﻿r28 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  juncture 
  with 
  Black 
  creek. 
  In 
  the 
  not 
  very 
  remote 
  past 
  the 
  vohiine 
  

   of 
  this 
  stream 
  must 
  have 
  been 
  great, 
  for 
  the 
  extremely 
  level 
  floor 
  

   of 
  its 
  bed 
  is 
  worn 
  into 
  iiiuumerai)le 
  pot-holes, 
  three 
  inches 
  to 
  six 
  

   feet 
  in 
  diameter 
  and 
  still 
  retaining 
  the 
  rounded 
  boulders 
  of 
  granite, 
  

   gabbro, 
  and 
  other 
  hard 
  rocks 
  which 
  formed 
  them. 
  (Fig. 
  2) 
  

   Beneath 
  the 
  bridge, 
  below 
  the 
  quarries, 
  the 
  ledges 
  cease 
  and 
  the 
  

   remainder 
  of 
  the 
  channel 
  of 
  Sugar 
  river 
  as 
  well 
  as 
  of 
  Black 
  river, 
  

   into 
  which 
  it 
  flows, 
  is 
  carved 
  through 
  boulder 
  drift 
  until 
  the 
  

   gabbro 
  at 
  Hawkinsville 
  is 
  reached, 
  so 
  that 
  the 
  contact 
  with 
  the 
  Cal- 
  

   ciferous 
  limestone 
  is 
  not 
  seen. 
  The 
  section 
  (140 
  A) 
  presented 
  is 
  as 
  

   follows 
  : 
  

  

  140A1 
  ; 
  — 
  Kather 
  impure, 
  tough, 
  black 
  limestone, 
  12 
  feet 
  

  

  Columnaria 
  alveolata 
  Goldfuss 
  Isotelus 
  gigas 
  DeKay 
  

   Stromatocerium 
  rugosum 
  Hall 
  Enomphalus 
  sp. 
  

   Zwphrentis 
  canadensis 
  Billings 
  and 
  large 
  Orthocerata 
  

  

  140A2 
  ; 
  — 
  Zone 
  of 
  Pa^rastrophia 
  hemiplicata 
  This 
  appears 
  to 
  be 
  

   a 
  well 
  marked 
  zone 
  of 
  the 
  upper 
  Black 
  river 
  of 
  New 
  York, 
  

   and 
  is 
  fonnd 
  in 
  similar 
  relations 
  in 
  the 
  Lake 
  Champlain 
  

   valley. 
  The 
  Triplesia 
  zone, 
  that 
  follows 
  it 
  here, 
  has 
  not 
  yet 
  

   been 
  found 
  in 
  eastern 
  New 
  York, 
  and 
  the 
  fact 
  that 
  large 
  and 
  

   smooth 
  adult 
  specimens 
  of 
  /*. 
  hemiplicata 
  often 
  so 
  nearly 
  

   resemble 
  T. 
  extans 
  may 
  indicate 
  that 
  the 
  latter 
  is 
  a 
  subsequent 
  

   development 
  from 
  the 
  former 
  in 
  central 
  New 
  York. 
  The 
  

   Parastrophia 
  beds 
  are 
  shaly, 
  with 
  compact, 
  dark 
  gray 
  seams. 
  

   1 
  to 
  4 
  inches 
  thick, 
  which 
  are 
  very 
  fossiliferous. 
  5 
  feet 
  

  

  Parastrophia 
  hemiplicata 
  Hall 
  Pajinesquina 
  alternata 
  (Em- 
  

  

  Plectambonites 
  sericeus 
  (Sowerby) 
  mons) 
  

   (a 
  large 
  form 
  resembling 
  Ostracods 
  

   P.saxea 
  Sardeson). 
  Lamellibranchs, 
  too 
  imperfect 
  for 
  

  

  Palmanella 
  testudjinariaij}2\m.'m) 
  identiflcation. 
  

  

  Isotelus 
  gigas 
  DeKay 
  

  

  140 
  A3; 
  — 
  Zone 
  of 
  Triplesia 
  extans, 
  3 
  feet 
  

  

  Plectambonites 
  se7'iceus 
  (Sowerby), 
  very 
  abundant. 
  

   Paflnesquina 
  alternata 
  (Emmons) 
  

  

  140 
  A 
  4; 
  — 
  Trenton. 
  Thin 
  layers 
  of 
  black, 
  hard, 
  almost 
  flinty, 
  

   barren 
  limestone, 
  with 
  shaly 
  alternations 
  and 
  thin 
  zones 
  with 
  

  

  