136 A FOSSIL HORSE. [chap. vii. 



Pampas was slowly elevated into dry land, the water 

 covering it was brackish. Below Buenos Ayres there are 

 upraised beds of sea-shells of existing species, which also 

 proves that the period of elevation of the Pampas was 

 within the recent period. 



In the Pampgean deposit at the Bajada I found the 

 osseous armour of a gigantic armadillo-like animal, the 

 inside of which, when the earth was removed, was like a 

 great cauldron ; I found also teeth of the toxodon and 

 mastodon, and one tooth of a horse, in the same stained 

 and decayed state. This latter tooth greatly interested me,* 

 and I took scrupulous care in ascertaining that it had been 

 embedded contemporaneously with the other remains ; for 

 I was not then aware that amongst the fossils from Bahia 

 Blanca there was a horse's tooth hidden in the matrix ; nor 

 was it then known with certainty that the remains of horses 

 are common in North America. Mr. Lyell has lately 

 brought from the United States a tooth of a horse ; and it 

 is an interesting fact, that Professor Owen could find in 

 no species, either fossil or recent, a slight but peculiar 

 curvature characterizing it, until he thought of comparing 

 it with my specimen found here : he has named this 

 American horse Equus curvidens. Certainly it is a mar- 

 vellous fact in the history of the mammalia, that in South 

 America a native horse should have lived and disappeared, 

 to be succeeded in after ages by the countless herds 

 descended from the few introduced with the Spanish 

 colonists ! 



The existence in South America of a fossil horse, of the 

 mastodon, possibly of an elephant, t and of a hollow-horned 

 ruminant, discovered by MM. Lund and Clausen in the 

 caves of Brazil, are highly interesting facts with respect to 

 the geographical distribution of animals. At the present 

 time, if we divide America, not by the Isthmus of Panama, 

 but by the southern part of Mexico, | in lat. 20°, where the 



* I need hardly state here that there is good evidence against any horse 

 living in America at the time of Columbus. 



t Cuvier, *' Ossemens Fossiles," torn, i., p. 158. 



X This is the geographical division followed by Lichtenstein, Swainson, 

 Erichson, and Richardson. The section from Vera Cruz to Acapulco, given 

 by Humboldt in the Polit. Essay on Kingdom of N. Spain, will show how 

 immense a barrier the Mexican table-land forms. Dr. Richardson, in his 

 admirable Report on the Zoolopry of N. America read before- the Brit. Assoc, 

 1836 (p. 157), talking of the identification of a Mexidan animal with the 

 Syrutheres prehensilis, says, " We do not know with what propriety, but if 

 correct, it is, if not a solitary instance, at least very nearly so, of a rodent 

 animal being common to North and Sou tit America." 



