﻿174 
  Ford 
  and 
  Bradley 
  — 
  Pyroxmangite. 
  

  

  3Mn,0 
  4 
  . 
  2Fe,0„ 
  and 
  sitaparite, 
  9Mn 
  2 
  3; 
  4Fe 
  2 
  3 
  . 
  Mn0.3CaO, 
  

   have 
  been 
  recently 
  described 
  by 
  Fermor.* 
  They 
  contain 
  ferric 
  

   oxide 
  in 
  considerable 
  amounts, 
  but 
  do 
  not 
  correspond 
  in 
  other 
  

   respects 
  to 
  this 
  mineral. 
  Consequently, 
  if 
  this 
  material 
  is 
  to 
  

   be 
  taken 
  as 
  a 
  distinct 
  species 
  it 
  must 
  be 
  considered 
  as 
  new. 
  

   The 
  grave 
  question 
  arises, 
  shall 
  a 
  mineral 
  which 
  is 
  so 
  obvi- 
  

   ously 
  an 
  alteration 
  product, 
  and 
  which 
  shows 
  no 
  crystal 
  form, 
  

   be 
  dignified 
  by 
  a 
  species 
  name 
  ? 
  The 
  close 
  agreement 
  of 
  the 
  

   analysis 
  with 
  the 
  assumed 
  formula 
  is 
  an 
  argument 
  in 
  favor 
  of 
  

   its 
  being 
  a 
  distinct 
  species, 
  but 
  yet 
  such 
  an 
  agreement 
  might 
  

   very 
  well 
  be 
  accidental. 
  Other 
  analyses 
  of 
  material 
  from 
  the 
  

   same 
  locality, 
  or 
  better, 
  of 
  material 
  from 
  some 
  other 
  occur- 
  

   rence, 
  would 
  help 
  to 
  settle 
  the 
  problem. 
  In 
  order, 
  however, 
  

   that 
  the 
  above 
  description 
  and 
  analysis 
  be 
  not 
  overlooked 
  in 
  

   any 
  future 
  work 
  on 
  similar 
  minerals, 
  the 
  name 
  ske?nmatite, 
  

   derived 
  from 
  the 
  Greek, 
  Gici\x\xa, 
  a 
  question, 
  is 
  proposed 
  for 
  

   the 
  material. 
  

  

  Mineralogical 
  Laboratory 
  of 
  the 
  Sheffield 
  Scientific 
  School 
  

  

  of 
  Yale 
  University, 
  New 
  Haven, 
  Conn., 
  

  

  May 
  6th, 
  1913. 
  

  

  Art. 
  XXI. 
  — 
  New 
  or 
  little 
  known 
  Paleozoic 
  Faunas 
  from 
  

   Wyoming 
  and 
  Idaho 
  ; 
  f 
  by 
  Eliot 
  Blackwelder. 
  

  

  Within 
  the 
  past 
  three 
  years 
  the 
  writer 
  has 
  had 
  occasion 
  to 
  

   collect 
  fossils 
  from 
  many 
  localities 
  and 
  horizons 
  in 
  the 
  moun- 
  

   tains 
  of 
  western 
  "Wyoming 
  and 
  a 
  few 
  in 
  southern 
  Idaho. 
  

   Among 
  these 
  collections 
  there 
  are 
  three 
  or 
  four 
  which 
  throw 
  

   new 
  light 
  upon 
  some 
  questions 
  of 
  Rocky 
  Mountain 
  strati- 
  

   graphy, 
  and 
  so 
  it 
  appears 
  worth 
  while 
  to 
  publish 
  a 
  brief 
  

   account 
  of 
  them 
  here 
  in 
  advance 
  of 
  the 
  more 
  detailed 
  official 
  

   reports, 
  the 
  preparation 
  of 
  which 
  will 
  require 
  several 
  years. 
  

  

  Ordovioian 
  graptolites 
  from 
  the 
  Wood 
  River 
  valley, 
  in 
  

   southern 
  Idaho. 
  — 
  The 
  region 
  about 
  Hailey, 
  on 
  the 
  northern 
  

   border 
  of 
  the 
  Snake 
  River 
  lava 
  plain, 
  has 
  long 
  been 
  known 
  as 
  

   an 
  important 
  mining 
  district. 
  Geologists 
  have 
  studied 
  the 
  

   valley 
  in 
  more 
  or 
  less 
  detail 
  with 
  special 
  reference 
  to 
  the 
  ore 
  

   deposits, 
  but 
  they 
  have 
  found 
  the 
  sedimentary 
  rocks 
  almost 
  

   entirely 
  devoid 
  of 
  fossils. 
  The 
  few 
  specimens 
  thus 
  far 
  discov- 
  

   ered 
  appear 
  to 
  be 
  of 
  Carboniferous 
  age. 
  

  

  *Mem. 
  Geol. 
  Survey, 
  India, 
  xxxvii, 
  1909. 
  

  

  f 
  Published 
  with 
  the 
  consent 
  of 
  the 
  Director 
  of 
  the 
  U. 
  S. 
  Geological 
  

   Survey. 
  

  

  