GRAPHITE    IN    THE    HAYSTACK    HILLS,    WYOMING.  427 
dipping  70°  NW.  The  graphitic  schist  is  exposed  in  two  outcrops 
2  feet  apart,  each  4  feet  wide  measured  across  the  bedding,  indi- 
cating, if  each  is  in  place,  a  thickness  of  10  feet.  This  rock  varies 
in  composition  across  the  strike  from  a  coarsely  schistose  muscovite- 
graphite  phase  to  a  graphite  schist  of  grayish-black  color.  Beyond 
this  point  the  rocks  are  covered  by  alluvium  for  1,000  feet  to  a  sec- 
ond exposure  along  the  same  strike,  showing  an  8-foot  band  of  rather 
high-grade  semischistose  graphitic  rock,  portions  of  which  are  con- 
siderably iron  stained.  From  this  exposure  the  band  can  be  traced 
westward  1,000  feet  on  the  north  side  of  McCanns  Pass,  at  first  by 
abundant  and  then  by  fewer  outcrops  and  many  residual  masses. 
The  graphitic  band  gradually  approaches  the  granite  and  is  finally 
cut  out  by  it.  At  the  contact  of  the  schist  with  the  granite  a  tunnel 
exposes  10  feet  of  graphitic  schist. 
A  band  of  graphitic  schist  2  feet  wide  occurs  on  the  south  side  of 
the  gap  in  the  center  of  the  NE.  £  sec.  1,  T.  27  N.,  R.  65  W.  This 
band  has  a  strike  of  N.  70°  E.  and  a  vertical  dip.  It  can  be  traced 
along  the  strike  for  several  hundred  feet  to  the  alluvium  on  either 
side.  Large  bodies  of  pegmatite  lie  within  35  feet  north  and  south 
of  the  graphite.  The  grade  of  the  graphite  is  lowered  by  the  pres- 
ence of  contorted  veins  of  quartz  which  lie  along  the  foliation  planes 
of  the  schist.  High-grade  graphitic  schist  has  also  been  thrown 
from  a  prospect  pit  in  the  center  of  the  W.  J  sec.  14,  T.  28  N.,  R. 
65  W.  It  occurs  also  in  the  north-central  part  of  the  NE.  |  sec.  26, 
in  the  northeast  corner  of  sec.  27,  in  the  center  of  the  SW.  I  SE.  | 
sec.  23,  and  in  the  northwest  corner  of  sec.  26,  T.  27  N.,  R.  65  W. 
In  sec.  26  some  tourmaline  is  associated  with  the  graphitic  schist. 
COMMERCIAL  CONDITIONS. 
As  seen  under  the  microscope  the  graphitic  schists  contain  much 
finely  disseminated  graphite  associated  with  quartz,  tourmaline,  and 
a  little  biotite,  muscovite,  and  feldspar.  The  richest  specimens 
appear  to  contain  up  to  16  per  cent  of  carbonaceous  matter,  all  of 
which  is  either  in  ragged  particles  or  hexagonal  plates  and  has  the 
microscopic  habit  of  graphite.  One  of  the  richer  specimens  analyzed 
by  E.  C.  Sullivan  afforded  by  the  Wittstein  method  13  per  cent 
total  carbonaceous  matter  and  5  per  cent  graphite.  Doctor  Sullivan 
states  that  this  method  may  not  determine  all  of  the  graphite  and 
that  the  other  carbonaceous  matter  present  is  practically  nonvolatile. 
On  chemical  and  microscopic  grounds,  then,  it  is  probable  that  all 
the  carbonaceous  matter  present  may  be  commercially  considered 
graphite.  It  is  estimated  that  the  10-foot  bed  in  McCanns  Pass 
would  run  from  6  to  8  per  cent  graphite.  The  graphite  individuals 
are  very  small,  having  an  average  diameter  in  various  thin  sections 
