emmons.]  NEGLECTED    MINE,    COLORADO.  127 
OTHER   MINES  AND   PROSPECTS. 
The  Jenny  Lind  claim  is  also  in  Walls  Gulch  and  its  ore  deposits 
are  said  to  be  similar  in  character  to  those  of  the  Durango  Girl,  which 
lies  below.  The  Kuby  claim,  located  south  of  Cumberland  Peak  on 
a  small  tributary  to  Junction  Creek,  is  interesting  on  account  of  the 
occurrence  of  a  considerable  amount  of  native  mercury  in  the  ore. 
In  Leavenworth  Gulch  the  Porcupine  Company  is  developing  a 
group  of  twelve  claims,  and  the  Londonderry  Company,  which  also 
owns  a  large  group,  has  a  force  of  men  at  work  in  the  same  neigh- 
borhood. 
In  Fassbinder,  in  Stamboul,  and  in  Mineral  Wonder  gulches,  all 
at  the  head  of  Junction  Creek,  are  a  number  of  prospects  which  have 
been  worked  intermittently  for  many  years.  Upon  some  of  these  a 
considerable  amount  of  development  work  has  been  done.  These 
properties  were  not  examined  during  the  present  field  season.  The 
relations  of  the  surrounding  rocks  are  very  similar  to  those  at  the 
Neglected  and  Durango  Girl  mines. 
SUMMARY. 
The  ore  deposits  in  the  western  part  of  the  Durango  quadrangle 
are  in  an  area  of  red  sedimentary  rocks,  which  have  been  intruded 
by  dikes  and  sheets  of  grayish-green  porphyry.  Later  basic  dikes 
cut  these  sediments  and  also  the  porphyry  bodies.  Along  certain 
nearly  vertical  planes  the  rocks  have  been  fissured  and   fractured. 
ome  of  the  more  prominent  fissures  trend  a  few  degrees  south  of 
3ast.  These  fissures  have  been  and  are  channels  for  circulating 
waters.  Along  these  fissures  the  porphyry  and  the  sediments  are 
impregnated  with  metallic  minerals  and  contain  small  veins  and 
stringers  very  rich  in  sylvanite.  The  occurrence  of  mercury  sulphide 
md  of  native  mercury  is  of  peculiar  interest.  Where  the  ores  have 
)een    deposited    the    circulating    waters    have    metamorphosed    the 
ed  sandstones  and   shales,  changing  them  to  light-gray  or  white 
uartzites. 
