HAHNS    PEAK    GOLD    FIELD,    COLORADO.  31 
the  uplift  of  the  Hahns  Peak  porphyry.  Similar  shales  show  at  many  other  parts  of  the 
field,  and  wherever  exposed  over  a  considerable  area  they  take  the  form  of  an  open  Hal  or 
park.  It  is  probable  that  the  large  parks  now  buried  in  rock  debris  have  been  eroded  on 
areas  of  these  soft  black  shales.  Above  the  black  shales,  but  not  showing  within  the  field 
of  this  report,  are  light-colored  sandstones  and  shales,  2,000  to  3,000  feet  thick,  carrying 
many  coal  seams. 
Recent  gravels. — These  deposits  are  in  two  forms,  the  "bars"  and  the  stream  gravels. 
The  bars  are  original  alluvial  fans,  partly  cut  away  by  recent  erosion.  The  remaining 
portions  of  these  fans  stand  above  the  present  stream  grades  to  a  height  of  perhaps  50  feet. 
Their  position  at  the  mouths  of  narrow  gulches  along  the  margins  of  the  parks  is  evidence 
that  they  were  built  up  of  the  rock  debris  washed  from  the  mountain  slopes.  The  stream 
beds  in  the  open  parks  are  bowlder  and  gravel  filled,  in  some  cases  to  a  considerable  depth 
below  water  level.  Practically  all  of  the  park  land  in  this  vicinity  is  buried  in  bowlder 
and  gravel  deposits,  all  of  which  seem  to  be  more  or  less  gold  bearing. 
DEVELOPMENT. 
THE   PLACERS. 
On  the  south  side  of  Hahns  Peak  the  bars  have  been  worked  in  two  places.  A  consid- 
erable pit  has  been  left  by  the  washing  on  the  bar  immediately  west  of  Ways  Gulch,  hut 
no  report  was  obtained  of  the  results  of  this  work.  The  most  extensive  workings  in  the 
field  have  been  those  of  Poverty  Bar.  On  a  lower  portion  of  these  deposits  the  town  of 
Hahns  Peak  itself  is  located.  Here  the  gravels  stand  some  40  to  60  feet  above  the  present 
stream  grade.  A  large  proportion,  variously  estimated  at  from  75  to  90  per  cent,  of  this 
material  is  composed  of  rounded  bowlders  and  pebbles  of  the  white  porphyry,  vesicular  in 
appearance,  the  cavities  being  probably  those  left  by  weathering  out  of  the  feldspar  pheno- 
crysts.  Besides  the  white  porphyry  are  pebbles  of  vein  quartz,  quartzite,  conglomerate, 
black  shale,  and  slate,  and  some  pebbles  of  granite,  both  angular  and  rounded,  the  whole 
very  slightly  agglomerated.  The  gravels  are  covered  by  a  thin  layer  of  soil.  All  of  this 
rests  upon  a  bed  rock  of  stiff  sandy  clay,  very  uniform  in  character  and  similar  to  the  bed 
rock  found  throughout  the  field. 
Water  for  hydraulicking  has  been  brought  in  a  long  ditch  (about  27  miles)  from  a  head- 
water tributary  of  Elk  River  to  the  east  of  Farwell  Mountain.  A  large  proportion  of  this 
bar  has  been  worked  over,  but  it  is  claimed  that  there  is  as  much  good  ground  left  as  has 
been  washed.     It  is  said  that  $84,000  was  taken  from  it  in  one  summer. 
The  earliest  and  richest  of  the  workings  were  in  the  stream-level  gravels  of  Ways  Gulch 
at  the  western  foot  of  Grouse  Mountain.  These  were  worked  over  with  shovel  and  sluice 
box,  and  are  reported  to  have  yielded  large  returns.  The  stream  bed  was  narrow,  however, 
and  the  gravels  there  have  long  since  been  worked  out.  A  test  pan  taken  from  these 
tailings  showed  several  coarse  colors. 
The  lower  courses  of  these  streams  have  been  thoroughly  prospected  and  the  gravels 
have  very  uniformly  shown  values.  That  these  values  were  not  sufficient  to  repay  working 
by  hand  is  evident  from  the  fact  that  these  claims  have'  never  been  worked.  After  leaving 
the  bars  the  streams  come  down  to  such  light  grades  that  much  difficulty  would  be  encoun- 
tered in  the  disposal  of  the  tailings.  Where  these  streams  leave  the  park  (about  at  the 
southern  edge  of  the  area  shown  in  the  topographic  map),  they  again  fall  of!  more  rapidly, 
and  would  here  afford  a  dump.  Some  of  the  placer  claims  now  held  on  this  lower  ground 
are  represented  on  the  geologic  map,  to  indicate  roughly  the  extent  of  these  low  gravels. 
The  question  of  the  origin  of  the  Hahns  Peak  gold  is  by  no  means  solved.  In  character 
it  is  in  large  part  moderately  coarse  flake  gold,  and  is  alloyed  with  silver  to  such  an  extent 
that  it  sells  for  about  $13  an  ounce.  Many  very  small  nuggets  are  found  inclosed  in  vein 
quartz.  Away  from  the  mountain  slopes,  in  the  open  bottoms,  the  gold  is  said  to  be 
slightly  purer.     It  is  possible  that  the  gold  of  the  placers  is  a  reconcentration  from  the 
