﻿98 
  H. 
  S. 
  Williams 
  — 
  Recurrence 
  of 
  Devonian 
  

  

  the 
  latest 
  Devonian 
  horizon 
  of 
  the 
  local 
  section 
  ; 
  by 
  three 
  

   thousand 
  feet 
  of 
  conglomerate 
  in 
  the 
  Eureka 
  District, 
  and 
  by 
  

   some, 
  at 
  present, 
  unknown 
  amount 
  of 
  sediments 
  in 
  Shasta 
  

   County, 
  California. 
  

  

  The 
  second 
  point 
  requiring 
  verification 
  is 
  the 
  presence 
  of 
  

   actual 
  Devonian 
  species 
  in 
  this 
  limestone 
  of 
  Carboniferous 
  age. 
  

   There 
  are 
  two 
  species 
  both 
  of 
  which 
  are 
  represented 
  by 
  

   numerous 
  specimens 
  in 
  the 
  same 
  strata 
  with 
  the 
  Carboniferous 
  

   species 
  : 
  they 
  are 
  Leiorhynchus 
  guadricostatum 
  Yanuxem, 
  and 
  

   Productella 
  lachrymosa, 
  varieties 
  stigmata, 
  onusta, 
  etc. 
  Hall. 
  

  

  The 
  first 
  of 
  these 
  species 
  was 
  reported 
  by 
  Meek 
  from 
  the 
  

   White 
  Pine 
  Mountains, 
  Eureka 
  District 
  (= 
  White 
  Pine 
  shale 
  

   of 
  Walcott) 
  in 
  1877.* 
  

  

  The 
  age 
  of 
  these 
  shales, 
  was, 
  in 
  the 
  same 
  report 
  (p. 
  201), 
  

   referred 
  to 
  the 
  Devonian 
  by 
  Hall 
  and 
  Whitfield 
  on 
  the 
  evi- 
  

   dence 
  of 
  this 
  species 
  and 
  a 
  Lunulicardium 
  (Z. 
  fragosa, 
  Meek 
  

   sp.) 
  and 
  an 
  Avicula 
  {A. 
  equilatera), 
  while 
  the 
  beds 
  immedi- 
  

   ately 
  above 
  were 
  called 
  Carboniferous 
  without 
  hesitation. 
  

   Walcott 
  noted 
  the 
  mixture 
  of 
  the 
  Devonian 
  and 
  Carbonif- 
  

   erousf 
  species 
  in 
  this 
  White 
  Pine 
  shale, 
  but 
  concluded 
  from 
  

   study 
  of 
  the 
  section 
  that 
  the 
  beds 
  in 
  question 
  covered 
  a 
  fauna 
  

   uniting 
  the 
  two 
  systems 
  but 
  of 
  pre-Carboniferous 
  age 
  (p. 
  6). 
  

  

  The 
  second 
  species 
  in 
  some 
  of 
  its 
  varieties 
  is 
  also 
  reported 
  

   by 
  Walcott 
  from 
  Upper 
  Devonian 
  limestones 
  of 
  the 
  Eureka 
  

   District;}; 
  associated 
  with 
  many 
  typical 
  eastern 
  Devonian 
  species. 
  

   The 
  Phynchonella 
  Eurekensis 
  Walcott, 
  found 
  in 
  the 
  Lower 
  

   Carboniferous 
  limestones 
  of 
  the 
  Eureka 
  District 
  above, 
  and 
  

   separated 
  from 
  the 
  White 
  Pine 
  shales 
  by 
  3000 
  feet 
  of 
  quartz- 
  

   ite 
  conglomerate, 
  is 
  associated 
  with 
  the 
  two 
  above-mentioned 
  

   Devonian 
  species 
  in 
  the 
  Spring 
  Creek 
  limestone 
  of 
  Arkansas. 
  

   The 
  two 
  species 
  L. 
  quadricostatum 
  and 
  P. 
  lachrymosa, 
  have 
  

   been 
  regarded 
  by 
  Meek, 
  by 
  Hall, 
  Whitfield 
  and 
  Walcott 
  as 
  

   Devonian 
  species. 
  They 
  are 
  characteristic 
  of 
  Devonian 
  rocks 
  

   of 
  New 
  York, 
  although 
  the 
  Leiorhynchus 
  has 
  been 
  reported, 
  

   with 
  early 
  Carboniferous 
  species 
  in 
  Pennsylvania, 
  as 
  it 
  has 
  in 
  

   Nevada. 
  Not 
  only 
  the 
  species 
  but 
  the 
  subgeneric 
  types 
  in 
  

   both 
  cases 
  are 
  Devonian 
  ; 
  both 
  Productella 
  and 
  Leiorhynchus 
  

   are 
  characteristic 
  Devonian 
  modifications 
  of 
  the 
  genera 
  Pro- 
  

   ductus 
  and 
  Rhynchonella 
  respectively. 
  These 
  two 
  species 
  

   then 
  are 
  not 
  only 
  characteristic 
  Devonian 
  species 
  but 
  De- 
  

   vonian 
  subgenera, 
  and 
  where 
  seen 
  in 
  Nevada 
  they 
  are 
  still 
  

   below 
  the 
  fauna 
  with 
  which 
  the 
  general 
  fauna 
  of 
  the 
  Spring 
  

   Creek 
  limestone 
  is 
  correlated 
  in 
  the 
  Nevada 
  sections. 
  

  

  * 
  Geol. 
  Expl. 
  Fortieth 
  Par., 
  vol. 
  iv, 
  p. 
  79. 
  

   f 
  Paleontology 
  of 
  the 
  Eureka 
  District, 
  p. 
  5. 
  

   % 
  1. 
  c, 
  p. 
  132. 
  

  

  