kemp.1  GRAPHITE    IN    THE    EASTERN    ADIRONDACK^,   N.  Y.  513 
infer  at  first  sight.  A  large  deposit  of  this  sort  would  be  the  richest 
and  most  desirable  of  all,  but  veins  have  not  yet  been  found  crossing 
the  gneisses  in  sufficient  abundance  to  justify  mining. 
3.  Graphitic  quartzites. — The  deposits  of  this  type  are  much  the 
most  persistent  and  reliable  of  all.  They  form  regularly  stratified 
members  of  the  sedimentary  series,  and  in  the  two  cases  near  Hague, 
where  they  have  been  mined,  they  are  associated  with  garnetiferous 
sillimanite-gneiss,  a  very  interesting  type  of  rock.  The  quartzites 
are  rather  feldspathic  as  quartzites  go,  but  nevertheless  exhibit  all 
the  characteristics  of  f ragmental  rocks.  There  is  a  little  pyrite  asso- 
ciated with  the  graphite,  and  from  the  tailings  of  the  mills  some 
interesting  concentrates  of  heav}^  minerals  can  be  obtained  by  pan- 
ning. The  graphite  appears  in  scales  of  various  fineness  interleaving 
the  f ragmental  minerals  of  the  quartzite.  It  is  never  so  coarse  as  in 
the  pegmatites  and  veins,  but  its  quantity  is  much  greater.  In  actual 
amount  it  varies  from  5  to  15  per  cent  of  the  rock  as  roughly  esti- 
mated. It  often  shows  slickensides  and  evidence  of  rubbing,  caused 
by  the  movement  of  the  individual  beds  of  the  quartzite  upon  one 
another  as  the  result  of  compression.  The  beds,  too,  pinch  and  swell 
more  or  less,  and  while  their  dip  is  flat  they  ha^e  evidently  passed 
through  severe  dynamic  processes. 
The  quartzites  which  are  used  in  the  two  mills  at  Hague  are  dif- 
ferently treated.  In  the  more  westerly  mill,  at  Graphite,  they  are 
concentrated  by  a  wet  process,  being  first  stamped  in  California  drop 
stamps  and  then  washed  in  buddies  to  a  state  of  considerable  purity. 
The  final  process  of  concentration  is,  however,  kept  secret.  In  the 
Lakeside  mill  at  Hague  the  rock  is  crushed  without  water  and  then 
carefully  dried  to  remove  all  moisture.  The  concentration  is  then 
performed  by  Hooper  air  jigs. 
The  whole  problem  of  the  concentration  of  the  graphite  is  in  great 
contrast  to  that  of  metallic  ores,  in  that  in  the  former  case  we  seek  to 
save  the  light  mineral  and  reject  the  heavy,  while  in  the  latter  case 
the  reverse  is  true.  Graphite  has  a  specific  gravity  of  only  2.25-2.27, 
and  its  scaly  nature  makes  it  very  prone  to  float  in  moving  water. 
One  mineral  which  would  furnish  a  great  drawback  in  the  treatment 
of  a  graphitic  quartzite  is  mica.  Although  it  has  a  higher  specific 
gravity,  its  scaly  nature  would  make  it  remain  in  suspension  and 
occasion  great  difficulty. 
The  graphitic  quartzites  have  thus  far  been  discovered  chiefly  in  the 
town  of  Hague,  on  the  western  side  of  Lake  George,  and  in  the  towns 
of  Dresden  and  Whitehall  on  both  sides  of  South  Bay,  Lake  Champlain. 
Indications  and  poorly  exposed  outcrops  have  also  been  observed  in 
the  mountains  west  of  Silver  Bay,  Lake  George,  and  on  the  east  side 
of  the  lake  as  well.  The  rocks  also  occur  along  Lake  Champlain 
south  of  the  village  of  Putnam. 
Bull.  225—04 33 
