598  PRE-CAMBRTAN    GEOLOGY   OF    NORTH   AMERICA. 
The  Primitive  limestone  is  always  coarse,  crystalline,  and  friable. 
It  occurs  in  most  intricate  and  curious  relations  to  the  granite  and 
hypersthene  rock,  many  of  its  areas  being  in  veinlike  form.  This 
fact,  combined  with  the  presence  of  foliated  plumbago  and  the  indu- 
ration of  sandstone  when  in  contact  with  the  limestone,  leads  to  the 
conclusion  that  it  is  of  igneous  origin. 
Vanuxem,6  in  1838,  finds  Primitive  rocks  in  Montgomery,  Herki- 
mer, and  Oneida  counties. 
Emmons  (E.),7  in  1839,  describes  Primitive  rocks  in  Hamilton, 
Clinton,  and  Warren  counties.  The  Primitive  rocks  are  gneiss,  horn- 
blende, limestone,  and  serpentine.  The  limestone  and  serpentine 
occur  in  irregular  veins  or  beds,  which  are  sometimes  analogous  to 
the  greenstone  dikes  so  prevalent  in  the  hypersthene  rocks. 
Emmons  (E.),8  in  1840,  states  that  magnetic  iron  ore  occurs  asso- 
ciated with  granite,  gneiss,  and  hypersthene  rock  in  veins  which  are 
regarded  as  of  igneous  origin.  The  specular  oxide  occurs  in  two 
horizons,  the  first  associated  with  the  Primary  limestone,  the  second 
with  gneiss  or  some  other  Primary  rock  beneath  it. 
Vanuxem,9  in  1840,  states  that  the  Primary  rocks,  which  are  de- 
fined as  earlier  than  any  which  bear  organic  bodies  in  Lewis  County, 
consist  mostly  of  granite  and  gneiss,  but  are  associated  with  amphibo- 
lite  or  hornblende,  forming  syenite  and  hornblende  rock.  The  Pots- 
dam sandstone  rests  unconformably  upon  the  Primary  rocks.  There 
is  a  great  contrast  between  the  two  classes,  the  latter  presenting  a 
disturbed  appearance,  exhibiting  high  grades  of  inclination,  while 
those  of  the  Transition  are  like  the  deposits  of  tranquil  waters. 
Mather,10  in  1841,  states  that  the  Primitive  rocks  occupy  two-fifths 
of  Saratoga  and  one-fifth  of  Washington  County,  being  mostly  gneiss 
and  granite,  although  coarsely  crystalline  white  limestone  containing 
plumbago,  augite,  and  hornblende  is  a  common  rock. 
Emmons  (E.),11  in  1841,  mentions  Primary  limestone  at  Lake 
Janet,  gneiss  at  Long  Lake,  and  hypersthene  rock  on  Racket  River. 
Emmons  (E.),12  in  1842,  gives  a  report  on  the  entire  Adirondack 
region.  The  older  rocks  are  classified  under  Primary  and  Transition. 
There  are  few  transitions  from  the  Primary  into  the  sedimentary 
rocks.  There  are,  however,  many  transitions  among  the  Primary 
masses  themselves,  and  often  intermediate  series  are  found  which  are 
with  difficulty  placed  under  appropriate  names.  The  Primary  rocks 
are  divided  into  unstratified,  stratified,  and  subordinate.  Among  the 
u  ust ratified  rocks  are  included  granite,  hypersthene  rock,  Primitive 
limestone,  serpentine,  and  rensellaerite.  The  stratified  rocks  include 
gneiss,  hornblende,  syenite,  and  talc  or  steatite ;  the  subordinate  rocks 
include  porphyry,  trap,  and  magnetic  and  specular  oxides  of  iron. 
The  granites  occupy  a  comparatively  small  extent  in  the  region, 
being  in  limited  patches  of  irregular  appearance.    One  of  the  largest 
