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  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1927 
  

  

  were 
  several 
  truly 
  glacial 
  and 
  interglacial 
  stages 
  when 
  there 
  were 
  

   great 
  climatic 
  changes, 
  and 
  some, 
  at 
  least, 
  of 
  the 
  interglacial 
  times 
  

   were 
  actually 
  warmer 
  than 
  the 
  present. 
  Ver^'^ 
  convincing 
  evidence 
  

   to 
  this 
  effect 
  has 
  been 
  found 
  on 
  the 
  north 
  shore 
  of 
  Lake 
  Ontario, 
  

   near 
  Toronto. 
  There 
  a 
  series 
  of 
  stratified, 
  water-laid 
  clays, 
  contained 
  

   between 
  two 
  bowlder 
  beds, 
  is 
  divisible 
  into 
  an 
  upper 
  and 
  a 
  lower 
  

   series. 
  The 
  lower 
  and 
  older 
  series 
  has 
  many 
  fossil 
  plants 
  which 
  

   indicate 
  a 
  flora 
  such 
  as 
  nftw 
  occurs 
  several 
  hundred 
  miles 
  to 
  the 
  

   south, 
  in 
  Kentucky 
  and 
  Tennessee. 
  Of 
  the 
  upper 
  series, 
  the 
  fossils 
  

   resemble 
  Labrador 
  species 
  and 
  eloquently 
  indicate 
  the 
  return 
  of 
  the 
  

   cold, 
  culminating 
  in 
  the 
  ice 
  sheet 
  Avhich 
  deposited 
  the 
  upper 
  bowlder 
  

   beds. 
  Professor 
  Coleman 
  has 
  reported 
  that 
  on 
  the 
  shores 
  of 
  Hudson 
  

   Bay 
  large 
  forest 
  trees 
  are 
  found 
  between 
  two 
  ground 
  moraines, 
  trees 
  

   which 
  are 
  indicative 
  of 
  milder 
  climatic 
  conditions 
  than 
  those 
  of 
  

   Recent 
  time 
  in 
  that 
  latitude. 
  

  

  Similarly, 
  the 
  interglacial 
  mammalian 
  fauna 
  which 
  occurs 
  at 
  

   Afton, 
  Iowa, 
  is 
  decidedly 
  suggestive 
  of 
  a 
  warmer 
  climate 
  than 
  the 
  

   present 
  for 
  the 
  region 
  involved. 
  In 
  this 
  case, 
  however, 
  the 
  evidence 
  

   is 
  less 
  convincing, 
  for 
  the 
  habits 
  of 
  extinct 
  species 
  of 
  mammals 
  can 
  

   only 
  be 
  conjectured, 
  and 
  as 
  in 
  the 
  famous 
  case 
  of 
  the 
  Siberian 
  mam- 
  

   moth, 
  some 
  ludicrous 
  mistakes 
  have 
  been 
  due 
  to 
  inferences 
  concern- 
  

   ing 
  the 
  climatic 
  adaptations 
  of 
  extinct 
  species, 
  reasoning 
  from 
  the 
  

   distribution 
  of 
  their 
  existing 
  allies. 
  Whether 
  all 
  the 
  interglacial 
  

   stages 
  were 
  characterized 
  by 
  a 
  warmer 
  climate 
  than 
  that 
  of 
  modern 
  

   times, 
  it 
  is 
  not 
  yet 
  possible 
  to 
  determine 
  for 
  lack 
  of 
  the 
  necessary 
  

   fossiliferous 
  deposits. 
  

  

  In 
  any 
  satisfactory 
  theory 
  of 
  the 
  Pleistocene 
  climates 
  we 
  must 
  

   account 
  for 
  world-wide 
  climatic 
  change, 
  or 
  series 
  of 
  changes, 
  so 
  that 
  

   local 
  causes 
  are 
  inadequate, 
  for 
  in 
  all 
  of 
  the 
  continents 
  of 
  both 
  

   Northern 
  and 
  Southern 
  Hemispheres 
  there 
  is 
  proof 
  of 
  the 
  great 
  

   extension 
  of 
  glaciers 
  in 
  that 
  period 
  of 
  time. 
  Inasmuch, 
  however, 
  as 
  

   the 
  Southern 
  Hemisphere 
  is 
  chiefly 
  a 
  region 
  of 
  sea, 
  with 
  but 
  a 
  rela- 
  

   tively 
  small 
  amount 
  of 
  land, 
  climatic 
  fluctuations 
  in 
  that 
  hemisphere 
  

   have 
  been 
  and 
  still 
  are 
  much 
  less 
  extreme 
  than 
  in 
  the 
  Northern, 
  where 
  

   there 
  is 
  so 
  large 
  a 
  proportion 
  of 
  land. 
  This 
  is 
  an 
  explanation 
  of 
  the 
  

   fact 
  that 
  in 
  the 
  South 
  Temperate 
  Zone 
  Pleistocene 
  glaciation 
  was 
  

   much 
  less 
  extreme 
  than 
  in 
  the 
  corresponding 
  northern 
  belt. 
  This 
  

   southern 
  glaciation, 
  as 
  is 
  so 
  well 
  exemplified 
  in 
  Patagonia, 
  was 
  

   chiefly 
  confined 
  to 
  a 
  great 
  extension 
  of 
  the 
  mountain 
  glaciers 
  rather 
  

   than 
  to 
  the 
  formation 
  of 
  continental 
  ice 
  caps, 
  such 
  as 
  appeared 
  in 
  

   Europe 
  and 
  on 
  so 
  vast 
  a 
  scale 
  in 
  North 
  America. 
  

  

  Penck 
  has 
  made 
  it 
  very 
  probable 
  that 
  all 
  over 
  the 
  world 
  the 
  sno\\ 
  

   line 
  was 
  lowered 
  approximately 
  4,000 
  feet 
  below 
  its 
  present 
  altitude 
  — 
  • 
  

   an 
  amount 
  which 
  he 
  first 
  deduced 
  from 
  his 
  studies 
  in 
  the 
  Alps 
  and 
  

  

  