﻿NIAGARA 
  FALLS 
  AND 
  VICINITY 
  

  

  215 
  

  

  chamber 
  lodges 
  the 
  animal. 
  The 
  septa 
  are 
  pierced 
  by 
  a 
  correspond- 
  

   ing 
  series 
  of 
  holes, 
  the 
  walls 
  of 
  which 
  are 
  often 
  prolonged 
  backward 
  

   or 
  forward 
  into 
  siphonal 
  funnels, 
  the 
  whole 
  constituting 
  the 
  siphuncle. 
  

   In 
  the 
  Nautiloidea, 
  the 
  sutures 
  are, 
  as 
  a 
  rule, 
  simple 
  or 
  but 
  

   slightly 
  lobed, 
  and 
  the 
  siphuncle 
  is 
  commonly 
  central 
  or 
  eccentric, 
  

   but 
  seldom 
  marginal, 
  with 
  the 
  funnels 
  generally 
  di- 
  

   rected 
  backward. 
  The 
  'embryonic 
  shell, 
  or 
  proto- 
  

   conch, 
  is 
  rarely 
  retained. 
  

  

  The 
  shells 
  of 
  cephalopods 
  are 
  either 
  straight 
  

   (more 
  or 
  less 
  conic) 
  or 
  variously 
  curved 
  and 
  coiled 
  

   to 
  close 
  involution. 
  

  

  NAUTILOIDEA 
  

  

  Genus 
  orthoceras 
  Breyn 
  

  

  [Ety. 
  : 
  6f>06^, 
  straight; 
  z£7>«9, 
  horn] 
  

  

  (1732. 
  Dissert 
  at 
  io 
  pJiysica 
  de 
  polythalamiis) 
  

  

  Fig. 
  146 
  Orthoceras 
  Shell 
  a 
  Straight 
  conic 
  tube, 
  with 
  a 
  large 
  body 
  

   muitiseptum 
  chamber 
  and 
  numerous 
  air 
  chambers, 
  separated 
  by 
  

  

  convex 
  septa. 
  Sutures 
  simple, 
  at 
  right 
  angles 
  to 
  

   the 
  long 
  axis 
  of 
  the 
  shell; 
  siphuncle 
  central, 
  sub- 
  

   central, 
  or 
  eccentric, 
  cylindric 
  or 
  sometimes 
  

   widening 
  in 
  the 
  chambers. 
  Surface 
  smooth 
  or 
  

   variously 
  ornamented 
  by 
  transverse 
  or 
  longitud- 
  

   inal 
  striae, 
  or 
  by 
  annulations. 
  

  

  Orthoceras 
  muitiseptum 
  Hall 
  (Fig. 
  146) 
  (1852. 
  

   Pal 
  N. 
  Y. 
  2:14, 
  pi. 
  4 
  (bis)) 
  

  

  Distinguishing 
  characters. 
  Cylindric, 
  gradually 
  

   tapering; 
  septa 
  distant 
  one 
  sixth 
  to 
  one 
  seventh 
  

   the 
  diameter. 
  

  

  Found 
  in 
  the 
  upper 
  Medina 
  sandstone 
  at 
  Lock- 
  

   port, 
  etc. 
  (Hall). 
  Probably 
  also 
  at 
  Niagara. 
  

  

  Orthoceras 
  annulatum 
  Sowerby 
  (Fig. 
  147). 
  

   Orthoceras 
  undulatum 
  Hall 
  (1852. 
  

   Pal 
  N. 
  Y. 
  2 
  :293, 
  pi. 
  64, 
  65) 
  

  

  Distinguishing 
  characters. 
  Strong 
  annulations; 
  

  

  moderately 
  strong 
  longitudinal 
  lines 
  which 
  node 
  ^J^^-^. 
  

  

  147 
  Orthof 
  eras 
  an- 
  

   nulatum. 
  Terminal 
  por- 
  

   , 
  . 
  r- 
  . 
  . 
  • 
  11- 
  J.- 
  lion 
  siiowing 
  sliellof 
  liv- 
  

  

  the 
  annulations, 
  fine 
  transverse 
  striae; 
  elliptic 
  ingciiamber 
  and 
  section- 
  

   ed 
  camerae 
  (aft3r 
  Bar- 
  

  

  cross-section; 
  subcentral 
  siphuncle. 
  rande) 
  

  

  Found 
  in 
  the 
  Clinton 
  limestone 
  lenses 
  in 
  the 
  Rome, 
  Watertown 
  

   and 
  Ogdensburg 
  railroad 
  cut 
  above 
  Lewiston. 
  Also 
  in 
  the 
  Roches- 
  

  

  