﻿398 
  Forty-seventh 
  Report 
  on 
  the 
  State 
  Museum, 
  

  

  considerable 
  area 
  or 
  represented 
  by 
  occasional 
  lenses 
  of 
  chert. 
  

   In 
  Ulster 
  county 
  it 
  attains 
  a 
  thickness 
  of 
  thirty 
  feet, 
  but 
  is 
  

   usually 
  about 
  ten 
  feet 
  thick 
  and 
  is 
  predominantly 
  calcareous. 
  In 
  

   central 
  New 
  York, 
  also, 
  the 
  thickness 
  and 
  character 
  is 
  variable 
  ; 
  

   at 
  Columbia, 
  in 
  Herkimer 
  county, 
  it 
  is 
  a 
  silicious 
  limestone 
  ten 
  

   feet 
  thick, 
  but 
  a 
  few 
  miles 
  west 
  it 
  is 
  absent, 
  though 
  reappearing 
  

   farther 
  to 
  the 
  westward. 
  South 
  of 
  Utica 
  it 
  comes 
  in 
  again 
  as 
  a 
  

   bed 
  of 
  quartzite 
  three 
  to 
  six 
  feet 
  thick, 
  which 
  thickens 
  to 
  eighteen 
  

   to 
  twenty 
  feet 
  at 
  Oriskany 
  Falls. 
  " 
  Between 
  Elbridge 
  and 
  

   Skaneateles, 
  on 
  the 
  old 
  Seneca 
  road, 
  the 
  sandstone 
  shows 
  itself 
  

   on 
  the 
  road, 
  and 
  of 
  a 
  thickness 
  of 
  about 
  thirty 
  feet."* 
  Thence 
  

   westward 
  it 
  is 
  represented 
  by 
  lenticular 
  masses 
  of 
  quartzite 
  of 
  

   greater 
  or 
  less 
  length, 
  and 
  varying 
  from 
  a 
  mere 
  film 
  to 
  six 
  or 
  

   eight 
  feet 
  in 
  thickness. 
  Hall 
  reports 
  the 
  westernmost 
  outcrop 
  at 
  

   Morganville, 
  in 
  Genesee 
  county. 
  f 
  

  

  The 
  Helderberg 
  limestones 
  attain 
  their 
  greatest 
  development 
  

   in 
  eastern 
  New 
  York, 
  and 
  the 
  thickness 
  reported 
  by 
  Davis 
  of 
  

   about 
  tSOO 
  feet 
  in 
  the 
  Catskill 
  region 
  is 
  the 
  maximum. 
  They 
  

   thin 
  gradually 
  southward 
  in 
  New 
  York, 
  but 
  expand 
  again 
  in 
  

   New 
  Jersey. 
  In 
  the 
  Helderberg 
  mountains 
  there 
  are 
  200 
  feet, 
  

   and 
  at 
  Schoharie 
  not 
  over 
  240 
  feet. 
  "Westward 
  from 
  Schoharie 
  

  

  * 
  Vanuxem; 
  Final 
  Report 
  on 
  the 
  Third 
  District 
  of 
  New 
  York. 
  p. 
  126. 
  1843. 
  

   t 
  A 
  section 
  of 
  the 
  Lower 
  Helderberg 
  as 
  represented 
  in 
  Schoharie 
  and 
  Albany 
  counties 
  is 
  as 
  

   follows, 
  from 
  the 
  top 
  down 
  wards: 
  

  

  1. 
  A 
  crystalline 
  gray, 
  heavy-bedded 
  limestone, 
  largely 
  consisting 
  of 
  broken 
  and 
  drifted 
  

   fragments 
  of 
  fossils 
  and 
  known 
  as 
  the 
  upper 
  Pentatnerus 
  beds. 
  

  

  2. 
  A 
  series 
  of 
  highly 
  fossiliferous 
  shaly 
  limestone 
  beds, 
  known 
  as 
  the 
  Shaly 
  limestone 
  of 
  the 
  

   Lower 
  Helderberg. 
  This 
  part 
  of 
  the 
  formation 
  has 
  furnished 
  much 
  the 
  greater 
  portion 
  of 
  the 
  

   fossils 
  from 
  the 
  Lower 
  Helderberg 
  series. 
  

  

  3. 
  Heavy-bedded 
  gray 
  subcrystalline 
  limestone 
  containing 
  abundant 
  fossils, 
  which 
  are 
  mainly 
  

   in 
  a 
  fragmentary 
  condition. 
  This 
  formation 
  is 
  locally 
  known 
  as 
  the 
  lower 
  Pentamerus, 
  or 
  Pen- 
  

   tamerus 
  beds 
  of 
  the 
  Lower 
  Helderberg. 
  

  

  4. 
  The 
  Tentaculite 
  limestone, 
  consisting 
  in 
  the 
  upper 
  part 
  of 
  heavy-bedded, 
  dark-blue 
  lime- 
  

   stones, 
  becoming 
  below 
  and 
  finally 
  alternating 
  in 
  layers 
  of 
  a 
  quarter 
  to 
  one-half 
  an 
  inch 
  in 
  

   thickness, 
  with 
  similarly 
  attenuated 
  layers 
  of 
  the 
  upper 
  part 
  of 
  the 
  waterlime. 
  

  

  At 
  Hudson, 
  on 
  the 
  east 
  side 
  of 
  the 
  Hudson 
  river, 
  the 
  Lower 
  Helderberg 
  gives 
  the 
  following: 
  

   A 
  shaly 
  or 
  irregularly 
  thinly-bedded 
  limestone, 
  quite 
  fossiliferous 
  in 
  character. 
  This 
  limestone 
  

   is 
  much 
  more 
  developed 
  in 
  the 
  neighborhood 
  of 
  Catskill 
  and 
  Rondout 
  than 
  at 
  Hudson. 
  

  

  1. 
  A 
  heavy-bedded 
  crystalline 
  limestone, 
  usualiy 
  known 
  as 
  the 
  Scutella 
  limestone 
  and 
  now 
  

   proposed 
  to 
  be 
  designated 
  as 
  the 
  Becraft 
  limestone, 
  from 
  the 
  locality, 
  Becraft's 
  mountain. 
  

   This 
  Scutella 
  limestone 
  in 
  some 
  localities 
  of 
  the 
  Helderberg 
  region 
  merges 
  with 
  the 
  upper 
  Pen- 
  

   tamerus 
  limestone. 
  They 
  are 
  undoubtedly 
  of 
  corresponding 
  age. 
  

  

  2. 
  Shaly 
  limestone, 
  highly 
  fossiliferous, 
  but 
  not 
  so 
  readily 
  decomposing 
  as 
  in 
  the 
  Helderberg 
  

   and 
  at 
  Schoharie. 
  

  

  3. 
  The 
  lower 
  Pentamerus 
  beds, 
  less 
  developed 
  than 
  in 
  the 
  Helderberg 
  and 
  Schoharie. 
  

  

  4. 
  Tentaculite 
  limestone, 
  which 
  is 
  usually 
  less 
  heavily 
  bedded 
  and 
  of 
  lighter 
  color 
  than 
  in 
  the 
  

   Helderberg 
  and 
  Schoharie, 
  the 
  upper 
  beds 
  being 
  sometimes 
  semi- 
  cry 
  stalline.—H. 
  

  

  