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• and 

 many 



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 ■ mk 



id the 

 it tke 



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iquent 



kn it 



i Borne 



alated 



ocene, 

 in tie 

 .trn to 



tion d 







CHAPTER XII. 



VICISSITUDES IN CLIMATE CAUSED BY GEOGRAPHICAL 



CHANGES. 



ON THE C LVBBB OF VICISSITUDES IN CLIMATE— ON THE PBESENT DIFFUSION 

 OF HEAT OYER THE GLOBE -MEAN ANNUAL ISOTHERMAL LINES— DEPENDENCE 

 OF THE MEAN TEMPERATURE ON THE RELATIVE POSITION OF LAND AND SEA 



CLIMATE OF SOUTH GEORGIA AND TIERRA DEL FUEGO-COLD OF THE ANTARC- 

 TIC REGION— OPEN SEA NEAR THE NORTH POLE-EFFECT .OF CURRENTS IN 

 EQUALISING THE TEMPERATURE OF HIGH AND LOW LATITUDES-THE PRESENT 

 PROPORTION OF POLAR LAND ABNORMAL -SUCCESSION OF GEOGRAPHICAL 

 CHANGES REVEALED TO US BT GEOLOGY-MAP SHOWING THE AMOUNT OF 

 EUROPEAN LAND WHICH HAS BEEN UNDER WATER SINCE THE COMMENCEMENT 

 OF THE EOCENE PERIOD-ANTIQUITY OF THE EXISTING CONTINENTS- 

 CHANGES IN GEOGRAPHY WHICH PRECEDED THE TERTIARY EPOCH-MAP 

 SHOWING THE UNEQUAL DISTRIBUTION OF LAND AND WATER ON THE GLOBE 

 -FORMER GEOGRAPHICAL CHANGES WHICH MAY HAVE CAUSED THE FLUCTU- 

 ATIONS IN CLIMATE REVEALED TO US BY GEOLOGY- ID EAL MAP WITH THE 

 EXCESS OF LAND REMOVED FROM POLAR TO TROPICAL REGIONS-GREAT 

 DEPTH OF THE SEA AS COMPARED TO THE MEAN HEIGHT OF THE LAND, 

 AND ITS CONNECTION WITH THE SLOWNESS OF CLIMATAL CHANGES. 



>/ 



As our retrospective sur- 



iven in 



vey of the fossiliferous rocks of successive periods, | 

 the last two chapters, has led us to infer that the earth's 

 surface has experienced great changes of climate since it has 

 been inhabited by living beings, we have next to enquire how 

 such vicissitudes can be reconciled with the existing order of 



nature. The earlier 



them 



problem 



views concerning a period when the planet was in a nascent 

 or half-formed state, or when the laws of the animate and 

 inanimate world differed essentially from those now estab- 

 lished ; and in this, as in many other cases, they succeeded, 



from 



mi 



an explanation of the phenomena. 



imagined 



