334 Journal of Travel and Natural History 



are represented in miocene deposits. Thus the sabre-toothed hon 

 is found at Eppelsheim; an arboreal ape, the giraffe, camel, and 

 innumerable antelopes lie buried in the plains of Marathon ; the 

 hipparion in France, Germany, Britain, and the Spanish Penin- 

 sula. The needs of their existence demanded a tropical climate 

 throughout that vast area. In Europe from that time up to the 

 glacial epoch the climate gradually grew colder, and with each 

 successive lowering of temperature a new group of animals made 

 its appearance, driving before it the former inhabitants that A\ere 

 fitted for warmer conditions of life, and leaving behind their fossil 

 bones to mark the geological age of the deposits in which they are 

 found. Thus the sole survivors out of the forms of life found in 

 the miocenes of Europe are now to be sought in the tropical 

 regions of Africa, whither they have been driven by the change in 

 the European climate. No changes of this kind have taken place 

 in India. The climate of the Siwalik hills is as hot now, if not 

 hotter, than during the lifetime of the extinct Indian mammalia. 



"Instead of numerous sub-divisions of the tertiary period with successive 

 faunas, facts tend to the conchision that India had one long term and one pro- 

 tracted fauna which lived through a period corresponding to several terms of the 

 tertiary period in Europe." — (Vol. i., p. 28.) 



This, in our opinion, is the true explanation of the mixed cha- 

 racter of the Siwalik fauna. To assume with Sir Charles Lyell* 

 and M, Gaudryt that it corresponds with that of Europe in the 

 miocene, is to abandon the course of reasoning by which we have 

 hitherto been accustomed to correlate the remains of life imbedded 

 in deposits far removed from one another. The first step in any 

 palaeontological inquiry is to master the fauna and flora living at 

 the present time in the country in which the fossils occur, and then 

 to calculate the age of the latter in direct proportion to the cor- 

 respondence between them and the existing forms of life. If there 

 be many species in common then the fossils are of comparatively 

 small antiquity, while, on the other hand, if there be no agreement 

 whatever they are relegated to a period infinitely remote from the 

 present. All the tertiary mammalia that have yet been found 

 have been classified in accordance with this method. Thus the 

 gigantic extinct sloths of America are still represented by the 

 small one living in the same area, and they are considered, thcrc- 



* Elements of Geology, 6lh edit., p. 273. 



+ " Animaux Fossiles ct Geologic dc rAlliipie." I'ar. M. Gaudry, Tart i. 



Animaux Fossiles." 410, Taris 1867. 



