﻿58 
  E. 
  Bose 
  — 
  Ammonoids. 
  

  

  forms 
  represented 
  only 
  by 
  a 
  single 
  shell 
  each. 
  None 
  of 
  

   them 
  is 
  very 
  characteristic, 
  or 
  intimately 
  related 
  to 
  any 
  

   known 
  form. 
  One 
  of 
  these 
  species 
  shows 
  a 
  scnlptnre 
  

   different 
  from 
  that 
  of 
  all 
  the 
  other 
  species 
  of 
  the 
  locality. 
  

   It 
  consists 
  of 
  thin 
  radial 
  costas 
  slightly 
  curved 
  forward 
  

   on 
  the 
  venter; 
  on 
  the 
  umbilical 
  border, 
  which 
  is 
  well 
  

   rounded, 
  they 
  are 
  crossed 
  by 
  rather 
  strong 
  spiral 
  lines 
  

   which 
  cause 
  a 
  kind 
  of 
  crenulation, 
  but 
  which 
  seemingly 
  

   become 
  very 
  faint 
  or 
  disappear 
  entirely 
  on 
  the 
  venter. 
  

   Unfortunately 
  the 
  suture 
  could 
  not 
  be 
  made 
  visible. 
  

  

  Another 
  form 
  is 
  characterized 
  by 
  a 
  very 
  great 
  number 
  

   of 
  septa 
  ; 
  the 
  flanks 
  of 
  the 
  external 
  saddles 
  of 
  the 
  differ- 
  

   ent 
  septa 
  touch 
  each 
  other. 
  The 
  species 
  is 
  rather 
  invo- 
  

   lute, 
  has 
  a 
  deep 
  narrow 
  umbilicus 
  with 
  a 
  well 
  rounded 
  

   border, 
  well 
  rounded 
  flanks 
  and 
  venter, 
  and 
  a 
  nearly 
  

   semicircular 
  cross-section. 
  Three 
  rather 
  shallow 
  con- 
  

   strictions 
  are 
  visible 
  on 
  the 
  whorl. 
  The 
  specimen 
  is 
  a 
  

   cast 
  and 
  does 
  not 
  show 
  any 
  ornamentation. 
  

  

  Another 
  form 
  has 
  very 
  numerous 
  septa 
  but 
  the 
  umbili- 
  

   cal 
  border 
  is 
  rather 
  sharp 
  ; 
  no 
  ornamentation 
  is 
  preserved 
  

   on 
  it. 
  

  

  There 
  is 
  still 
  a 
  further 
  species 
  in 
  our 
  collection, 
  the 
  

   generic 
  position 
  of 
  which 
  has 
  not 
  been 
  quite 
  ascertained. 
  

   It 
  is 
  represented 
  by 
  four 
  specimens 
  of 
  different 
  sizes, 
  

   the 
  largest 
  one 
  having 
  a 
  diameter 
  of 
  about 
  12mm. 
  The 
  

   suture 
  resembles 
  that 
  of 
  Muensteroceras, 
  although 
  the 
  

   lobes 
  are 
  not 
  quite 
  as 
  angular 
  as 
  in 
  that 
  genus 
  and 
  

   the 
  first 
  lateral 
  saddle 
  is 
  rather 
  high 
  and 
  not 
  extremely 
  

   broad. 
  On 
  the 
  umbilical 
  border 
  we 
  find 
  a 
  row 
  of 
  rather 
  

   strong 
  tubercles 
  ; 
  each 
  volution 
  has 
  four 
  to 
  five 
  deep 
  con- 
  

   strictions 
  which 
  are 
  curved 
  forward 
  on 
  the 
  venter. 
  The 
  

   umbilicus 
  is 
  moderately 
  narrow 
  and 
  with 
  a 
  rather 
  sharp 
  

   border; 
  the 
  wall 
  is 
  steep. 
  

  

  These 
  specimens 
  may 
  be 
  the 
  young 
  of 
  some 
  Goniolob- 
  

   oceras 
  different 
  from 
  the 
  one 
  described 
  above, 
  or 
  they 
  

   may 
  belong 
  to 
  a 
  new 
  genus. 
  This 
  question 
  cannot 
  be 
  

   decided 
  until 
  more 
  material 
  has 
  been 
  found. 
  

  

  The 
  fauna 
  of 
  ammonoids 
  from 
  the 
  lower 
  Abo 
  beds 
  of 
  

   Tularosa 
  is 
  of 
  considerable 
  interest 
  as 
  it 
  gives 
  a 
  quite 
  

   precise 
  determination 
  of 
  the 
  age 
  of 
  this 
  formation. 
  

  

  There 
  is 
  not 
  a 
  single 
  form 
  related 
  to 
  Permian 
  species, 
  

   but 
  everything 
  indicates 
  that 
  the 
  beds 
  belong 
  to 
  the 
  

   Pennsylvanian 
  and 
  especially 
  to 
  the 
  upper 
  part 
  of 
  this 
  

   system. 
  Gonioloboceras 
  is 
  certainly 
  a 
  form 
  character- 
  

  

  