vanhise.]  THE    CORDILLERAS.  335 
by  veins  of  quartz  and  red  syenite.  This  sandstone  is  somewhat  meta- 
morphosed, but  its  consolidation  is  not  due  to  volcanic  heat,  but  rather 
to  molecular  changes  induced  by  long-continued  pressure  of  the  im- 
mense mass  of  superincumbent  rocks.  The  Oerbat  mountains  have  a 
core  of  granite. 
Whitney,80  in  1865,  describes  the  Coast  range,  the  region  between 
the  Canada  de  las  Uvas  and  Soledad  pass,  and  the  Sierra  Nevada,  in 
all  of  which  regions  are  found  granitic  and  metamorphic  rocks. 
Granite  occurs  at  many  points  in  the  Coast  range  and  is  described 
and  figured  as  breaking  through  the  Cretaceous  and  Tertiary  strata 
and  metamorphosing  them. 
In  the  Canada  de  las  Uvas  region,  at  San  Emidio  canyon,  occur  gran- 
ite, mica-slate,  syenite,  hornblende- slate  and  limestone,  turned  on  end 
and  unconformably  overlain  by  unaltered  Cretaceous  and  Tertiary 
strata.  In  the  Tejon  pass  are  found  mica-slate,  granite,  gneiss,  and 
syenite.  Near  the  fort  occurs  crystalline  limestone  associated  with 
mica-slate  and  gneiss,  together  with  magnetic  iron  ore. 
At  many  localities  in  the  Sierra  Nevada  are  described  areas  of  gran- 
ite, many  of  them  of  great  magnitude.  With  them  are  associated  met- 
amorphic slates,  a  portion  of  these  being  mica-slates.  In  places  granite 
dikes  and  veins  are  seen  to  intrude  the  slates.  At  Dome  mountains, 
near  the  head  of  Kern  and  Kings  rivers,  a  granite  has  a  peculiar  con- 
centric dome  structure  which  is  not  regarded  as  due  to  sedimentation, 
but  results  from  the  cooling  of  igneous  material.  The  few  fossils  de- 
scribed in  the  slates  of  the  Sierra  are  such  as  to  cause  them  to  be 
referred  to  the  Jurassic. 
Gilbert,36  in  1875,  states  that  in  the  Inyo  range  are  found  syenite, 
granite  and  gneissoid  rocks.  On  its  east  face  quartzites,  siliceous 
schists,  green  schists  and  limestones  make  the  section  over  1,100  feet 
thick.  In  the  Amargosa  range  the  Whites  peak  series  is  11,500  feet 
thick,  and  is  composed  of  quartzites,  green  garnetiferous  schists  and 
siliceous  and  argillaceous  schists.  At  thebase  of  the  section  in  the  Amar- 
gosa range  is  900  feet  of  quartzite  resting  conformably  upon  600  feet 
of  mica-schist  and  chlorite-schist.  A  section  at  Boundary  canyon 
2,500  feet  thick  is  made  up  of  limestones,  micaceous  and  other  schists 
and  quartzites.  None  of  these  rocks  are  regarded  as  pre- Silurian. 
Although  no  fossils  are  found,  the  Whites  peak  section  is  presump- 
tively Silurian. 
Marcou,81  in  1876,  states  that  granitic  rocks  occur  in  the  Sierra 
Madre  in  southern  California  at  a  number  of  points.  This  mountain 
chain  is  described  as  the  most  ancient  of  the  modern  chains  of  southern 
California ;  that  is  to  say  the  granite,  pegmatite,  gneiss  and  metamor- 
phic rocks  which  form  its  principal  mass  date  from  times  anterior  to 
the  Paleozoic. 
Loew,82  in  1876,  states  that  nearly  all  the  mountain  ranges  of  south- 
ern California  belong  to  the  Primitive  formation.    In  the  San  Bernar- 
