352 



SCIENCE 



[N. S. Vol. XXVI. No. 663 



should give us iuformation about the time 

 •when the antarctic lands sank for the last 

 time and became covered with ice. 



The age of the Pampas is difficult to deter- 

 mine by means of the mammals indigenous to 

 Southern America since they differ so much 

 from those of our country that a comparison 

 of the two teaches us nothing. Hovcever, 

 among so many remarkable facts shown by 

 the paleontology of the new world, one of the 

 most singular is the invasion of the genera 

 of the northern hemisphere, the Mastodons, 

 Hippidium, tapir, llama, peccary, Machairodus, 

 bear, etc., among the animals of the Argen- 

 tine Eepublic which show an absolutely dif- 

 ferent physiognomy. 



The best known of the new comers, Masto- 

 don Andium is not quaternary in Europe nor 

 in the United States. Cope found it in the 

 Pliocene of Blanco, Texas. The Mastodon 

 angustidens and Pentelici of the European 

 Tertiary are not far removed from it. 



Hippidium neogmum and the species of 

 Eippidium with eye-pockets (?) known as 

 Onohippidium, are more nearly related to the 

 pliocene forms of our country (Equus sten- 

 onis), than to the Quaternary horses. Dr. 

 Matthew has said: "The teeth of Eippidium 

 are lihe those of Phiohippus (upper Miocene) 

 from which it is supposed to he descended." * 



The genus Tapir, unknown in the quater- 

 nary, is well distributed in the European 

 Pliocene; it might have sprung from 

 Tapiravus of the upper Miocene. 



In the simplicity of the dentition of its 

 molars the peccary is an archaic type; it is 

 found in the upper Miocene." 



The llama (Auchenia) is possibly derived 

 from the Pliauchenia of the Pliocene of 

 Blanco. ', 



Machairodus, in the United States and in 

 Europe, has left numerous tertiary remains. 

 Mr. Boule has reported on the Machairodus 



* Matthew, "Illustrations of Evolution among 

 Fossil Mammals," Bull. Am. Mus. of Nat. Hist., 

 Vol. III., Extr. 1903, p. 24. 



° Blainville in his " Osteographie " has said that 

 the peccary is the Sus with the simplest and most 

 normal dentition. 



aphanistes of Pikermi and Machairodus 

 neogmus." 



Ursus honariensis which has persistent 

 premolars and shortened molars differs less 

 from the tertiary bear of our country than 

 from CrsMS prisons and U. spelxus of the quat- 

 ernary. 



If to these citations we add the fact that 

 no elephant has appeared in Southern Amer- 

 ica, we may suppose that the invasion of the 

 forms of the northern hemisphere took place 

 in the pliocene and not in the quaternary. 

 Dr. Osborn has pointed out recently that the 

 invasion of the Edentates of South America 

 and the migration of the North American 

 mammalia into South America, was quite 

 characteristic of the pliocene phase in the 

 United States.' It is important to note that, 

 according to the lists of fossils, divided into 

 numerous stages by Mr. E. Ameghino, it is 

 only from the time of the lower Pampeen that 

 the animals of the north multiplied.' They 

 are not present in the beds of Mt. Hermoso. 



The greater part of the Pampeen beds are 

 Pliocene, but this is no reason why the upper- 

 most should not belong to the quaternary. 

 Mr. Ameghino attributes the lowest beds of 

 the Pampeen which he calls Lujanean (?) 

 to this deposit (terrain). Now in these beds 

 the American animal world shows still more 

 strength, since the quadrupeds from the 

 United States are there side by side with the 

 gigantic animals born in the southern regions. 

 If the age attributed to the Lujanean is correct 

 we must conclude, from our remarks above, 

 that, at the beginning of the quaternary, that 

 is to say in the epoch when Man was living 

 in Europe, the antarctic territory could not 

 have been completely separated from America. 

 It would not be impossible to find buried 



" Boule, " Revision des espfeces Europfiennes de 

 Machairodus," Bull, de la Sao. g6ol. de France, 

 4""= series, vol. 1, p. 572, 1901. 



' Osborn, " Tertiary Mammal Horizons of North 

 America," Bull. Am. Mus. Nat. Hist., Vol. XXIII., 

 p. 251, 1907. 



' Florentino Ameghgne, " Les formations S6di- 

 mentaires du Cretacg Supgrieur et du Tertiares de 

 Patagonie," no. 8, pp. 480-498, Buenos Aires, 1906. 



