74 MOSTLY MAMMALS 



there is not a vestige of rock or stone to be seen, unless 

 it be in the few places where the aforesaid " tosca " has 

 been brought to the surface. In spite of its fresh-water 

 origin, there is, however, evidence that portions of the 

 Pampean formation have been submerged beneath the sea. 

 For instance, in the neighbourhood of the city of La Plata 

 there occurs a bed of marine shells overlying the alluvial 

 mud, all the species of molluscs being now found living 

 in the Bay of Monte Video. I have also observed a 

 similar bed at Santa Lucia, in the Banda Oriental, at an 

 elevation of about one hundred feet above the sea, which 

 was overlain by a considerable thickness of sands ; and 

 the same deposit occurs far inland, at the town of Parana. 

 From these data it may be inferred that after the temporary 

 subsidence of the Pampas, during which the marine beds 

 were deposited, there has been a considerable elevation 

 (which is probably still going on) of the whole country ; 

 and that these movements have taken place at a very recent 

 epoch indeed. 



At the present day the Argentine Pampas, with the 

 exception of a few willows along the river courses, is 

 practically destitute of trees (save where they have of late 

 years been planted around the various settlements), and 

 forms a boundless sea of grass, relieved here and there by 

 tussocks of the tall Pampas-grass, or giant thistles, and 

 adorned in spring with scarlet verbena and other bright- 

 hued flowers. Till the introduction of the countless herds 

 of horses, cattle, and sheep, which now roam over its 

 extent, this vast tract of country was tenanted by the 

 guanaco, the Pampas-deer, the viscacha, and the rhea, 

 which, with the exception of certain carnivores, were 

 almost the only animals of any size to be found throughout 

 its length and breadth. 



