THE   CORDILLERAS.  881 
section  toward  Gateway.  It  was  found  that  both  the  Creston  quartz- 
ite  and  the  Kitchener  quartzite  gradually  become  charged  with  inter- 
leaved beds  of  calcareous  quartzite.  calcareous  argillite,  and  siliceous 
limestone,  betokening  open-water  conditions  during  the  formation  of 
these  sediments.  The  nearest  relatives  of  the  Creston  and  Kitchener 
quartzites  in  the  Rockies  are  respectively  the  two  thick  members 
of  the  Altyn-  limestone  delimited  by  Willis,  who,  in  the  year  1901, 
carried  out  a  reconnaissance  survey  of  the  boundary  belt  on  the  Mon- 
tana side.0  No  fossils  have  as  yet  been  found  in  these  old  rocks  of 
the  Purcell  Range,  but  fossils  of  so-called  Algonkian  age  were  dis- 
covered in  the  Altyn  limestone. 
Associated  with  these  rocks  are  lava  flows,  volcanic  tuffs,  and 
gabbro  sills. 
See  further  summaries  in  sections  8  and  9,  Idaho  and  Montana, 
pages  849-865. 
SUMMARY  OF   PRESENT  KNOWLEDGE. 
Dawson's  Shuswap  "  series  "  includes  granites  and  gneisses,  which 
he  regards  as  similar  to  the  fundamental  gneiss  of  the  original 
Laurentian  area,  and  altered  sediments  associated  with  the  gneisses 
and  schists,  which  he  regards  as  similar  to  the  Grenville  series  of 
the  same  region.  The  distribution  and  characters  of  the  Shuswap 
group  are  reviewed  by  Dawson  in  the  article  above  summarized.  It 
is  now  known  that  a  part  of  the  Shuswap  group  is  of  Paleozoic  or 
later  age.  The  true  pre-Cambrian  rocks  included  in  the  Shuswap 
group  may  represent  both  the  Archean  and  the  Algonkian. 
Extending  northward  from  the  international  boundary  is  the  con- 
tinuation of  the  little  deformed  or  metamorphosed  Belt  sediments, 
Algonkian,  of  Montana.  Along  the  boundary  it  has  been  described 
by  Daly.  To  the  north  it  is  believed  by  Walcott  to  be  represented 
by  Dawson's  Nisconlith  "series"  and  a  part  of  his  Adams  Lake 
"  series,"  which  unconformably  overlie  the  Shuswap  group.  Daly  and 
Walcott  call  attention  to  the  change  in  the  character  of  the  sediments 
from  Avest  to  east,  agreeing  that  the  source  of  the  sediments  probably 
lay  to  the  west  of  Kootenai  Lake.  The  Bow  River  group  of  McCon- 
nell  is  lower  Cambrian  and  may  represent  in  part  continuous  sedi- 
mentation between  the  Belt  Algonkian  and  the  Cambrian.  Walcott, 
in  1907,  found  Olenellus  fauna  down  through  2.000  feet  of  sediments 
in  the  How  River  group.  The  limits  of  the  Belt  Algonkian  of  British 
Columbia  are  not  known,  for  it  has  been  grouped  with  true  Cambrian 
sediments  and  mapped  as  Cambrian.  The  outlines  given  on  the  ac- 
companying map  (PI.  I)  are  very  general  ones. 
"  Bull.  Geol.  Soc.  America,  vol.  13,  1902,  p.  '505. 
55721— Hull.  360—09 56 
