﻿PALEONTOLOGY 
  WELLER 
  317 
  

  

  When 
  man 
  was 
  limited 
  to 
  his 
  own 
  physical 
  efforts 
  for 
  means 
  of 
  

   communication 
  from 
  place 
  to 
  place, 
  all 
  sorts 
  of 
  barriers 
  confronted 
  

   him 
  on 
  every 
  side. 
  The 
  residents 
  of 
  one 
  continent 
  were 
  almost 
  com- 
  

   pletely 
  isolated 
  from 
  those 
  of 
  every 
  other 
  continent, 
  and 
  consequently 
  

   their 
  evolution 
  progressed 
  along 
  wholly 
  independent 
  lines. 
  Many 
  

   physical 
  features 
  within 
  the 
  continents 
  themselves 
  were 
  almost 
  as 
  

   insurmountable 
  barriers 
  as 
  were 
  the 
  oceans 
  separating 
  the 
  con- 
  

   tinents. 
  Under 
  these 
  conditions 
  the 
  races 
  and 
  tribes 
  of 
  men 
  developed 
  

   extreme 
  provincialism, 
  just 
  as 
  did 
  the 
  faunas 
  of 
  the 
  past 
  under 
  the 
  

   conditions 
  of 
  isolation. 
  

  

  During 
  the 
  past 
  few 
  centuries 
  conditions 
  making 
  for 
  human 
  pro- 
  

   vincialism 
  have 
  been 
  disappearing 
  with 
  accelerating 
  rapidity. 
  No 
  

   corner 
  of 
  the 
  earth 
  is 
  out 
  of 
  touch 
  with 
  the 
  rest 
  of 
  the 
  world 
  at 
  this 
  

   time. 
  Men 
  have 
  visited 
  both 
  the 
  North 
  and 
  the 
  South 
  Poles. 
  A 
  

   trip 
  around 
  the 
  world 
  is 
  of 
  less 
  moment 
  to-day 
  than 
  a 
  voyage 
  across 
  

   the 
  Atlantic 
  Ocean 
  a 
  few 
  years 
  ago. 
  With 
  the 
  development 
  of 
  rapid 
  

   transit 
  through 
  the 
  agency 
  of 
  steamships, 
  express 
  trains, 
  automobile, 
  

   and 
  airplane, 
  man 
  can 
  transport 
  himself 
  anywhere, 
  and 
  with 
  the 
  

   telegraph, 
  telephone, 
  and 
  radio 
  he 
  can 
  communicate 
  instantly 
  with 
  

   his 
  fellows 
  over 
  vast 
  distances. 
  Under 
  these 
  conditions 
  do 
  not 
  the 
  

   paleontologic 
  lessons 
  of 
  the 
  past 
  warrant 
  our 
  reaching 
  the 
  conclusion 
  

   that 
  unity 
  and 
  uniformity 
  may 
  be 
  attained 
  in 
  the 
  social 
  and 
  poli- 
  

   tical 
  organization 
  of 
  mankind 
  in 
  the 
  not-distant 
  future, 
  judging 
  

   from 
  the 
  time 
  standards 
  of 
  the 
  geologist 
  ? 
  

  

  The 
  human 
  race 
  is 
  in 
  its 
  infancy; 
  it 
  is 
  just 
  stepping 
  over 
  the 
  

   threshold 
  of 
  its 
  existence. 
  The 
  wars, 
  the 
  struggles, 
  and 
  the 
  conflicts 
  

   which 
  engage 
  us 
  at 
  this 
  time 
  are 
  but 
  the 
  children's 
  diseases 
  of 
  the 
  

   race. 
  Diseases 
  of 
  old 
  age 
  may 
  come 
  in 
  the 
  future, 
  but 
  these 
  infantile 
  

   ailments 
  will 
  doubtless 
  be 
  left 
  behind. 
  No 
  paleontologist 
  with 
  his 
  

   outlook 
  on 
  the 
  continual 
  forward-moving 
  progress 
  of 
  living 
  things 
  

   of 
  the 
  past 
  can 
  fail 
  to 
  be 
  an 
  optimist 
  in 
  his 
  outlook 
  into 
  the 
  future. 
  

  

  While 
  delving 
  into 
  the 
  life 
  records 
  of 
  the 
  past, 
  paleontologists 
  

   have 
  found 
  that 
  societies 
  of 
  organisms 
  have 
  been 
  continually 
  chang- 
  

   ing 
  their 
  characteristics; 
  many 
  forms 
  and 
  even 
  large 
  groups 
  of 
  or- 
  

   ganisms 
  have 
  passed 
  into 
  extinction; 
  but 
  with 
  all 
  of 
  these 
  changes 
  

   there 
  has 
  persisted 
  a 
  continual 
  forward 
  progression. 
  In 
  the 
  course 
  

   of 
  their 
  evolution 
  through 
  the 
  geological 
  ages 
  many 
  groups 
  of 
  organ- 
  

   isms 
  have 
  developed 
  at 
  some 
  time 
  in 
  their 
  history, 
  along 
  certain 
  

   side 
  lines 
  of 
  evolution, 
  extravagant 
  characteristics 
  of 
  ornamentation, 
  

   apparently 
  useless 
  to 
  the 
  creatures 
  themselves, 
  which 
  have 
  culminated 
  

   in 
  the 
  extinction 
  of 
  that 
  particular 
  phylogenetic 
  line. 
  A 
  notable 
  ex- 
  

   ample 
  of 
  this 
  sort 
  may 
  be 
  found 
  among 
  the 
  Lichad 
  group 
  of 
  trilo- 
  

   bites. 
  These 
  creatures 
  make 
  their 
  first 
  appearance 
  in 
  Ordovician 
  

   time. 
  In 
  the 
  faunas 
  of 
  this 
  period 
  they 
  are 
  characterized 
  by 
  the 
  

  

  