bain. j  GOLD    DEPOSITS    OF    THE    WICHITA    MOUNTAINS.  1.21 
At  Lugart,  near  the  junction  of  the  two  forks  of  Red  River  and  about 
12  miles  south  of  Lone  Wolf,  there  is  an  additional  group  of  prospects. 
The  important  camps  in  the  area  extending  from  Lawton  to  Lugart 
were  visited,  and  samples  were  taken  from  the  leading  mines  in  each 
camp.  In  every  instance  an  effort  was  made  to  get  samples  from  the 
prospects  on  which  the  most  work  had  been  done  or  where  the  most 
encouraging  results  were  reported.  It  was  thought  that  if  some  of 
these  prospects  had  a  demonstrable  value  others  might  reasonably  be 
considered  worthy  of  further  effort,  but  that  if  the  best  prospects  had 
no  value,  the  less  promising  ones  were  not  likely  to  yield  any  profit. 
It  was  found  that  five  modes  of  occurrence  were  being  prospected: 
(1)  Certain  well-defined  quartz  veins  which  cut  both  granite  and  gab- 
bro;  (2)  greenstone  dikes  which  apparently  cut  indiscriminately  all  the 
crystalline  rocks;  (3)  contacts  of  the  granite  and  the  gabbro,  particu- 
larly where,  as  often  happens,  the  granite  sends  off  into  the  gabbro 
long  apoplryses  or  dikes  usually  assuming  an  aplitic  phase;  (4)  disinte- 
gration products  of  the  gabbro;  (5)  in  a  very  few  cases  simple  shear 
zones  in  the  granite. 
Some  of  the  classes  of  occurrences  enumerated  are  of  the  sort  which, 
in  view  of  the  relations  of  the  rocks,  might  well  be  expected  to  war- 
rant prospecting.  For  example,  quartz  veins  very  commonly  canw 
gold  and  other  metals  in  sufficient  amount  to  make  the  material  an  ore, 
though  it  is  also  true  that  many  of  the  largest  and  best-defined  quartz 
veins  known  cany  no  values  or  values  so  low  as  to  preclude  the  work- 
ing of  the  vein.  On  the  other  hand,  shear  zones  in  granite  seldom  have 
been  found  to  carry  ore,  and  when  present  it  is  only  in  the  immediate 
neighborhood  of  well-recognized  ore  bodies  of  other  types  and  of 
considerable  richness.  Since,  however,  assays  are  reported  to  have 
shown  values  in  all  the  situations  noted  above,  samples  were  taken 
from  both  probable  and  improbable  occurrences,  and  in  many  cases 
where  there  seemed  to  be  no  reason  to  suspect  any  values  at  all,  the 
owner  or  person  in  charge  was  invited  to  select  samples  of  what  he 
considered  his  richest  material.  In  all  cases  where  the  workings  were 
accessible  samples  were  carefully  taken  from  across  the  entire  vein. 
Occasionally  these  were  taken  in  duplicate,  and  usually  with  hand 
specimens  of  the  wall  rock  and  of  any  horses  or  included  rock  present, 
so  that  the  occurrence  of  the  ore  might  if  necessary  be  studied  in 
detail.  Having  in  mind  the  disappointment  which  has  so  often  come 
from  incomplete  or  inaccurate  sampling,  the  utmost  care  was  taken  to 
get  fair  samples  of  the  material  which  would  be  shipped  if  mining 
should  be  carried  on.  As  already  suggested,  where  any  bias  was  intro- 
duced it  was  in  the  direction  favorable  to  the  miner,  and  arose  from 
taking  picked  samples  of  the  better  grade  rather  than  average  samples 
of  the  vein.  Whenever  possible  with  a  reasonable  expenditure  of  time 
the  owner  or  his  representative  was  invited  to  be  present  while  the 
