GRAPHITE  IN  THE  HAYSTACK   HILLS,  LARAMIE 
COUNTY,  WYO. 
P.v  Sydney   II.   Ball. 
GEOGRAPHY  AND   GEOLOGY. 
In  the  summer  of  L906  the  writer  examined  the  graphite  proper- 
ties of  Laramie  County,  Wyo.,  situated  in  the  rugged  hills  around 
Haystack  Peak,  which  lies  to  the  east  of  Whalen  Canyon  and  to  the 
wesl  of  Cottonwood  Canyon.  (See  fig.  5,  p.  192.)  The  most  prom- 
ising graphite-bearing  area  includes  sees.  14,  15,  22,  24,  25,  26,  27, 
34,  35,  and  36,  T.  28  N.,  K.  65  W.,  and  see.  I .  T.  27  N.,  R.  65  W., 
although  graphitic  schist  occurs  in  the  vicinity  of  Rawhide  Buttes. 
The  first  prospecting  for  graphite  in  these  hills  was  done  by  Messrs. 
Lauck  Ac  Stein,  who  in  1881  located  the  so-called  Sentinel  claim, 
south  of  Hamilton  Pass.  Since  that  time  little  interest  has  been 
shown  in  the  graphite  and  no  shipments  have  been  made. 
The  graphite  occurs  in  the  immediate  vicinity  of  granite  and  peg- 
matite as  a  constituent  of  the  pre-Cambrian  muscovite  schist  of  sedi- 
mentary origin.0  Of  the  larger  intrusive  granite  masses  of  the 
Haystack  Hills  one  alone  Hint  to  the  north  of  McCanns  Pass — has 
metamorphosed  this  schist  to  a  graphitic  phase.  The  schist  varies 
from  a  silvery  muscovite  variety  containing  hut  little  graphite  to  a 
grayish-black  sectile  rock.  Such  gradations  occur,  as  a  rule,  across 
t  he  strike,  although  t<»  a  l<-»  degree  along  it.  On  microscopic  exami- 
nation the  schist  unaffected  by  the  granitic  and  pegmatitic  intru- 
sions is  seen  to  contain  carbonaceous  matter,  and  the  graphite  is 
this  material  altered  by  the  intense  heat  and  other  agents  attendant 
on  the  intrusions. 
OCCURRENCES. 
The  most  extensive  graphite  showing  is  on  the  north  side  of 
McCanns  Pass,  2,000  feet  east  of  the  summit,  in  sec.  26,  T.  28  N., 
R.  65  W.  About  300  feet  of  schist,  which,  although  it  is  intruded 
by  a  large  pegmatite  dike,  is  of  the  normal  muscovitic  variety,  lies 
between  the  granite  and  the  graphitic  hand,  striking  X.  55°  E.  and 
o  For  an  account  of  the  pre-Cambrian  succession  of  the  Hartville  uplift,  see  pp.  193-194  of  this  volume. 
426 
