36  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1903.  [bull. 225. 
Sheep  Creek  mines. — The  lode  system  of  Gold  Creek  extends  with- 
out interruption  southward  across  the  Sheep  Creek  divide,  though  its 
physical  character  and  its  metallic  contents  are  somewhat  different. 
Strong  and  fairly  continuous  veins  of  quartz  occur  in  the  black  slates 
for  a  distance  of  from  400  to  500  feet  from  the  greenstone  contact,  and 
these  veins,  almost  without  exception,  follow  the  slaty  structure. 
Veining  is  prominent  at  four  horizons,  though  but  two  of  these  have 
been  systematically  explored  and  worked.  The  main  operations  have 
been  in  the  Glacier  and  Silver  Queen  mines,  which  have  produced  in 
the  neighborhood  of  $500,000.  The  sulphides  are  the  same  as  those  in 
the  adjacent  part  of  Gold  Creek,  but  the  silver  values  are  very  much 
higher,  and  the  ores  are  really  silver  ores. 
Farther  to  the  southeast,  though  still  undeveloped,  the  four  veins  are 
well  marked  and  locally  mineralized,  as  far  as  the  Regan  group  of  claims, 
beyond  which  they  are  covered  by  rocky  debris  and  vegetation  in  the 
bottom  of  the  gulch.  Where  they  reappear  in  the  ridge  between 
Sheep  Creek  and  Grindstone  Creek  they  are  much  less  prominent,  and 
probably  too  small  and  too  much  interrupted  to  be  of  value.  This 
lode  system  does  not  seem  to  attain  any  importance  on  the  opposite 
side  of  the  ridge  in  the  basin  of  Grindstone  Creek  nor  upon  the  shore 
of  Taku  Inlet  beyond. 
Mines  south  of  Juneau. — Most  of  the  veins  which  have  been  dis- 
covered and  worked  south  of  Juneau  lie  on  or  near  the  line  joining  the 
mines  of  Gold  Creek  with  those  near  the  head  of  Windham  Bay. 
This  line  trends  about  N.  40°  E.,  nearly  parallel  with  Stephens  Passage, 
and  follows  approximately  the  extension  of  the  contact  between  the 
upper  greenstone  and  the  overlying  shales. 
Southeastward  from  Sheep  Creek  no  important  veining  is  known 
near  the  contact  until  the  vicinity  of  Port  Snettisham  is  reached.  On 
the  south  side  of  this  long  inlet,  near  Snettisham  post-office,  about  3 
miles  from  Stephens  Passage,  there  has  been  considerable  prospecting, 
and  one  mine  has  already  produced  a  few  thousand  dollars.  Again, 
at  Sumdum,  on  Endicott  Arm,  20  miles  farther  down  the  coast,  the 
black  shales  carry  veins  from  which  approximately  $450,000  have 
been  extracted.  From  these  properties  mineralization  is  fairly  con- 
tinuous across  the  intervening  mountains  to  the  head  of  Windham 
Bay. 
Placers  located  on  the  streams  tributary  to  Windham  Bay  were 
worked  in  a  small  way  with  more  or  less  profit  at  various  times  between 
their  discovery,  in  1869,  and  1888.  In  1888  a  hydraulic  plant  was! 
installed  to  work  deposits  of  gravel  near  the  mouth  of  Spruce  Creek, 
about  one-fourth  mile  from  the  head  of  the  bay.  About  the  same 
time  an  attempt  was  also  made  to  work  a  higher  basin  on  the  same 
creek,  but  these  large-scale  operations  failed,  presumably  because  of 
inexperienced  management,  since   the  possibility  of   making  wage 
