SULPHUR  AND  PYRITE. 
PYRITE  DEPOSITS  OF  THE  WESTERN  ADIRONDACK^,  NEW  YORK. 
By  Edwin  C.  Eckel. 
Several  important  pyrite  deposits,  which  have  long  been  worked, 
are  located  in  St.  Lawrence  County,  N.  Y.  As  these  deposits  are 
of  considerable  economic  interest  because  of  their  location,  inter- 
mediate between  the  Appalachian  pyrite  bodies  and  those  of  Ontario, 
the  following  brief  notes  on  the  subject  are  presented.  The  principal 
mines  and  prospects  were  visited  by  the  writer  in  June,  1904,  while 
engaged  in  an  examination  of  the  red  hematite  deposits  which  occur 
in  the  same  area,  though  in  entirely  different  geologic  relations. 
The  Stella  mine  is  located  about  2  miles  southeast  of  De  Kalb 
Junction,  on  the  road  to  Hermon. 
The  country  rock  is  a  light-gray  gneiss,  which  is  usually  rather 
fine  grained,  but  which  in  places  contains  coarser  bands.  It  is  well 
foliated,  the  foliation  planes  near  the  mine  showing  a  strike  of  N.  20° 
to  30°  ft.,  and  dipping  20°  to  30°  to  the  northwest.  This  rock  is 
probably  a  sheared  igneous  rock  of  pre-Cambrian  age.  Near  the 
Stella  mine  it  is  well  shown  in  little  ridges  east  and  west  of  the  vein,  a 
small  depression  marking  the  location  of  the  ore  body. 
At  the  mine  this  gray  gneiss  incloses  a  baud  of  fine-grained,  dark- 
colored  schist  15  to  20  feet  in  width.  Though  this  schist  band  is  at 
this  point  parallel  to  the  foliation  of  the  gneiss,  it  is  probably  an 
intrusive  rock  of  much  more  recent  age  than  the  gneiss. 
The  pyrite  at  the  Stella  mine  occurs  as  a  series  of  overlapping 
lenses  in  this  schist.  Each  lens  may  average  12  feet  in  thickness 
and  200  to  250  feet  in  extent  along  the  dip  and  strike.  At  the  main 
slope  the  strike  of  the  schist  and  pyrite  belt  is  N.  20°  E.,  and  its  dip 
is  23°  to  the  northwest. 
The  mine  has  been  opened  by  a  slope  TOO  feet  long,  which  runs 
down  on  the  dip  of  the  ore  body  to  a  depth  of  285  feet. 
The  lump  ore,  as  shipped,  contains  from  34  to  35  per  cent  sulphur. 
The  average  mill  ore  contains  from  26  to  27  per  cent  sulphur.     By 
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