CLASSIFICATION OF IGNEOUS ROCKS 159 



Orthorhyolite is the extrusive equivalent of this fa^lil5^ 



Comendite Bertolio' is an aegirite-rhyoKte. 



Paisanite Osann. Paisanite was named from Paisano 



Pass, Texas, by Osann.^ It is a dike rock composed of quartz, 



microperthite, and riebeckite. 



(217) Albite-granite. The term albite-granite is here applied 

 to a normal granite containing orthoclase and plagioclase between 

 the proportions 95:5 and 65:35. The plagioclase, however, is 

 albite, and not the usual oligoclase. A new name should be 

 chosen, since the terms soda-granite, albite-granite, albite-syenite, 

 etc., have been used for rocks with albite as the only feldspar, 

 that is, for rocks which properly are called albite-tonalite, albite- 

 diorite, etc., in this classification. 



Albite-rhyolite. The extrusive equivalent of the pre- 

 ceding. The objection to the term albite-granite applies also to 

 albite-rhyoHte. 



(218) Albite-adamellite. No confusion can result from the 

 use of this term, since adamelHte conveys the idea of a quartz- 

 monzonitic rock, and the prefix indicates that the plagioclase of 

 the orthoclase-plagioclase combination is albite. A number of 

 grorudites fall here, as does also a lindoite, and numerous arfvedson- 

 ite- and riebeckite-granites, so called. 



Albite-dellenite. The extrusive of the preceding. 



(219) Albite-granodiorite. There is no possibility of misunder- 

 standing this name. See notes under (218) and (229). 



Albite-rhyodacite. See note under (229). 

 (2 1 10) Albite-tonalite. The meaning of this term alsois uimiis- 

 takable. See note under (217). For the use of tonalite for quartz- 

 diorite see (2210). 



Albite-dacite. The extrusive of preceding. 



' S. Bertolio, "Sulle comenditi, nuovo gruppo di rioliti con aegirina," Atii. della 

 Reale Accad. dei Lincei, CI. scienze fisiche, mat. e nat., IV (1895), 2 semestre, pp. 

 49-50- 



» A. Osann, "Report on the Rocks of Trans-Pecos, Texas," 4ih Ann. Kept. Geol. 

 Surv. Texas (1892), p. 132. 



