﻿410 
  Richardson 
  — 
  Paleozoic 
  Section 
  in 
  Northern 
  Utah. 
  

  

  Haven 
  dolomite, 
  which 
  is 
  a 
  fine-textured 
  medium-bedded 
  dark 
  

   gray 
  to 
  blue-black, 
  locally 
  cherty, 
  dolomite 
  about 
  500 
  feet 
  

   thick 
  containing 
  a 
  Richmond 
  fauna. 
  The 
  name 
  is 
  derived 
  

   from 
  Fish 
  Haven 
  Creek, 
  which 
  enters 
  Bear 
  Lake, 
  Idaho, 
  about 
  

   2 
  miles 
  north 
  of 
  the 
  Utah 
  State 
  Line. 
  A 
  sample 
  from 
  the 
  

   head 
  of 
  Fish 
  Haven 
  Creek, 
  analyzed 
  by 
  Walter 
  C. 
  Wheeler 
  of 
  

   the 
  IT. 
  S. 
  Geological 
  Survey, 
  showed 
  21 
  '35 
  per 
  cent 
  of 
  magnesia. 
  

   The 
  following 
  fossils, 
  identified 
  by 
  Edwin 
  Kirk, 
  were 
  obtained 
  

   by 
  R. 
  W. 
  Richards 
  in 
  the 
  Fish 
  Haven 
  dolomite 
  near 
  the 
  crest 
  

   of 
  the 
  Bear 
  River 
  Range 
  at 
  the 
  head 
  of 
  Fish 
  Haven 
  Creek 
  in 
  

   the 
  Montpelier 
  quadrangle, 
  Idaho, 
  immediately 
  north 
  of 
  the 
  

   Randolph 
  quadrangle 
  : 
  Oalapoecia 
  cf. 
  Canadensis 
  Bill., 
  Strej?- 
  

   telasma 
  sp., 
  Haly 
  sites 
  catemdatus 
  var. 
  gracilis 
  Hall, 
  Rhyn- 
  

   chotrema 
  cf. 
  capax 
  Conrad, 
  Columnaria 
  thomii 
  Hall. 
  This 
  

   represents 
  a 
  widespread 
  western 
  Richmond 
  fauna. 
  

  

  Silurian. 
  

   Laketown 
  Dolomite. 
  

  

  The 
  Laketown 
  dolomite, 
  named 
  from 
  Laketown 
  Canyon 
  4 
  

   miles 
  southeast 
  of 
  Laketown 
  in 
  the 
  Randolph 
  quadrangle, 
  is 
  a 
  

   massive 
  light 
  gray 
  to 
  whitish 
  dolomite, 
  containing 
  lenses 
  of 
  

   calcareous 
  sandstone, 
  having 
  a 
  thickness 
  of 
  approximately 
  1000 
  

   feet. 
  An 
  analysis 
  of 
  a 
  sample 
  from 
  SEJ 
  sec. 
  IT, 
  T. 
  12 
  N., 
  R. 
  

   6 
  E. 
  showed 
  21*38 
  per 
  cent 
  MgO. 
  In 
  the 
  Montpelier 
  quadran- 
  

   gle, 
  Idaho, 
  R. 
  W. 
  Richards 
  reports 
  a 
  few 
  feet 
  of 
  the 
  Laketown 
  

   dolomite 
  lying 
  above 
  the 
  Fish 
  Haven 
  dolomite 
  apparently 
  con- 
  

   formably, 
  but 
  the 
  most 
  complete 
  section 
  of 
  this 
  formation 
  is 
  in 
  

   Laketown 
  Canyon. 
  There, 
  however, 
  because 
  of 
  the 
  scarcity 
  

   of 
  fossils, 
  the 
  lower 
  boundary 
  and 
  consequently 
  the 
  thickness 
  

   of 
  the 
  Laketown 
  dolomite 
  has 
  not 
  yet 
  been 
  determined. 
  Fos- 
  

   sils 
  in 
  general 
  are 
  rare 
  in 
  the 
  Laketown 
  dolomite 
  although 
  

   locally 
  there 
  occur 
  considerable 
  quantities 
  of 
  a 
  poorly 
  pre- 
  

   served 
  Pentamerus 
  cf. 
  oblongus 
  Sow. 
  Specific 
  identification 
  

   is 
  impossible, 
  but 
  they 
  clearly 
  point 
  to 
  the 
  Silurian 
  age 
  of 
  the 
  

   containing 
  beds. 
  A 
  similar 
  fauna 
  was 
  reported 
  by 
  Kindle* 
  

   from 
  Green 
  Canyon 
  east 
  of 
  Cache 
  Valley. 
  Some 
  poorly 
  pre- 
  

   served 
  corals, 
  identified 
  provisionally 
  as 
  Halysites 
  catenulatus 
  f 
  

   Linn., 
  Favosites 
  sp. 
  and 
  Cyathophyllum 
  f 
  sp., 
  were 
  found 
  in 
  

   the 
  lower 
  part 
  of 
  the 
  dolomite 
  in 
  Laketown 
  Canyon, 
  but 
  it 
  is 
  

   doubtful 
  whether 
  these 
  fossils, 
  here 
  tentatively 
  referred 
  to 
  the 
  

   Silurian, 
  may 
  not 
  be 
  Richmond. 
  It 
  is 
  proposed 
  to 
  restrict 
  the 
  

   name 
  Laketown 
  dolomite 
  to 
  beds 
  of 
  Silurian 
  age. 
  

  

  * 
  Kindle, 
  E. 
  M. 
  : 
  The 
  fauna 
  and 
  stratigraphy 
  of 
  the 
  Jefferson 
  limestone 
  in 
  

   the 
  northern 
  Kocky 
  Mountain 
  region. 
  Bull, 
  of 
  American 
  Paleontology, 
  No. 
  

   20, 
  p. 
  17, 
  1908. 
  

  

  