116  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,   1903.  [bull. 225. 
granitic  rock.  These  show  good  gold  values  in  segregated  bunches  of 
quartz  and  in  the  adjacent  siliceous  alaskite.  The  quartz  lenses  are 
limited  in  size  and  have  not  been  proved  to  have  any  regular  connec- 
tion. 
(2)  Quartz  veins  in  granite:  These  have  formed  along  crushed  or 
sheared  zones.  The  amount  of  quartz  is  variable  and  the  walls  are 
ill  denned.  The  mineralogical  character  is  like  the  first  class  of 
deposits.  The  gold  values  are  locally  good,  but  all  workings  up  to 
the  present  have  been  near  the  surface. 
(3)  Veins  near  the  contact  of  granite  and  limestone:  Noble  .silver- 
quartz  veins  containing  rich  black  sulphide,  carrying  copper,  silver, 
and  gold.  These  veins  are  very  persistent,  following  the  contact  for 
miles,  though  different  parts  may  not  always  be  perfectly  connected. 
Where  noted,  they  follow  the  contact  of  alaskite  dikes,  which  are 
probably  border  phases  of  the  granitic  inclusions.  They  do  not  have 
well-defined  walls,  and  probably  are  to  be  regarded  as  replacements 
of  the  limestone  along  the  dike  contacts.  Frequently  a  dike  has  such 
a  vein  on  both  sides,  though  more  or  less  intermittently. 
PALMETTO   DISTRICT. 
Such  prospects  of  the  Palmetto  district  as  fall  within  the  quadrangle 
were  examined.  The  principal  one  is  the  old  MacNamara,  located  in 
1880.  Although  assessment  work  has  been  faithfully  done  upon  these 
claims,  they  have  not  produced  any  shipping  ore.  The  vein  is  near 
the  contact  of  limestone  with  a  large  intrusive  body  of  alaskite  which 
itself  is  probably  a  border  phase  of  a  large  granitic  intrusion  just  south 
of  this  place.  The  ore  occurs  as  quartz  replacing  and  penetrating  lime- 
stone on  the  under  side  of  an  alaskite  dike.  The  limestone  near  the 
alaskite  shows  contact  metamorphism,  becoming  altered  to  garnet, 
epidote,  etc. 
As  an  example  of  other  prospects  in  the  vicinity  may  be  mentioned 
the  Paymaster  vein,  which  is  a  short  distance  south  of  the  MacNamara, 
and,  like  it,  runs  in  a  northeasterly  direction.  This  Pa}^master  must 
be  distinguished  from  the  Paymaster  already  mentioned  as  occurring 
in  the  Lone  Mountain  district.  It  was  located  eight  or  ten  years  ago, 
but  was  abandoned  and  relocated  in  1902.  The  lead  seems  to  be  a 
long  band  in  a  contact  metamorphic  zone  of  the  intrusive  granite 
mass,  this  band  being  marked  by  garnet,  specular  iron,  and  auriferous 
quaitz  veins  or  lenses. 
AURIFEROUS   SAND   DUNES. 
A  conspicuous  bunch  of  large  sand  dunes  appears  in  the  southern 
portion  of  the  quadrangle  in  the  middle  of  Clayton  Valley.  These 
have  been  sampled  as  gold  ores,  and  some  relatively  good  assays  have 
been  obtained.     As  a  consequence  of  this  some  very  careful  sampling 
