﻿32 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  ocean 
  was 
  thousands 
  of 
  feet 
  deep 
  when 
  the 
  deposition 
  began, 
  be- 
  

   cause 
  there 
  may 
  well 
  have 
  been 
  a 
  gradual 
  subsidence 
  of 
  the 
  sea 
  floor 
  

   during 
  the 
  process 
  of 
  sedimentation), 
  which 
  means 
  that 
  there 
  was 
  

   not 
  necessarily 
  very 
  deep 
  water 
  at 
  any 
  time. 
  In 
  fact, 
  the 
  very 
  

   character 
  of 
  the 
  sediments 
  clearly 
  indicates 
  that 
  the 
  Grenville 
  ocean 
  

   was, 
  for 
  most 
  part 
  at 
  least, 
  of 
  shallow 
  water, 
  for 
  such 
  sediments 
  as 
  

   sands 
  and 
  muds 
  have 
  rarely 
  if 
  ever 
  been 
  carried 
  far 
  out 
  into 
  an 
  

   ocean 
  of 
  deep 
  water. 
  The 
  great 
  ocean 
  abysses 
  of 
  today 
  are 
  not 
  re- 
  

   ceiving 
  any 
  appreciable 
  amount 
  of 
  land-derived 
  sediments. 
  Hence 
  

   it 
  is 
  practically 
  certain 
  that 
  the 
  very 
  ancient 
  Grenville 
  sea 
  bottom 
  

   gradually 
  settled 
  as 
  the 
  sediments 
  accumulated. 
  Similar 
  phenomena 
  

   are 
  definitely 
  known 
  to 
  have 
  occurred 
  in 
  many 
  later 
  basins 
  of 
  

   deposition. 
  

  

  The 
  reader 
  may 
  naturally 
  be 
  disposed 
  to 
  ask, 
  How 
  long 
  ago 
  did 
  

   the 
  Grenville 
  ocean 
  exist? 
  There 
  are 
  grave 
  difficulties 
  in 
  the 
  way 
  

   of 
  answering 
  this 
  question 
  in 
  terms 
  of 
  years, 
  as 
  we 
  have 
  nothing 
  

   like 
  an 
  exact 
  standard 
  of 
  this 
  kind 
  for 
  comparison. 
  While 
  it 
  is 
  fully 
  

   recognized 
  that 
  not 
  even 
  approximate 
  figures 
  can 
  be 
  given, 
  a 
  very 
  

   conservative 
  statement 
  would 
  ascribe 
  an 
  age 
  of 
  twenty 
  to 
  twenty- 
  

   five 
  million 
  years 
  to 
  the 
  Grenville 
  strata. 
  Whatever 
  its 
  exact 
  dura- 
  

   tion 
  may 
  have 
  been, 
  the 
  time 
  is 
  utterly 
  inconceivable 
  to 
  us, 
  and 
  the 
  

   important 
  thing 
  to 
  bear 
  in 
  mind 
  is 
  that 
  the 
  great 
  events 
  of 
  earth 
  

   history 
  which 
  have 
  transpired 
  since 
  that 
  time 
  require 
  a 
  lapse 
  of 
  

   many 
  million 
  years 
  as 
  shown 
  by 
  the 
  enormous 
  accumulations 
  of 
  

   sediments 
  in 
  many 
  parts 
  of 
  the 
  earth, 
  and 
  by 
  the 
  building 
  up 
  and 
  

   wearing 
  away 
  of 
  one 
  great 
  mountain 
  range 
  after 
  another. 
  The 
  

   reader 
  will 
  better 
  appreciate 
  the 
  significance 
  . 
  of 
  these 
  statements 
  

   after 
  he 
  has 
  studied 
  the 
  following 
  pages. 
  In 
  the 
  table 
  of 
  geological 
  

   time 
  divisions 
  given 
  in 
  chapter 
  i, 
  the 
  two 
  oldest 
  periods 
  are 
  the 
  

   Archean 
  and 
  Algonkian 
  respectively. 
  The 
  Grenville 
  can 
  not 
  with 
  

   certainty, 
  as 
  yet, 
  be 
  placed 
  in 
  either 
  of 
  these 
  periods, 
  although 
  ac- 
  

   cording 
  to 
  the 
  best 
  evidence 
  it 
  should 
  be 
  classed 
  with 
  the 
  Archean. 
  

   In 
  the 
  meantime 
  it 
  is 
  advisable 
  to 
  refer 
  to 
  all 
  formations 
  older 
  than 
  

   the 
  Paleozoic 
  simply 
  as 
  Preeambrie. 
  

  

  LIFE 
  IN 
  THE 
  GRENVILLE 
  OCEAN 
  

  

  All 
  that 
  can 
  be 
  said 
  regarding 
  the 
  life 
  of 
  the 
  Grenville 
  ocean 
  is 
  

   that 
  it 
  existed 
  as 
  indicated 
  by 
  the 
  presence 
  of 
  the 
  graphite. 
  Al- 
  

   though 
  we 
  can 
  not 
  even 
  state 
  whether 
  the 
  organisms 
  were 
  plant 
  or 
  

   animal, 
  the 
  fact 
  that 
  there 
  was 
  life 
  in 
  that 
  very 
  ancient 
  ocean 
  is 
  a 
  

   matter 
  of 
  no 
  little 
  significance. 
  Anthracite 
  coal, 
  which 
  is 
  chemically 
  

  

  