100         CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,   1906,   PART    I. 
or  hematite  and  which  is  evidently  a  relatively  shallow  alteration 
product  of  the  schist,  formed  in  pre-Carboniferous  time. 
The  copper  workings  of  the  Sunrise  mine  have  largely  been  cut 
away  or  rendered  inaccessible  by  the  Sunrise  open  cut,  and  at  present 
but  small  portions  of  the  ore  body  are  open  to  investigation.  Con- 
cerning the  form  of  the  deposit,  Ricketts  states"  that  it  lies  in  len- 
ticular bodies  which  expand  and  contract  irregularly,  in  gashes,  andl 
in  pear-shaped  bodies,  one  of  which  was  over  30  feet  in  height  and  20 
feet  in  diameter.  These  were  irregularly  distributed  through  the 
country  rock.  He  also  writes:  "A  stringer  of  ore  was  followed  fart  her 
up  the  hill  and  led  up  vertically  through  the  hematite  to  the  overlying 
[Guernsey]  limestone  cap,  where  the  hematite  ceased.  The  copper, 
however,  could  be  followed  up  as  a  stringer  along  jointing  planes  of 
the  limestone  and  led  to  several  small  bodies  of  ore  spread  out  parallel 
to  bedding  planes.  A  very  interesting  specimen  from  this  horizon 
was  a  piece  of  copper  ore  with  numerous  pieces  of  Carboniferous  fos- 
sils impressed  on  one  side  of  it ."  ''  As  seen  in  cross  seel  ion  on  the  side 
of  the  Sunrise  open  cut ,  t  he  copper  ores  stop  60  feet  below  the  former 
surface  and  no  trace  of  copper  is  seen  in  any  of  the  workings  on  the 
first,  second,  or  third  levels  of  the  iron  mine,  although  these  com- 
pletely undermine  the  ground  beneath  the  deposit. 
Within  these  lenticular  or  pear-shaped  bodies  the  copper  ores  occur 
as  ramifying  veinlets  and  masses  occupying  joint  and  irregular  frac- 
tures  and  cavities  in  the  country  rock.  The  copper  ore  is  especially 
abundant  in  the  more  heavily  iron-stained  portions  of  the  flint  and  in 
hematite.  The  ores,  named  in  the  order  of  their  importance,  are> 
chrysocolla,  malachite,  chalcocite,  azurite,  and  native  copper.  Rick- 
etts states  that  copper  oxides  were1  present  in  considerable  amounts. 
Malachite  is  finely  granular,  although  in  cavities  it  forms  tufted  aggre- 
gates of  acicular  crystals  or  mamniillary  masses  of  radiate4  structure. 
Thegla>M-  green  or  brown  chrysocolla  in  cavities  is  botryoidal.  Chal- 
cocite. chrysocolla,  and  malachite  are  practically  contemporaneous 
the  last  two  in  particular  replacing  each  other  along  the  length  of  the 
veinlets.  Azurite,  which  is  especially  characteristic  of  the  immediate 
surface,  is  on  the  whole  somewhat  younger  than  the  others,  although 
in  places  contemporaneous  with  them. 
Quartz  and  calcite  and  more  rarely  chalcedony,  selenite,  and  baritj 
occur  as  gangues.  In  general  quartz  is  younger  than  the  copper  min- 
erals, and  either  incrusts  them  in  vugs  or  cuts  them  in  veinlets.  The 
quartz,  though  as  a  rule  white,  is  in  places  stained  green  by  cop- 
per salts.  Many  crystals  of  white  or  lemon-yellow  calcite  coat  the 
quartz  and  are  hence  younger.  The  colorless  gypsum  called  selenite 
is  also  younger  than  the  ores,  although  in  a  few  places  it  incloses  fibers 
a  inn.  Rept.  Territorial  Geologisl  to  Governor  of  Wyoming,  1888,  p.  66. 
i>  [dem,  i>.  t',r,. 
