosopisk, lysoiet, 4,5 Vo, homo lap- ponicus var. nordicus. 11. En hyperbrachycephal, leptomesoprosopisk, bruneiet, 1,1 9/0, homo lap- ponicus var. alpinus. 12. En hyperbrachycephal, euryprosopisk, lysoiet, 3,6 %0, homo lapponicus. XI. Jeg har i de foregaaende avsnit gjort rede for utbredelsen av de væsentligste antropologiske karaktertræk inden den nulevende befolkning. Den senere tids arvelighetsforskning har bragt paa det rene at flere av disse træk er overmaade stabile. De kan indgaa nye forbindelser, men de blir ellers uforanderlige. Dette gjælder særlig index cephalicus, index facialis og eienfarven. Professor E. FiscHers og andre forskeres undersøkelser taler for at de nævnte træk ved krydsning følger de Mendelske lover. Vor kjendskap til de faktorer som fremkalder de her nævnte træk, er endnu lik nul. Sandsynligheten taler dog for at der er særskilte faktorer for hodets bredde og hodets længde, ansigtets hoide og ansigtets bredde o.s.v. I en undersøkelse som denne vil det imidlertid være mest praktisk at betragte disse karaktertræk som arvelige enheter. Ved den taksinometriske undersøkelse kom jeg til det resultat, at den her omhandlede befolkning er opstaat ved krydsning av 3 urtyper: en nordisk, en alpin og en lappoid i forholdet 66:30:4. Disse tal kan natur- ligvis ikke gjøre krav paa nogen matematisk nøiagtighet. I avsnit X gjorde jeg rede for utbredelsen av de nulevende bastarder. Hvorledes svarer nu denne fordeling av bastardene til det man vil faa, om urtypene har krydset sig i det mængdeforhold som jeg har for- utsat. Resultatet vil naturligvis avhænge av hvilke træk som er dominerende og hvilke recessive. Om jeg tænker mig at to ,rene" racer krydses, saa vil selvfølgelig i F,-generationen alle recessive træk forsvinde saafremt de to blokker som krydses, har neiagtig samme størrelse. I F,-generationen vil de igjen komme frem, men i mindre antal end før krydsningen, medens de dominerende træk har øket i tilsvarende grad. Ved den fortsatte krydsning (panmiksi) vil de procentforhold som fandtes i F,-generationen, forbli uforandret. Om den ene blok fra første stund har været større end den anden, saa vil selvfølgelig dette medføre at dennes karaktertræk forekommer i et større procenttal i F,-generationen. Og dette vil ogsaa bli tilfældet i de senere generationer. Vi har herigjennem et utmerket middel til at utdype vor forstaaelse av et menneskesamfunds raceologiske oprindelse. Jeg har nu paa en række tabeller utregnet, hvorledes det vil gaa hvis de 3 av mig forutsatte urtyper krydses panmiktisk. Paa tabel 55 findes utregnet resultatet, hvis hyperbrachycephali dominerer over brachycephali og dolichomesocephali, brachycephali over dolichomesocephali, euryprosopi over leptomesoprosopi, brune gine over lyse gine. Resultatet er opført i kolonne 10, og i kolonne 11 findes angit det av mig fundne antal av hver 164 HALFDAN BRYN. M.-N. Kl. av disse varieteter. Det vil med en gang sees at efter disse lover kan krydsningen ikke vaere foregaat. Jeg har derefter prøvet alle andre muligheter og kommer til slut til folgende resultat: 1. Den av mig undersokte befolkning er opstaat ved krydsning av 3 forskjellige urtyper i de av mig forutsatte mængdeforhold. 2. Krydsningen er foregaat i alt væsentlig overensstemmende med de Mendelske lover og saaledes at hyperbrachycephali dominerer over brachy- cephali og dolichomesocephali, brachycephali dominerer over dolichomeso- cephali, leptoprosopi dominerer over euryprosopi. De brune og de mørkt melerte oine eier ikke fuld dominans over de blaagraa eine, idet hetero- zygotene har mellemfarvede oine. Under disse forutsætninger vil ialfald resultatet av krydsningen bli saaledes som fremstillet paa fig 15 a. Nu er resultatet av min undersokelse saaledes som fremstillet paa fig. 15 b. Uover- ensstemmelsene er, som man vil se, ganske smaa og uveesentlige og er hovedsagelig begrænset til den hyperbrachycephale gruppe. XU. De fremmede elementer bestaar av /apper og kvæner. Om de norske /appers hoide kan denne undersokelse ikke gi nogen oplysning, da alle de smaa lapper ved utskrivningen er slettet som utjenstdygtige. Det er værd at lægge merke til at ingen av de av mig undersokte lapper var heiere end 171 cm. Disse lapper har