554 PALEONTOLOGY 



fauna agrees with the associated whole flora in indicating certain 

 climatic conditions, the mean temperature under which it flourished 

 is doubtless approximately determinable. When the evidence is less 

 nearly complete, it can hardly be satisfactory. To appreciate this, it is 

 only necessary to remember that a fossil elephant, a rhinoceros, and 

 a tiger have been found in undoubted glacial deposits in the arctic 

 regions; while the hippopotamus is represented by abundant remains 

 in the Pleistocene river-gravels of England, which were deposited 

 under a by no means warm clime. Even in the case of plants, there is 

 the oft-quoted occurrence of palms at the present day in the neigh- 

 borhood of glaciers in New Zealand. 



Allowing for such difficulties and uncertainties, the general inference 

 to be deduced from all the available evidence of fossils is, perhaps, 

 that until the end of the Mesozoic period the difference of mean tem- 

 perature between the various latitudes was much less than it is at 

 present. Paleontology suggests, indeed, that the polar ice-caps 

 were comparatively insignificant until the latter half of the Tertiary 

 period. Fossils of many ages, indicating at least a temperate climate, 

 have long been known within the Arctic Circle; l and similar discov- 

 eries have just begun in the ice-bound Antarctic regions. The Swedish 

 Antarctic expedition has brought back from Louis-Philippe Land in 

 8. lat. 63 15' a series of Jurassic ferns, cycads, and conifers, which, 

 according to Professor Nathorst, 2 might have been collected in the 

 Inferior Oolite of the Yorkshire coast. The same expedition has also 

 obtained remains of ferns, conifers, and dicotyledons from a Tertiary 

 formation in S. lat. 64 15'. In this case, however, the fossils were 

 found in a marine deposit and may possibly have been drifted for 

 along distance. As remarked by Professor Nathorst, 3 "The dredg- 

 ings of Dr. Agassiz have proved that a mass of leaves, wood, and 

 fruits may occur at the bottom of the sea even at a distance of more 

 than 1000 kilometers from the nearest land." Hence it must be 

 left for future discoveries to decide whether or not the Tertiary Ant- 

 arctic plants actually grew in the latitude where they were found. 



While thus of some value in indicating ordinary climatal changes, 

 fossils do not date back far enough to be considered in relation to any 

 of the fundamental problems of cosmogony. It has been ingeniously 

 argued 4 that life must have originated at the poles because those 

 regions cooled first; and some authors have maintained that even 

 during the Tertiary period fossils prove the land within the Arctic 

 Circle to have been the main centre from which successive new types 



1 J.W. Gregory, Some Problems of Arctic Geology, Nature, vol. 56 (1897), pp. 301- 

 303,351, 352. 



2 A. G. Nathorst, Sur la Flore fossile des Regions antarctiques, Com ptes Rendvs, 

 vol. 138, pp. 1447-1450 (June 6, 1904). 



3 Loc. cit. p. 1450. 



4 G. Hilton Scribner, Where did Life begin? (ed. 2, New York, 1903). 



