124  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1904.         [bull.  260. 
not  appear  to  be  any  constant  difference  between  the  development  of 
the  ore  in  the  sandstone  and  in  the  shale.  In  the  Neglected  mine  the 
shale  is  considered  the  most  productive  horizon,  while  in  the  Duraiigc 
Girl  the  richer  ores  so  far  have  occurred  in  the  quartzite  below  the- 
shale.  It  appears  that  the  movement  which  shattered  the  sandstone 
also  shattered  at  least  the  lower  portion  of  the  bed  of  shale. 
Alteration  of  the  ores.— The  surface  portions  of  the  ore  are  partly 
oxidized  or  altered.  Free  gold  occurs  in  small  quantities  associate^ 
with  sylvanite,  and  the  pyrite  has  altered  into  limonite.  Ores  taker 
near  the  surface  in  the  Ruby  claim,  which  is  in  the  gulch  south  olf 
Cumberland  Mountain,  show  a  considerable  quantity  of  native  quick- 
silver, which  occurs  as  small  globules  in  a  matrix  of  quartz  and  syl- 
vanite: and  small  flakes  of  a  yellow  mineral,  belieATed  to  be  native  gold 
also  occur  in  the  same  hand  specimen.  Satisfactory  identification  o:l 
the  form  of  the  gold  is  difficult  in  such  an  association,  since  the  usuai 
treatment  designed  to  separate  the  metals  from  the  gangue  would 
amalgamate  them.  This  intimate  association  of  native  gold  and 
native  quicksilver  not  amalgamated  is  unusual.  It  is  probable  thai 
both  are  the  alteration  products  of  the  original  ore.  The  altered  rocfl 
is  also  stained  with  malachite. 
THE  NEGLECTED   MINE. 
History. — The  Neglected  mine  is  situated  near  the  head  of  Gaine 
Gulch  on  the  west  slope  of  Monument  Hill  at  an  elevation  of  10,30 
feet  above  tide.  The  property  has  been  known  as  a  prospect  for  te  i 
or  fifteen  years,  but  was  not  extensively  exploited  until  the  early  pai 
of  1902,  when  an  ore  body  was  struck  from  which,  in  the  followin 
year,  1,070  tons  of  ore  were  shipped,  and  the  returns  from  whic  | 
amounted  to  $117,041.28  in  gold  and  $1,682.30  in  silver.  The  mine  ha 
been  operated  most  of  the  time  since  then,  and  recently  a  mill  has  bee 
installed  for  working  low-grade  ores,  which  can  not  be  profitabl 
shipped. 
Equipment. — The  mine  is  worked  through  a  vertical  shaft  froi 
which  levels  running  east  and  west  have  been  opened  at  depths  ( 
85,  125,  and  175  feet.  The  drifts  at  these  levels  aggregate  nearl 
2,000  feet.  The  shaft  is  supplied  with  a  friction  hoist,  and  a  duple 
pump  running  a  2-inch  stream  about  half  of  the  time  keeps  the  mil  < 
dry. 
The  ore  passes  from  the  shaft  house  over  a  surface  tramway 
the  crusher,  which  prepares  it  for  a  Chilian  mill.     This  reduces 
to  fine  size,     From  the  mill  it  passes  over  amalgamating  plates  ar 
over  Frue  vanners  and  canvas  tables. 
Geology. — The  mine  is  located  in  the  lower  "  Red  Beds,'"  the  Cui 
formation,  which,  in  the  vicinity  of  the  workings  of  the  mine?, 
