REVIEWS. 275 
the flint knives of Scandinavia were made by chipping off strips from a mass 
1. Flame-shaped arrow-head; obsidian: Teteohtiacan. 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 aa 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 
