1915.] 



NATURAL SCIENCES OF PHILADELPHIA. 



US 



c. Weathered 

 Sulfates : 

 Carbonates : 

 Nitrates : 



barite, gypsum 

 calcite, aragonite 

 nitromagnesite, nitrocalcite 



11. 1. C. Ferruginous (also Manganiferous and Zinciferous) 



Sediments 



a. Primary 



Silicon oxides: (quartz) 



SiUcates : glaucdnite 



