﻿ODMALO 
  

  

  THE 
  

  

  AMERICAN 
  JOURNAL 
  OF 
  SCIENCE 
  

  

  [THIRD 
  SERIES.] 
  

  

  Aet. 
  X. 
  — 
  Some 
  of 
  the 
  features 
  of 
  non-volcanic 
  Igneous 
  

   Ejections, 
  as 
  illustrated 
  in 
  the 
  four 
  " 
  Rocks 
  " 
  of 
  the 
  JVew 
  

   Haven 
  Region, 
  West 
  Rock, 
  Pine 
  Rock, 
  Mill 
  Rock 
  and 
  

   East 
  Rock 
  ; 
  by 
  James 
  D. 
  Dana. 
  With 
  Plates 
  II 
  to 
  VII. 
  

  

  The 
  observations 
  on 
  the 
  igneous 
  ejections 
  of 
  the 
  New 
  Haven 
  

   region 
  here 
  recorded 
  and 
  discussed 
  were 
  mostly 
  completed 
  

   during 
  the 
  years 
  1879 
  and 
  1880, 
  shortly 
  after 
  the 
  publication 
  

   (in 
  1877) 
  of 
  a 
  detailed 
  topographical 
  map 
  of 
  the 
  region 
  by 
  the 
  

   II. 
  S. 
  Coast 
  and 
  Geodetic 
  Survey, 
  made 
  under 
  the 
  special 
  

   direction 
  of 
  R. 
  M. 
  Bache. 
  As 
  this 
  map 
  is 
  on 
  the 
  large 
  scale 
  

   of 
  towo, 
  or 
  about 
  6-J 
  inches 
  to 
  the 
  mile, 
  and 
  has 
  £0-foot 
  

   contour 
  lines, 
  it 
  afforded 
  a 
  very 
  convenient 
  basis 
  for 
  the 
  record 
  

   of 
  geological 
  facts. 
  

  

  A 
  reduction 
  of 
  a 
  portion 
  of 
  this 
  map 
  to 
  a 
  scale 
  of 
  two 
  miles 
  

   to 
  the 
  inch, 
  is 
  presented 
  on 
  Plate 
  II.* 
  Excepting 
  the 
  hills 
  in 
  

   the 
  southwestern 
  corner 
  of 
  the 
  map, 
  its 
  whole 
  area, 
  even 
  that 
  

   of 
  the 
  JSTew 
  Haven 
  plain, 
  is 
  underlaid 
  by 
  the 
  Jura-Trias 
  Red- 
  

   sandstone 
  formation. 
  (The 
  excepted 
  hills 
  are 
  part 
  of 
  the 
  bor- 
  

   der 
  of 
  metamorphic 
  schists 
  that 
  bounds 
  the 
  Jura-Trias 
  region 
  

  

  * 
  This 
  map 
  is 
  a 
  portion 
  of 
  Plate 
  II 
  in 
  the 
  writer's 
  paper 
  on 
  the 
  " 
  Phenomena 
  

   of 
  the 
  Glacial 
  and 
  Champlain 
  Periods 
  about 
  the 
  mouth 
  of 
  the 
  Connecticut 
  Valley, 
  

   or 
  the 
  New 
  Haven 
  Region" 
  (This 
  Journal, 
  xxvii, 
  113, 
  Feb. 
  1884). 
  The 
  limit 
  of 
  

   the 
  New 
  Haven 
  plain 
  is 
  marked 
  by 
  a 
  dotted 
  line 
  at 
  the 
  base 
  of 
  the 
  hills, 
  and 
  the 
  

   contour-lines 
  over 
  it 
  are 
  omitted, 
  the 
  heights 
  instead 
  being 
  given 
  after 
  a 
  special 
  

   survey. 
  The 
  small 
  nearly 
  circular 
  depressions 
  marked 
  on 
  the 
  map 
  represent 
  

   " 
  Kettle-holes." 
  The 
  New 
  Haven 
  plain 
  was 
  of 
  river-flood 
  origin 
  and 
  it 
  is 
  pre- 
  

   sented 
  on 
  the 
  map 
  with 
  the 
  outlines 
  and 
  height 
  unaltered 
  by 
  the 
  gradings 
  for 
  

   road-making, 
  and 
  by 
  the 
  making 
  of 
  mill-dams 
  ; 
  and 
  hence 
  the 
  map 
  is 
  a 
  map 
  of 
  

   the 
  region 
  of 
  New 
  Haven 
  before 
  1640, 
  as 
  stated 
  in 
  its 
  title. 
  

  

  Am. 
  Jotjr. 
  Sci. 
  — 
  Third 
  Series, 
  Vol. 
  XLII, 
  No. 
  248. 
  — 
  August, 
  1891. 
  

  

  