14 Lisbon — Pebbles on the Central Plateau of Brazil. 



stable. The opposite face is polished and lias deep pits black- 

 ened by vegetation. On one side these two -faces are united 

 by a thick rounded edge which is as well polished as the face 



4a 



Facetted pebbles from the central plateau of Brazil. 

 About half the natural size. 



opposite to the base, this polished surface continuing for some 

 millimeters down the under part of the stone. These two 

 flat faces of the pebble are joined on the other side by a 

 rounded surface, such as may be observed on a common water- 

 worn pebble. 



Facetted pebbles from the central plateau of Brazil. 

 About half the natural size. 



id) Number 7 is flat having the two opposite faces parallel. 

 The largest face or the base is rough and plane. The upper 

 side is only partly polished and is very much blackened by 



