PIEDMONT  PLATEAU  AND  PORTIONS  OF  THE  APPALACHIANS.      681 
from  it  in  degree  of  metamorphism  and  lithological  character,  so  that 
the  change  from  one  to  the  other  is  obvious  along  the  whole  line  of 
contact,  The  slates  included  are  often  highly  plumbaceous,  some- 
times containing  as  high  as  50  per  cent  of  graphite,  and  the  belts 
also  contain  beds  of  coarse  granular  limestone,  in  which  is  tremolite 
as  well  as  magnetic  iron  in  bedded  veins  sometimes  -JO  feet  in  thick- 
ness. Conglomerate  belts  are  common.  The  second  Huronian  area 
is  the  largest,  is  from  20  to  40  miles  wide,  frequently  contains  quartz- 
ite,  which  often  passes  into  conglomerate,  and  in  it  are  most  of  the 
mineral  veins.  The  western  dips  prevail,  but  in  the  western  part  of 
the  tract  the  dip  is  east  for  several  miles.  This  belt  is  bounded  on 
both  sides  by  the  Laurentian,  on  which  it  lies  imconformably  and 
from  it  its  materials  were  derived.  This  is  the  principal  area  of 
Emmons's  Taconic.  Safford  and  Bradley  have  concluded  that  the 
western  Huronian  area  is  Potsdam  and  sub-Potsdam.  If  this  turn- 
out to  be  Silurian  it  is  probable  that  the  Cherokee,  Blue  Ridge, 
and  Kings  Mountain  belts  are  of  the  same  age  and  therefore  post  - 
I  Iuronian. 
Furman,69  in  1889,  describes  a  section  through  Kings  Mountain, 
running  from  5  miles  northwest,  and  another  from  the  old  gold  mine 
to  the  granite.    The  rocks  have  a  high  inclination  and  consist  of  inter 
stratified  quartzite,  limestone,  mica  slate,  etc.,  cut  by  dikes  of  trap 
and  greisen  veins. 
Nitze  and  Hanna,70  in  1896,  in  a  description  of  the  gold  deposits 
of  North  Carolina,  map  and  discuss  the  crystalline  rocks.  The  Caro- 
lina slate  belt  includes :  (1)  Argillaceous,  sericitic  (hydromicaceous) , 
and  chloritic  metamorphosed  slates  and  crystalline  schists;  (2)  sedi- 
mentary pre-Juratrias  slates;  (3)  ancient  volcanic  rhyolites,  quartz 
porphyries,  etc.  (Hint,  hornstone,  etc.),  and  pyroclastic  breccias,  often 
sheared. 
This  area  of  metamorphic  slates  and  schists  embraces  a  bell  extend- 
ing in  a  general  southwesterly  direction  across  the  central  part  of  the 
State,  and  varying  in  width  from  8  to  50  miles.  It  is  bounded  on 
the  west  by  the  central  igneous  area  (Emmons's  pyrocrystalline  rocks, 
Kerr's  Lower  Laurentian),  and  on  the  east  for  the  greater  part  by 
the  Juratrias;  also  in  the  northern  part  by  a  small  area  of  Archeau 
rocks  (Kerr's  Upper  Laurentian),  and  in  the  southeastern  part  by  a 
small  embayment  of  the  Coastal  Plain.  This  is  the  so-called  "great 
slate  belt"  of  Olmsted,  the  "  Taconic  "  of  Kmmons.  and  the  -  Huro- 
nian "  of  Kerr.  The  rocks  of  this  belt  must  in  time  be  differentiated 
and  recorrelated,  when  they  have  been  more  carefully  studied. 
Along  the  extreme  western  {h\<xo  of  the  State,  from  Mitchell  to 
Cherokee  County,  the  quartzites,  slates,  limestones,  and  conglomer- 
ates (here  also  in  a  great  measure  sheared  and  metamorphosed)  which 
constitute  Kerr's  western  Huronian  belt   of  "Cherokee  slates."  have 
