﻿444 
  J. 
  D. 
  Dana 
  — 
  The 
  Upturning 
  of 
  

  

  that 
  of 
  the 
  latter 
  ended 
  in 
  producing 
  monoclinal 
  uplifts, 
  and 
  

   also, 
  it 
  is 
  believed, 
  great 
  faults. 
  Further, 
  while 
  the 
  post-Car- 
  

   boniferous 
  uplifts 
  of 
  the 
  Atlantic 
  border 
  include 
  three 
  individ- 
  

   ual 
  mountain-ranges: 
  (1) 
  That 
  of 
  the 
  Appalachian 
  area 
  from 
  

   Alabama 
  to 
  the 
  Oatskills, 
  1500 
  miles 
  long; 
  (2) 
  That 
  extending 
  

   from 
  Newfoundland 
  southwestward 
  through 
  Nova 
  Scotia, 
  and 
  

   probably 
  to 
  Rhode 
  Island, 
  in 
  all 
  1000 
  miles 
  long, 
  and 
  that 
  of 
  

   the 
  Gaspe-Worcester 
  range,* 
  the 
  post-Jura-Trias 
  system 
  em- 
  

   braced 
  eight 
  or 
  more 
  individual 
  ranges, 
  of 
  cotemporaneous 
  

   origin, 
  each 
  of 
  the 
  several 
  basins 
  having 
  been 
  independent 
  in 
  

   its 
  geosyncline 
  and 
  in 
  its 
  uplifts. 
  

  

  Of 
  the 
  two 
  mountain-making 
  epochs, 
  only 
  the 
  latter 
  included, 
  

   among 
  the 
  events 
  of 
  each 
  mountain-individual, 
  extensive 
  igne- 
  

   ous 
  eruptions. 
  Of 
  the 
  ejections 
  in 
  the 
  Connecticut 
  Yalley, 
  

   those 
  of 
  West 
  Rock 
  Ridge 
  and 
  of 
  at 
  least 
  two 
  others 
  in 
  East 
  

   Haven 
  occurred, 
  in 
  the 
  course, 
  or 
  near 
  the 
  close, 
  of 
  the 
  moun- 
  

   tain-making 
  movements. 
  If 
  this 
  proves 
  to 
  be 
  the 
  time 
  of 
  the 
  

   event 
  in 
  general 
  for 
  the 
  other 
  trap 
  ridges 
  of 
  the 
  valley, 
  then 
  

   all 
  were 
  a 
  result 
  of, 
  or 
  a 
  sequel 
  to, 
  the 
  movements. 
  But 
  if, 
  as 
  

   Professor 
  W. 
  M. 
  Davis 
  holds, 
  the 
  trap 
  of 
  most 
  of 
  the 
  ridges 
  

   originally 
  alternated 
  in 
  sheets 
  with 
  horizontal 
  layers 
  of 
  sand- 
  

   stone 
  and 
  both 
  were 
  uplifted 
  together 
  into 
  monoclines, 
  then 
  

   the 
  ejections 
  occurred 
  while 
  deposition 
  in 
  the 
  geosyncline 
  

   was 
  in 
  slow 
  and 
  quiet 
  progress. 
  The 
  decision 
  of 
  the 
  question 
  

   is, 
  therefore, 
  one 
  of 
  dynamical 
  importance. 
  Professor 
  Davis 
  

   states 
  that 
  the 
  eruptions 
  had 
  nothing 
  to 
  do 
  with 
  the 
  upturn- 
  

   ing, 
  and 
  this 
  is 
  true 
  in 
  either 
  case. 
  

  

  Fault 
  planes 
  concerned 
  in 
  the 
  uplift. 
  

  

  The 
  conformity 
  between* 
  the 
  general 
  direction 
  of 
  the 
  struc- 
  

   ture-lines 
  of 
  the 
  Jura-Trias 
  formation 
  and 
  that 
  of 
  the 
  crystalline 
  

   schists 
  adjoining 
  and 
  the 
  mountain 
  ranges 
  to 
  the 
  west, 
  has 
  

   long 
  been 
  recognized. 
  The 
  view 
  suggested 
  by 
  Prof. 
  Davis 
  

   goes 
  beyond 
  this 
  in 
  supposing 
  a 
  conformity 
  also 
  between 
  the 
  

   dips 
  of 
  the 
  foliation-planes 
  and 
  those 
  of 
  the 
  fault-planes. 
  He 
  

   says 
  : 
  " 
  A 
  group 
  of 
  inclined 
  slabs 
  compressed 
  by 
  a 
  horizontal 
  

   force 
  about 
  at 
  right 
  angles 
  to 
  their 
  strike 
  might 
  yield 
  in 
  part 
  

   by 
  minute 
  internal 
  rearrangement, 
  and 
  in 
  part 
  by 
  slipping 
  on 
  

   their 
  divisional 
  surfaces, 
  so 
  as 
  to 
  reduce 
  their 
  breadth 
  by 
  

   standing 
  more 
  nearly 
  vertical, 
  that 
  is, 
  more 
  nearly 
  at 
  right 
  

   angles 
  to 
  the 
  compressing 
  force. 
  In 
  so 
  doing, 
  the 
  upper 
  sur- 
  

   face 
  of 
  the 
  group 
  would 
  be 
  somewhat 
  elevated, 
  and 
  at 
  the 
  

   same 
  time 
  the 
  .bevelled 
  edge 
  of 
  every 
  slab 
  would 
  be 
  tilted 
  over 
  

   by 
  a 
  tolerably 
  constant 
  angle 
  in 
  one 
  direction, 
  and 
  separated 
  

   from 
  the 
  neighboring 
  slabs 
  by 
  a 
  dislocation 
  with 
  the 
  uplift 
  on 
  

  

  * 
  This 
  Journal, 
  xxxix, 
  380, 
  1890. 
  

  

  