Aug. 1833. 



FOSSIL QUADRUPEDS. 



103 



many degrees beyond the limit where the gromid at the 

 depth of a few feet remains perpetually congealed^ are 

 covered by forests of large and tall trees. In a like 

 manner^ in Siberia, we have woods of birch, fir, aspen, and 

 larch, growing in a latitude* (64°), where the mean tem- 

 perature of the air falls below the freezing point, and where 

 the earth is so completely frozen, that the carcass of an 

 animal embedded in it is perfectly preserved. With these 

 facts we must grant, as far as quantity alone of vegetation is 

 concerned, that the great quadrupeds of the later tertiary 

 epochs might, in most parts of Northern Europe and Asia, 

 have lived on the spots where their remains are now found. 

 I do not here speak of the kind of vegetation necessary for 

 their support ; because, as there is evidence of physical 

 changes, and as the animals have become extinct, so may 

 we suppose that the species of plants have likewise been 

 changed. 



These remarks directly bear on the case of the Siberian 

 animals preserved in ice. The firm conviction of the 

 necessity of a vegetation, possessing a character of tropical 

 luxuriance, to support such large animals, and the impos- 

 sibility of reconciling this with the proximity of perpetual 

 congelation, was one chief cause of the several theories of 

 sudden revolutions of climate, and of overwhelming catas- 

 trophes, which were invented to account for their entomb- 

 ment. I am far from supposing that the climate has not 

 changed since the period when those animals lived, which now 

 lie buried in the ice. At present I only wish to show, that 

 as far as quantity of food alone is concerned, the ancient rhi- 

 noceroses might have roamed over the steppes of central 

 Siberia (the northern parts probably being under water) 

 even in their present condition, as well as the living rhi- 



* See Humboldt Fragmens Asiatiques, p. 386 : Barton's Geography 

 of Plants : and Make Brun. In the latter work it is said, that the hmit 

 of the growth of trees in Siberia may be drawn under the parallel 

 of 70°. 



