﻿Chapter 
  5 
  

  

  MESOZOIC 
  HISTORY 
  

  

  TRIASSIC 
  PERIOD 
  

  

  We 
  have 
  observed 
  that 
  as 
  a 
  result 
  of 
  the 
  Appalachian 
  revolution 
  

   New 
  York 
  State 
  was 
  raised 
  well 
  above 
  sea 
  level 
  and 
  this 
  was 
  its 
  

   condition 
  at 
  the 
  opening 
  of 
  the 
  Triassic 
  period. 
  The 
  total 
  absence 
  

   of 
  any 
  Triassic 
  strata 
  of 
  marine 
  origin 
  makes 
  it 
  quite 
  certain 
  that 
  

   the 
  continent 
  extended 
  farther 
  eastward 
  than 
  it 
  does 
  today 
  and 
  if 
  

   so, 
  the 
  old 
  Paleozoic 
  land 
  mass 
  called 
  Appalachia 
  still 
  existed, 
  

   though 
  probably 
  much 
  diminished 
  in 
  height 
  by 
  this 
  time. 
  The 
  

   absence 
  of 
  marine 
  rocks, 
  however, 
  does 
  not 
  mean 
  that 
  no 
  deposition 
  

   of 
  Triassic 
  sediments 
  occurred 
  within 
  the 
  borders 
  of 
  the 
  State, 
  

   because 
  a 
  remarkable 
  series 
  of 
  nonmarine 
  strata 
  which 
  were 
  ac- 
  

   cumulated 
  along 
  the 
  Atlantic 
  slope 
  are, 
  in 
  part, 
  shown 
  in 
  south- 
  

   eastern 
  New 
  York 
  (Rockland 
  county 
  and 
  Staten 
  island). 
  

  

  These 
  nonmarine 
  strata 
  are 
  of 
  Upper 
  Triassic 
  age, 
  as 
  told 
  by 
  the 
  

   fossils, 
  and 
  their 
  present 
  distribution 
  and 
  mode 
  of 
  occurrence 
  clearly 
  

   show 
  that 
  they 
  were 
  deposited 
  in 
  a 
  series 
  of 
  long 
  troughlike 
  de- 
  

   pressions 
  whose 
  trend 
  was 
  parallel 
  to 
  that 
  of 
  the 
  main 
  axis 
  of 
  the 
  

   Appalachian 
  range. 
  These 
  troughs 
  lay 
  between 
  the 
  Appalachians 
  

   proper 
  and 
  old 
  Appalachia. 
  The 
  latter 
  also 
  was 
  now 
  partly 
  made 
  

   up 
  of 
  the 
  greatly 
  worn-down 
  Taconics. 
  The 
  facts 
  that 
  these 
  

   troughs 
  are 
  truly 
  down-warps, 
  and 
  that 
  they 
  so 
  perfectly 
  follow 
  the 
  

   trend 
  of 
  the 
  Appalachian 
  folds, 
  make 
  it 
  certain 
  that 
  they 
  were 
  

   formed 
  by 
  a 
  great 
  lateral 
  pressure 
  which 
  was 
  a 
  continuation 
  of 
  the 
  

   Appalachian 
  disturbance. 
  Thus 
  the 
  Appalachian 
  mountains 
  still 
  

   seem 
  to 
  have 
  been 
  growing 
  well 
  into 
  the 
  Triassic 
  period, 
  and 
  while 
  

   the 
  Paleozoic 
  strata 
  were 
  being 
  folded 
  the 
  surface 
  of 
  .old 
  Appala- 
  

   chia, 
  including 
  part 
  of 
  the 
  Taconic 
  region, 
  was 
  also 
  more 
  or 
  less 
  

   warped, 
  and 
  the 
  downwarps 
  formed 
  the 
  troughs 
  in 
  which 
  the 
  

   Triassic 
  beds 
  were 
  deposited. 
  One 
  of 
  these 
  troughs 
  extends 
  along 
  

   the 
  Connecticut 
  river 
  through 
  Connecticut 
  and 
  Massachusetts 
  ; 
  an- 
  

   other, 
  and 
  the 
  largest, 
  reaches 
  from 
  Rockland 
  county, 
  New 
  York, 
  

   through 
  northern 
  New 
  Jersey, 
  southeastern 
  Pennsylvania, 
  Mary- 
  

   land, 
  and 
  into 
  northern 
  Virginia 
  ; 
  while 
  several 
  smaller 
  ones 
  lie 
  in 
  

   Virginia 
  and 
  North 
  Carolina. 
  These 
  depressions 
  were 
  most 
  favor- 
  

   ably 
  situated 
  for 
  rapid 
  accumulation 
  of 
  thick 
  deposits 
  because 
  of 
  

   their 
  position 
  immediately 
  between 
  the 
  two 
  great 
  land 
  masses 
  which 
  

  

  [61] 
  

  

  