﻿406 
  Richardson 
  — 
  Paleozoic 
  Section 
  in 
  Northern 
  Utah. 
  

  

  Art. 
  XXXIX. 
  — 
  The 
  Paleozoic 
  Section 
  in 
  Northern 
  Utah 
  ; 
  

   by 
  G. 
  B. 
  Richardson.* 
  

  

  Introduction. 
  — 
  One 
  of 
  the 
  most 
  complete 
  Paleozoic 
  sections 
  

   known 
  in 
  the 
  entire 
  Cordilleran 
  region 
  is 
  exposed 
  in 
  the 
  

   vicinity 
  of 
  Bear 
  Lake, 
  northern 
  Utah. 
  This 
  section 
  embraces 
  

   more 
  than 
  14,000 
  feet 
  of 
  strata 
  and 
  includes 
  seven 
  Cambrian, 
  

   three 
  Ordovician, 
  one 
  Silurian, 
  two 
  Devonian 
  and 
  four 
  Car- 
  

   boniferous 
  formations. 
  The 
  entire 
  sequence 
  is 
  well 
  exposed 
  

   in 
  the 
  Randolph 
  quadrangle, 
  which 
  was 
  studied 
  in 
  the 
  summer 
  

   of 
  1912 
  by 
  the 
  writer, 
  assisted 
  by 
  Paul 
  V. 
  Roundy, 
  to 
  whom 
  

   he 
  is 
  indebted 
  for 
  measuring 
  a 
  number 
  of 
  sections 
  and 
  collect- 
  

   ing 
  many 
  of 
  the 
  fossils. 
  G. 
  H. 
  Girty 
  visited 
  the 
  party 
  during 
  

   the 
  progress 
  of 
  field 
  work 
  and, 
  in 
  addition 
  to 
  identifying 
  the 
  

   Carboniferous 
  fossils, 
  was 
  of 
  great 
  help 
  in 
  making 
  collections. 
  

   The 
  writer 
  also 
  acknowledges 
  his 
  indebtedness 
  to 
  Messrs. 
  E. 
  

   O. 
  Ulrich, 
  E. 
  M. 
  Kindle, 
  L. 
  D. 
  Burling 
  and 
  Edwin 
  Kirk 
  for 
  

   examining 
  the 
  fossils. 
  

  

  The 
  table 
  on 
  page 
  407 
  summarizes 
  the 
  Paleozoic 
  rocks 
  of 
  

   northern 
  Utah. 
  

  

  Cambrian. 
  

  

  The 
  Cambrian 
  section 
  in 
  the 
  Randolph 
  quadrangle 
  is 
  essen- 
  

   tially 
  that 
  described 
  by 
  Walcottf 
  as 
  occurring 
  in 
  Blacksmith 
  

   Fork, 
  Utah, 
  and 
  in 
  the 
  vicinity 
  of 
  Liberty, 
  Idaho, 
  and 
  need 
  

   not 
  be 
  described 
  here. 
  This 
  section 
  is 
  finely 
  exposed 
  on 
  the 
  

   eastern 
  flank 
  of 
  Bear 
  River 
  Range 
  west 
  of 
  Garden 
  City, 
  where 
  

   the 
  thicknesses 
  recorded 
  in 
  the 
  table 
  were 
  measured. 
  There 
  

   the 
  formations 
  named 
  by 
  Walcott 
  were 
  recognized 
  by 
  their 
  

   lithology, 
  stratigraphic 
  position 
  and 
  fossils, 
  which 
  latter 
  were 
  

   examined 
  by 
  L. 
  D. 
  Burling, 
  who 
  assisted 
  Walcott 
  in 
  the 
  study 
  

   of 
  the 
  type 
  section. 
  In 
  the 
  preparation 
  of 
  the 
  geologic 
  map 
  

   of 
  the 
  Randolph 
  quadrangle 
  it 
  was 
  found 
  desirable 
  to 
  differen- 
  

   tiate 
  the 
  Hodges 
  shale 
  member 
  at 
  the 
  base 
  of 
  the 
  Bloomington 
  

   formation 
  and 
  the 
  Worm 
  Creek 
  quartzite 
  member 
  at 
  the 
  base 
  

   of 
  the 
  St. 
  Charles 
  limestone. 
  

  

  The 
  Hodges 
  shale 
  member 
  of 
  the 
  Bloomington 
  formation 
  is 
  

   a 
  persistent 
  zone 
  of 
  drab 
  clay 
  shale 
  about 
  350 
  feet 
  thick, 
  occur- 
  

   ring 
  at 
  the 
  base 
  of 
  the 
  formation. 
  It 
  lies 
  apparently 
  conform- 
  

   ably 
  on 
  the 
  massive 
  Blacksmith 
  limestone, 
  and 
  is 
  overlain 
  by 
  

   thin-bedded 
  limestone 
  of 
  the 
  Bloomington 
  formation. 
  The 
  

   name 
  is 
  derived 
  from 
  Hodges 
  Creek, 
  which 
  crosses 
  the 
  shale 
  

   and 
  enters 
  Bear 
  Lake 
  1J 
  miles 
  south 
  of 
  Garden 
  City. 
  

  

  * 
  Published 
  by 
  permission 
  of 
  the 
  Director, 
  TJ. 
  S. 
  Geological 
  Survey. 
  

  

  f 
  Walcott, 
  C. 
  D. 
  : 
  Cambrian 
  Geology 
  and 
  Paleontology, 
  Smithsonian 
  Mis- 
  

   cellaneous 
  Collections, 
  vol. 
  liii, 
  pp. 
  5-9 
  and 
  190-200, 
  1908 
  ; 
  also 
  Mon. 
  TJ. 
  S. 
  

   Geol. 
  Survey, 
  No. 
  51, 
  pp, 
  148-153, 
  1912. 
  

  

  