jo i hei grad preg av at vere bastarder; de har faat den nordiske races haar og oienfarve, men ingen har faat den nordiske races middelhoide. Dette taler ikke til gunst for den opfatning, at stor legemshoide dominerer over liten legemshoide ved kryds- ning. Ved de aller fleste krydsninger har moren veeret lap, og disse lappe- bastarders ringe legemshoide taler for at den kvindelige part av forældrene har en dominerende betydning ialfald for dette træks vedkommende. Hodets bredde var 15,63 cm. og hodets længde 18,54 cm. Bredden svarer. til 9,5 /0 og længden til 11,89/o av legemshoiden. Hodets orehoide er 12,56 cm. Lappekraniets kapacitet blir da 1444 cm.2. Index cephalicus var 84,29. Ansigtsindex var 82,98. Index nasalis 73,9. Paa tabel 62 findes angit haarfarven. Oienfarven var hos 30 %0 blaagraa, hos 5090 melert, hos 20 %0 brun. Karakteristisk for lappene er den ringe pandebredde. Blandt nordmændene var der 14 9/0 stenometope, 37,5 0/0 metriometope og 49,5 /0 eurymetope. Blandt lappene derimot 50 0/0 steno- metope, 20 0/0 metriometope og 30°/0 eurymetope. Sammenligner man de av mig fundne middeltal og serier med MANTEGAZZAS, saa blir det klart at selv disse reneste norske lapper dog er sterkt opblandet med fremmede elementer. Kvænenes legemshoide (M) var 166,2 cm. Deres index cephalicus var 82,06. Hodets orehoide var 13,06 cm. Kraniets kubikindhold blir da 1432 cms. Deres ansigtsindex var 84,29 cm. Ansigtet er relativt firkantet, idet kjævebredden er meget stor. Deres index nasalis var 67,35. De er meget lyse baade av haar og øine, men naar dog i denne henseende paa eats No. 20. TROMS FYLKES ANTROPOLOGI. 165 langt nær op mot den norske befolkning. Jeg fandt lyse eine hos 65 0/0 og mørke eine hos 33 0/0, lyst haar hos 53/0 og mørkt haar hos 47 0/0. XIII. I dette avsnit gives en kort oversigt over de enkelte herreders antropologi. Opsummeret i faa ord maa man si om den her beskrevne befolkning, at den er hei av vekst (169,3 cm.), subbrachycephal (ind. 80,7), mesopros- opisk (ind. 85,1), leptorhin (68,5), lys av oine og haar. Kyst- og obefolkningen er av samme slags som den saakaldte vest- norske befolkning, som vi kjender vest fra Jæderen og Sondmer. Jordbruksdistriktenes befolkning og indlandsbefolkningen til eks. i Bardu og Maalselv svarer i alt væsentlig til indlandsbefolkningen i Sydnorge (Østerdalen). De fremmede elementer (som lapper og kvaener) er saa spar- somme at de ikke kan sætte noget præg paa befolkningen. 2. Deutsch. I. Die Untersuchung umfaft 662 Månner im Alter von 20—21 Jahren, sämtlich aus Troms Amte im nördlichen Norwegen. Man nimmt jetzt an, dafs die Besiedelung tooo Jahre v. Chr. hier herauf gelangt war. Die Bevölkerung ist hier sehr ungleichartig. Der Grundstamm ist zweifellos norwegisch; 8/0 halten sich selbst für Lappen und 2%0 für Finnländer. Durch viele Generationen haben sich jedoch Norweger, Lappen und Finnen untereinander gekreuzt Man darf daher hier oben nur mit Vorsicht von Rassenreinheit reden. Aus der Tabelle 2 scheint hervorzu- gehen, dafa das norwegische Element in gleichmäßigem Wachstum begriffen ist. Dieses ist jedoch nur ein Selbstbetrug. Die Bastarde rechnen sich nämlich als norwegisch in der 2ten und 3ten Generation. Da nun die Rasseeigentümlichkeiten nicht verschwinden, wird dieses in der Wirklichkeit sagen, daß die norwegische Rasse im Troms Amte für jedes Jahr, das vergeht, immer mehr durch fremde Elemente verunreinigt wird. An den Fjords entlang und auf den Inseln im Troms Amte wohnt eine Bevölkerung, die gewöhnlich „Sjöfinner“ (Seefinnen) genannt werden. Diese bilden einen ziemlich großen Prozentsatz von der jetzigen Bevölkerung. Über die Her- kunft dieser Seefinnen ist man noch nicht einig. Einige meinen, dafs es nur verarmte Gebirgslappen sind. Andere meinen, dafs diese Seefinnen zum Teil die Reste einer alten „anarischen“ Bevölkerung sind, die hier oben gewohnt haben, ehe die Norweger dahinkamen. II. Die Kórperhóhe (M) ist 169,28; cm. Die Standardabweichung (5) beträgt 6,78. Der Variationskoefficient (v) = 4,004. Die Körperhöhe ist in den verschiedenen Bezirken sehr ungleich (siehe Tabelle 4). Am geringsten ist sie in den Bezirken, wo es viele Lappen oder Seefinnen gibt (Lyngen und Karlsóy). Am größten ist sie in den Bezirken, wo es viele Zugezogene 166 HALFDAN BRYN. M.