﻿So 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  Lowville 
  limestone. 
  The 
  Lowville 
  limestone 
  which 
  is 
  the 
  

   **' 
  Birdseye 
  limestone 
  '* 
  of 
  the 
  old 
  Geological 
  Survey 
  reports 
  has 
  

   its 
  maximum 
  development 
  in 
  Xew 
  York 
  in 
  the 
  region 
  of 
  the 
  

   lower 
  Black 
  river, 
  or 
  in 
  the 
  southern 
  portion 
  of 
  the 
  area 
  here 
  

   mapped. 
  It 
  reaches 
  there 
  about 
  60 
  feet 
  in 
  thickness. 
  It 
  consists 
  

   typically 
  of 
  thick 
  and 
  thin 
  bedded, 
  fine 
  grained 
  dove 
  limestone 
  

   which 
  shows 
  a 
  characteristic 
  ashen 
  gray 
  weathering 
  and 
  con- 
  

   tains 
  either 
  numerous 
  more 
  or 
  less 
  vertical 
  worm 
  tubes 
  denoted 
  

   as 
  Phytopsis 
  and 
  filled 
  with 
  calcite 
  (producing 
  the 
  '' 
  birdseyes 
  " 
  

   in 
  sections) 
  or 
  shows 
  in 
  profusion 
  the 
  horizontally 
  spreading 
  

   tabulate 
  coral 
  Tetradium 
  cellulosum 
  and 
  related 
  

   species. 
  Between 
  these 
  typical 
  Low^'ille 
  beds 
  there 
  are 
  inter- 
  

   calated 
  others 
  of 
  subcr\-stalline 
  dark 
  to 
  black 
  limestone, 
  or 
  of 
  

   oolitic 
  or 
  also 
  of 
  shaly 
  whitish 
  weathering 
  limestone. 
  These 
  inter- 
  

   calations 
  usually 
  contain 
  a 
  larger 
  fauna 
  than 
  the 
  dove 
  limestone 
  

   and 
  carry 
  lamellibranchs. 
  gastropods 
  and 
  cephalopods, 
  as 
  well 
  

   as 
  ostracods 
  and 
  trilobites. 
  

  

  The 
  basal 
  bed 
  is 
  conglomeratic 
  and 
  of 
  very 
  variable 
  thickness 
  ; 
  

   it 
  is 
  overlain 
  by 
  several 
  feet 
  of 
  strata 
  that 
  contain 
  quartz 
  grains 
  

   or 
  grit 
  bands 
  and 
  are 
  more 
  or 
  less 
  shaly, 
  the 
  shaly 
  limestone 
  

   gradually 
  becoming 
  more 
  massive 
  upward 
  and 
  assuming 
  the 
  

   characters 
  of 
  the 
  typical 
  rock. 
  These 
  more 
  or 
  less 
  sandy 
  beds 
  

   comprise 
  about 
  4 
  feet. 
  

  

  The 
  uppermost 
  portion 
  of 
  the 
  Lowville 
  beds 
  which 
  has 
  been 
  

   mentioned 
  by 
  the 
  earlier 
  authors 
  as 
  the 
  *' 
  cherty 
  beds 
  " 
  has 
  been 
  

   found 
  by 
  Professor 
  Gushing 
  and 
  the 
  writer 
  to 
  be 
  quite 
  distinct 
  

   from 
  the 
  t}-pical 
  Lowville 
  beds 
  and 
  separated 
  from 
  them, 
  by 
  an 
  un- 
  

   conformit)-. 
  It 
  has 
  for 
  that 
  reason 
  been 
  here 
  distinguished 
  as 
  a 
  

   subdivision 
  under 
  the 
  name 
  Leray 
  limestone 
  and 
  will 
  be 
  described 
  

   separately 
  [see 
  below]. 
  

  

  It 
  appears 
  that 
  in 
  this 
  region 
  the 
  Lowville 
  beds 
  beneath 
  the 
  Leray 
  

   member 
  can 
  be 
  conveniently 
  divided 
  into 
  an 
  upper 
  and 
  lower 
  diA-i- 
  

   sion 
  of 
  nearly 
  equal 
  thickness, 
  the 
  upper 
  division 
  alone 
  containing 
  

   the 
  abundant 
  Tetradium 
  cellulosum 
  and 
  larger 
  Phytop- 
  

   sis, 
  as 
  well 
  as 
  the 
  t\'pical 
  massive 
  dove 
  limestone 
  strata, 
  while 
  in 
  

   the 
  lower 
  division 
  more 
  dark 
  or 
  black 
  subscrj-stalline 
  limestones 
  

   containing 
  only 
  smaller 
  forms 
  of 
  Tetradium 
  and 
  Phytopsis 
  and 
  

   more 
  thin 
  bedded 
  dove 
  limestones 
  abound. 
  

  

  In 
  this 
  low^er 
  di\asion 
  also 
  two 
  or 
  more 
  horizons 
  of 
  Stromato 
  

   cerium 
  can 
  be 
  obser^'ed. 
  which 
  give 
  the 
  beds 
  a 
  very 
  irregular 
  con- 
  

   cretionary 
  appearance. 
  These 
  horizons 
  are 
  well 
  seen 
  in 
  the 
  rail- 
  

   road 
  cut 
  iust 
  south 
  of 
  Sanford 
  Center, 
  also 
  where 
  the 
  road 
  crosses 
  

  

  