the rise and progress of palaeontology-第2部分

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existing　marine　or　freshwater　animals；　they　must　have　been

produced　by　similar　animals；　and　the　like　reasoning　is　applied

by　Steno　to　the　fossil　bones　of　vertebrated　animals；　whether

aquatic　or　terrestrial。　To　the　obvious　objection　that　many

fossils　are　not　altogether　similar　to　their　living　analogues；

differing　in　substance　while　agreeing　in　form；　or　being　mere

hollows　or　impressions；　the　surfaces　of　which　are　figured　in　the

same　way　as　those　of　animal　or　vegetable　organisms；　Steno

replies　by　pointing　out　the　changes　which　take　place　in　organic

remains　embedded　in　the　earth；　and　how　their　solid　substance　may

be　dissolved　away　entirely；　or　replaced　by　mineral　matter；　until

nothing　is　left　of　the　original　but　a　cast；　an　impression；　or　a

mere　trace　of　its　contours。　The　principles　of　investigation　thus

excellently　stated　and　illustrated　by　Steno　in　1669；　are　those

which　have；　consciously　or　unconsciously；　guided　the　researches

of　palaeontologists　ever　since。　Even　that　feat　of　palaeontology

which　has　so　powerfully　impressed　the　popular　imagination；　the

reconstruction　of　an　extinct　animal　from　a　tooth　or　a　bone；　is

based　upon　the　simplest　imaginable　application　of　the　logic　of

Steno。　A　moment's　consideration　will　show；　in　fact；　that　Steno's

conclusion　that　the　glossopetrae　are　sharks'　teeth　implies　the

reconstruction　of　an　animal　from　its　tooth。　It　is　equivalent　to

the　assertion　that　the　animal　of　which　the　glossopetrae　are

relics　had　the　form　and　organisation　of　a　shark；　that　it　had　a

skull；　a　vertebral　column；　and　limbs　similar　to　those　which　are

characteristic　of　this　group　of　fishes；　that　its　heart；　gills；

and　intestines　presented　the　peculiarities　which　those　of　all

sharks　exhibit；　nay；　even　that　any　hard　parts　which　its

integument　contained　were　of　a　totally　different　character　from

the　scales　of　ordinary　fishes。　These　conclusions　are　as　certain

as　any　based　upon　probable　reasonings　can　be。　And　they　are　so；

simply　because　a　very　large　experience　justifies　us　in　believing

that　teeth　of　this　particular　form　and　structure　are　invariably

associated　with　the　peculiar　organisation　of　sharks；　and　are

never　found　in　connection　with　other　organisms。　Why　this　should

be　we　are　not　at　present　in　a　position　even　to　imagine；　we　must

take　the　fact　as　an　empirical　law　of　animal　morphology；　the

reason　of　which　may　possibly　be　one　day　found　in　the　history　of

the　evolution　of　the　shark　tribe；　but　for　which　it　is　hopeless

to　seek　for　an　explanation　in　ordinary　physiological　reasonings。

Every　one　practically　acquainted　with　palaeontology　is　aware

that　it　is　not　every　tooth；　nor　every　bone；　which　enables　us　to

form　a　judgment　of　the　character　of　the　animal　to　which　it

belonged；　and　that　it　is　possible　to　possess　many　teeth；　and

even　a　large　portion　of　the　skeleton　of　an　extinct　animal；　and

yet　be　unable　to　reconstruct　its　skull　or　its　limbs。　It　is　only

when　the　tooth　or　bone　presents　peculiarities；　which　we　know　by

previous　experience　to　be　characteristic　of　a　certain　group；

that　we　can　safely　predict　that　the　fossil　belonged　to　an　animal

of　the　same　group。　Any　one　who　finds　a　cow's　grinder　may　be

perfectly　sure　that　it　belonged　to　an　animal　which　had　two

