422  PRE-CAMBRIAN    ROCKS    OF    NORTH    AMERICA.  [bull.  88. 
vious  along  the  whole  line  of  contact.  The  slates  included  are  often 
highly  plumbaceous,  sometimes  containing  as  high  as  50  per  cent 
of  graphite,  and  also  contain  beds  of  coarse  granular  limestone,  in 
which  is  tremolite  as  well  as  magnetic  iron  in  bedded  veins  some 
times  20  feet  in  thickness.  Conglomerate  belts  are  common.  The 
second  Huronian  area  is  the  largest,  is  from  20  to  40  miles  wide,  fre- 
quently contains  quartzite,  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  un- 
conformably  and  from  it  its  materials  were  derived.  This  is  the  prin- 
cipal area  of  Emmons's  Taconic.  The  western  Huronian  area  by  Safford 
and  Bradley  has  been  concluded  to  be  Potsdam  and  sub-Potsdam.  If 
this  turns  out  to  be  Silurian  it  is  probable  that  the  Cherokee,  Blue 
ridge,  and  King  mountain  belts  are  of  the  same  age  and  therefore  post- 
Huronian. 
Furman,193  in  1889,  describes  a  section  through  King's  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. 
LITERATURE   OF    TENNESSEE. 
Troost,194  in  1840,  describes  the  Primordial  rocks  of  Tennessee  as 
occurring  in  detached  areas  along  the  eastern  side  of  the  state.  These 
are  granitic  and  are  associated  with  greywackes,  which  are  fossilifer- 
ous.  The  state  line  is  approximately  the  dividing  line  between  the 
crystallines  and  the  fossiliferous  rocks. 
Owen,195  in  1842,  states  that  the  metamorphic  rocks  in  the  Unaka 
mountains  dip  at  a  high  angle  toward  the  granitic  rocks.  These  rela- 
tions are  supposed  to  be  due  to  dislocations. 
Cltrrey,196  in  1857,  states  that  the  Great  Smoky  mountains  are  of 
granite,  gneiss,  mica- slate,  talcose  slate  and  quartz  rock.  The  sand- 
stones, shales,  and  slates  on  the  western  descent  of  the  mountains  are 
regarded  as  primitive  or  metamorphic.  They  are  in  an  inclined  posi- 
tion, dipping  inwardly  toward  the  center  of  the  mountain,  the  Primor- 
dial rocks  appearing  to  overlie  them.  No  anticlinal  or  synclinal  axes 
are  found,  and  the  tilting  is  explained  by  faults. 
Safford,197  in  1869,  places  the  lowest  formations  of  Tennessee  as 
Potsdam  and  metamorphic.  The  Ocoee  group  is  at  the  base  of  the 
Potsdam  and  is,  so  far  as  known,  Eozoic.  The  metamorphic  formations 
are  altered  rocks,  Azoic  or  Eozoic  in  part,  mountain-making,  and  many 
thousand  feet  thick.  They  include  the  talcose  slate,  in  part,  of  Beech 
mountain  and  Slate  face,  in  Johnson  county;  gneissoid  rocks  of  Stone 
mountain ;  the  syenitic  gneiss  of  Roan  mountain;  the  gneiss  and  mica- 
schist  of  the  Great  Bald;  the  talcose  slates  and  hornblendic  beds  of 
Ducktown. 