-N. Kl. aus den größten Tälern, Østerdalen und Gudbrandsdalen, des südlichen Norwegens gibt. Die Kurve für die Körperhöhe (Fig. 3) hat 6 sehr deutliche Spitzen und hat einen viel mehr langgedehnten Verlauf, als man sonst für gewöhnlich in Norwegen findet. III. Pigmentierung. Blaugraue Augen haben 58,5 0/0, hell melierte Augen 19,9 %/0, dunkel melierte Augen 8,99/0, braune Augen 12,7 0/0. jraune Augen entsprechen Martins Tafeln 4 und 5. Die meisten braun- äugigen findet man im Bezirke Lyngen (30,6 %0), sie Tabelle 11. Es sind die Lappen und die sogenannten Seefinnen, die der Bevölkerung hier so viele braunäugige Individuen zuführen. Bei den echten Gebirgslappen hat MANTEGAZZA folgende Zahlen gefunden; blauäugige 30 9/0, melierte Augen 40 9/0, braune Augen 300. Die echten Gebirgslappen haben demnach nicht dunklere Augen als die Bevölkerung in Lyngen. Da nun mindestens 50 0/0 von der Bevölkerung in Lyngen von rein nordischer Herkunft sind, und also blaue Augen gehabt haben, erscheint es wenig wahrscheinlich, dafs die Bevölkerung in Lyngen durch Kreuzung mit Gebirgslappen so stark braunäugig geworden sein kann. Dieses spricht dafür, daf es die See- finnen sein müssen, die der Bevölkerung in Lyngen so viele braunäugige zugeführt haben, und die Seefinnen müssen dann mehr braunäugig gewesen sein als die Lappen. Die größte Anzahl blauäugige Individuen findet man in Bardu und Maalselv. Die Bevölkerung hier ist zum großen Teil vor ca. 100 Jahren aus Österdalen und Gudbrandsdalen zugezogen. Aus der Tabelle ro geht auch hervor, dafs die Augenfarbe in Bardu und Maalselv derjenigen sehr nahe steht, die jetzt im nördlichen Österdal vorherrscht. Das ist ein neuer Beweis für die Zähigkeit, womit diese Eigenschaft vererbt wird. Die Haarfarbe. Unter sämtlichen untersuchten Individuen fanden sich 23,4 0/0 hellblonde, 1,5 9/0 rothaarige, 34,0 9/0 mit hellbraunem Haar, 33,9 9/0 mit dunkelbraunem und 7,2 %0 mit schwarzem Haar. Die meisten Schwarz- haarigen entsprechen FiscHERS Typus Nr. 4. Diejenigen Bezirke, wo die meisten Dunkelhaarigen vorkommen, sind dieselben, welche die meisten Braunäugigen und die meisten kleinen Leute aufzuweisen hatten. Es scheint sicher zu sein, daß es die Seefinnen sind, die der Bevölkerung so viele Schwarzhaarige zugeführt haben. Wenn man die Haarfarbe der Bevölkerung z.B. in Lyngen mit dem vergleicht, was Mantecazza bei den Gebirgs- lappen gefunden hat, erscheint es klar, daß es nicht die Lappen sind, die der Bevölkerung ihre dunklen Haare gebracht haben. Es gibt weniger Schwarzhaarige unter den Lappen als bei dieser Bevölkerung. In Fig. 5 ist der Pigmentierungsgrad für die verschiedenen Bezirke dargestellt, indem Haarfarbe und Augenfarbe zusammengerechnet worden sind (Pigmentindex). IV. Der Kopf. Die mittlere Länge ist für sämtliche Individuen 19,28 cm. Bei den Norwegern ist sie 19,4 cm., bei den Lappen 18,5 cm. Die mittlere Breite ist 15,41 cm., bei den Lappen 15,6 cm. OC .2———— 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 167 Die durchschnittliche Größe des Index cephalicus ist 80,77. Den niedrigsten Index findet man in Bardu (79,3) und Maalselv (79,1) Im übrigen kann ich auf die Indexkarte (Fig. 8) hinweisen. Die Kurve für Index cephalicus (siehe Fig. 9) hat eine deutliche Spitze bei Index 80, außerdem zwei deutliche Spitzen bei Index 83 und 87. Es ist anzunehmen, dafs die letztere den Lappen zuzuschreiben ist. Die Spitze bei Index 83 entspricht ganz dem, was man auch sonst in Norwegen, besonders im west- lichen findet. In der Tabelle 20 ist das Verhältnis zwischen Länge und Breite des Kopfes samt Körperhöhe bei Norwegern und Lappen dargestellt. Bei den Lappen beträgt die Kopfbreite ca. 15,6 °/0 von der Körperhöhe, diese möge nun groß oder klein sein. Bei Norwegern dagegen nur 15,2 °/9. Die Länge des Kopfes beträgt bei den Lappen 18,0— 18,4 %0 von der Körperhöhe, bei den Norwegern dagegen von 19,0— 19,3 9/0. Ich fand 6 0/0 Dolichoceph., 47 Yo Mesoceph., 39 %/o Brachyceph., 89/0 Hyperbrachyceph. V. Die mittlere Höhe des Gesichts ist 12,05, die mittlere Breite 14,14, Der Index facialis morphologicus ist 85,1. Dieser letztere ist sehr ver- schieden in den verschiedenen Bezirken (siehe Karte Fig. 10). Die schmalsten Gesichter findet man in Bardu und Maalselv, wo man auch die größte Körperhöhe, den kleinsten Index cephalicus, die größte Anzahl Blond- haarige und Helläugige hatte. Die breitesten Gesichter findet man in Helgöy (Nr. 23 in Fig. 10). Dieses ist recht auffällig. Denn unter den von mir Untersuchten aus Helgöy war niemand von lappischer Herkunft, und es ist ja überhaupt wenig wahr- scheinlich, daf die Lappen jemals in solcher Anzahl auf einer Insel im Eismeer gewohnt haben sollten, daß sie der Bevölkerung ihren Stempel einimpfen konnten. Die jetzige Bevölkerung muß daher ihr breites Gesicht einem anderen Volkstypus als den Lappen verdanken. Die Kurve für den Gesichtsindex (Index facialis morphologicus) ist in Fig. 11 gezeichnet und hat, wie man sieht, 3 Spitzen: bei Index 83, 85 und 88. Im ganzen Amte habe ich 37/0 Euryprosopen, 33 9/0 Mesoprosopen und 30 0/0 Leptoprosopen (siehe Tabelle 24) gefunden. Der Index nasalis ist 68,55. In den Küstenbezirken Helgöy, Torsken und Salangen findet man einen beträchtlich höheren Index, etwa 73, was ungefähr dessen Größe in den westländischen brachycephalen Bezirken entspricht. Von sämtlichen Untersuchten waren 57 9/0 leptorhin, 40 9/0 mesorhin und 3/0 chamärhin. Die durchschnittliche Entfernung zwischen den innern Augenwinkeln war 32,96 mm. VI. Plica marginalis war vorhanden bei 12,8 0/0 (siehe fig. 12). Sie kommt vor sowohl bei Norwegern wie bei Lappen und Finnen und in allen Bezirken des Amtes. Wie ich aber in einem späteren Abschnitt nach- 168 HALFDAN BRYN. M.-N. Kl. weisen werde, ist diese Eigentümlichkeit der Bevölkerung durch Kreuzung mit den Lappen zugeführt worden. Das durchschnittliche Maß der kleinsten Stirnbreite ist 11,09 cm. Der transversale fronto-parietale Index (siehe Tabelle 29) ist am kleinsten bei den Lappen und am größten bei den Kvänen. Das Verhältnis zwischen Cephalindex und Stirnbreite geht aus der Tabelle 31 hervor. Von sämtlichen Untersuchten sind 14,0 9/0 stenometop, 37,5 9/0 metrio- metop und 49,5 0/0 eurymetop. VII. In den Tabellen 33 bis 37 sind die verschiedenen Kombinationen von Haarfarbe und Augentypus angeführt. Man sieht aus der Tabelle 34, daf3 die hellen Kombinationen: blaugraue Augen mit blondem oder hell- braunem Haar, bei den Dolichocephalen am häufigsten vorkommen. Die dunkelste Kombination (Nr. 8), braune Augen und schwarzes Haar, kommt am häufigsten unter den Brachycephalen vor. Wenn ich alle hellen und alle dunklen Züge für sich addiere und ihnen ihren Wert nach dem Pigmen- tierungsgrade gebe, finde ich, dafs der helle Block innerhalb dieser Be- völkerung 66 9/0, und der dunkle Block 34 Vo umfaßt. Wenn ich für jeden Haupttypus ebenso verfahre, finde ich, dafs der helle Block folgende relative Größe hat: bei den Dolichocephalen 68,7 9/0, bei den Mesocephalen 70,3 0/5, bei den Brachycephalen 63,9 %/o, bei den Hyperbrachycephalen 62,3 %0. VIII. Affinitätsuntersuchungen. Diese sind nach dem Verfahren des Dr. ANDREAS M. Hansen ausgeführt, das nach meiner Meinung der Berechnung von Korrelations-Koefficienten nach der Formel Bnavais vorzu- ziehen ist. Die Affinitätszahl ist das Verhältnis zwischen dem gefundenen Bruch- teil von Untersuchten, bei denen die zwei Eigenschaften zusammen vor- kommen, und dem aus der Wahrscheinlichkeitsberechnung hervorgehenden Bruchteil, wenn die zwei Eigenschaften als von einander unabhàngige Variable auftreten. Eine große Affinitätszahl deutet also im allgemeinen auf einen biologischen Zusammenhang, während eine kleine Affinitätszahl gegen den biologischen Zusammenhang spricht. Das Resultat dieser Untersuchungen ist aus den Tabellen 38 bis 43 zu ersehen. Aus diesen Untersuchungen geht Folgendes hervor: I. Es besteht in unserer Bevölkerung ein großer mesocephaler Block, leptoprosop, von grof3er Kórperhóhe, euryprosop, mit grofsem jugo-frontalem Index, leptorhin, mit blonden Haaren und blauàugig, 2. sowie ein kleinerer Block, brachycephal, euryprosop, von kleiner Körperhöhe, mesometop, mit kleinem jugo-frontalem Index, mesorhin, schwarz- haarig und braunäugig. Endlich haben wir auch 3. einen noch kleineren, aber hyperbrachycephalen Block, stark eury- prosopisch und von noch geringerer Körperhöhe als die vorhergehende Gruppe, hochgradig stenometop, chamärhin, mit braunem Haar und helleren braunen Augen als die vorhergehende Gruppe, sowie mit Plica marginalis. 