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THE  GOLD-QUARTZ  DEPOSITS  OP  PAHANG. 
[Feb.  1893, 
these  outcrops  is  found  in  the  peculiar  detrital  deposit  into  'which 
they  become  superficially  converted  and  which  is  often  extraordi¬ 
narily  productive  of  gold,  the  precious  metal  having  concentrated 
in  pockets  as  the  outcrop  becomes  reduced  in  level  and  volume. 
These  ‘  drift  deposits/  as  they  may  be  styled,  have  been  the  object 
of  some  of  the  most  extensive  ancient  workings  in  Pahang,  as  pro¬ 
bably  elsewhere  in  the  Malay  Peninsula,  both  on  the  dyke-veins 
and  on  parts  of  the  slate  stoekwork-formation. 
A  characteristic  and  notable  example  of  the  irregular  stockwork- 
form  of  deposit,  combining  both  impregnated  zones  of  slate  and  a 
strong  associated  dyke-quartz,  is  found  in  the  very  extensive  deposit- 
on  which  the  Penjom  Mines  are  situated.  Here  a  continuous  belt 
of  auriferous  quartz-bearing  rocks  is  traceable  for  about  7  miles 
from  north  to  south ;  the  breadth  of  this  belt  is  several  hundred  feet, 
and  in  places  several  hundred  yards,  but  its  extent  and  nature  are 
as  yet  only  slightly  known  from  actual  mining  operations.  Through¬ 
out  its  length  the  porphyry  dyke,  which  in  places  is  many  hundred 
feet  thick,  is  highly  important ;  enormous  surface-workings  show 
that  it  has  been  worked  on  a  very  large  scale  by  the  Chinese,  in 
ground-sluices  with  banks  over  100  feet  high. 
The  dyke  is  intermixed  with  the  neighbouring  sedimentary  rocks, 
and  quartz  occurs  throughout  the  confused  mass.  In  the  best 
known  and  richer  portions,  the  rock  carrying  most  gold-quartz  and 
otherwise  most  highly  4  mineralized  ’  is  the  same  peculiar  black  slate 
as  that  which  distinguishes  the  Paub  Hole.  There,  in  direct 
contact  with  the  dyke-rock,  this  slate  is  either  very  soft  and  highly 
graphitic  as  well  as  pyritous,  and  auriferous  throughout,  or  of  a 
harder  grey  type  much  converted  into  a  breccia  and  sprinkled  with 
large  crystals  of  arsenical  pyrites.  In  the  dyke  and  graphitic  reef- 
mass  the  quartz-veins  are  generally  small  and  run  more  or  less 
parallel,  conformably  with  the  general  strike ;  but  in  the  grey  slate 
they  follow  an  opposite  direction  like  cross-courses,  sometimes  of 
considerable  magnitude,  and  the  two  series  join,  fault,  and  intersect 
one  another  with  great  irregularity. 
