﻿AGE 
  OF 
  THE 
  EARTH 
  — 
  CHAMBERLIN 
  AND 
  OTHERS. 
  263 
  

  

  paleontologists 
  make 
  our 
  allegiance. 
  The 
  problem 
  behind 
  the 
  Neo- 
  

   lenus 
  is 
  that 
  of 
  having 
  developed 
  out 
  of 
  the 
  unicellular 
  expression 
  of 
  

   life, 
  under 
  favoring 
  physical 
  conditions 
  and 
  directive 
  impulse, 
  this 
  

   intricate 
  and 
  closely 
  functioning 
  organism. 
  How 
  long 
  did 
  it 
  take? 
  

   I 
  would 
  like 
  to 
  put 
  the 
  problem 
  to 
  the 
  experimental 
  biologist 
  : 
  Given 
  

   an 
  organism 
  with 
  a 
  full 
  equipment 
  of 
  motor 
  and 
  sensory 
  nerves 
  and 
  

   an 
  elaborated 
  digestive 
  tract, 
  with 
  specific 
  organs 
  of 
  circulation, 
  re- 
  

   production, 
  and 
  of 
  waste 
  — 
  is 
  the 
  distance 
  greater 
  from 
  that 
  starting 
  

   point 
  to 
  the 
  specialized 
  creatures 
  of 
  the 
  present, 
  ourselves 
  if 
  you 
  will, 
  

   or 
  from 
  the 
  nuclear 
  cell 
  (which 
  we 
  must 
  hold 
  to 
  be 
  not 
  alone 
  the 
  seat 
  

   but 
  the 
  radial 
  point 
  of 
  life) 
  up 
  to 
  that 
  marvelously 
  specialized 
  crea- 
  

   ture? 
  Starts 
  are 
  slow, 
  progress 
  to 
  be 
  secure 
  must 
  be 
  deliberate, 
  the 
  

   momentum 
  of 
  the 
  impulse 
  must 
  be 
  acquired 
  gradually, 
  the 
  passage 
  

   from 
  a 
  protozoan 
  to 
  a 
  metazoan 
  means 
  the 
  crossing 
  of 
  a 
  deep 
  moat, 
  

   the 
  climbing 
  of 
  a 
  high 
  wall. 
  But 
  the 
  directive 
  once 
  acquired, 
  then 
  

   matters 
  may 
  go 
  forward 
  with 
  acceleration. 
  On 
  the 
  basis, 
  then, 
  of 
  

   the 
  structure 
  of 
  this 
  ancient 
  trilobite 
  alone, 
  it 
  is 
  safe 
  and 
  probably 
  

   necessary 
  to 
  answer 
  that 
  Neolenus 
  was 
  farther 
  away 
  from 
  the 
  begin- 
  

   ning 
  of 
  life, 
  very, 
  very 
  much 
  farther 
  away, 
  in 
  the 
  highest 
  probability, 
  

   than 
  we 
  of 
  to-day 
  are 
  from 
  Neolenus. 
  

  

  This 
  is 
  a 
  relative 
  expression, 
  but 
  we 
  can 
  not 
  be 
  more 
  concrete. 
  

   The 
  Walcott 
  discoveries 
  have 
  lifted 
  the 
  veil 
  from 
  a 
  scene 
  in 
  the 
  

   panorama 
  of 
  life 
  that 
  was 
  barely 
  guessed 
  before. 
  In 
  our 
  previous 
  

   general 
  understanding 
  there 
  was, 
  in 
  the 
  still 
  earlier 
  faunas, 
  a 
  group 
  

   of 
  creatures 
  believed 
  to 
  be 
  of 
  simple 
  structure 
  and 
  lowly 
  place 
  in 
  the 
  

   category 
  of 
  life; 
  it 
  was 
  thought 
  that 
  with 
  these 
  simple 
  things 
  the 
  

   caravan 
  of 
  life 
  had 
  got 
  under 
  way 
  for 
  its 
  journey 
  through 
  the 
  ages; 
  

   and 
  now 
  we 
  are 
  compelled 
  to 
  believe 
  that 
  the 
  journey 
  was 
  half 
  over 
  

   when 
  this 
  caravan 
  first 
  came 
  under 
  our 
  eye. 
  

  

  It 
  is 
  not 
  my 
  part 
  to 
  make 
  a 
  review 
  of 
  statements 
  and 
  calculations 
  

   of 
  earth 
  age 
  based 
  on 
  the 
  rates 
  of 
  sedimentation 
  from 
  the 
  Cambrian 
  

   time 
  on 
  to 
  the 
  present; 
  but 
  whatever 
  these 
  are, 
  they 
  may, 
  from 
  the 
  

   biological 
  point 
  of 
  view, 
  reasonably 
  be 
  doubled 
  and 
  then 
  increased 
  by 
  

   some 
  improper 
  fraction, 
  if 
  we 
  are 
  to 
  reach 
  a 
  competent 
  expression 
  of 
  

   the 
  duration 
  of 
  the 
  life 
  day 
  of 
  extinct 
  species 
  — 
  the 
  zoehemera, 
  as 
  I 
  

   termed 
  it 
  many 
  years 
  ago, 
  and 
  of 
  the 
  sum 
  of 
  these 
  which 
  go 
  to 
  make 
  

   a 
  fraction 
  of 
  earth 
  history. 
  

  

  It 
  has 
  not 
  been 
  the 
  practice 
  of 
  students 
  of 
  evolutionary 
  pale- 
  

   ontology 
  to 
  raise 
  the 
  question 
  as 
  to 
  whether 
  there 
  were 
  time 
  enough 
  

   available 
  for 
  the 
  production 
  of 
  the 
  succession 
  of 
  results 
  which 
  pass 
  

   under 
  their 
  eye. 
  Such 
  an 
  attitude 
  would 
  of 
  itself 
  be 
  highly 
  unphilo- 
  

   sophical, 
  and 
  only 
  a 
  natural 
  inquisitiveness 
  or 
  curiosity 
  quite 
  unessen- 
  

   tial 
  to 
  the 
  real 
  philosophy 
  of 
  the 
  succession 
  and 
  purpose 
  of 
  life 
  has 
  

   led 
  to 
  the 
  occasional 
  investigation 
  as 
  to 
  the 
  possible 
  time 
  rate 
  of 
  

   evolutionary 
  processes 
  under 
  historic 
  and 
  under 
  natural 
  conditions. 
  

  

  