QUARTZ-FELDSPAR-PORPHYRY FROM LLANO, TEX. 231 



alkalies it is sodipotassic, and hence an alaskose near liparose : lipa- 

 rose-alaskose. If the norm derived from the mode were made a 

 basis of classification, the rock would be quardofelic, a britannare, 

 near columbare. From this it is evident that the rock is interme- 

 diate between these orders, and may be a liparose-alaskose, or an 

 alaskose-liparose. 



Joseph P. Iddings. 



