PIEDMONT  PLATEAU  AND  PORTIONS  OF  THE  APPALACHIANS.       683 
Carolina  gneiss,  including  interbedded  mica  gneiss  and  mica  schist, 
coarse  and  fine,  bluish  gray  and  gray,  small  beds  of  hornblende  gneiss, 
large  bodies  of  garnet  schist  and  cyanite  schist,  and  dikes  of  biotite 
granite,  both  altered  and  unaltered;  Roan  gneiss,  including  horn- 
blende gneiss  and  schist,  with  some  massive  and  schistose  diorite, 
many  beds  of  mica  gneiss,  mica  schist,  and  hornblende-mica  gneiss, 
and  dikes  of  altered  and  unaltered  biotite  granite;  metagabbro,  in- 
cluding dark-green  and  black,  massive  metagabbro;  soapstone,  dunite, 
and  serpentine,  dunite  in  part  serpentinized,  and  soapstone  contain- 
ing talc  and  tremolite;  Cranberry  granite,  including  biotite  granite 
and  granite  gneiss,  coarse  and  fine,  colors  light  gray,  dark  gray,  and 
white,  dikes  of  schistose  and  unaltered  diabase,  fragments  of  horn- 
blende gneiss,  and  dikes  of  unaltered,  fine  biotite  granite ;  Maxpatch 
granite,  including  coarse  biotite  granite,  usually  massive,  but  in 
places  porphyritic  and  altered  to  augen  gneiss,  colors  usually  light 
gray  in  the  eastern  areas  and  reddish  in  the  western.  Assigned  to 
the  Algonkian  ( ?)  are  later  igneous  rocks,  including  metadiabase  and 
metarhyolite. 
Watson,73  in  1904,  maps  and  petrographically  describes  the  gran- 
ites of  North  Carolina. 
Keith,74  in  1905,  maps  and  describes  the  geology  of  the  Mount 
Mitchell  quadrangle,  in  North  Carolina  and  Tennessee.  The  oldest 
rock  is  the  Carolina  gneiss,  of  unknown  origin,  assigned  to  the  Arch- 
ean,  occupying  the  larger  part  of  the  quadrangle.  Intrusive  into  it 
are  the  Roan  gneiss,  Cranberry  granite,  Henderson  granite,  soap- 
stone,  dunite,  and  serpentine,  also  assigned  to  the  Archean.  A  single 
belt  of  conglomerate,  graywacke,  and  similar  rocks  of  unknown  age 
surrounded  entirely  by  the  Carolina  gneiss  lies  in  the  south-central 
part  of  the  quadrangle.  Between  it  and  the  adjoining  Carolina 
gneiss  there  is  apparent  conformity.  Overlying  all  are  Cambrian 
rocks. 
Pratt  and  Lewis,75  in  1905,  in  connection  with  a  description  of 
the  corundum  of  western  North  Carolina,  briefly  describe  and  map  the 
distribution  of  the  pre-Cambrian  rocks  of  the  area,  especially  the 
peridotites. 
(Jkaton  and  Lindgren,70  in  190C>,  report  on  a  reconnaissance  of 
gold  and  tin  deposits  of  the  southern  Appalachians,  centering  at 
about  the  middle  of  the  North  Carolina-South  Carolina  boundary  line 
and  including  parts  of  Cleveland,  Lincoln,  Gaston,  and  Union  conn- 
ties  in  North  Carolina  and  of  Union,  Cherokee,  York,  Lancaster,  and 
Chesterfield  counties  in  South  Carolina. 
The  rocks  of  this  area  belong  to  three  great  classes  -igneous,  sedi- 
mentary, and  metamorphic.  Sedimentary  and  igneous  rocks  of  great 
age  have  been  much  contorted  and  folded.  The  forces  producing  and 
attendant  on  these  movements  have  extremely   metamorphosed  the 