complete　toes　on　each　foot　and　ruminated；　any　one　who　finds　a

horse's　grinder　may　be　as　sure　that　it　had　one　complete　toe　on

each　foot　and　did　not　ruminate；　but　if　ruminants　and　horses　were

extinct　animals　of　which　nothing　but　the　grinders　had　ever　been

discovered；　no　amount　of　physiological　reasoning　could　have

enabled　us　to　reconstruct　either　animal；　still　less　to　have

divined　the　wide　differences　between　the　two。　Cuvier；　in　the

〃Discours　sur　les　Revolutions　de　la　Surface　du　Globe；〃　strangely

credits　himself；　and　has　ever　since　been　credited　by　others；

with　the　invention　of　a　new　method　of　palaeontological　research。

But　if　you　will　turn　to　the　〃Recherches　sur　les　Ossemens

Fossiles〃　and　watch　Cuvier；　not　speculating；　but　working；　you

will　find　that　his　method　is　neither　more　nor　less　than　that　of

Steno。　If　he　was　able　to　make　his　famous　prophecy　from　the　jaw

which　lay　upon　the　surface　of　a　block　of　stone　to　the　pelvis　of

the　same　animal　which　lay　hidden　in　it；　it　was　not　because

either　he；　or　any　one　else；　knew；　or　knows；　why　a　certain　form

of　jaw　is；　as　a　rule；　constantly　accompanied　by　the　presence　of

marsupial　bones；　but　simply　because　experience　has　shown　that

these　two　structures　are　co…ordinated。　





The　settlement　of　the　nature　of　fossils　led　at　once　to　the　next

advance　of　palaeontology；　viz。　its　application　to　the

deciphering　of　the　history　of　the　earth。　When　it　was　admitted

that　fossils　are　remains　of　animals　and　plants；　it　followed

that；　in　so　far　as　they　resemble　terrestrial；　or　freshwater；

animals　and　plants；　they　are　evidences　of　the　existence　of　land；

or　fresh　water；　and；　in　so　far　as　they　resemble　marine

organisms；　they　are　evidences　of　the　existence　of　the　sea　at　the

time　at　which　they　were　parts　of　actually　living　animals　and

plants。　Moreover；　in　the　absence　of　evidence　to　the　contrary；　it

must　be　admitted　that　the　terrestrial　or　the　marine　organisms

implied　the　existence　of　land　or　sea　at　the　place　in　which　they

were　found　while　they　were　yet　living。　In　fact；　such　conclusions

were　immediately　drawn　by　everybody；　from　the　time　of　Xenophanes

downwards；　who　believed　that　fossils　were　really　organic

remains。　Steno　discusses　their　value　as　evidence　of　repeated

alteration　of　marine　and　terrestrial　conditions　upon　the　soil　of

Tuscany　in　a　manner　worthy　of　a　modern　geologist。

The　speculations　of　De　Maillet　in　the　beginning　of　the

eighteenth　century　turn　upon　fossils；　and　Buffon　follows　him

very　closely　in　those　two　remarkable　works；　the　〃Theorie　de　la

Terre〃　and　the　〃Epoques　de　la　Nature〃　with　which　he　commenced

and　ended　his　career　as　a　naturalist。



The　opening　sentences　of　the　〃Epoques　de　la　Nature〃　show　us　how

fully　Buffon　recognised　the　analogy　of　geological　with

archaeological　inquiries。　〃As　in　civil　history　we　consult　deeds；

seek　for　coins；　or　decipher　antique　inscriptions　in　order　to

determine　the　epochs　of　human　revolutions　and　fix　the　date　of

moral　events；　so；　in　natural　history；　we　must　search　the

archives　of　the　world；　recover　old　monuments　from　the　bowels　of

the　earth；　collect　their　fragmentary　remains；　and　gather　into

one　body　of　evidence　all　the　signs　of　physical　change　which　may

enable　us　to　look　back　upon　the　different　ages　of　nature。　It　is

our　only　means　of　fixing　some　points　in　the　immensity　of　space；

and　of　setting　a　certain　number　of　waymarks　along　the　eternal

