THE   CORDILLERAS.  875 
SECTION  11.     BRITISH  COLUMBIA  AND  YUKON. 
SUMMARY   OF   LITERATURE. 
Selwyn,178  in  1877,  in  a  report  on  exploration  in  British  Columbia, 
separates  the  rocks  into  five  divisions.  Division  4  consists  of  semi- 
crystalline  rocks,  among  which  are  limestones,  shales,  mica  schists, 
and  quartzites,  which  appear  to  have  obscure  fossils.  The  age  of 
these  rocks  is  not  clearly  determined.  Division  5  consists  of  granitic 
rocks. 
Macotjn,179  in  1877,  finds  granite  gneiss  and  gneiss  a  few  miles  up 
the  Quatre  Fourches  River,  which  are  referred  to  the  Laurentian. 
Dawson  (G.  M.),180  in  1877,  states  that  a  crystalline  series  occurs  in 
the  Cascade  Mountains  about  Eagle  and  Tatla  lakes.  These  are 
chiefly  highly  crystalline  gneisses,  granites,  and  diorites. 
Dawson  (G.  M.),181  in  1879,  describes  in  some  detail  the  Cascade 
crystalline  series,  which  are  referred  to  the  Carboniferous  period. 
The  only  rocks  tentatively  referred  to  the  Laurentian  are  crystalline 
rocks  of  Shuswap  Lake  and  the  gold  range,  which  comprise  gneisses, 
greenstones,  schists,  limestones,  and  granites. 
Bauerman,182  in  1885,  describes,  near  the  forty-ninth  parallel,  west 
of  the  Rocky  Mountains,  large  areas  of  crystalline  rocks,  among  which 
are  granites,  gneisses,  basalt,  etc.  The  gneiss  of  Spokane  resembles 
the  typical  Laurentian  gneiss  of  Canada.  The  metamorphic  slates 
and  greenstones  perhaps  belong  to  the  Huronian. 
Dawson  (G.  M.)  ,183  in  188G,  in  a  report  on  the  portion  of  the  Rocky 
Mountains  between  latitudes  40°  and  50°  30',  places  in  the  Cambrian 
the  lowest  rocks  found.  These  comprise  quartzite,  quartzitic  shales, 
argillites,  limestones,  and  conglomerates.  One  section,  between  South 
Kootenai  Pass  and  Flathead  River,  has  a  maximum  thickness  of  more 
than  11,000  feet.  These  rocks  are  apparently  destitute  of  fossils  and 
are  compared  in  their  lithological  character  with  the  Cambrian  of  the 
Wasatch,  but  they  have  a  still  closer  resemblance  to  the  Chuar  and 
Grand  Canyon  groups  of  Colorado  River. 
McConnell,184  in  1887,  describes  the  Bow  River  series  in  the  east- 
ern part  of  the  Rocky  Mountains.  It  consists  of  dark-colored  argil- 
lites, associated  with  sandstones,  quartzites,  and  conglomerates.  The 
base  is  not  seen,  but  the  part  exposed  has  an  estimated  thickness  of 
11,000  feet.  The  argillites  are  occasionally  cleaved  and  have  scales 
of  mica  often  developed  along  the  divisional  planes.  The  only  fossils 
obtained  from  this  formation  are  a  couple  of  trilobitic  impressions, 
one  of  which  was  identified  by  Walcott  as  Olenellus  gilberti. 
Bowman,185  in  1889,  states  that  certain  schists  are  found  in  the 
Cariboo  gold  belt  of  British  Columbia,  which  are  referred  to  the 
lower  Paleozoic.  These  consist  in  the  main  of  slates  and  sandstones, 
the  total  thickness  being  placed  in  the  neighborhood  of  5,000  to  8,000 
