THE   CORDILLERAS.  877 
Associated  with  the  Archean  schists  are  certain  granitoid  rocks 
which  may  represent  either  portions  of  the  schists  in  which  the  bed- 
ding has  been  obliterated  or  very  ancient  intrusives.  Besides  these 
there  is  at  least  one  later  series  of  intrusive  granites  which  are  prob- 
ably later  than  most  of  the  Paleozoic  rocks.  The  Shuswap  series  of 
the  Adams  Lake  section  appears  to  be  traceable  on  its  line  of  strike 
into  diabases  and  diabase  rocks,  which  are  often  agglomerates  and 
pass  into  volcanic  ash  rocks.  In  the  Shuswap  series  of  the  Selkirk 
nearly  half  of  the  entire  mass  of  the  rocks  exposed  consists  of  intru- 
sive or  vein  granite  with  pegmatitic  tendencies.  In  the  Xisconlith 
series  the  lamination  is  often  true  bedding,  but  in  some  places  a  slaty 
cleavage  is  developed.  In  the  Castle  Mountain  group  and  the  upper 
3,000  feet  of  the  Bow  River  series  of  the  Rock  Mountain  section  the 
Olenellus  fauna  is  found.  Nowhere  in  any  of  the  sections  were  uncon- 
formities seen.  In  sections  1  and  2  no  fossils  have  been  discovered. 
The  correlations  are  made  upon  relative  positions  and  lithological 
grounds.  Between  the  Shuswap  and  overlying  series  there  is  believed 
to  be  a  great  time  break,  for  this  lower  series  is  of  a  markedly  more 
crystalline  character,  and  the  numerous  granite  veins  which  every- 
where cut  it  at  no  point  enter  the  overlying  Cambrian  strata.  The 
rocks  placed  in  the  Cambrian  are,  then,  40,000  feet  thick.  The  use 
of  the  term  Algonkian  to  designate  the  rocks  conformably  below  the 
Olenellus  fauna  is  objected  to,  it  being  more  philosophical  to  include, 
for  the  present  at  least,  the  whole  of  this  great  conformable  mass  of 
rocks  to  its  base  under  the  name  Cambrian. 
McConnell,187  in  1896,  reports  on  an  exploration  of  Finlay  and 
Omenica  rivers  in  the  Rocky  Mountains  of  western  Canada.  The 
Archean  a  rocks  of  the  district  consist  of  a  series  of  well- foliated  mica 
gneisses,  mica  schists,  hornblende  and  actinolite  schists,  quartzose 
schists,  and  crystalline  limestones.  The  rocks  of  the  series  are  usually 
evenly  bedded,  and  conform  in  dip  to  the  overlying  formations.  To 
the  series  the  local  term  Shuswap  is  applied. 
Shuswap  rocks  are  found  on  both  sides  of  Finlay  River  from  its 
mouth  up  to  its  junction  with  the  Ingenica.  North  of  this  point  the 
formation  divides.  The  eastern  limb  follows  the  eastern  slope  of  the 
Finlay  Valley  northwestward  to  the  Quadacha  and  for  sonic  distance 
beyond.  It  has  a  width  of  4  miles  at  Pauls  Branch,  where  it  forms 
the  most  westerly  range  of  the  Rocky  Mountains.  This  width  de- 
creases toward  the  north  and  increases  toward  the  south.  The  western 
limb  bends  away  from  the  Finlay  above  the  Ingenica,  but  crosses  it 
again  at  the  great  bend  which  the  Finlay  describes  after  leaving  the 
Rocky  Mountains,  and  continues  on  to  the  north.  The  width  of  this 
band  was  not  ascertained,  as  its  western  boundary  was  not  reached. 
a  In  conformity  with  the  usage  of  Canadian  geologists,  Archean  is  above  used  in  the 
sense  of  pre-Carnbrian. 
