﻿404 
  PROF. 
  J. 
  D. 
  DANA 
  ON 
  THE 
  GEOLOGICAL 
  

  

  The 
  results 
  arrived 
  at 
  sustain 
  those 
  of 
  the 
  several 
  investigators 
  

   mentioned 
  in 
  proving 
  (1) 
  that 
  the 
  Taconic 
  schists 
  and 
  the 
  adjoining 
  

   limestones, 
  as 
  well 
  as 
  quartzite, 
  are 
  one 
  in 
  system 
  of 
  stratification, 
  

   and 
  (2) 
  that 
  they 
  have 
  in 
  general 
  a 
  high 
  eastward 
  dip. 
  

  

  In 
  1875 
  I 
  traversed 
  with 
  Mr. 
  Wing 
  the 
  region 
  of 
  his 
  explora- 
  

   tions 
  in 
  Vermont, 
  saw 
  the 
  fossils 
  in 
  the 
  metamorphic 
  limestone 
  at 
  

   some 
  of 
  their 
  localities, 
  and 
  found 
  that 
  his 
  palseontological 
  demon- 
  

   stration 
  (1) 
  of 
  the 
  Lower-Silurian 
  ago 
  of 
  the 
  limestone, 
  and 
  (2) 
  of 
  

   its 
  covering 
  the 
  periods 
  of 
  the 
  Lower 
  Silurian 
  from 
  the 
  Trenton 
  to 
  

   the 
  Calciferous 
  inclusive 
  (if 
  not 
  also 
  the 
  Primordial), 
  was 
  complete. 
  

   I 
  was 
  shown 
  also 
  (3) 
  that 
  this 
  demonstration 
  from 
  fossils 
  had 
  been 
  

   obtained 
  both 
  from 
  the 
  limestone 
  on 
  the 
  east 
  and 
  that 
  on 
  the 
  west 
  

   side 
  of 
  the 
  Taconic 
  belt, 
  proving 
  that 
  they 
  were 
  alike 
  in 
  geological 
  

   age, 
  and 
  therefore 
  parts 
  of 
  the 
  same 
  great 
  limestone 
  formation 
  — 
  a 
  

   fact 
  apparent 
  also 
  in 
  their 
  joining 
  and 
  becoming 
  one 
  mass 
  near 
  

   Middlebury, 
  Vermont. 
  I 
  was 
  convinced, 
  further, 
  that 
  the 
  strati- 
  

   graphical 
  facts 
  left 
  no 
  reasonable 
  doubt 
  as 
  to 
  the 
  limestone 
  forma- 
  

   tion 
  being 
  inferior 
  in 
  position 
  to 
  the 
  Taconic 
  schists. 
  

  

  In 
  my 
  observations 
  among 
  these 
  rocks 
  over 
  the 
  region 
  extending 
  

   from 
  Vermont 
  through 
  Massachusetts, 
  I 
  aimed 
  chieny 
  at 
  tracing 
  

   southward 
  the 
  evidence 
  as 
  to 
  the 
  continuity 
  and 
  unity 
  in 
  system 
  of 
  

   the 
  Taconic 
  and 
  associated 
  formations 
  ; 
  for 
  the 
  beds 
  were 
  too 
  highly 
  

   crystalline 
  to 
  contain 
  fossils, 
  though 
  not 
  so 
  highly 
  but 
  that 
  I 
  looked 
  

   for 
  them 
  at 
  some 
  of 
  the 
  more 
  favourable 
  localities. 
  Besides 
  finding 
  

   a 
  general 
  eastward 
  dip 
  along 
  the 
  region 
  in 
  the 
  schists 
  and 
  the 
  

   limestone 
  of 
  this 
  eastern 
  side 
  of 
  the 
  Taconic 
  belt, 
  I 
  discovered 
  also 
  

   that 
  in 
  South-western 
  Massachusetts, 
  where 
  the 
  Taconic 
  belt 
  is 
  

   widened 
  to 
  treble 
  its 
  usual 
  breadth, 
  and 
  rises 
  into 
  the 
  high 
  moun- 
  

   tain 
  region 
  called 
  Mount 
  Washington 
  — 
  its 
  highest 
  point 
  2634 
  feet 
  

   above 
  the 
  sea 
  — 
  there 
  the 
  limestone 
  and 
  schists 
  dip 
  ivestward, 
  the 
  

   limestone 
  passing 
  beneath 
  the 
  schists 
  ; 
  and 
  hence, 
  inasmuch 
  as 
  the 
  

   dip 
  on 
  the 
  west 
  side 
  of 
  the 
  range 
  is 
  eastward, 
  they 
  apparently 
  gave 
  

   proof 
  of 
  a 
  synclinal, 
  just 
  such 
  as 
  is 
  afforded 
  by 
  several 
  mountain- 
  

   summits 
  of 
  the 
  Taconic 
  range 
  to 
  the 
  north 
  — 
  Mounts 
  Anthony, 
  

   Spruce, 
  Dorset, 
  and 
  others 
  in 
  Vermont. 
  Mount 
  Washington 
  is 
  

   continued 
  southward 
  through 
  North-western 
  Connecticut 
  ; 
  and 
  in 
  

   this 
  part 
  also 
  the 
  same 
  evidence 
  of 
  a 
  synclinal 
  — 
  a 
  westward 
  dip 
  on 
  

   the 
  cast, 
  and 
  eastward 
  on 
  the 
  west 
  — 
  was 
  obtained. 
  

  

  To 
  the 
  west 
  of 
  the 
  northern 
  half 
  of 
  the 
  State 
  of 
  Connecticut, 
  the 
  

   Taconic 
  schists 
  and 
  the 
  adjoining 
  western 
  limestone 
  extend 
  south- 
  

   westward, 
  over 
  Dutchess 
  County, 
  New 
  York, 
  to 
  the 
  Hudson 
  river. 
  

   As 
  they 
  spread 
  westward, 
  the 
  schists 
  and 
  limestone 
  become 
  less 
  and 
  

   less 
  crystalline, 
  and 
  hence 
  arc 
  in 
  a 
  more 
  and 
  more 
  favourable 
  con- 
  

   dition 
  for 
  the 
  preservation 
  of 
  the 
  original 
  fossils 
  of 
  the 
  rocks. 
  In 
  

   1879, 
  while 
  pursuing 
  my 
  investigations 
  over 
  this 
  county, 
  I 
  found 
  

   fossils 
  of 
  Trenton 
  age 
  at 
  Pleasant 
  Valley 
  in 
  this 
  western 
  limestone, 
  

   about 
  a 
  dozen 
  miles 
  west 
  of 
  the 
  Taconic 
  belt, 
  and 
  subsequently 
  ob- 
  

   tained 
  other 
  fossils 
  from 
  points 
  half 
  nearer 
  the 
  belt. 
  Professor 
  W« 
  

   B. 
  Dwight, 
  of 
  Ponghkeepsie 
  (in 
  Dutchess 
  County, 
  on 
  the 
  Hudson 
  

   river) 
  was 
  with 
  me 
  at 
  the 
  first 
  discovery, 
  and 
  has 
  since 
  extended 
  

  

  