One  of  the  most  astonishing  facts  in  the  geological  history  of  the  earth,
is  that  vast  areas  in  various  continents,  now  highly  fruitful  and  contain-
ing populous  cities,  were  formerly  deeply  buried  beneath  ice  sheets.  A  well-
established  part  of  the  chapter  of  geological  history  referred  to,  is  the
fact  that  an  ice  sheet,  similar  to  the  one  now  covering  Greenland,  form-
erly occupied  the  region  of  which  Michigan  is'  a  part.  Not  only  was
there  one  advance  of  the  ice  from  the  north  over  this  region,  but  several
such  invasions,  with  intervals  of  mild  climate  intervening,  during  which
forests  flourished.  This  series  of  stupendous  physical  events  and  their
attendant  influences  on  plant  and  animal  life,  as  well  as  the  direct  bear-
ing of  the  conditions  they  produced  on  human  history,  when  once  under-
stood and  thoroughly  appreciatedj  produce  a  profound  impression  on
an  enquiring  mind  and  awaken  an  earnest  desire  to  know  more  concern-
ing the  earth  on  which  we  live.  Such  an  awakening  of  interest  is  one
of  the  main  factors  of  education.
It  is  for  the  purpose  of  systematically  and  accurately  recording  the
data  pertaining  to  the  glacial  and  other  of  the  later  chapters  of  the
geological  history  of  Michigan,  that  the  publication  of  a  soil  map  of  the
State  has  been  undertaken.
The  present  report  is  a  minor  contribution  to  the  preparation  of  the
map  referred  to,  the  larger  part  of  which  will  be  based  on  detailed  work
continued  through  several  years,  by  Mr.  Frank  Leverett,  under  the
auspices  of  the  U.  S.  Geological  Survey.
