vanhise.]  LAKE    SUPERIOR    REGION.  63 
Michipicoten  island,  Gargantua,  Mamainse,  etc.  (3)  The  Sault  Ste. 
Marie  sandstone,  which  may  be  only  the  upper  part  of  2  without  any 
intermingling  of  volcanic  material.  The  whole  together  is  Lower  Cam- 
brian, there  being  no  evidence  whatever  of  their  holding  any  other 
place  in  the  geological  series.  The  first  of  these  groups  is  the  Animi- 
kie  series  while  the  second  is  the  Keweenian. 
JSelwyn,31  in  1885,  places  the  crowning  overflow  of  McKays  moun- 
tain, Thunder  cape  and  Pie  island,  etc.,  as  a  part  of  the  Animikie. 
There  was  found  no  evidence  of  unconformity  from  the  base  of  the 
Animikie  to  the  top  of  the  Keweenian  as  developed  on  Thunder  cape 
and  the  surrounding  region. 
Lawson,3*  in  1886,  gives  a  report  on  the  geology  of  the  lake  of  the 
Woods  region,  with  special  reference  to  the  Keewatin  (Huronian?)  belt 
of  the  Archean  rocks. 
Comprising  a  large  part  of  the  lake  of  the  Woods  is  a  series  of  crys- 
talline and  semi-crystalline  schists  to  which  the  term  Keewatin  is 
applied.  The  term  Huronian  is  not  used,  because  it  is  very  doubtful 
if  the  series  belongs  to  this  period.  The  rocks  are  found  to  differ  fun- 
damentally in  lithological  character  from  Logan's  Original  Huronian. 
In  the  Keewatin,  quartzites  are  unimportant;  there  are  no  true  basal 
conglomerates;  and  the  fragnientals  of  the  lake  of  the  Woods  are  of 
volcanic  origin,  No  bedded  limestones  were  observed.  Structurally, 
also,  the  two  series  are  fundamentally  different.  The  lake  of  the  Woods 
schists  are  folded  with  the  associated  granite  gneisses,  which  are  re- 
ferred to  the  Laurentian,  while  the  Huronian  series  has  not  partaken 
of  the  folding  to  which  the  adjacent  gneisses  have  been  subject.  Fur- 
ther, the  large  areas  of  granite  are  found  to  be  intrusive  in  both  the 
Laurentian  gneiss  and  Keewatin  schists,  while  in  the  Huronian  of 
Logan  such  intrusions,  if  present  at  all,  are  mentioned  at  only  one  lo- 
cality. The  slate  conglomerate  of  Dore"  river  appears  to  resemble  the 
lake  of  the  Woods  agglomerates,  but  this  area  is  distant  from  the  typical 
Huronian  region  and  appears  to  differ  from  it  lithologically,  as  Avell  as 
being  in  a  nearly  vertical  attitude.  These  differences  between  the 
J3or6  and  Huron  areas,  with  their  geographical  separation,  may  warrant 
the  belief  that  possibly  Logan  embraced  under  one  designation  two 
distinct  series.  As  to  Prof.  Irving's  position  that  the  Animikie  series 
is  probably  the  equivalent  of  the  Huronian,  it  is  considered  exceedingly 
probable  that  the  flat-lying  unfolded  Animikie  is  much  later  than  the 
lake  of  the  Woods  schists. 
The  rocks  of  the  region,  including  both  the  Laurentian  and  Keewatin, 
comprise  gneiss,  granite,  felsite,  schistose  hornblende  rocks,  diabase, 
diorite,  serpentine,  coarse  clastic  rocks  and  agglomerates,  mica-schists, 
slates,  quartzites,  clay-slates,  felsitic  schists,  hydromica  and  chlorite- 
schists,  carbonaceous  schists  and  limestones.  The  massive  granites 
sometimes  grade  into  foliated  gneisses.  Dikes  of  granite  have  some- 
times foliated  structures  parallel  to  their  sides.    The  agglomerates  are 
