164  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1904.         [bull.  260. 
found.  Thirty-seven  tons  of  ore  of  good  grade  have  been  shipped 
from  the  former  property.  A  little  cassiterite  has  been  found  at 
the  Brewer  gold  mine,  in  Chesterfield  County,  S.  C. 
Georgia. — Tin  ore  has  been  found  in  Lumpkin  County,  northeast 
of  Dahlonega,  where  schists  are  said  to  be  interfoliated  with  granitic 
rock.  A  very  small  amount  of  tin  has  been  found  near  Dahlonega 
in  the  process  of  gold  washing. 
Alabama. — At  two  localities  in  Alabama  cassiterite  has  been  found. 
In  Coosa  County  a  few  pounds  were  found  on  the  surface  in  associa- 
tion with  a  ledge  of  coarse-grained  granite  (pegmatite?)  which  cut 
the  schists  of  the  gold  belt. 
Near  Ashland,  in  Clay  County,  work  was  done  in  the  eighties  at 
the  Broad  Arrow  mines.     Bands  of  gneiss  are  said  to  alternate  with  ! 
layers  of  schist,  all  resting  on  a  feldspathic  granite.     The  cassiterite 4 
occurred  in  the  gneiss.     A  stamp  mill  was  erected,  but  the  venture'1 
proved  unsuccessful. 
Lake  Superior  anal  Missouri. — Reported  discoveries  of  tin  ore  attic 
the  head  of  Lake  Superior  and  in  the  Ozark  region  proved  to  be  ,r 
fraudulent. 
South  Dakota  and  Wyoming. — Probably  the  most  widely  knownii 
occurrence  of  tin  in  the  United  States  is  in  the  Black  Hills.     Tin  j 
in  place  was  discovered  in  1883  near  Harney  Peak,  South  Dakota,  in  L 
the  southern  part  of  the  Black  Hills  region,  and  shortly  afterwards  in  i 
the  Nigger  Hill  region,  Wyoming,  in  the  northwestern  part  of  the  ** 
hills.     Since   that  time   the   known   area   of   distribution   has   been  k 
extended  over  much  of  the  intervening  territory. 
Cassiterite  appears  to  occur  there  in  four  ways :  L 
1.  As  impregnation  deposits  from  solutions  or  vapors  in  the  pre-  ;  , 
Cambrian   pegmatite  dikes,  sometimes  also  partially  replacing  the  I 
mica-schist  wall   rock   of   the   pegmatite.     In   this   occurrence   it  isij , 
accompanied   by   spodumene,   lepidolite,   columbite,   tantalite,   tour- I , 
marine,  arsenopyrite  and  other  minerals. 
2.  In  quartz  veins  cutting  the  pre-Cambrian  core  of  the  hills  with  > 
spodumene  and  other  accompanying  minerals.  j, 
3.  As  an  original  constituent  of  some  of  the  pegmatite,  with  prac- 
tically no  other  uncommon  minerals  present. 
4.  In  placers  resulting  from  the  breaking  down  of  any  or  all  oi 
the  foregoing  deposits. 
Judging  from  many  estimates  which  have  been  made,  it  is  |)rob- 
able  that  the  veins  average  1  to  2  per  cent  metallic  tin. 
A  great  deal  of  money  has  been  expended  in  development,  par- 
ticularly in  the  vicinity  of  Harney  Peak,  but  the  output  has  been 
only  a  lew  small  shipments.  A  little  development  work  is  now  going 
on  in  the  Nigger  Hill  region. 
Montana, — In  Jefferson  Countv  wood  tin,  associated   with  white 
