630 CROSS, ID DINGS, PIRSSON, WASHINGTON 



graniphyro = microgranitic, megaporphyritic (granophyric in the Vogelsang 

 sense); graniphyri= microgranitic, microporphyritic. 



Porphyritic graphic ; graphophyro = megagraphic, megaporph}'ritic ; 

 graphiphyro = micrographic, megaporphyritic ; graphiphyri = micrographic, 

 microporphyritic. 



Porphyritic felsitic ; felsophyro = megascopically felsitic and porphy- 

 ritic ; felsophyri = megafelsitic, microporphyritic ;felsiphyri = microscopically 

 felsitic and porphyritic. 



Porphyritic vitreotis ; vitrophyro, vitrophyri, vitriphyro, vitriphyri. 



Porphyritic poikilitic ; poikilophyro, poikiliphyro, etc. 



Porphyritic ophitic ; ophitophyro, ophitiphyro, etc. 



Aphyro — megascopically non-porphyritic, or aphyric. 



Aphyri= microscopically non-porphyritic, or aphyric. 



Salphyro = megascopically porphyritic with salic phenocrysts, salphyric 



Fempliyro = megascopically porphyritic with femic phenocrysts, fem- 

 phyric, 



A Iferphyro = megascopically porphyritic with alferric phenocrysts,. 

 alferphyric. 



Salfemphyric, alfersalphyric, alferfemphyric etc. 



From the foregoing statement we may summarize the method 

 of formulating the nomenclature here proposed as follows : 



1. The magmatic ?iame, of whatever division is to be indicated, 

 which is formed by the use of the locality root and appropriate 

 termination, stands as the basis of nomenclature, and is the 

 substantive part of the terminology. This is because the 

 fundamental character of igneous rocks is the chemical composi- 

 tion of the magma, which persists whatever be the mineral 

 development or the texture determined by conditions obtaining^ 

 during solidification. 



2. According to the information at hand, or to be conveyed,, 

 the magmatic name must be selected which represents the Class, 

 Order, or other division to which the rock belongs. And this 

 name may be qualified by mineral and textural adjectives. Thus 

 it is possible to indicate the Class of a rock, when first observed 

 in the field, and to describe its chararteristic mineral compo- 

 nents, and its texture. If the relative proportions of its domi- 

 nant minerals, salic or femic, can be readily determined, the 

 magmatic name for the Order can be used. Subsequently more 



