year；　so　that　you　might　very　safely　double　the　period　as　the　time
  during　which　the　Pacific　Ocean；　the　general　state　of　the　climate；　and
  the　sea；　and　the　temperature　has　been　substantially　what　it　is　now；　and
  yet　that　state　of　things　which　now　obtains　in　the　Pacific　Ocean　is　the
  yesterday　of　the　history　of　the　life　of　the　globe。　　Those　pyramids　of
  coral　rock　are　built　upon　a　foundation　which　is　itself　formed　by　the
  deposits　which　the　geologist　has　to　deal　with。　　If　we　go　back　in　time
  and　search　through　the　series　of　the　rocks；　we　find　at　every　age　of　the
  world's　history　which　has　yet　been　examined；　accumulations　of
  limestone；　many　of　which　have　certainly　been　built　up　in　just　the　same
  way　as　those　coral　reefs　which　are　now　forming　the　bottom　of　the
  Pacific　Ocean。　　And　even　if　we　turn　to　the　oldest　periods　of　geologic
  history；　although　the　nature　of　the　materials　is　changed；　although　we
  cannot　apply　to　them　the　same　reasonings　that　we　can　to　the　existing
  corals；　yet　still　there　are　vast　masses　of　limestone　formed　of　nothing
  else　than　the　accumulations　of　the　skeletons　of　similar　animals；　and
  testifying　that　even　in　those　remote　periods　of　the　world's　history；　as
  now；　the　order　of　things　implies　that　the　earth　had　already　endured　for
  a　period　of　which　our　ordinary　standards　of　chronology　give　us　not　the
  slightest　conception。　　In　other　words；　the　history　of　these　coral　reefs；
  traced　out　honestly　and　carefully；　and　with　the　same　sort　of　reasoning
  that　you　would　use　in　the　ordinary　affairs　of　life；　testifies；　like
  every　fact　that　I　know　of；　to　the　prodigious　antiquity　of　the　earth
  since　it　existed　in　a　condition　in　the　main　similar　to　that　in　which　it
  now　is。
  End