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 169 4. Bei der Affinitätsuntersuchung unter den Lappen findet man auch bei ihnen dieselben 3 Rasseelemente wieder. Die Lappen sind daher durchaus nicht reinrassig. Sie haben in hohem Grade das Gepräge von Bastarden. IX. Das Mosaikbild der Bevölkerung bei Kombination der einzelnen Züge. Ich werde hier eine Darstellung davon geben, wie die 6 wichtigsten Züge kombiniert sind, und muf mich dabei für jeden Zug auf eine möglichst geringe Anzahl Typen beschränken. Wenn ich 4 Kopftypen, 3 Gesichts- typen, 2 Nasentypen, 2 Augentypen, 2 Haartypen und 2 Höhentypen rechne, werde ich im ganzen 192 mögliche Kombinationen haben. Von diesen 192 denkbaren Kombinationen bleibt doch ein ganzer Teil unbesetzt oder so schwach besetzt, dafs man sie gleich außer Betracht setzen kann. Dafür umfassen andere Linien so viele Individuen, daß man diese deutlich zeichnen kann, und diese „Linien“ geben der Bevölkerung so zu sagen ihr Gepräge. Für die Dolichocephalen ist die am stärksten markierte Linie: Dolichocephalie — Leptoprosopie — Leptorhinie — helle Augen — helles Haar (Tab. 44). Die Mesocephalie folgt genau derselben Linie, nämlich: Mesocephalie — Leptoprosopie — Leptorhinie — helle Augen — helles Haar, und man kann hier mit größerer Sicherheit hinzufügen, dafs die Linie mit großer Körperhöhe abschließt. Da innerhalb der Gruppe der Dolichocephalen diese Linie die einzige scharfe und kontinuierliche ist und gleichzeitig hohe Affinitätszahlen hat, liegt auch kein Grund zu der Annahme vor, dafs die Dolichocephalen inner- halb dieser Bevölkerung einen gesonderten Typus darstellen. Die Dolicho- cephalen bilden nur eine reinere Linie, sie sind die —-Abweichenden inner- halb der großen dolichomesocephalen Gruppe. Es ist auch innerhalb dieser zwei Gruppen nicht möglich, einen Unterschied zwischen Leptoprosopen und Mesoprosopen zu entdecken. Die Leptoprosopen sind nur als ---Ab- weichende von der grofsen leptomesoprosopen Gruppe anzusehen. Nach meiner Meinung sprechen demnach diese Tabellen dafür, daß in unserer Bevölkerung eine große dolichomesocephale Gruppe besteht und zwar mit folgenden Zügen: Leptomesoprosopie — Leptorhinie — helle Augen — helles Haar — große Körperhöhe. Diesen Typus werde ich im folgenden Homo nordicus nennen. Die Brachycephalen findet man in der Tabelle 46. Aus dieser geht hervor, dafs zwischen Leptoprosopie und Brachycephalie ein Gegensatz besteht, während zweifellos starke biologische Bande die Brachycephalie mit der Mesoeuryprosopie verbinden. Verfolgt man diese Linie weiter, wird man sehen, dafs es eine zusammenhängende, biologisch wohl begründete Reihe gibt, die durch Mesoeuryprosopie — Mesorhinie — dunkle Augen — dunkles Haar zu kleinem Körperbau geht. Man findet also hier eine Reihe von Zügen wieder, die sämtlich für Homo alpinus charakteristisch sind. Die Hyperbrachycephalen findet man in der Tabelle 47. Unten in dieser Tabelle findet man eine durch hohe Affinitätszahlen scharf gekennzeichnete [70 HALFDAN BRYN. M.-N. KL und biologisch gut zusammenhängende Linie, die durch Zuryprosopie — Mesorhinie dunkle Augen — dunkles Haar zu kleinem Körperbau ver- läuft. Diese Züge erkennen wir gleich als für denjenigen Menschentypus charakteristisch, der von GiIUFFRIDA-RUGGERI der paläoarktische genannt wird, und der Samojeden und Lappen umfaßt. Im folgenden will ich diesen Typus Homo paleoarcticus nennen. 6,8°/0 von den Hyperbrachycephalen oder 0,75 0/0 von sämtlichen gehörten zu diesem Typus. In der Tabelle 47 finden wir, daß die am besten besetzte Linie durch Hyperbrachycephalie -— Euryprosopie Mesorhinie — helle Augen — helles Haar zu kleinem Körperbau geht. Diese ganze Linie hat auch hohe Affinitätszahlen, und die Züge entsprechen durchaus dem, was wir jetzt bei den Lappen finden. Anthropologisch gesehen zeichnet sich, dieser Bastard Nr. 185 aus als Bastard ersten Grades des Homo palwoarcticus und Homo nordicus. Hierzu kann man auch die Bastarde Nr. 186 — 189 rechnen. Ich werde im Folgenden diese Bastarde als Homo lapponicus bezeichnen. Als Bastarde zweiten Grades