634 CROSS, ID DINGS, PIRSSON, WASHINGTON 



zonose,&x\d the mica-basalt of Santa Maria Basin, Arizona, 1 a 

 felsophyro-biotite-monzonose. A glassy facies of any of these, with 

 hornblende phenocrysts, for example, would be hornblende -vitro- 

 monzonose. A pure glass of this composition would be simply a 

 vitro- monzonose, or aphyrovitro-mo?izonose ; if microlitic it would 

 be a phyrivitro-mo7izonose . 



To take another example, the normal, lithoidal, micro-spher- 

 ulitic and porphyritic rhyolite of the Yellowstone National Park 

 is spheriphyro-alaskose , which is a very concise expression for a 

 rock that is microscopically spherulitic, megascopically porphy- 

 ritic, having the chemical composition of a rock whose norm 

 consists of extreme salic minerals, of which quartz and feldspar 

 are nearly equal, the feldspars extremely alkalic, and soda and 

 potash in nearly equal proportions. 



An example of intermediate rock is to be found in the granite 

 of Butte, Mont., whose composition is discussed at length in 

 connection with the calculation of norm and mode. This rock 

 belongs near the border line between Classes I and II, and the 



rock from Walkerville Station, Butte, has -. — = 7.14. It is a 



fem ' 



persalane near dosalane, and may be called dosalane-persalane, 

 which contracts to do-persalane. 

 The Order is quardofelic, 



F 7 5 



e= 3 - 4 ' < 7 > l i 



it is britannare (Class I) near austrare (Class II), or austrare 

 britannare. The Rang is alcalicalcic, 



K 2 0'+Na 2 Q' <r 5 > 3. 



it is coloradase (Class I) near tonalase (Class II), or tonalase- 

 coloradase. The Subrang is sodipotassic, 



= .,-<s>|i 



3 5 

 it is amiatose (Class I) near harzose (Class II) or harzose-amiatose. 



'Bull, 148 U. S. G. S., p. 187 (B, C, D), 1897. 



