﻿150 
  /Scientific 
  Intelligence. 
  

  

  tion 
  and 
  incoherence 
  unavoidable 
  in 
  the 
  discussion 
  of 
  the 
  geology 
  

   by 
  counties 
  were 
  not 
  sufficiently 
  bad, 
  the 
  evil 
  is 
  aggravated 
  by 
  

   the 
  separate 
  discussion 
  of 
  19 
  distinct 
  areas 
  in 
  as 
  many 
  chapters, 
  

   each 
  accompanied 
  by 
  a 
  geological 
  map. 
  These 
  areas 
  are 
  scat- 
  

   tered 
  over 
  the 
  region 
  that 
  has 
  just 
  been 
  discussed 
  by 
  counties, 
  

   and 
  their 
  treatment 
  is 
  not 
  more 
  exhaustive 
  than 
  that 
  of 
  the 
  

   counties. 
  The 
  plates 
  are 
  admirable 
  and 
  tell 
  their 
  story 
  well, 
  

   except 
  that 
  geological 
  sections 
  are 
  conspicuously 
  absent 
  ; 
  but 
  

   they 
  should 
  have 
  been 
  used 
  as 
  illustrative 
  material 
  of 
  a 
  general 
  

   discussion 
  of 
  the 
  region, 
  not 
  made 
  the 
  basis 
  of 
  reducing 
  that 
  dis- 
  

   cussion 
  to 
  a 
  series 
  of 
  platitudes. 
  In 
  point 
  of 
  arrangement 
  of 
  its 
  

   subject 
  matter, 
  then, 
  the 
  book 
  is 
  weak. 
  There 
  is 
  no 
  treatment 
  of 
  

   the 
  region 
  by 
  geological 
  provinces 
  such 
  as 
  one 
  might 
  reasonably 
  

   expect 
  to 
  find 
  in 
  a 
  final 
  report 
  on 
  the 
  areal 
  geology 
  of 
  the 
  State. 
  

   The 
  repetition 
  of 
  the 
  same 
  theme 
  in 
  a 
  long 
  array 
  of 
  chapters 
  

   is 
  very 
  wearying 
  to 
  the 
  reader. 
  

  

  In 
  spite 
  of 
  the 
  bad 
  arrangement 
  of 
  the 
  book, 
  however, 
  and 
  in 
  

   spite 
  of 
  the 
  peculiarly 
  antique, 
  even 
  Wernerian, 
  tone 
  of 
  the 
  preface 
  

   to 
  the 
  volume, 
  the 
  work 
  has 
  many 
  valuable 
  contributions 
  to 
  

   geology 
  within 
  its 
  covers. 
  These 
  consist 
  partly 
  of 
  records 
  of 
  

   observations 
  confirmatory 
  of 
  accepted 
  generalizations, 
  often 
  

   tabulated, 
  as 
  in 
  the 
  case 
  of 
  hypsometric 
  and 
  glacial 
  data, 
  partly 
  

   of 
  observations 
  not 
  yet 
  generalized 
  and 
  partly 
  of 
  new 
  generaliza- 
  

   tions 
  presented 
  presumably 
  for 
  scientific 
  criticism. 
  The 
  latter 
  

   naturally 
  make 
  up 
  the 
  smallest 
  but 
  most 
  important 
  part 
  of 
  the 
  

   report, 
  and 
  it 
  is 
  to 
  some 
  of 
  these 
  that 
  we 
  may 
  address 
  ourselves 
  

   most 
  profitably 
  in 
  the 
  present 
  brief 
  review, 
  leaving 
  the 
  data 
  

   which 
  are 
  simply 
  recorded, 
  on 
  the 
  assumption 
  that 
  they 
  have 
  

   been 
  printed 
  for 
  the 
  sake 
  of 
  giving 
  permanence 
  to 
  the 
  record 
  and 
  

   not 
  to 
  invite 
  comment. 
  

  

  The 
  geology 
  of 
  the 
  Archean 
  as 
  set 
  forth 
  in 
  the 
  report 
  may 
  be 
  

   summarized 
  as 
  follows: 
  The 
  oldest 
  rocks 
  found 
  in 
  the 
  region 
  are 
  

   more 
  or 
  less 
  altered 
  fragmentals 
  and 
  volcanics 
  which 
  are 
  referred 
  

   to 
  the 
  Keewatin. 
  This 
  is 
  divided 
  into 
  two 
  parts, 
  designated 
  as 
  

   Lower 
  and 
  Upper 
  Keewatin, 
  with 
  a 
  well 
  defined 
  unconformity 
  

   separating 
  them. 
  In 
  the 
  Lower 
  Keewatin 
  are 
  incorporated 
  a 
  

   large 
  volume 
  of 
  mica 
  schists 
  and 
  feldspathic 
  mica 
  schists 
  (often 
  

   called 
  gneisses) 
  which 
  the 
  reviewer 
  some 
  years 
  ago 
  segregated 
  from 
  

   the 
  Keewatin 
  and 
  designated 
  the 
  Coutchiching 
  series. 
  In 
  the 
  

   Lower 
  Keewatin 
  also 
  are 
  placed 
  certain 
  greenstones 
  which 
  are 
  

   not 
  regarded 
  as 
  altered 
  volcanics 
  but 
  which 
  (sad 
  confession) 
  are 
  

   " 
  supposed 
  to 
  represent 
  the 
  cooled 
  original 
  crust 
  of 
  the 
  earth." 
  

   This 
  chilly 
  proposition 
  is 
  thrown 
  out 
  nonchalantly 
  in 
  the 
  preface 
  

   but 
  was 
  probably 
  frozen 
  out 
  of 
  the 
  body 
  of 
  the 
  book 
  as 
  it 
  is 
  not 
  

   further 
  discussed. 
  The 
  rocks 
  which 
  underlie 
  the 
  Lower 
  Keewatin 
  

   wherever 
  exposed, 
  and 
  the 
  exposures 
  are 
  numerous 
  and 
  extensive, 
  

   are 
  granites 
  or 
  granitoid 
  rocks 
  with 
  or 
  without 
  a 
  gneissic 
  struc- 
  

   ture, 
  such 
  as 
  have 
  been 
  repeatedly 
  mapped 
  and 
  designated 
  as 
  

   Laurentian. 
  These 
  granites 
  and 
  gneisses 
  are 
  intrusive 
  in 
  the 
  

  

  