﻿82 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  These 
  species 
  are 
  not 
  known 
  to 
  occur 
  above 
  or 
  below 
  the 
  Low- 
  

   ville 
  limestone, 
  and 
  are 
  common 
  enough 
  to 
  occur 
  in 
  every 
  exposure 
  

   of 
  the 
  foi-mation. 
  

  

  Tetradium 
  cellulosum 
  forms 
  large 
  colonies, 
  attain- 
  

   ing 
  sometimes 
  a 
  diameter 
  of 
  several 
  feet 
  (specimens 
  of 
  this 
  size 
  

   collected 
  by 
  the 
  writer 
  along 
  Black 
  river) 
  and 
  consisting 
  of 
  fre- 
  

   quently 
  dividing 
  branches 
  that 
  radiate 
  horizontally 
  and 
  obliquely 
  

   upward 
  from 
  a 
  common 
  center. 
  Its 
  most 
  characteristic 
  aspect, 
  

   however, 
  is 
  seen 
  on 
  sections 
  where 
  the 
  squarish 
  cells 
  wirh 
  their 
  

   fission 
  septa 
  produce 
  a 
  neat 
  lattice 
  pattern. 
  Different, 
  hitherto 
  

   undescribed 
  species 
  with 
  looser 
  arrangement 
  of 
  the 
  polyparies 
  or 
  

   cells, 
  occur 
  in 
  tower 
  horizons. 
  

  

  Both 
  Orthoceras 
  multicameratum 
  and 
  O. 
  

   recticameratum 
  are 
  easily 
  recognized 
  by 
  the 
  close 
  ar- 
  

   rangement 
  of 
  their 
  septa 
  and 
  the 
  latter 
  form 
  possesses 
  in 
  the 
  

   angular 
  course 
  of 
  the 
  septa 
  a 
  character 
  not 
  shown 
  by 
  other 
  

   species. 
  

  

  Bathyurus 
  extans 
  apparently 
  occurs 
  throughout 
  the 
  

   formation 
  but 
  is 
  most 
  frequent 
  in 
  several 
  bands. 
  It 
  is, 
  as 
  Dr 
  

   Ulrich 
  informs 
  us, 
  preceded 
  by 
  closely 
  related 
  and 
  very 
  similar 
  

   prenuncial 
  forms 
  in 
  the 
  Pamelia 
  formation. 
  

  

  On 
  account 
  of 
  the 
  but 
  slight 
  difference 
  in 
  the 
  compactness 
  of 
  

   the 
  rocks 
  between 
  the 
  Lowville 
  and 
  Pamelia 
  formations, 
  the 
  

   former 
  is 
  not 
  set 
  off 
  by 
  an 
  escarpment 
  from 
  the 
  other, 
  but 
  both 
  

   form 
  one 
  continuous 
  plateau. 
  In 
  some 
  districts 
  the 
  lower 
  Low- 
  

   ville 
  contains 
  easily 
  worked 
  layers, 
  furnishing 
  subcubical 
  blocks 
  

   and 
  the 
  composition 
  of 
  the 
  fences 
  of 
  such 
  blocks 
  is 
  a 
  quite 
  char- 
  

   acteristic 
  aspect 
  for 
  this 
  horizon. 
  

  

  Since 
  the 
  formation 
  received 
  its 
  name 
  from 
  Lowville 
  and 
  a 
  

   section 
  of 
  this 
  tv-pe 
  locality^ 
  has 
  not 
  yet 
  been 
  furnished, 
  we 
  insert 
  

   here 
  the 
  section, 
  obtained 
  at 
  this 
  place 
  in 
  the 
  quarry 
  at 
  the 
  railroad 
  

   bridge 
  over 
  Mill 
  creek, 
  where 
  in 
  the 
  creek 
  bank 
  the 
  uppermost 
  

   part 
  of 
  the 
  Pamelia 
  (about 
  12 
  feet) 
  is 
  shown 
  and 
  a 
  continuous 
  

   section 
  into 
  the 
  Leray 
  limestone 
  can 
  be 
  obtained. 
  On 
  account 
  of 
  the 
  

   nearness 
  of 
  Lowville 
  to 
  the 
  area 
  here 
  mapped, 
  the 
  Lowville 
  section 
  

   is 
  to 
  be 
  considered 
  as 
  tv^pical 
  also 
  for 
  this 
  area. 
  For 
  comparison 
  

   we 
  add 
  the 
  section 
  measured 
  in 
  the 
  Sanford 
  cut 
  which 
  contains 
  

   about 
  three 
  fourths 
  of 
  the 
  formation. 
  Another 
  fine 
  section 
  was 
  

   observ^ed 
  in 
  the 
  bank 
  of 
  the 
  Black 
  river 
  above 
  Watertown, 
  opposite 
  

   the 
  filter 
  plant, 
  just 
  outside 
  the 
  map 
  limits, 
  and 
  a 
  section 
  of 
  about 
  

   56 
  feet 
  from 
  the 
  7 
  foot 
  tier 
  downward 
  is 
  exposed 
  in 
  the 
  high 
  river 
  

   bank 
  opposite 
  the 
  Ontario 
  Paper 
  miU, 
  2 
  miles 
  east 
  of 
  Brownville. 
  

  

  