COPPER    DEPOSITS    NEAR    LDRAY,   YA.  141 
and  are  given  subject  to  revision,  as  the  writer  is  aware  of  their  somewhat  doubtful 
character. 
The  basalt  is  comparatively  simple  and  is  composed  of  plagioclase-feldspar,  pyroxene, 
and  magnetite,  which  may  be  titaniferous,  together  with  olivine  and  the  secondary  con- 
stituents epidote,  chlorite,  serpentine-asbestos,  quartz,  the  iron  oxides,  and  leucoxene. 
The  olivine  occurs  frequently  as  phenocrysts,  sometimes  3  or  4  mm.  in  diameter,  and  gen- 
erally presents  a  thoroughly  corroded  periphery  surrounding  a  tolerably  fresh  nucleus. 
At  times  even  this  has  disappeared,  leaving  a  brownish-red  mass  of  iron  oxide  to  mark  its 
former  position.  The  results  of  the  microscopic  examination  show  profound  alteration 
and  the  original  constituents  are  not  readily  determined.  Cf  the  secondary  constituents 
enumerated  above,  epidote  is  by  far  the  most  important.  Some  of  this  constituent, 
including  part  of  that  seen  at  the  lowest  worked  levels,  has  been  formed  by  interreaction 
between  feldspar  and  pyroxene.  The  question  of  its  various  modes  of  origin  is  one  of  the 
most  interesting  chemico-geological  problems  of  the  region. 
The  syenite  of  the  west  slope  has  been  referred  to  the  hypersthenc-akerite  type  of  Brogger 
and  is  essentially  a  quartzose  augite-syenite.  It  is  a  coars  -grained  dark  rock  with  the 
feldspar,  pyroxene,  and  quartz  visible  to  the  naked  eye.  It  is  made  up  of  the  minerals 
orthoclase/much  of  which  is  microperthitic,  plagioclase,  quartz,  hypersthene,  diallage, 
magnetite,  apatite,  zircon,  and  microcline,  together  with  the  alteration  products  epidote, 
chlorite,  and  sericite.  Sometimes  this  rock  is  thoroughly  epidotized,  and  then  forms  that 
peculiar  rock  known  as  unakite.a 
The  granite  of  the  east  base  of  the  mountain,  near  Fishers  Gap,  is  the  biotite  variety 
and  has  not  been  examined  by  the  writer  in  thin  sections. 
THE  COPPER  ORES. 
Developments. — The  Blue  Ridge  in  this  part  of  the  State  is  a  single  ridge  composed 
entirely  of  igneous  rocks.  It  has  been  mentioned  that  of  these  the  basalt  carries  the  copper. 
The  occurrence  of  copper  in  this  region  has  long  been  known.  There  is  a  tradition  that 
on  the  land  of  the  Blue  Ridge  Copper  Company,  1  mile  southeast  of  Fishers  Gap,  the 
metal  was  mined  and  shipped  before  the  civil  war.  At  the  time  of  the  writer's  last  visit, 
in  May,  1905,  an  incline  42  feet  in  depth  had  been  dug  by  this  company  about  150  feet 
above  the  confluence  of  the  main  head  forks  of  Robertson  River,  and  from  the  foot  of  the 
incline  a  40-foot  drift  had  been  run  in  a  northeasterly  direction  to  intercept  a  supposed 
cupriferous  zone  in  the  old  shaft  100  feet  higher  on  the  hill.  Before  this  zone  was  reached 
operations  were  temporarily  suspended  and  drilling  had  just  begun  on  a  third  shaft  north- 
west of  the  old  shaft  and  higher  on  the  hill.  It  is  the  company's  intention  to  resume 
f)perations  at  an  early  date  on  the  drift  from  the  incline,  and  when  the  copper-bearing  zone 
s  reached  to  sink  the  old  shaft  still  lower.  A  few  tons  of  ore  have  already  been  shipped 
rom  this  property. 
The  most  extensive  developments  in  this  part  of  the  State  are  those  of  the  Virginia  Con- 
solidated Copper  Company,  whose  property  lies  on  one  of  the  foothills  at  the  west  base  of 
he  Blue  Ridge  about  a  mile  northwest  of  Ida  post-office,  6  miles  southeast  of  Luray.  An 
nclined  shaft  has  been  sunk  about  300  feet,  and  at  the  80,  120,  and  280  foot  levels,  drifts 
3f  varying  lengths  have  been  run  off.  At  present  (May,  1905)  operations  are  temporarily 
Suspended.  It  is  the  intention,  however,  to  continue  the  shaft  at  least  200  iw\  lower. 
Besides  the  work  of  these  two  companies,  more  or  less  prospecting  has  been  done  in  the 
ivicinity  of  Stony  Man  and  at  the  head  of  Overall  Run,  13  miles  northeast  of  Luray.  The 
pork  seen  at  the  former  locality  is  very  old.  The  most  noteworthy  instance  is  the  old 
shaft  reported  60  feet  deep,  but  filled  with  water  when  visited.  Near  the  head  of  Overall 
[Run,  in  Warren  County,  prospecting  on  a  small  scale  has  been  done  very  recently  for 
iFront  Royal  people  on  the  so-called  " Empire  vein."  Two  abandoned  shafts  lower  on  the 
hills  than  the  "vein"  indicate  that  interest  in  the  copper  resources  of  the  region  was  aroused 
= 
a  Phalen,  Smithsonian  Miscellaneous  Collections,  vol.  45,  1903,  p.  309, 
