﻿THE 
  GEOLOGICAL 
  HISTORY 
  OF 
  NEW 
  YORK 
  STATE 
  47 
  

  

  In 
  the 
  strata 
  of 
  Cambric 
  age 
  in 
  New 
  York, 
  animal 
  or 
  plant 
  re- 
  

   mains 
  are 
  comparatively 
  rare, 
  while 
  the 
  Ordovicic 
  rocks 
  throughout 
  

   fairly 
  teem 
  with 
  fossils. 
  If 
  any 
  single 
  formation 
  deserves 
  special 
  

   mention, 
  it 
  is 
  the 
  Trenton 
  limestone 
  which 
  is 
  exceedingly 
  rich 
  in 
  

   fossils. 
  The 
  type 
  locality, 
  at 
  Trenton 
  Falls, 
  is 
  justly 
  famous 
  as 
  a 
  

   collecting 
  place 
  for 
  Ordovicic 
  fossils. 
  Among 
  plants, 
  none 
  above 
  

   very 
  simple 
  seaweeds 
  or 
  algae 
  are 
  known 
  to 
  have 
  existed. 
  Among 
  

   animals, 
  hundreds 
  of 
  species 
  have 
  been 
  described 
  as 
  occurring 
  in 
  

   the 
  Ordovicic 
  strata 
  of 
  New 
  York. 
  These 
  species 
  represent 
  all 
  the 
  

   more 
  important 
  subkingdoms 
  and 
  classes 
  of 
  animals 
  below 
  the 
  verte- 
  

   brates. 
  Especially 
  prominent 
  are 
  : 
  corals, 
  graptolites, 
  star-fishes, 
  

   brachiopods, 
  gastropods 
  and 
  trilobites. 
  All 
  the 
  organisms 
  men- 
  

   tioned 
  lived 
  in 
  the 
  salt 
  water, 
  and 
  if 
  land 
  life 
  forms 
  existed 
  we 
  

   know 
  practically 
  nothing 
  about 
  them. 
  It 
  must 
  be 
  borne 
  in 
  mind 
  

   that 
  not 
  a 
  single 
  species 
  of 
  that 
  time 
  is 
  known 
  to 
  live 
  today, 
  so 
  

   complete 
  have 
  been 
  the 
  evolutionary 
  changes 
  since 
  the 
  Ordovicic 
  

   age. 
  Certain 
  remarkable 
  classes 
  of 
  animals 
  like 
  the 
  graptolites 
  and 
  

   trilobites, 
  which 
  often 
  fairly 
  swarmed 
  in 
  the 
  Ordovicic 
  sea, 
  have 
  

   been 
  wholly 
  extinct 
  for 
  millions 
  of 
  years. 
  

  

  TACONIC 
  MOUNTAIN 
  REVOLUTION 
  (CLOSE 
  OF 
  THE 
  

   ORDOVICIC) 
  

  

  We 
  are 
  now 
  ready 
  to 
  discuss 
  the 
  second 
  well-known 
  mountain- 
  

   making 
  epoch 
  which 
  affected 
  New 
  York 
  State. 
  We 
  have 
  learned 
  

   that 
  sedimentation 
  along 
  the 
  middle 
  eastern 
  border 
  and 
  south- 
  

   eastern 
  parts 
  of 
  the 
  State 
  was 
  practically 
  uninterrupted 
  during 
  all 
  

   the 
  Cambric 
  and 
  Ordovicic 
  periods, 
  and 
  that 
  some 
  thousands 
  of 
  

   feet 
  of 
  strata 
  had 
  accumulated. 
  At 
  the 
  same 
  time 
  extensive 
  sedi- 
  

   mentation 
  was 
  taking 
  place 
  in 
  the 
  seas 
  which 
  covered 
  all 
  the 
  regions 
  

   of 
  the 
  present 
  Berkshire 
  hills, 
  Green 
  and 
  White 
  mountains, 
  as 
  well 
  

   as 
  southward, 
  at 
  least 
  as 
  far 
  as 
  Virginia, 
  over 
  the 
  region 
  occupied 
  

   by 
  the 
  present 
  Piedmont 
  plateau. 
  At 
  or 
  tozvard 
  the 
  close 
  of 
  the 
  

   Ordovicic 
  period 
  a 
  great 
  compressive 
  force 
  in 
  the 
  earth's 
  crust 
  was 
  

   brought 
  to 
  bear 
  upon 
  the 
  mass 
  of 
  sediments 
  which 
  reached 
  from 
  

   north 
  of 
  New 
  England 
  to 
  Virginia, 
  or 
  possibly 
  farther 
  southward. 
  

   As 
  a 
  result 
  of 
  this 
  compression 
  the 
  strata 
  were 
  tilted, 
  highly 
  folded, 
  

   and 
  elevated 
  far 
  above 
  sea 
  level 
  into 
  a 
  magnificent 
  mountain 
  range 
  

   known 
  as 
  the 
  Taconic 
  mountains. 
  In 
  structure, 
  the 
  range 
  consisted 
  

   of 
  a 
  series 
  of 
  rock 
  folds, 
  both 
  great 
  and 
  small, 
  whose 
  axes 
  were 
  

   parallel 
  to 
  the 
  main 
  axis 
  of 
  the 
  range, 
  that 
  is 
  north-northeast 
  by 
  

   south-southwest. 
  Examination 
  of 
  figures 
  14 
  and 
  20 
  will 
  give 
  the 
  

  

  