REVIEWS. 275 



the flint knives of Scandinavia were made by chipping off strips from a mass 



1. Flame-shaped arrow-head ; obsidian : Teteohuacan. 2. Arrow-head ; opake obsidian : 

 Teteohuacan. 3. Knife or razor of obsidian, shown in two aspects ; Mexico. 4. Leaf-shaped 

 knife or javelin-head ; obsidian ; from Real del Monte. 5. Spear -head of chalcedony ; one 

 of a pair supposed to be spears of state ; found in excavating for the Casa Grande, Tezcuco. 

 (This peculiar opalescent chalcedony occurs as concretions, sometimes of large size, in the 

 trachytic lavas of Mexico.) 



is proved by the many-sided prisms occasionally found there, and particularly 

 by that one which was discovered just where it had been worked, with the 



