191J^] Certain Mineral Resources 103 



Xorth Carolina, Soiitli Carolina, and Georgia. In Xorth Car- 

 olina there are a number of mica-schists that carry monazite, 

 as that near the Deake mica mine, Mitchell County, and at 

 Milholland's mill, Alexander County. 



The rocks of this monazite area are for the most part 

 gneisses, schists and granites. These vary considerably and are 

 grouped under the following heads : 



1. Carolina g-neiss.^ 



2. Eoan gneiss.^ 



3. Granites. 



4. Pegmatites. 



The_ Carolina gneiss is the oldest formation and is of Ar- 

 chean age. Its structure varies considerably, the more com- 

 mon types being mica, garnet, cyanite and graphite gneisses 

 and schists. Associated with this Carolina to such an extent 

 that it is a rather characteristic feature is pegmatite and, as 

 will be seen later, this pegmatite is common throughout the 

 portions of the area that carry monazite in commercial quan- 

 tity. 



The Roan gneiss, which is the next oldest formation in 

 the monazite region, consists almost entirely of hornblende 

 gneiss and schist. The granites of the area are gneissoid, por- 

 phyritic and massive in structure and while of uncertain age, 

 they are probably Archean. 



The peg-matite occurs in two distinct phases ; one in which 

 it fonns distinct masses or bodies with the typical composi- 

 tion and texture of pegmatite, while the other phase is a peg- 

 matized gTieiss which represents the addition of the pegmatite 

 minerals to the gneisses which has caused a partial recrystalli- 

 zation of portions of the gneiss. The structure of the pegmatite 

 is irregular, occuring in some places in sheets or lenses 

 interbedded and folded with the enclosing gneisses and schists, 

 while in other places it occurs in dikes, veins or lenses either 

 conformable with the enclosing rocks through j^art of its extent 

 and cutting across them in other parts, or in irregular masses 



8U. S. Geological Survey, Asheville Folio, No. 116, 1904; pp. 2 and 3. 



