THE   CORDILLERAS.  841 
schists.  That  the  older  schists  and  Prozoic  granites  do  not  appear  is 
due  to  the  thickness  of  the  youngest  metamorphic  series,  erosion  not 
having  succeeded  in  cutting  through  them.  The  metamorphics  are  all 
referred  to  the  Huronian  system. 
WIND   RIVER   MOUNTAINS. 
Hayden,111  in  1861,  states  that  the  Wind  River  Mountains  have  a 
nucleus  of  red  and  gray  feldspathic  granite. 
Hayden/12  in  1868,  states  that  the  stratified  rocks  rest  unconform- 
ably  upon  the  granites  and  syenites  of  the  Wind  River  Mountains 
along  the  eastern  slope. 
Hayden,34  in  1872,  describes  the  Wind  River  Range  as  forming  a 
complete  anticline.  It  has  a  nucleus  of  granitic  or  gneissic  rocks  ris- 
ing on  either  side  step  by  step  toward  the  central  axis,  and  on  each 
side  of  the  nucleus  are  the  various  unchanged  rocks  inclining  at  a 
variety  of  angles.  From  Fort  Stambaugh  northwest  toward  the 
granites  of  Wind  River  are  found  for  a  distance  of  10  miles  meta- 
morphic slates. 
Comstock,116  in  1875,  describes  the  Wind  River  Mountains  as  hav- 
ing a  nucleal  area  of  gray  and  reddish  granites,  gneissoid  granites, 
gneisses,  metamorphic  slates  and  schists,  and  pre-Potsdam  meta- 
morphics, this  being  the  order  of  succession  from  the  center  to  either 
flank.  It  is  doubtful  whether  any  igneous  rocks  occur  here,  and  there 
appears  to  be  a  gradation  from  the  structureless  granites  to  the  pre- 
Potsdam  metamorphics. 
Endlich,109  in  1879,  describes  the  geology  of  the  Wind  River 
Mountains  and  the  country  eastward.  The  crystalline  rocks  are 
divided  into  Prozoic  and  metamorphic.  Placed  as  belonging  to  the 
Prozoic  is  the  coarse-grained,  structureless  red  granite  forming  the 
subsidiary  range  along  the  western  base  of  the  mountains.  Fast  ward 
the  granites  disappear  and  in  the  Wind  River  Range  scliists  take 
their  place.  These  granites  and  those  of  the  Sweetwater  and  Granite 
hills  are  believed  to  have  a  subterranean  connection  and  are  regarded 
as  the  oldest  rocks  of  the  Wind  River  Mountains  because  of  the 
absence  of  all  structure,  their  position  relative  to  the  range,  and  their 
relations  to  the  undoubted  metamorphics  to  the  east.  A-gainst  them 
were  deposited  the  old  metalliferous  schists.  Granite  composing  the 
main  chain  followed,  and  this  was  succeeded  by  a  narrow  hand  of 
schist,  and  the  fourth  or  lowest  group  is  represented  by  the  younger 
granites.  The  metamorphic  rocks  of  the  Wind  River  Mountains  arc 
mainly  granites  but  are  associated  with  schists;  but  the  Layers  of 
different  mineral ogical  constitution  do  not  appear  to  remain  constanl 
in  certain  zones.  Eastward  the  granites  disappear  and  are  replaced 
by  schistose  granites  or  typical  schists.  The  granites  are  Hexed  and 
contorted   in   every   possible  direction   and   contain   simple   band-   of 
