160  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,   1903.  [bull.  225. 
When  the  dike  was  examined  in  the  latter  part  of  July,  1903,  no 
excavations  had  been  made  on  it,  and  it  was  therefore  impossible  to 
measure  its  exact  width  at  any  point,  owing  to  the  talus  covering  it, 
though  considerable  breadth  was  indicated  by  the  fragments  on  the 
sin- face.  Since  that  time  crosscut  trenches  have  been  made  near  Cas- 
siterite  Creek,  which  are  reported  to  reveal  a  width  of  approximately 
100  feet.  The  excavations  have  not  gone  far  enough  to  allow  of  sys- 
tematic sampling,  and  the  value  of  the  lode  must  therefore  be  left  an 
open  question  until  further  developments  are  made. 
Tin  ore  has  also  been  found  in  place  on  Tin  Creek,  about  half  a  mile 
south  of  this  main  lode,  at  the  northern  contact  of  the  large  granite 
area  which  has  been  described.  Specimens  of  mineralized  granite  were 
obtained  that,  on  examination  in  the  laboratory  at  Washington,  are 
found  to  contain  stannite,  or  tin  pyrites,  together  with  other  metallic 
sulphides.  Mineralized  granite  of  this  character  apparently  covers  a 
considerable  area,  but  the  ore  is  probably  of  little  value  except  as 
indicating  a  wider  distribution  of  tin  through  the  granites. 
In  1898  and  1899  some  prospecting  for  gold  was  done  in  the  vicinity 
of  Lost  River,  but  nothing  of  importance  was  found,  and  the  region 
was  abandoned  by  prospectors  for  several  years.  In  the  winter  of 
1902  prospectors,  searching  for  tin  ore,  again  turned  their  attention  to 
this  region.  Early  in  the  summer  of  1903  the  interesting  minerals 
above  described  were  discovered  in  the  bowlders  in  Tin  Creek,  and 
a  thorough  search  for  tin  was  made.  When  the  Geological  Survey 
party  arrived  at  Teller,  in  July,  1903,  they  were  enabled  to  exam- 
ine a  large  collection  of  minerals  from  this  vicinity.  Metallic  tin 
was  readily  obtained  from  one  small  specimen  by  the  aid  of  a  blow- 
pipe, while  the  larger  part  of  the  collection  was  shown  to  contain  min- 
erals of  no  value.  After  examining  these  minerals,  Mr.  Hess  and  the 
writer  proceeded  to  the  Lost  River  country  and  made  an  examination 
of  a  part  of  the  region  in  more  detail  than  had  been  done  in  1901,  and 
were  able  to  trace  the  tin  ore  which  had  been  seen  at  Teller  to  the 
granite-porphyry  dike  above  described,  on  Cassiterite  Creek. 
CAPE    MOUNTAIN. 
The  Cape  Mountain  tin  deposits  occur  in  a  high  peak  which  marks 
the  most  western  point  of  America.  A  settlement  called  Tin  City  has 
grown  up  within  the  last  year  on  the  southeastern  side,  while  on  the 
northwest  side,  facing  toward  Bering  Strait,  the  old  Eskimo  village 
of  Kingegan  is  located.  East  Cape  and  other  points  on  the  Siberian 
coast,  only  60  miles  distant,  are  plainly  visible  on  a  clear  day  from  the 
summit  of  this  mountain.  On  the  west  and  south  sides  the  mountain 
slopes  down  to  bluffs  which  drop  almost  perpendicularly  into  the  sea. 
southeast  side,  where  Tin  City  is  located,  there  is  a  small  bight 
oast  line  that  affords  some  protection  from  west  winds,  but  for 