path　of　time。〃



Buffon　enumerates　five　classes　of　these　monuments　of　the　past

history　of　the　earth；　and　they　are　all　facts　of　palaeontology。

In　the　first　place；　he　says；　shells　and　other　marine　productions

are　found　all　over　the　surface　and　in　the　interior　of　the　dry

land；　and　all　calcareous　rocks　are　made　up　of　their　remains。

Secondly；　a　great　many　of　these　shells　which　are　found　in　Europe

are　not　now　to　be　met　with　in　the　adjacent　seas；　and；　in　the

slates　and　other　deep…seated　deposits；　there　are　remains　of

fishes　and　of　plants　of　which　no　species　now　exist　in　our

latitudes；　and　which　are　either　extinct；　or　exist　only　in　more

northern　climates。　Thirdly；　in　Siberia　and　in　other　northern

regions　of　Europe　and　of　Asia；　bones　and　teeth　of　elephants；

rhinoceroses；　and　hippopotamuses　occur　in　such　numbers　that

these　animals　must　once　have　lived　and　multiplied　in　those

regions；　although　at　the　present　day　they　are　confined　to

southern　climates。　The　deposits　in　which　these　remains　are　found

are　superficial；　while　those　which　contain　shells　and　other

marine　remains　lie　much　deeper。　Fourthly；　tusks　and　bones　of

elephants　and　hippopotamuses　are　found　not　only　in　the　northern

regions　of　the　old　world；　but　also　in　those　of　the　new　world；

although；　at　present；　neither　elephants　nor　hippopotamuses　occur

in　America。　Fifthly；　in　the　middle　of　the　continents；　in　regions

most　remote　from　the　sea；　we　find　an　infinite　number　of　shells；

of　which　the　most　part　belong　to　animals　of　those　kinds　which

still　exist　in　southern　seas；　but　of　which　many　others　have　no

living　analogues；　so　that　these　species　appear　to　be　lost；

destroyed　by　some　unknown　cause。　It　is　needless　to　inquire　how

far　these　statements　are　strictly　accurate；　they　are

sufficiently　so　to　justify　Buffon's　conclusions　that　the　dry

land　was　once　beneath　the　sea；　that　the　formation　of　the

fossiliferous　rocks　must　have　occupied　a　vastly　greater　lapse　of

time　than　that　traditionally　ascribed　to　the　age　of　the　earth；

that　fossil　remains　indicate　different　climatal　conditions　to

have　obtained　in　former　times；　and　especially　that　the　polar

regions　were　once　warmer；　that　many　species　of　animals　and

plants　have　become　extinct；　and　that　geological　change　has　had

something　to　do　with　geographical　distribution。



But　these　propositions　almost　constitute　the　frame…work　of

palaeontology。　In　order　to　complete　it　but　one　addition　was

needed；　and　that　was　made；　in　the　last　years　of　the　eighteenth

century；　by　William　Smith；　whose　work　comes　so　near　our　own

times　that　many　living　men　may　have　been　personally　acquainted

with　him。　This　modest　land…surveyor；　whose　business　took　him

into　many　parts　of　England；　profited　by　the　peculiarly

favourable　conditions　offered　by　the　arrangement　of　our

secondary　strata　to　make　a　careful　examination　and　comparison　of

their　fossil　contents　at　different　points　of　the　large　area　over

which　they　extend。　The　result　of　his　accurate　and　widely…

extended　observations　was　to　establish　the　important　truth　that

each　stratum　contains　certain　fossils　which　are　peculiar　to　it；

and　that　the　order　in　which　the　strata；　characterised　by　these

fossils；　are　super…imposed　one　upon　the　other　is　always　the

same。　This　most　important　generalisation　was　rapidly　verified

and　extended　to　all　parts　of　the　world　a