﻿C. 
  D. 
  Walcott 
  — 
  Lower 
  Cambrian 
  Rocks 
  in 
  California. 
  143 
  

  

  h. 
  Gray, 
  arenaceous 
  limestone, 
  with 
  bands 
  of 
  

   buff-colored, 
  mostly 
  thick-bedded 
  lime- 
  

   stone 
  10 
  ft. 
  

  

  i. 
  Thick-bedded, 
  bluish-gray 
  limestone 
  10 
  ft. 
  

  

  j. 
  Brownish 
  and 
  buff-colored, 
  calcareous 
  sand- 
  

   stone, 
  with 
  inclosed 
  brecciated, 
  thin-bedded 
  

  

  brown 
  sandstone 
  . 
  _ 
  5 
  ft. 
  

  

  k. 
  Dark, 
  banded 
  quartzite 
  30 
  ft. 
  

  

  1. 
  Massive, 
  bedded, 
  gray, 
  arenaceous 
  limestone 
  225 
  ft. 
  

  

  Total 
  of 
  No. 
  2 
  1,525 
  ft. 
  

  

  3. 
  Dark, 
  irregular, 
  thin-bedded, 
  siliceous 
  slates, 
  with 
  

   interbedded, 
  dark, 
  quartzitic 
  sandstone 
  (dip 
  25-30 
  E. 
  

   mag., 
  strike 
  1ST. 
  and 
  S.) 
  _ 
  635 
  ft. 
  

  

  The 
  section 
  is 
  terminated 
  at 
  this 
  point 
  by 
  a 
  fault 
  line. 
  

  

  On 
  the 
  north 
  side 
  of 
  Silver 
  Canyon, 
  No. 
  3 
  is 
  well 
  exposed, 
  

   and 
  is 
  estimated 
  to 
  have 
  a 
  thickness 
  of 
  2,000 
  feet. 
  Above 
  

   this 
  a 
  series 
  of 
  limestones 
  and 
  calcareous 
  and 
  siliceous 
  shales 
  

   occurs, 
  and 
  some 
  interbedded, 
  dark, 
  quartzitic 
  sandstones, 
  that 
  

   extend 
  upward 
  1,000 
  feet. 
  Near 
  the 
  base 
  a 
  massive, 
  bedded 
  

   limestone 
  100 
  feet 
  in 
  thickness 
  occurs, 
  in 
  which 
  great 
  quanti- 
  

   ties 
  of 
  Lower 
  Cambrian 
  corals 
  (Archo3ocyathi?ice) 
  occur. 
  This 
  

   series 
  is 
  capped 
  by 
  about 
  200 
  feet 
  of 
  compact, 
  thin-bedded, 
  

   arenaceous 
  argillite, 
  with 
  interbedded 
  layers 
  of 
  dark-brown, 
  

   fine-grained 
  quartzite. 
  

  

  The 
  entire 
  section, 
  briefly 
  summarized 
  from 
  summit 
  down- 
  

   ward, 
  is 
  as 
  follows 
  : 
  

  

  4. 
  Upper 
  arenaceous 
  beds 
  200 
  ft. 
  

  

  3. 
  Alternating 
  limestones 
  and 
  shales 
  1,000 
  ft. 
  

  

  2. 
  Siliceous 
  slates 
  and 
  quartzites 
  _ 
  2,000 
  ft. 
  

  

  1. 
  Siliceous 
  limestones 
  ._ 
  1,700 
  ft. 
  

  

  Total 
  _ 
  4,900 
  ft. 
  

  

  In 
  round 
  numbers 
  the 
  section 
  exposed 
  in 
  the 
  White 
  Moun- 
  

   tain 
  range, 
  between 
  White 
  Mountain 
  peak 
  and 
  Waucobi 
  Can- 
  

   yon, 
  is 
  5,000 
  feet 
  in 
  thickness. 
  

  

  No 
  fossils 
  were 
  found 
  in 
  the 
  lower 
  limestona 
  Numerous 
  

   annelid 
  trails 
  occur 
  in 
  the 
  lower 
  siliceous 
  series, 
  and 
  in 
  the 
  

   slaty 
  portion 
  near 
  the 
  summit 
  heads 
  of 
  Olenellus 
  were 
  found. 
  

   In 
  places 
  the 
  lower 
  portion 
  of 
  the. 
  upper 
  limestone 
  series 
  is 
  

   almost 
  a 
  solid 
  bed 
  of 
  different 
  forms 
  of 
  the 
  Archceocyat/iince. 
  

   Ethmophyllum 
  whitneii 
  Meek 
  is 
  very 
  abundant, 
  and 
  the 
  genera 
  

   Protopharetra, 
  Coscinocyatfius, 
  and 
  probably 
  Archceocyathus 
  

   occur. 
  Ethmophyllum 
  ranges 
  throughout 
  the 
  limestone 
  series 
  

   into 
  the 
  base 
  of 
  the 
  shales 
  in 
  Tollgate 
  Canyon, 
  where 
  it 
  is 
  

   associated 
  with 
  Cystidean 
  plates 
  and 
  fragments 
  of 
  Olenellus. 
  

   On 
  the 
  north 
  side 
  of 
  Silver 
  Canyon 
  the 
  Archseocyathinae 
  are 
  

  

  