vanhwe.]  THE    COKDILLERAS.  279 
were  supposed  to  be  unchanged  sedimentary  ones,  and  the  suspicion 
presented  itself  that  a  portion  of  these  are  metamorphosed  Silurian 
beds.  The  Potsdam  quartzite  with  an  easterly  dip  is  found  to  rest 
upon  the  schists,  and  at  the  western  end  of  the  Sweetwater  hills  sub- 
Carboniferous  dolomites  rest  directly  upon  the  Prozoic  granites.  In 
the  Sweetwater  region  the  younger  metamorphics  occupy  a  more  con- 
spicuous position  than  the  older  metalliferous  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  cut- 
ting through  them.  The  metamorphics  are  all  referred  to  the  Huro- 
nian  system. 
LITERATURE   OF  THE   WIND   RIVER  MOUNTAINS. 
Hayden,10  in  1861,  states  that  the  Wind  river  mountains  have  a 
nucleus  of  red.  and  gray  feldspathic  granite. 
Hayden,11  in  1868,  states  that  the  stratified  rocks  rest  uncon form- 
ably  upon  the  granites  and  syenites  of  the  Wind  river  mountains  along 
the  eastern  slope. 
Hayden,4  in  1872,  describes  the  Wind  river  range  as  forming  a  com- 
plete anticline.  It  has  a  nucleus  of  granitic  or  gneissic  rocks  rising  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  is  found  for  a  distance  of  10  miles  metamorphic  slates. 
Comstock,14  in  1875,  describes  the  Wind  river  mountains  as  having 
a  nucleal  area  of  gray  and  reddish  granites,  gneissoid  granites,  gneisses, 
metamorphic  slates  and  schists,  and  pre-Potsdam  metamorphics,  this 
being  the  order  of  succession  from  the  center  to  either  flank.  It  is 
doubtful  whether  any  igneous  rocks  here  occur,  and  there  appears  to 
be  a  gradation  from  the  structureless  granites  to  the  pre-Potsdam  meta- 
morphics. 
Endlicii,8  in  1879,  describes  the  geology  of  the  Wind  river  moun- 
tains and  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.  Going  eastward  the  granites 
disappear  and  in  the  Wind  river  range  schists  take  their  place.  These 
ranites  and  those  of  the  Sweetwater  and  Granite  hills  are  believed  to 
lave  a  subterranean  connection  and  are  regarded  as  the  oldest  rocks  of 
me  Wind  river  mountains  because  of  the  absence  of  all  structure,  their 
position  relative  to  the  range  and  their  relations  to  the  undoubted  meta- 
norphics  to  the  east.  Against  them  were  deposited  the  old  metallifer- 
ous schists.  Granite  composing  the  main  chain  followed,  and  this  was 
succeeded  by  a  narrow  band  of  schist,  and  the  fourth  or  lowest  group 
s  represented  by  the  younger  granites.  The  metamorphic  rocks  of  the 
Wind  river  mountains  are  mainly  granites  but  are  associated  with 
schists;  but  the  layers  of  different  miueralogical  constitution  do  not 
