﻿616 
  Forty-seventh 
  Report 
  on 
  the 
  State 
  Museum. 
  

  

  Birdseye, 
  Black 
  Biver 
  and 
  Trenton 
  limestones. 
  — 
  This 
  series 
  of 
  

   limestones 
  constituting 
  the 
  Trenton 
  group 
  presents 
  considerable 
  

   variation 
  in 
  character 
  from 
  east 
  to 
  west 
  and 
  north 
  to 
  south 
  and 
  

   the 
  Black 
  river 
  beds 
  are 
  apparently 
  wanting 
  in 
  the 
  Mohawk 
  

   valley. 
  Yanuxem's 
  statements 
  regarding 
  the 
  character 
  of 
  these 
  

   formations 
  are 
  particularly 
  explicit, 
  and 
  I 
  shall 
  present 
  only 
  a 
  

   summary 
  of 
  the 
  general 
  facts 
  with 
  some 
  additional 
  statements 
  

   regarding 
  certain 
  local 
  features 
  and 
  distribution. 
  

  

  The 
  Birdseye 
  member 
  is 
  in 
  greater 
  part 
  an 
  impalpably 
  fine- 
  

   grained, 
  light 
  dove-colored 
  limestone 
  more 
  or 
  less 
  filled 
  with 
  

   dark-colored, 
  vertical, 
  columnar 
  fucoidal 
  stems. 
  It 
  weathers 
  to 
  

   white 
  or 
  a 
  light 
  ash 
  gray 
  tint, 
  which 
  is 
  an 
  especially 
  character- 
  

   istic 
  feature. 
  Owing 
  to 
  its 
  very 
  fine 
  grain 
  and 
  compact 
  structure 
  

   its 
  fracture 
  is 
  smooth 
  or 
  conchoidal 
  and 
  the 
  texture 
  of 
  the 
  rock 
  

   is 
  rather 
  brittle. 
  The 
  ends 
  of 
  the 
  dark 
  fucoidal 
  stems 
  which 
  are 
  

   spotted 
  over 
  the 
  surface 
  of 
  the 
  bedding 
  planes 
  resemble 
  birds' 
  

   eyes, 
  and 
  from 
  this 
  feature 
  the 
  name 
  of 
  the 
  formation 
  is 
  derived. 
  

   It 
  is 
  in 
  moderately 
  heavy, 
  regular 
  beds 
  and 
  has 
  a 
  vertical 
  cleav- 
  

   age. 
  In 
  some 
  localities 
  its 
  color 
  is 
  dark 
  gray 
  or 
  black, 
  but 
  the 
  

   light 
  weathering 
  is 
  general. 
  Exposures 
  are 
  very 
  abundant 
  in 
  the 
  

   Mohawk 
  valley, 
  mainly 
  in 
  the 
  many 
  quarries 
  at 
  which 
  the 
  beds 
  

   have 
  been 
  worked. 
  The 
  beds 
  lie 
  directly 
  on 
  the 
  surface 
  of 
  the 
  

   Caloif 
  erous 
  sandstone 
  usually 
  with 
  a 
  sharp 
  break, 
  which 
  suggests 
  an 
  

   intervening 
  unconformity 
  by 
  erosion. 
  In 
  the 
  Mohawk 
  valley 
  

   the 
  formation 
  attains 
  its 
  maximum 
  thickness 
  of 
  nine 
  feet 
  about 
  

   Fort 
  Plain. 
  The 
  amount 
  decreases 
  westward 
  to 
  seven 
  feet 
  in 
  

   the 
  many 
  exposures 
  east 
  of 
  St. 
  Johnsville 
  ; 
  it 
  is 
  five 
  feet 
  on 
  East 
  

   Canada 
  creek, 
  five 
  feet 
  at 
  the 
  fault 
  in 
  the 
  hollow 
  three 
  miles 
  

   northwest 
  of 
  Little 
  Falls, 
  four 
  feet 
  about 
  Little 
  Falls 
  and 
  to 
  the 
  

   southeastward 
  and 
  five 
  to 
  six 
  feet 
  on 
  West 
  Canada 
  creek 
  about 
  

   Middleville, 
  Newport 
  and 
  Cold 
  Creek. 
  At 
  Ingram's 
  Mills 
  on 
  

   East 
  Canada 
  creek 
  there 
  are 
  some 
  unusual 
  features 
  in 
  this 
  forma- 
  

   tion 
  and 
  its 
  relations. 
  The 
  section 
  is 
  as 
  follows 
  : 
  

  

  Feet. 
  

  

  Thin-bedded, 
  black, 
  very 
  fine-grained 
  limestone, 
  with 
  slaty 
  

  

  intercalation 
  ; 
  it 
  extends 
  to 
  top 
  of 
  bank; 
  Trenton 
  8 
  

  

  Loose, 
  pyritiferous, 
  impure 
  limestones 
  of 
  dark 
  color, 
  with 
  

  

  i 
  diminutive 
  birdseye 
  fucoids 
  1 
  

  

  Light-colored 
  limestone, 
  with 
  a 
  moderate 
  amount 
  of 
  " 
  birds- 
  

  

  ■ 
  ,[©yes" 
  1* 
  

  

  