AREA   NORTH   AND   NORTHEAST   OF   LAKE    HURON.  435 
This  succession  does  not  differ  essentially  from  that  in  the  Cobalt 
district,  except  that  there  is  an  apparent  lack  of  iron  formation  in 
the  Keewatin. 
Knight,71  in  1908,  discusses  the  geology  of  an  area  south  of  the 
township  of  Lorrain  and  finds  essentially  the  same  succession  and 
structure  as  in  the  Cobalt  district. 
Hore,72  in  1908,  finds  the  succession  and  structure  of  the  townships 
of  Casey  and  Harris  at  the  north  end  of  Lake  Temiskaming  to  be  the 
same  as  described  by  Miller  for  the  Cobalt  district. 
Similar  results  are  reached  from  the  study  of  an  area  south  of 
Lake  Wendigo. 
DeLtjey,73  in  1908,  discusses  the  geology  of  an  area  west  of  Bay 
Lake,  on  Montreal  Kiver.  He  finds  Huronian  sediments  and  in- 
trusives  similar  to  those  in  the  Cobalt  district,  but  not  Keewatin  rocks. 
SUMMARY   OF  PRESENT  KNOWLEDGE. 
NORTH    SHORE    OF    LAKE    HURON. 
Logan  and  Murray 's  work. — Bigsby's  Transition  series  (1821)  is 
that  to  which  the  term  "  Huronian  "  was  later  applied  by  Logan  and 
Murray,  and  hence  his  description  of  this  series  is  the  earliest.  Logan 
and  Murray,  beginning  their  studies  of  the  north  shore  of  Lake  Huron 
in  the  forties,  first  applied  the  term  "  Huronian  "  to  the  clastic  rocks 
of  the  district  in  1857.  In  their  general  report,  1863,  they  applied 
the  term  "  Huronian  "  to  nearly  all  of  the  pre-Animikie  rocks  (except 
granites  and  gneisses  of  the  "  Laurentiah ")  of  the  Lake  Superior 
and  Lake  Huron  regions,  and  showed  the  distribution  of  the  "  Huro- 
nian "  on  a  general  map  of  the  eastern  half  of  Canada  and  adjacent 
portions  of  the  United  States.  But  the  north  shore  of  Lake  Huron, 
which  gives  the  series  its  name,  is  the  original  Huronian  district. 
Discussion  of  correlation  and  nomenclature  of  the  Huronian  series  in 
general  correctly  refers  to  this  district  as  the  type. 
The  pre-Cambrian  succession  in  the  original  Huronian  district,  as 
given  by  Logan  and  Murray,  is  as  follows : 
"White  quartzite,  chert,  and  limestone. 
Yellow  chert  and  limestone. 
White  quartzite. 
Red  jasper  conglomerate. 
Red  quartzite. 
«Upper  slate  conglomerate. 
Limestone. 
Lower  slate  conglomerate. 
Green  chlorite  slate. 
While  quartzite. 
.Gray  quartzite. 
[Upper  Laurent  inn    ( wanting  i . 
Laurentian <_ 
[Lower  Laurentian,  granites,  and  gneisses. 
_    .       .  (Greenstone. 
Intrusive \n 
ISyemte. 
