collier.]        TIN    DEPOSITS    OF    THE    YORK    REGION,   ALASKA.  167 
at  Cape  Mountain.  There  are  a  number  of  other  places  where  pros- 
pectors report  its  occurrence  in  lode  or  placer  form. 
The  tin  ore  is  almost  all  cassiterite,  though  a  little  stannite  has  been 
found  at  one  locality.  Its  original  source  is  in  deposits  of  at  least  two 
essentially  different  types.  In  the  one  it  is  in  quartz  veins,  which  cut 
phyllites  or  metamorphic  slates;  in  the  other  the  cassiterite  is  dissem- 
inated through  more  or  less  altered  granitic  rocks.  This  second 
type  of  lode  deposit  is  the  one  which  gives  promise  of  commercial 
importance. 
In  estimating  the  value  of  tin  ores  in  this  northern  region  several 
facts  should  be  borne  in  mind.  The  region  is  utterly  without  timber 
and  is  accessible  by  ocean  steamers  only  from  June  to  the  end  of 
October  at  the  longest.  Harbor  facilities  are  poor,  and  all  supplies 
and  wages  are  high.  On  the  other  hand,  the  construction  of  railroads 
and  wagon  roads  is  not  difficult,  and  will  require  comparatively  small 
outlay.  All  of  the  occurrences  described  are  within  a  few  miles  of 
tidewater.  Freight  rates  to  Puget  Sound  ports  should  be  very  low, 
as  the  large  fleet  of  ocean  steamers  which  run  to  Nome  returns  empty. 
Last  summer  upward  of  98,000  tons  of  freight  were  brought  to  Alaska 
by  vessels  that  called  at  Nome.  It  is  fair  to  say  that  these  tin  deposits 
are  well  worth  careful  and  systematic  prospecting. 