von Homo nordicus und Homo palæoarcticus muß man die Bastarde Nr. 177—184 bezeichnen. Diese sind leptorhin, die charakteristischen Lappenzüge sind stark verwässert in dieser Gruppe, die auch der Zahl nach nur spärlich vertreten ist. Bastarde dritten Grades sind die Typen Nr. 161—176. Hier hat das norwegische Element die Oberhand. Sie haben nur die Kopfform vom Homo palæoarcticus. Bezeichnend ist es auch, dafs innerhalb dieser Gruppe die hohen Menschen in der Majorität sind, während bei den Bastarden ersten und zweiten Grades die kleinen in der Majorität waren. Was die Gesichtsform anbetrifft, so wird diese ganze Gruppe wohl am richtigsten als +-Abweichende von der nordischen Rasse bezeichnet. Denn Leptoprosopie geht sehr schlecht mit Hyperbrachycephalie zusammen. Diese Kombination kommt nur bei 13 von sämtlichen Untersuchten vor. Die Bastarde der Brachycephalen stehen in der Tabelle 48. Die ursprünglichen Züge des brachycephalen Urtypus findet man alle zugleich nur bei ro Individuen (Typus Nr. 127) = 4,3 0/0. Die ursprünglichen Züge des dolichocephalen Urtypus findet man zusammen bei 24%o. Die Aus- rechnung ist hier für beide Typen in Prozent von der Anzahl jedes einzelnen Typus innerhalb der jetzigen Bevölkerung ausgedrückt. Es er- scheint da deutlich, daf der brachycephale Block eine ganz andere gewaltige Einwirkung erlitten hat, ganz anders zersplittert worden ist als der dolicho- cephale Block. Dieses kann vielleicht darin begründet sein, daß das nordische Element sich immer als das überlegene gefühlt hat. Tropfenweise ist daher das brachycephale Element so zu sagen in das nordische Element einge- sickert. Erst wenn dieses durch Generationen stattgefunden hat und die fremde Einmischung angefangen hat in’s Vergessen zu geraten, haben die besseren Elemente der nordischen Rasse sich mit dem fremden Elemente vermischt. Aus diesem Grunde ist das brachycephale Element so sehr zerstückelt worden, während das nordische Element sich mehr unbeschädigt 1921. No. 20. TROMS FYLKES ANTROPOLOGI. 171 erhalten hat. Eine andere Erklärung ist allerdings auch denkbar, auf die ich weiter unten zurückkommen werde. In diesem Abschnitt habe ich festzustellen versucht, ob Typen nach- gewiesen werden können, die der Bevölkerung ihr Gepräge geben. Ich habe hierzu 6 von den charakteristischen Zügen gewählt. Jeder von diesen Zügen ist wahrscheinlich von mehreren Faktorpaaren abhängig. Da nun schon ro Faktorpaare 1,048,576 mögliche Kombinationen geben, sollte man glauben, dafs man innerhalb einer so heterogenen Bevölkerung, wie die vorliegende, so viele Kombinationen finden würde, daß es nicht mehr möglich wäre, in dem Chaos eine Ordnung zu finden. Um so interessanter ist es zu sehen, daf eine Reihe von Hauptlinien sehr scharf hervortreten. Dieses hängt wahrscheinlich, wie folgt, zusammen: Jede einzelne Linneische Art besteht aus vielen verschiedenen Genotypen, die in ihrer Zusammen- setzung eine mehr oder weniger feste Gruppierung von den Genen der Art sein können. Ein großer Teil von den theoretisch möglichen Geno- typen ist wahrscheinlich verhältnismäßig wenig lebensfähig und geht schon in einem frühen Stadium seines Lebens im Kampfe um’s Dasein zugrunde. Das charakteristische und oft ziemlich gleichartige Aussehen der Linnéischen Arten ist ziemlich sicher dem Umstande zuzuschreiben, daf viele von den Kreuzungsabarten, die mit Rücksicht auf die Genen der Art möglich sind, ständig im Kampfe um’s Dasein niedergehalten werden. In der Tabelle 49 sind die Varietäten angeführt, die die hier beschriebene Bevölkerung besonders prägen. Die dicken Linien deuten die Züge der Urtypen an und die dünnen diejenigen der hybriden Varietäten. X. In diesem Abschnitt werden wir trachten, das Mosaikbild der Be- völkerung weiter zu vereinfachen, indem wir nur 3 Züge mitnehmen: 1. Index cephalicus, 2. Index facialis morphologicus, 3. Die Augenfarbe. Ich bin der Ansicht, dafs man auf diesem Wege ein sehr scharfes und wertvolles Bild von der anthropologischen Zusammensetzung einer Be- völkerung erhalten kann. In dieser Bevölkerung finde ich folgende 12 Gruppen (siehe Fig. 13): 1. Eine dolichomesocephale, leptomesoprosopische, helläugige, 33,2 9/o, Homo nordicus. 2. Eine brachycephale, euryprosopische, braunäugige, 4,0 °/9, Homo alpinus. 