﻿Blackwelder 
  — 
  Little 
  hioivn 
  Paleozoic 
  Faunas. 
  177 
  

  

  Marine 
  Permian 
  (f 
  ) 
  fossils 
  from 
  the 
  Wind 
  Piver 
  Pange. 
  

  

  •From 
  the 
  Black 
  Hills 
  of 
  South 
  Dakota 
  west 
  to 
  the 
  eastern 
  

   boundary 
  of 
  Idaho 
  there 
  are 
  two 
  prominent 
  and 
  relatively 
  con- 
  

   stant 
  formations 
  of 
  late 
  Paleozoic 
  and 
  early 
  Mesozoic 
  age. 
  

   One 
  of 
  these, 
  the 
  Tensleep 
  sandstone, 
  is 
  characteristically 
  a 
  

   massive, 
  buff-colored 
  sandstone 
  which 
  makes 
  prominent 
  cliffs, 
  

   hogback 
  ridges, 
  and 
  dip-slopes, 
  wherever 
  it 
  appears. 
  The 
  

   upper 
  terrane 
  is 
  the 
  Chugwater 
  formation, 
  the 
  brilliant 
  color 
  

   of 
  which 
  makes 
  it 
  the 
  most 
  easily 
  recognized 
  member 
  of 
  the 
  

   entire 
  sedimentary 
  column. 
  These 
  two 
  prominent 
  terranes 
  — 
  

   the 
  one 
  apparently 
  Pennsylvanian, 
  the 
  other 
  usually 
  referred 
  

   to 
  the 
  Triassic 
  — 
  are 
  separated 
  almost 
  invariably 
  by 
  300-500 
  feet 
  

   of 
  shale, 
  limestone, 
  sandstone, 
  and 
  chert. 
  This 
  is 
  the 
  Embar 
  

   formation 
  of 
  Darton.* 
  At 
  almost 
  any 
  of 
  its 
  outcrops, 
  this 
  

   formation 
  may 
  yield 
  a 
  few 
  fossils, 
  but 
  most 
  of 
  those 
  which 
  

   have 
  been 
  collected 
  are 
  pelecypods, 
  difficult 
  to 
  determine 
  and 
  

   of 
  doubtful 
  significance 
  even 
  when 
  well 
  preserved. 
  This 
  

   meager 
  fauna 
  has 
  led 
  paleontologists 
  to 
  refer 
  the 
  Embar 
  to 
  the 
  

   Permian, 
  the 
  u 
  Permo-Carboniferous," 
  or 
  the 
  Pennsylvanian, 
  

   and 
  always 
  with 
  a 
  large 
  element 
  of 
  doubt. 
  

  

  In 
  1877 
  Orestes 
  St. 
  John 
  of 
  the 
  Hayden 
  Survey 
  found 
  some 
  

   richly 
  fossiliferous 
  beds 
  in 
  a 
  formation 
  which 
  is 
  evidently 
  the 
  

   same 
  as 
  the 
  Embar, 
  near 
  Bull 
  Lake 
  on 
  the 
  northeast 
  side 
  of 
  

   the 
  Wind 
  River 
  Range. 
  In 
  his 
  report, 
  f 
  he 
  gave 
  an 
  admirable 
  

   detailed 
  section 
  of 
  the 
  beds 
  and 
  referred 
  to 
  some 
  of 
  the 
  fossils 
  

   generically. 
  Apparently 
  the 
  names 
  were 
  given 
  as 
  the 
  result 
  of 
  

   rough 
  field 
  identifications, 
  rather 
  than 
  after 
  a 
  critical 
  study 
  of 
  

   collections 
  in 
  the 
  laboratory. 
  So 
  far 
  as 
  I 
  am 
  able 
  to 
  learn 
  no 
  

   collections 
  were 
  brought 
  home 
  by 
  St. 
  John 
  from 
  this 
  remark- 
  

   able 
  locality, 
  — 
  doubtless, 
  because 
  of 
  the 
  difficulty 
  of 
  transport- 
  

   ing 
  them 
  more 
  than 
  200 
  miles 
  to 
  the 
  railroad, 
  — 
  and 
  for 
  many 
  

   years 
  no 
  attention 
  was 
  paid 
  to 
  the 
  find. 
  Within 
  the 
  past 
  

   decade, 
  the 
  same 
  beds 
  with 
  similar 
  fossils 
  more 
  or 
  less 
  well 
  

   preserved 
  have 
  been 
  visited 
  by 
  Dart-on 
  and 
  Woodruff 
  along 
  

   the 
  north 
  slope 
  of 
  the 
  Wind 
  River 
  Range. 
  Their 
  published 
  

   reports, 
  \ 
  however, 
  suggest 
  that 
  they 
  made 
  but 
  small 
  collections 
  

   and 
  obtained 
  material 
  some 
  of 
  which 
  was 
  not 
  in 
  a 
  satisfactory 
  

   state 
  of 
  preservation. 
  

  

  In 
  1910 
  a 
  party 
  in 
  charge 
  of 
  the 
  writer 
  examined 
  many 
  of 
  

   the 
  canyons 
  on 
  the 
  northeast 
  slope 
  of 
  the 
  Wind 
  River 
  Range 
  

   in 
  some 
  detail, 
  and 
  there 
  made 
  careful 
  stratigraphic 
  sections 
  

   and 
  tolerably 
  complete 
  collections 
  of 
  fossils 
  from 
  many 
  hori- 
  

  

  * 
  Darton, 
  N. 
  H. 
  Op. 
  cit. 
  

  

  f 
  U. 
  S. 
  Geog. 
  and 
  Geol. 
  Survey 
  of 
  the 
  Territories, 
  F. 
  V. 
  Hayden 
  in 
  charge, 
  

   1878, 
  vol. 
  xii, 
  part 
  1, 
  pp. 
  242-248. 
  

  

  {Darton. 
  N. 
  H.. 
  Paleozoic 
  and 
  Mesozoic 
  of 
  Central 
  Wvoming, 
  Bull. 
  Geol. 
  

   Soc. 
  Am., 
  vol. 
  xix, 
  1908, 
  pp. 
  403-474. 
  

  

  Woodruff, 
  E. 
  G., 
  The 
  Lander 
  oil 
  field, 
  U. 
  S. 
  Geol. 
  Survey, 
  Bull. 
  452 
  

   1911, 
  pp. 
  12-14. 
  

  

  