﻿E. 
  Bose 
  — 
  Ammonoids. 
  51 
  

  

  Aet. 
  III. 
  — 
  On 
  Ammonoids 
  from 
  the 
  Abo 
  Sandstone 
  of 
  

   New 
  Mexico 
  and 
  the 
  Age 
  of 
  the 
  Beds 
  which 
  contain 
  

   them; 
  by 
  Dr. 
  Emil 
  Bose. 
  

  

  The 
  Abo 
  sandstone 
  of 
  New 
  Mexico 
  is 
  the 
  lowermost 
  

   member 
  of 
  a 
  group 
  of 
  sedimentary 
  Paleozoic 
  rocks 
  com- 
  

   prised 
  under 
  the 
  name 
  of 
  the 
  Manzano 
  group, 
  the 
  higher 
  

   members 
  of 
  which 
  are 
  the 
  Yeso 
  formation 
  and 
  the 
  San 
  

   Andreas 
  limestone. 
  The 
  fauna 
  of 
  this 
  group 
  has 
  been 
  

   described 
  by 
  G. 
  H. 
  Girty, 
  who 
  judged 
  that 
  the 
  whole 
  

   group 
  belonged 
  to 
  the 
  Pennsylvanian. 
  

  

  While 
  studying 
  the 
  species 
  figured 
  by 
  Girty, 
  I 
  had 
  the 
  

   impression 
  that 
  the 
  fauna 
  of 
  the 
  Manzano 
  group 
  as 
  a 
  

   whole 
  repesented 
  a 
  curious 
  mixture 
  of 
  Carboniferous 
  

   and 
  Permian 
  types. 
  The 
  species 
  cited 
  and 
  described 
  

   from 
  the 
  Yeso 
  formation 
  and 
  the 
  San 
  Andreas 
  limestone 
  

   have 
  certainly 
  more 
  Permian 
  affinities 
  than 
  Carbonifer- 
  

   ous. 
  In 
  this 
  opinion 
  I 
  was 
  confirmed 
  when 
  together 
  

   with 
  Mr. 
  Charles 
  L. 
  Baker, 
  I 
  collected 
  a 
  number 
  of 
  fos- 
  

   sils 
  in 
  the 
  Yeso 
  formation 
  between 
  Anton 
  Chico 
  and 
  En- 
  

   cino 
  in 
  northeast 
  Torrance 
  County, 
  New 
  Mexico. 
  But 
  

   at 
  the 
  same 
  time 
  there 
  remained 
  some 
  doubt 
  about 
  the 
  

   age 
  of 
  the 
  Abo 
  sandstone, 
  which 
  contained 
  brachiopods 
  

   of 
  apparently 
  Pennsylvanian 
  character. 
  

  

  Fortunately 
  Mr. 
  Baker 
  and 
  Dr. 
  N. 
  P. 
  Drake 
  discovered 
  

   a 
  locality 
  near 
  Tularosa 
  (1.25 
  miles 
  due 
  east 
  on 
  the 
  road 
  

   to 
  the 
  Mescalero 
  Apache 
  reservation), 
  New 
  Mexico, 
  which 
  

   contained 
  a 
  great 
  number 
  of 
  ammonoids 
  promising 
  a 
  bet- 
  

   ter 
  determination 
  of 
  the 
  age 
  of 
  the 
  beds. 
  Mr. 
  Baker 
  had 
  

   the 
  kindness 
  to 
  submit 
  those 
  ammonoids 
  to 
  me 
  for 
  further 
  

   study, 
  the 
  result 
  of 
  which 
  I 
  shall 
  give 
  in 
  the 
  following 
  

   pages. 
  

  

  The 
  beds 
  which 
  contain 
  the 
  ammonoids, 
  as 
  well 
  as 
  a 
  

   great 
  number 
  of 
  other 
  fossils, 
  are 
  shales 
  in 
  the 
  lower 
  

   part 
  of 
  the 
  Abo 
  sandstone. 
  The 
  ammonoids 
  are 
  pre- 
  

   served 
  in 
  greater 
  part 
  as 
  pseudomorphs 
  after 
  limonite 
  

   and 
  are 
  generally 
  of 
  small 
  size, 
  while 
  the 
  larger 
  ones 
  

   are 
  calcareous. 
  

  

  Although 
  the 
  number 
  of 
  ammonoids 
  collected 
  at 
  Tula- 
  

   rosa 
  is 
  relatively 
  very 
  great, 
  only 
  two 
  genera 
  appear 
  to 
  

   be 
  represented: 
  Gonioloboceras 
  and 
  Gastrioceras. 
  The 
  

   number 
  of 
  species 
  is 
  very 
  small, 
  Gonioloboceras 
  being 
  

   represented 
  by 
  only 
  one, 
  and 
  Gastrioceras 
  by 
  about 
  four. 
  

   All 
  of 
  the 
  species 
  so 
  far 
  found 
  are 
  new, 
  but 
  two 
  at 
  least 
  

  

  