chap. xi. Banda Oriental. 337 



R. Nankay ; and at P. Gorda in Banda Oriental, a 

 distance of 170 miles, I found the same limestone, 

 containing the same fossil shells, lying at about the 

 same level above the river as at St. Fe. In a southerly 

 direction, these beds sink in height, for at another P. 

 Gorda in Entre Pios, the limestone is seen at a much 

 less height; and there can be little doubt that the 

 yellowish sandy clay, on a level with the river, between 

 the Carcarana and S. Nicolas, belongs to this same 

 formation ; as perhaps do the beds of sand at Buenos 

 Ayres, which lie at the bottom of the Pampean forma- 

 tion, about sixty feet beneath the surface of the Plata. 

 The southerly declination of these beds may perhaps be 

 due, not to unequal elevation, but to the original form 

 of the bottom of the sea, sloping from land situated to 

 the north ; for that land existed at no great distance, 

 we have evidence in the vegetable remains in the lowest 

 bed at St. Fe ; and in the silicified wood and in the 

 bones of Toxodon Paranensis, found (according to 

 M. d'Orbigny) in still lower strata. 



Banda Oriental. — This province lies on the north- 

 ern side of the Plata, and eastward of the Uruguay : it 

 has a gently undulatory surface, with a basis of primary 

 rocks ; and is in most parts covered up with an un- 

 stratified mass, of no great thickness, of reddish 

 Pampean mud. In the eastern half, near Maldonado, 

 this deposit is more arenaceous than in the Pampas ; it 

 contains many though small concretions of marl or 

 tosca-rock, and others of highly ferruginous sandstone ; 

 in one section, only a few yards in depth, it rested on 

 stratified sand. Near Monte Video this deposit in some 

 spots appears to be of greater thickness ; and the re- 

 mains of the Glyptodon and other extinct mammifers 

 have been found in it. In the long line of cliffs, between 

 fifty and sixty feet in height, called the Barrancas de 



