ADIRONDACK    MOUNTAINS.  601 
were  found  in  rather  persisted  beds.  A  graphite  mine  in  the  neigh- 
borhood of  Hague  is  a  layer  of  very  graphitic  gneiss,  comparable,  as 
said  by  Walcott,  to  a  coal  seam  in  an  ordinary  bedded  succession. 
Scales  of  graphite  are  uniformly  disseminated  through  the  coarsely 
crystalline  limestone,  the  amount  often  being  very  considerable.  Be- 
low the  crystalline  limestone  is  a  coarse  black  hornblendic  gneiss,  the 
contacts  between^it  and  the  limestone  being  of  a  most  extraordinary 
character.  The  plane  between  them  is  one  of  great  irregularity.  In 
the  limestone  are  contained  numerous  fragments  and  even  great 
bowlders  of  the  gneiss,  and  for  a  distance  of  some  feet  away  from  the 
contact  are  numerous  crystals  of  feldspar.  The  appearance  is  such 
as  to  suggest  very  strongly  that  here  is  an  unconformable  contact,  the 
limestone  being  deposited  along  an  encroaching  shore  line.  The 
phenomena  are,  however,  probably  due  to  the  breaking  up  of  layers 
of  gneiss  and  veins  of  pegmatite  by  powerful  dynamic  movements. 
In  passing  from  Westport  within  a  short  distance  appeared  coarse 
gabbro,  which  continued  as  far  as  the  region  was  penetrated,  nearly 
to  Mount  Marcy.  This  rock  in  the  interior  is  generally  massive,  but 
on  its  outer  border  grades  into  a  regularly  laminated  rock,  resembling 
in  exposure  very  closely  the  laminated  gneisses.  The  whole  is,  how- 
ever, clearly  an  eruptive  rock.  Granite  was  seen  locally  associated 
with  the  gneisses. 
Williams  and  Van  Hise,21  in  1890,  examined  the  western  side  of 
the  Adirondacks.  Just  as  on  its  eastern  side,  there  was  found  a 
peripheral  succession  of  regularly  laminated  gneisses  and  crystalline 
limestones  of  great  thickness.  The  latter  is  particularly  well  seen 
in  the  neighborhood  of  Gouverneur.  The  contacts  between  the  lime- 
stones and  the  lower  gneiss  were  found  to  be  almost  identical  with 
those  on  the  eastern  side  of  the  mountains,  but  the  appearance  here 
strongly  suggests  that  the  relations  have  been  produced  by  interior 
movements  of  the  rocks,  the  irregular  contact  surface  being  a  con- 
torted one  as  a  result  of  folding,  and  the  contained  fragments  broken 
off  and  included  in  the  limestone  by  means  of  dynamic  action.  The 
interior  of  the  Adirondacks  was  here  found  to  consist  of  gabbro,  in 
every  respect  like  that  on  the  east  side  of  the  mountains. 
In  passing  inward  from  the  gneissic  series  the  gabbro  is  found  first 
in  small  quantity,  then  in  more  and  more  abundance,  until  finally  it 
becomes  predominant.  At  Bonaparte  Lake  was  found  a  contact  <»!' 
the  gabbro  with  the  limestone  which  showed  all  the  characteristics  of 
an  intrusive  rock,  the  limestone  giving  evidence  of  contact  action. 
There  were  found,  both  in  the  limestone  and  in  tin1  gabbro  areas, 
smaller  areas  of  coarse  red  granite. 
Asa  result  of  the1  reconnaissance  it  was  concluded  m-  probable  that 
the  Adirondacks  core  is  an  eruptive  basic  rock,  which  has  been 
upthrust  and  intruded  within  the  gneissic  series.     Because  of  the 