3. Eine hyperbrachycephale, euryprosópische, braunäugige, 0,3 °/9, Homo paleoarcticus. 4. Eine dolichomesocephale, leptomesoprosopische, braunäugige, 6,6 9, Homo nordicus fuscus. 5. Eine dolichomesocephale, euryprosopische, helläugige, 14,0 07, Homo nordicus var. euryprosopicus. 6. Eine dolichomesocephale, euryprosopische, braunäugige, 2,0 %0, Homo alpinus var. dolichocephalicus. 172 HALFDAN BRYN. M.-N. Kl. Eine brachycephale, leptomesoprosopische, braunåugige, 16,4 °/9, Homo ~! nordicus var. brachycephalıcus. 8. Eine brachycephale, leptomesoprosopische, braunäugige, 4,8 0/5, Homo alpinus var. nordicus. 9. Eine brachycephale, euryprosopische, helläugige, 9,5%, Homo alpinus lividus. ro. Eine hyperbrachycephale, leptomesoprosopische, helläugige, 4,5 0/6, Homo lapponicus var. nordicus. tr. Eine hyperbrachycephale, leptomesoprosopische, braunäugige, 1,1 0/6, Homo lapponicus var. alpinus. 12. Eine hyperbrachycephale, prosopische, helläugige, 3,6 9/6, Homo lap- ponicus. XI. In den vorhergehenden Abschnitten habe ich das Auftreten der wesentlichsten anthropologischen Charakterzüge bei der jetzigen Bevölkerung dargelegt. Die Erblichkeitsforschung der neueren Zeit hat den Beweis erbracht, daf3 mehrere dieser Züge außerordentlich stabil sind. Sie können neue Verbindungen eingehen, bleiben aber sonst unveränderlich. Dieses gilt besonders vom Index cephalicus, Index facialis und der Augenfarbe. Die Untersuchungen Professor E. Fıschers und anderer Forscher sprechen dafür, daf die genannten Züge bei Kreuzungen den Mendelschen Gesetzen folgen. Unsere Kenntnisse über diejenigen Faktoren, die die hiergenannten Züge hervorrufen, sind bis jetzt gleich Null. Die Wahrscheinlichkeit spricht jedoch dafür, dafs es besondere Faktoren gibt für die Breite und Länge des Kopfes, die Höhe und Breite des Gesichtes u.s. w. Für eine Unter- suchung wie die vorliegende wird es jedoch am praktischsten sein, diese Charakterzüge als erbliche Einheiten zu betrachten. Bei der taxinometrischen Untersuchung kam ich zu dem Resultate, daß die hier besprochene Bevölkerung durch Kreuzung von 3 Urtypen: einer nordischen, einer alpinen und einer lappoiden im Verhältnis 66:30:4 entstanden ist. Diese Zahl kann selbstverständlich nicht auf irgend welche mathematische Genauigkeit Anspruch machen. Im Abschnitt X habe ich die Verbreitung der heute lebenden Bastarde besprochen. Wie weit stimmt nun diese Verteilung der Bastarde mit dem, was man erhalten muß, wenn die Urtypen sich in dem von mir angenommenen Mengenverhältnis gekreuzt haben? Das Resultat wird naturgemäß von der Frage abhängen, welche Züge dominierend und welche recessiv sind. Wenn ich mir vorstelle, daß zwei „reine“ Rassen sich kreuzen, so werden selbstverständlich in der Generation F, alle recessiven Züge ver- schwinden, wenn die zwei sich kreuzenden Blöcke genau gleich groß sind. In der Generation F, werden sie wieder zum Vorschein kommen, jedoch in geringerer Zahl als vor der Kreuzung, während die dominierenden Züge im entsprechenden Grade zugenommen haben. Bei der fortgesetzten Kreuzung (Panmixie) werden die prozentualen Verhältnisse, die man bei der Generation F, fand, unverändert bleiben. Wenn der eine Block von Anfang 1921. No. 20. TROMS FYLKES ANTROPOLOGI. ETS an größer gewesen ist als der andere, so wird die Folge selbstverständlich die sein, dafs die Charakterzüge desselben in der Generation F, in einem größeren prozentualen Verhältnis vorkommt. Und dieses wird auch in den späteren Generationen so sein. Wir haben hier ein ausgezeichnetes Mittel um unser Verständnis für den rasseologischen Ursprung einer Menschen- gemeinschaft zu vertiefen. In einer Reihe von Tabellen habe ich nun ausgerechnet, wie es sich gestalten wird, wenn die 3 von mir vorausgesetzten Urtypen panmiktisch gekreuzt werden. In der Tabelle 55 findet man das Resultat ausgerechnet für den Fall, daß Hyperbrachycephalie gegenüber Brachy- und Dolicho- mesocephalie dominiert, Brachycephalie über Dolichomesocephalie, Eury- prosopie über Leptomesoprosopie, braune Augen über helle Augen. Das Resultat ist in der Kolonne to angegeben, und in der Kolonne 11 ist die von mir gefundene Anzahl von jeder einzelnen dieser Varietäten angegeben. Man wird sofort sehen, dafs die Kreuzung nicht nach diesen Gesetzen statt- gefunden haben kann. Ich habe darnach alle anderen Möglichkeiten geprüft und komme schließlich zu folgendem Ergebnis: 1. Die von mir untersuchte Bevölkerung ist durch Kreuzung von 3 verschiedenen Urtypen in den von mir vorausgesetzten Mengenver- hältnissen entstanden. 