﻿516 
  Forty-seventh 
  Report 
  on 
  the 
  State 
  Museum. 
  

  

  points. 
  The 
  Hudson 
  river 
  members 
  are 
  thickly-bedded, 
  dark- 
  

   gray, 
  very 
  fine-grained 
  sandstones, 
  with 
  occasional 
  thin 
  shale 
  

   partings 
  between 
  the 
  beds. 
  They 
  dip 
  south-southeast 
  at 
  angles 
  

   from 
  forty 
  to 
  sixty 
  degrees 
  and 
  extend 
  about 
  half 
  way 
  up 
  the 
  

   slope 
  of 
  the 
  ridge. 
  Their 
  upper 
  surface 
  is 
  irregular, 
  and 
  Davis 
  

   has 
  given 
  a 
  figure 
  illustrating 
  an 
  exposure 
  in 
  one 
  of 
  the 
  quarries 
  

   in 
  which 
  the 
  limestones 
  are 
  seen 
  fitting 
  closely 
  into 
  channels 
  worn 
  

   along 
  the 
  strike 
  of 
  the 
  sandstones, 
  a 
  relation 
  which 
  precludes 
  the 
  

   possibility 
  of 
  a 
  fault. 
  He 
  adds: 
  u 
  It 
  is 
  noteworthy 
  that 
  the 
  

   limestone 
  begins 
  immediately 
  with 
  its 
  fully-determined 
  calcareous 
  

   character 
  ; 
  there 
  is 
  no 
  band 
  of 
  transitional 
  composition 
  ; 
  no 
  frag- 
  

   ments 
  of 
  the 
  sandstone 
  are 
  contained 
  in 
  the 
  overlying 
  rock. 
  The 
  

   old, 
  worn 
  surface 
  was 
  swept 
  clean 
  before 
  the 
  corals 
  and 
  crinoids 
  

   began 
  growing 
  upon 
  it, 
  and 
  their 
  fragments 
  and 
  grindings 
  make 
  

   the 
  first 
  deposit. 
  Some 
  little 
  pieces 
  of 
  crinoid 
  stems 
  lie 
  directly 
  

   on 
  the 
  bare 
  sandstones." 
  The 
  limestone 
  lying 
  above 
  this 
  uncon- 
  

   formity 
  is 
  the 
  dark-colored 
  massive 
  coralline 
  bed 
  which 
  has 
  long 
  

   been 
  known 
  to 
  be 
  of 
  Niagara 
  age. 
  Its 
  thickness 
  varies 
  slightly, 
  

   but 
  averages 
  seven 
  feet. 
  It 
  gives 
  place 
  quite 
  abruptly 
  to 
  the 
  

   overlying 
  cement 
  series, 
  but 
  with 
  no 
  signs 
  of 
  a 
  break 
  in 
  the 
  sedi- 
  

   mentation. 
  The 
  cement 
  series 
  consists 
  of 
  an 
  upper 
  and 
  lower 
  

   cement 
  bed 
  separated 
  by 
  a 
  few 
  beds 
  of 
  limestone. 
  The 
  thick- 
  

   nesses 
  vary 
  somewhat. 
  The 
  lower 
  cement 
  bed 
  attains 
  a 
  thickness 
  

   of 
  twenty-two 
  feet, 
  which 
  continues 
  for 
  some 
  distance 
  in 
  the 
  

   vicinity 
  of 
  section 
  IY. 
  The 
  overlying 
  limestones 
  are 
  here 
  about 
  

   three 
  feet 
  thick, 
  and 
  the 
  upper 
  cement 
  bed 
  five 
  feet. 
  Farther 
  

   northward 
  the 
  lower 
  cement 
  bed 
  thins 
  and 
  the 
  intervening 
  lime- 
  

   stones 
  and 
  upper 
  cement 
  bed 
  thicken 
  considerably. 
  The 
  course 
  

   of 
  the 
  cement 
  series 
  down 
  the 
  dip 
  westward 
  is 
  shown 
  by 
  the 
  

   broken 
  lines 
  C 
  — 
  C 
  on 
  the 
  section 
  in 
  plate 
  4. 
  Overlying 
  the 
  

   upper 
  cement 
  bed 
  there 
  are 
  several 
  thin 
  beds 
  of 
  impure 
  limestones 
  

   containing 
  Leper 
  ditia 
  alta 
  and, 
  .at 
  their 
  surface, 
  prismatic 
  mud 
  

   cracks, 
  as 
  noted 
  by 
  Lindsley. 
  The 
  Tentaculite 
  limestones 
  have 
  

   a 
  thickness 
  of 
  about 
  twenty-five 
  feet, 
  of 
  which 
  the 
  upper 
  six 
  feet 
  

   are 
  classed 
  as 
  the 
  ribbon 
  limestone 
  by 
  Lindsley 
  and 
  contain 
  

   Stromatopora. 
  The 
  Pentamerus 
  limestone 
  constitutes 
  the 
  crest 
  

   of 
  the 
  ridge, 
  and 
  outcrops 
  in 
  cliffs 
  of 
  light-gray 
  color. 
  It 
  

   presents 
  its 
  usual 
  character 
  of 
  a 
  lead-gray 
  massive 
  limestone, 
  

   and 
  carries 
  a 
  considerable 
  amount 
  of 
  chert 
  in 
  courses 
  and 
  dissemi- 
  

  

  