PIEDMONT  PLATEAU  AND  PORTIONS  OF  THE  APPALACHIANS.       685 
SECTION  6.     TENNESSEE. 
SUMMARY   OF   LITERATURE. 
Troost,79  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  graywackes,  which  are  fos- 
siliferous.  The  State  line  is  approximately  the  dividing  line  between 
the  crystallines  and  the  fossiliferous  rocks. 
Owen,80  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. 
Currey,81  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  toAvard  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,82  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  forma- 
tions 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;  gneiss- 
oid  rocks  of  Stone  Mountain ;  the  syenitic  gneiss  of  Roan  Mountain ; 
the  gneiss  and  mica  schist  of  the  Great  Bald,  and  the  talcose  slates 
and  hornblendic  beds  of  Ducktown. 
The  Ocoee  or  basal  division  of  the  Potsdam  is  semimet amorphic, 
Eozoic,  mountain  making,  and  has  a  thickness  of  10,000  feet.  Equiv- 
alent with  this  are  the  slates  and  conglomerates  of  Monroe  County, 
Little  Tennessee  River,  the  west  fork  of  Little  Pigeon,  of  Sevier 
County,  of  the  French  Broad  in  Cocke  County,  of  Big  Butt,  and  of 
Laurel  Gap  of  Iron  Mountain.  The  metamorphic  rocks  occur  in 
stratified  beds  and  are  mostly  of  the  variety  called  gneiss  or  strati- 
fied granite.  The  line  of  separation  between  the  metamorphic  rocks 
and  those  to  the  west  is  sometimes  well  defined,  but  often  poorly, 
the  rocks  gradually  losing  their  crystalline  characters  and  running 
insensibly  into  the  adjacent  conglomerates  and  >lates.  The  general 
line  of  separation  conforms  to  the  Appalachian  ridges.  The  meta- 
morphic beds  and  the  other  groups  all  appear  to  follow  the  same  law 
of  dip  and  strike.  The  dip  is  in  the  main  at  a  high  angle  to  the 
southeast.  The  author  has  not  been  able  to  satisfy  himself  as  to 
want  of  conformableness  in  the  beds,  although  in  Johnson  County 
the  metamorphic  gneiss  comes  abruptly  against  the  limestone;  and 
other   similar    eases   occur;    but   these    unconformable    junctions   arc 
