﻿64: 
  E. 
  H. 
  Perkins 
  — 
  Bight 
  on 
  Conglomerate. 
  

  

  The 
  sediments 
  have 
  been 
  compressed 
  into 
  a 
  series 
  of 
  

   folds, 
  which 
  in 
  the 
  southern 
  half 
  of 
  the 
  basin 
  run 
  nearly 
  

   north 
  and 
  south, 
  and 
  in 
  the 
  northern 
  half 
  of 
  the 
  basin 
  

   tend 
  a 
  little 
  north 
  of 
  east. 
  The 
  Dighton 
  conglomerate 
  

   is 
  found 
  in 
  the 
  axes 
  of 
  the 
  synclines. 
  The 
  chief 
  areas 
  of 
  

   the 
  conglomerate 
  are 
  the 
  Newport 
  synclines 
  in 
  the 
  south, 
  

   the 
  large 
  Dighton 
  and 
  Taunton 
  synclines 
  in 
  the 
  central 
  

   part 
  of 
  the 
  basin, 
  and 
  the 
  little 
  Attleboro 
  syncline 
  in 
  the 
  

   extreme 
  northwest. 
  

  

  The 
  Dighton 
  Conglomerate. 
  

  

  The 
  various 
  features 
  of 
  the 
  conglomerate 
  will 
  be 
  con- 
  

   sidered 
  under 
  the 
  heads 
  of 
  structure, 
  matrix, 
  larger 
  

   fragments, 
  color, 
  fossils 
  and 
  associated 
  sediments. 
  Em- 
  

   phasis 
  will 
  be 
  placed 
  on 
  criteria 
  by 
  which 
  the 
  method 
  of 
  

   origin 
  may 
  be 
  determined. 
  

  

  Structure. 
  

  

  Almost 
  without 
  exception 
  the 
  structure 
  of 
  the 
  conglom- 
  

   erates 
  is 
  what 
  is 
  known 
  as 
  pell-mell. 
  The 
  outcrops 
  show 
  

   jumbled 
  masses 
  of 
  pebbles, 
  cobbles 
  and 
  bowlders. 
  The 
  

   long 
  axes 
  are 
  tipped 
  at 
  all 
  angles 
  and 
  with 
  no, 
  or 
  at 
  

   least 
  very 
  slight, 
  traces 
  of 
  bedding. 
  In 
  certain 
  outcrops, 
  

   especially 
  in 
  the 
  Newport 
  area, 
  pressure 
  has 
  elongated 
  

   the 
  pebbles 
  in 
  parallel 
  lines. 
  This 
  is 
  clearly 
  a 
  secondary 
  

   feature 
  and 
  gives 
  no 
  clue 
  to 
  the 
  arrangement 
  of 
  the 
  peb- 
  

   bles 
  at 
  the 
  time 
  of 
  deposition. 
  Pell-mell 
  structure 
  may 
  

   be 
  the 
  result 
  of 
  glacial 
  deposition, 
  very 
  rapid 
  fluviatile 
  

   deposition 
  or 
  the 
  slumping 
  of 
  unconsolidated 
  bedded 
  

   deposits 
  of 
  any 
  origin. 
  The 
  wide 
  extent 
  of 
  the 
  structure 
  

   in 
  the 
  Narragansett 
  Basin 
  negatives 
  the 
  last 
  suggestion 
  

   and 
  leaves 
  ice 
  and 
  river 
  action 
  as 
  possibilities. 
  

  

  Although 
  the 
  conglomerate 
  beds 
  themselves 
  show 
  little 
  

   signs 
  of 
  bedding, 
  they 
  are 
  interstratified, 
  especially 
  in 
  

   the 
  lower 
  portions 
  of 
  the 
  formation, 
  with 
  beds 
  of 
  other 
  

   types. 
  These 
  beds 
  consist 
  of 
  sandstones, 
  shales 
  and 
  

   black 
  coaly 
  shales. 
  Vertical 
  variation 
  is 
  well 
  shown 
  in 
  

   many 
  parts 
  of 
  the 
  area. 
  Lateral 
  variation 
  is 
  best 
  shown 
  

   in 
  exposed 
  cliffs 
  around 
  Newport. 
  Some 
  sections 
  show 
  

   lateral 
  variation 
  nearly 
  as 
  well 
  developed 
  as 
  anything 
  in 
  

   modern 
  flood-plains. 
  This 
  variation 
  in 
  the 
  composition 
  

   of 
  the 
  beds 
  is 
  characteristic 
  of 
  stream 
  rather 
  than 
  of 
  

  

  