GRANITES OF NORTH CAROLINA 397 



Since both of these minerals are present in the epidote-bearing rock, 

 their absence in the unakite is very Hkely due to extreme epidotization 

 of the unakite, completely altering both the mica and the plagioclase 

 in case these were originally present. That mica or some ferro- 

 magnesian constituent was originally present in the unakite it seems 

 necessary to assume in order to meet the requisite conditions of for- 

 mation of so large a quantity of epidote. 



The principal component minerals in the unakite are quartz, ortho- 

 clase, epidote, rutile, titaniferous iron oxide, and secondary musco- 

 vite, kaolin, and leucoxene. Rutile is contained in the quartz anhedra 

 as inclusions of hair-like filaments. The orthoclase has a pronounced 

 pink color in the hand specimens which disappears in the thin sec- 

 tions. Here, as in the epidote-bearing rock, conclusive evidence is 

 furnished of the wholly secondary nature of the epidote. Its largest 

 occurrence is in the replacement of the feldspar individuals in the 

 form of a complete mass of microscopic granules, entirely obscuring 

 in many cases the feldspar substance, but preserving the outline of 

 the latter in a more or less perfect manner. The granular masses 

 of epidote appear in the hand specimens as single large epidote anhe- 

 dra. Other feldspar individuals show patchy areas and scattered 

 granules of epidote over their surfaces. Still a third occurrence of 

 the epidote is in irregular broken bands or stringers, following the 

 network of fractures in both the feldspar and the quartz. In some 

 cases these stringers ramify outward from the granular masses of 

 epidote, replacing the feldspar. Again the granular masses often 

 show irregular margins traced outward from the more compact mass 

 into scattered granules of epidote. All gradations between these 

 occurrences of the epidote are traced. Very little of the feldspar is 

 entirely free from epidotization. 



Some peripheral shattering accompanied by much fracturing of, 

 and strained shadows in, the quartz and feldspar, indicating the 

 effects of dynamic forces, characterizes to some degree all of the thin 

 sections. 



It seemed quite conclusive, from the different exposures studied of 

 the unakite in its relations to the inclosing epidote-bearing granite, 

 that the unakite is of distinct vein character which can be referred 



