A LAND OF SKELETONS 79 



the depletion of the fauna and flora of Argentina as one 

 of the unsolved problems of science. 



In regard to other formations, it must suffice to say that 

 at Parana, and also on the coast at Monte Hermoso, near 

 Bahia Blanca, there occur certain Tertiary deposits which 

 are evidently somewhat older than the Pampean beds, 

 although containing a closely allied fauna. The most 

 interesting feature connected with this formation (which 

 may probably be correlated with the upper Pliocene of 

 Europe) is that the mammals are for the most part of 

 smaller size than their relatives of the Pampean, this being 

 especially shown by the glyptodons, and by those ground- 

 sloths known as scelidotheres, which are near allies of the 

 mylodons. When we reach the still older beds of Santa 

 Cruz, in Patagonia, which are probably of Miocene age, we 

 find not only this diminution in the size of the mammals 

 still more marked, but we likewise notice the disappearance 

 of all the northern forms, such as deer, horses, guanacos, 

 and mastodons, thus showing that we have reached the 

 period when South America was disconnected from the 

 northern half of the continent, and possessed an absolutely 

 peculiar fauna. Instead of glyptodons with a shell of eight 

 or ten feet in length, we meet with species in which the 

 carapace did not measure more than a yard ; while in place 

 of mylodons bigger than a rhinoceros we are confronted with 

 a species not so large as a Highland sheep. The camel-like 

 Macrauchenia was likewise represented by several much 

 smaller allies, while the various species of Nesodon, which 

 represented the gigantic Toxodon of the Pampean, were either 

 small or moderate-sized animals. Somewhat curiously, there 

 were, however, several kinds of gigantic flightless birds, 

 which are quite unknown in the higher beds, and appear 

 to have been allied to the existing seriema of Brazil. 