2. Die Kreuzung hat in allem Wesentlichen mit den Mendelschen Gesetzen in Übereinstimmung stattgefunden und zwar so, das Hyperbrachy- cephalie über Brachycephalie und Dolichomesocephalie dominiert, Brachy- cephalie über Dolichomesocephalie, Leptoprosopie über Euryprosopie. Die braunen und die dunkel melierten Augen haben keine volle Dominanz über die blaugrauen Augen, indem die Heterozygoten mittelfarbige Augen haben. Unter diesen Voraussetzungen wird jedenfalls das Resultat der Kreuzung so werden, wie in der Fig. 15 a dargestellt. Nun ist das Resultat von meiner Untersuchung so wie in der Fig. 15 b dargestellt. Die Differenzen sind, wie man sieht, ganz klein und unwesentlich und sind hauptsächlich auf die hyperbrachycephale Gruppe beschränkt. XII. Die fremden Elemente bestehen aus Lappen und Kvånen. Über die Höhe der norwegischen Lappen kann diese Untersuchung keine Aus- kunft geben, da alle die kleinen Lappen bei der Aushebung als dienst- untauglich ausgeschaltet sind. Es ist bemerkenswert, dafs keiner von den von mir untersuchten Lappen höher war als 171 cm. Diese Lappen haben ja in hohem Grade die Merkmale der Bastarde; sie haben das Haar und die Augenfarbe der nordischen Rasse, aber keine von ihnen haben die mittlere Höhe der nordischen Rasse erreicht. Dieses spricht nicht zu Gunsten der Auffassung, daß bei Kreuzung große Körperhöhe über kleine Körperhöhe dominiert. Bei den. aller meisten Kreuzungen ist die Mutter Lappin gewesen, und die geringe Körperhöhe dieser Lappenbastarde spricht [74 HALFDAN BRYN. M.-N. Kl. dafür, dafs die weibliche Seite der Eltern jedenfalls diesen Zug betreffend eine dominierende Bedeutung hat. Die Breite des Kopfes war 15,63 cm. und seine Länge 18,54 cm. Die Breite entspricht 9,5 %0 und die Länge 11,8%0 von der Körperhöhe. Die Ohrenhóhe des Kopfes ist 12,56 cm. Die Kapacität des Lappenkraniums wird dann gleich 1444 cm.3. Der Index cephalicus war 84,29. Der Gesichtsindex war 82,98. Der Index nasalis 73,9. In der Tabelle 62 findet man die Angaben über die Haarfarbe. Die Augenfarbe war bei 30/0 blaugrau, bei 50 9/0 meliert, bei 20/0 braun. Charakteristisch für die Lappen ist die geringe Stirnbreite. Unter den Norwegern waren 14/0 stenometop, 37,5 0/0 metriometop und 49,5 Yo eurymetop. Unter den Lappen dagegen waren 50/0 stenometop, 20 0/0 metriometop und 30/0 eurymetop. Wenn man die von mir gefundenen Mittelzahlen und Serien mit denen MaxrEGAzzas vergleicht, so erscheint es klar, daf3 selbst diese reinsten norwegischen Lappen doch stark mit fremden Elementen vermischt sind. Die Körperhöhe der Kvànen (M) war 166,2 cm., ihr Index cephalicus 82,06, die Ohrenhóhe des Kopfes 13,06 cm. Der Kubikinhalt des Kraniums wird demnach 1432 cm.3. Ihr Gesichtsindex war 84,29 cm. Ihr Gesicht ist relativ viereckig, weil die Kiefernbreite sehr grof ist. Ihr Index nasalis war 67,35. Sie sind sehr hell sowohl in bezug auf die Haare wie in bezug auf die Augen, kónnen aber doch in dieser Beziehung bei weitem nicht mit den Norwegern verglichen werden. Helle Augen fand ich bei 65/0 und dunkle Augen bei 35 /o, helles Haar bei 53 9/9 und dunkles Haar bei 47 0/0. XIIL In diesem Abschnitt wird eine kurze Übersicht über die An- thropologie der einzelnen Bezirke gegeben. In wenige Worte zusammengefafst muf3 man von der hier beschriebenen Bevülkerung sagen, daf3 sie von hohem Wuchs ist (169,3 cm.), subbrachy- cephal (Index 80,7), mesoprosopisch (Index 85,1), leptorhin (68,5), mit hellen Augen und Haaren. . Die Bevölkerung der Küste und der Inseln. ist von ‘derselben Art wie die sogenannte westnorwegische Bevólkerung, die wir aus dem Westen, aus Jäderen und Sóndmór kennen. Die Bevülkerung der landwirtschaftlichen Gegenden und des Binnen- landes z. B. in Bardu und Maalselv entspricht in allem wesentlichen der Bevölkerung des Binnenlandes im südlichen Norwegen (Österdalen). 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