HESS    AND 
GRATON 
^D]  OCCURRENCE    AND   DISTRIBUTION    OP    TIN.  181 
rains  cease  and  smelt  it  in  rude  shaft  furnaces.  Mining  on  a  larger 
scale  has  so  far  not  been  very  successful. 
The  placers  now  known  are  not  rich  enough  to  be  worked. 
Tin  ore  has  been  found  in  Lower  California,  but  little  is  known  of 
its  occurrence. 
ALASKA. 
Tin  has  been  found  at  a  number  of  places  in  Alaska,  but  as  yet 
there  has  been  little  production. 
It  has  been  found  in  place  in  Seward  Peninsula,  at  Lost  River,  and 
Cape  Mountain,  and  is  reported  from  Brooks  Mountain,  Ears  Moun- 
tain, and  the  Darby  Mountains.  Alluvial  deposits  have  been  found 
on  Buck  Creek  and  Old  Glory  Creek,  and  are  reported  on  the  Arctic 
slope  north  of  Buck  Creek,  on  Gold  Bottom  Creek,  near  Nome,  and 
at  one  or  two  other  places. 
In  the  interior  L.  M.  Prindle  and  the  writer  found  pebbles  of 
stream  tin  in  the  gold  placers  of  Cleary  Creek,  near  Fairbanks,  in 
July,  1904,  and  miners  report  it  in  the  gold  placers  of  the  Koyukuk. 
At  Lost  River  the  country  rock  is  a  Silurian  limestone,  through 
which  is  thrust  a  granite  boss  about  one-half  mile  in  diameter. 
Quartz-porphyry  dikes  also  cut  the  limestones  in  various  places. 
These  dikes  are  frequently  much  kaolinized,  and  in  other  places 
replaced  by  fluorite,  which  sometimes  colors  the  dike  violet  or  purple. 
The  cassiterite  occurs  disseminated  through  the  dikes,  particularly 
in  the  kaolinized  portions,  and  in  veins  in  the  limestone.  Small 
amounts  of  tin  are  also  found  with  pyrite  in  the  granite.  The  accom- 
panying minerals  are  tourmaline,  topaz,  fluorite,  zinnwaldite,  wolf- 
ramite, quartz,  epidote,  garnet,  chalcopyrite,  iron  pyrites,  and  galena. 
About  10  tons  of  ore,  estimated  to  carry  10  to  20  per  cent  of  tin, 
have  been  produced. 
At  Cape  Mountain  cassiterite  has  been  found  near  the  contact  of 
the  Carboniferous  limestone  and  slates  with  granite,  occurring  in 
both  sedimentaries  and  granite. 
The  Buck  Creek  placers  occur  in  a  slate  country  rock,  which  is 
probably  underlain  at  no  great  depth  by  granite.  The  gravel  is 
nearly  all  of  slate  and  quartz.  Pyrites,  hematite,  and  a  small  amount 
of  gold  are  the  accompanying  minerals.  The  cassiterite  apparently 
comes  from  small  stringers  in  the  slate. 
During  the  last  two  years  probably  100  tons  of  stream  tin,  carry- 
ing 00  per  cent  tin,  have  been  produced. 
BRITISH    AMERICA. 
Small  amounts  of  tin  ore  have  been  found  in  the  auriferous  gravels 
near  Dawson,  Yukon  Territory,  near  Long  Lake,  British  Columbia, 
