458 GEOLOGY, 



Rang 1. — ^ n r\i ^ — >i"> alkalies extreme, peralkalic, 



7 5 



2. *' <Y>^, alkalies dominant, domalkalic. 



5 3 



3. *' <^>-r, alkalies and lime equal or nearly so, alkalicalcic. 



3 1 



4. '* <^>^, lime dominant, docalcic. 



o 7 



5. " <«-, lime extreme, percalcic. 



K O' 7 

 Subrang 1. ^ ^ ^^ >— , potash extreme, perpotassic. 



7 5 



2. " <:i->5-, potash dominant, dopotassic. 



1 o 



5 3 



3. " <-^>^, potash and soda equal, sodipotassic. 



3 1 

 5>7 



4. " <^>^, soda dominant, dosodic. 



5. " <y, soda extreme, persodic. 



In classes IV and V rangs are formed by comparing f emic MgO + FeO + CaO" 

 with femic alkalies K20'' + Na20". 



Minerals containing magnesia, iron, and lime are called mirlic. 



Rang 1. — T^ /^// I AT r\i, — >Ti extremely mirlic, permirlic. 

 i\.2\J +JNa2U i 



7 5 



2. '' <7->^, dominantly mirlic, domirlic. 



1 o 



5 3 



3. *' <^>-zr, equally mirlic and alkalic, alkalimirlic. 



o o 



3 1. 



4. ** <^>^, dominantly alkalic, domalkalic. 



5 7 



5. '* <^, extremely alkalic, peralkalic. 



Sections of rangs distinguish between MgO + FeO and CaO''. Minerals with 



MgO + FeO are called miric. 



^ ^. ^ MgO + FeO 7 ^ , . . 



Section 1. — p ^,f — >:j-, extremely mine, permiric, 



7 5 



2. '* <:j->y, dominantly miric, domiric. 



5 3 



3. *' <5->^, equally miric and calcic, calcimiric, 



3 1 



4. " <^>=r, dominantly calcic, docalcic. 



