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  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1922. 
  

  

  of 
  the 
  Cambrian 
  fauna 
  belongs 
  to 
  groups 
  against 
  which 
  the 
  charge 
  

   of 
  surrender 
  of 
  locomotive 
  independence 
  can 
  hardly 
  be 
  laid, 
  though 
  

   inclusive 
  of 
  groups 
  of 
  animals 
  which 
  in 
  later 
  stages 
  did 
  become 
  in- 
  

   fected 
  with 
  the 
  loss 
  of 
  independence, 
  but 
  still 
  in 
  a 
  capital 
  sense 
  

   embraced 
  those 
  whose 
  independent 
  living 
  was 
  unimpaired. 
  

  

  These 
  considerations 
  I 
  have 
  analyzed 
  elsewhere 
  in 
  some 
  detail 
  

   and 
  their 
  significance 
  is 
  this 
  — 
  that 
  the 
  degeneration 
  of 
  life 
  (for 
  de- 
  

   pendence 
  of 
  necessity 
  implies 
  degeneration 
  of 
  physiology) 
  has 
  been 
  

   a 
  process 
  attendant 
  upon 
  and 
  of 
  course 
  influencing 
  evolution, 
  but 
  

   apparently 
  limited 
  in 
  its 
  effects 
  to 
  that 
  part 
  of 
  the 
  procession 
  of 
  life 
  

   which 
  comes 
  under 
  our 
  actual 
  observation 
  ; 
  that 
  is, 
  since 
  the 
  days 
  of 
  

   the 
  free 
  and 
  independent 
  faunas 
  of 
  the 
  Cambrian. 
  If 
  this 
  is 
  an 
  

   approximation 
  to 
  the 
  truth, 
  as 
  we 
  believe 
  it 
  to 
  be, 
  then 
  in 
  a 
  broad 
  

   sense 
  the 
  real 
  vigor 
  of 
  life, 
  which 
  established 
  the 
  major 
  branches 
  and 
  

   laid 
  down 
  the 
  plan 
  of 
  all 
  future 
  ages, 
  was 
  dominant 
  in 
  its 
  purity 
  in 
  

   the 
  ages 
  before 
  the 
  beginning 
  of 
  the 
  life 
  record 
  in 
  the 
  rocks. 
  How 
  

   often 
  the 
  student 
  of 
  the 
  past 
  of 
  the 
  earth 
  has 
  exclaimed 
  at 
  the 
  wonder 
  

   that 
  man 
  came 
  through 
  to 
  his 
  excellence 
  in 
  a 
  world 
  permeated 
  with 
  

   ever-increasing 
  conditions 
  of 
  degeneration. 
  

  

  III. 
  

  

  With 
  such 
  propositions 
  as 
  the 
  foregoing 
  we 
  are 
  confronted 
  by 
  an 
  

   impressive 
  requirement 
  of 
  time 
  necessary 
  to 
  the 
  development 
  of 
  life 
  

   on 
  the 
  earth. 
  It 
  is 
  a 
  requirement 
  that 
  seems 
  to 
  roll 
  back 
  and 
  ever 
  

   backward 
  into 
  the 
  undifferentiated 
  ages 
  of 
  our 
  planetary 
  history. 
  It 
  

   is 
  a 
  magnitude 
  that 
  takes 
  on 
  proportions 
  before 
  which 
  the 
  outstand- 
  

   ing 
  estimates 
  of 
  time 
  based 
  on 
  processes 
  of 
  rock 
  building 
  would 
  seem 
  

   to 
  dwindle, 
  and 
  it 
  partakes 
  more 
  and 
  more 
  of 
  the 
  magnitudes 
  in 
  

   which 
  the 
  radiologist 
  has 
  been 
  wont 
  to 
  speak. 
  The 
  question 
  for 
  us 
  

   now 
  is 
  whether 
  our 
  present 
  knowledge 
  affords 
  any 
  basis 
  for 
  an 
  esti- 
  

   mate 
  or 
  calculation 
  of 
  this 
  time 
  or 
  any 
  part 
  thereof 
  into 
  a 
  concrete 
  

   expression. 
  If 
  it 
  were 
  possible 
  to 
  estimate 
  by 
  any 
  or 
  all 
  ap- 
  

   proaches, 
  the 
  length 
  of 
  the 
  life 
  of 
  a 
  single 
  extinct 
  species 
  in 
  any 
  

   part 
  of 
  the 
  world, 
  there 
  would 
  then 
  lie 
  a 
  possibility 
  of 
  determining 
  

   what 
  fraction 
  this 
  given 
  quantity 
  might 
  be 
  of 
  the 
  whole. 
  For 
  more 
  

   than 
  two 
  generations 
  the 
  evidence 
  has 
  been 
  sought, 
  paleontologists 
  

   endeavoring 
  first 
  to 
  establish 
  the 
  endurance 
  of 
  a 
  given 
  or 
  index 
  

   species 
  as 
  the 
  basis 
  of 
  a 
  geologic 
  or 
  stratigraphic 
  element 
  — 
  a 
  zone. 
  

  

  Into 
  the 
  discussion 
  of 
  the 
  zone 
  — 
  its 
  meaning 
  in 
  time 
  and 
  space 
  — 
  has 
  

   entered 
  a 
  very 
  long 
  list 
  of 
  eminent 
  names 
  in 
  the 
  science. 
  The 
  zone 
  

   has 
  been 
  looked 
  upon 
  as 
  a 
  sedimentary 
  element 
  in 
  which 
  a 
  datum 
  

   species 
  slowly 
  coming 
  to 
  its 
  acme 
  suddenly 
  culminates 
  and 
  abruptly 
  

   disappears; 
  as 
  such 
  sedimentary 
  unit 
  in 
  which 
  not 
  a 
  species, 
  but 
  a 
  

   mutation, 
  or 
  an 
  entire 
  fauna 
  rises 
  and 
  falls. 
  To 
  Oppel 
  the 
  zone 
  was 
  

   a 
  space 
  unit. 
  Buckman 
  has 
  embodied 
  the 
  time 
  conception 
  of 
  the 
  

  

  