chap, vii.] MAMMALIA OF THE NEW WORLD. 149 



and Netv Worlds. — Leaving the more special applications of 

 palaeontological evidence to be made after discussing the relations 

 of the existing fauna of the several regions, we propose here to 

 indicate briefly, some of the more general deductions from the 

 evidence which has now been laid before our readers. 



The first, and perhaps the most startling fact brought out by 

 our systematic review, is the very recent and almost universal 

 change that has taken place in the character of the fauna, over 

 all the areas we have been considering ; a change which seems 

 to be altogether unprecedented in the past history of the same 

 countries as revealed by the geological record. In Europe, in 

 North America, and in South America, we have evidence that a 

 very similar change occurred about the same time. In all three 

 we find, in the most recent deposits — cave-earths, peat-bogs, and 

 gravels — the remains of a whole series of large animals, which 

 have since become wholly extinct or only survive in far-distant 

 lands. In Europe, the great Irish elk, the Machairodus and 

 cave-lion, the rhinoceros, hippopotamus, and elephant ; — in North 

 America, equally large felines, horses and tapirs larger than any 

 now living, a llama as large as a camel, great mastodons and 

 elephants, and abundance of huge megatheroid animals of almost 

 equal size ; — in South America these same megatheroids in greater 

 variety, numerous huge armadillos, a mastodon, large horses and 

 tapirs, large porcupines, two forms of antelope, numerous bears and 

 felines, including & Machairodus, and a large monkey, — have all be- 

 come extinct since the deposition of the most recent of the fossil- 

 bearing strata. This is certainly not a great while ago, geologi- 

 cally ; and it is almost certain that this great organic revolution, 

 implying physical changes of such vast proportions that they 

 must have been due to causes of adequate intensity and propor- 

 tionate range, has taken place since man lived on the earth. 

 This is proved to have been the case in Europe, and is supported 

 by much evidence both as regards North and South America. 



It is clear that so complete and sudden a change in the higher 

 forms of life, does not represent the normal state of things. 

 Species and genera have not, at all times, become so rapidly 

 extinct The time occupied by the " Eecent period," that is the 



