Total - 100.45 99.41 99.91 



I. — Almerose. Cordierite andesite, Hoyazo, Cabo de Gata, 

 Almeria, Spain. 



II. — Riesenose. Granite, Wengenweise, Henweg, Hesse. 



III. — (Piemanose). Schliere in granite, Vorderberg, Riesen- 

 gebirge, Silesia. 



The norms for these rocks are : — 



As a result of the classification of the analyses of obsidianites, 

 we are now in a position to compare these analyses critically 

 with one another, and also with other analyses. It is self- 

 evident that there is a strong family resemblance between all 

 nine analyses. Most of the obsidianites, as already stated, 

 l)el()ng to the group Almerose, and the others do not diverge 

 greatly from this type. The subdivision Riesenose, though 

 belonging to a higher class than Almerose, still fulls into the 

 corresponding Order, Rang and Sub-rang, the only difference 

 being that the higher percentage of silica and lower percentage 



