66 
Journal of the Mitchell Society 
[. November 
The age of many of the granites and granite gneisses has not 
been determined though a part are probably Archaean. The 
granites and their different phases are next to the Carolina gneiss 
in importance, and are particularly prominent in areas where rich 
deposits of monazite exist. The types found in the monazite 
region are biotite granite, muscovite, and hornblende granite, 
while in some places considerable secondary garnet has developed 
in the gneissoid granites. The texture of the granites are gneissic 
or schistose, porphyritic, and massive. Where the granite is both 
porphyritic and schistose the feldspar phenocrysts often have an 
augen form, caused by crushing and shearing. Many of the 
granite masses have much quartz in veins and veinlets throughout 
their mass. Some of this quartz is massive crystalline and other 
occurs with more or less well-defined crystal form, or drusy sur- 
faces. The occurrence of quartz veins is not always confined to 
the granite masses, but in many places extends some distance 
from the contact of the granite into adjacent formations. The 
composition of the granite masses near the contact with other for- 
mations has in many cases been altered by the partial or complete 
absorption of inclusions of those formations. This phenomena is 
particularly evident where a mica granite, by intrusion into a 
mass of Roan gneiss, has become a hornblende granite near its 
borders through the absorption of hornblende. 
Pegmatite is a common rock throughout the monazite region 
and is especially prominent in those areas rich in monazite. Two 
principal methods of occurrence are here recognized. In one the 
pegmatite occurs in distinct masses or bodies composed of quartz 
and feldspar, with or without mica and other accessory con- 
stituents. The texture of these masses is, in some cases, extreme- 
ly coarse with the minerals composing the pegmatite separated out 
in crystals or masses many inches across. The other type is peg- 
matized gneiss, representing the addition of the pegmatite minerals 
to the gneiss, with perhaps some recrystallization of portions of 
the inclosing rocks. The nature of this pegmatized rock varies 
considerably. In some places secondary quartz is the principal 
mineral added, while feldspar is present in smaller quantities. In 
others feldspar is more prominent . Mica may or may not be 
