﻿382 
  A. 
  M. 
  Edwards 
  — 
  Infusorial 
  Earths 
  of 
  Pacific 
  Coast. 
  

  

  connection 
  with 
  the 
  examination 
  of 
  these 
  specimens 
  it 
  may 
  be 
  

   of 
  interest 
  here 
  to 
  quote 
  somewhat 
  from 
  his 
  report. 
  He 
  says 
  

   that 
  ' 
  they 
  appear 
  on 
  both 
  sides 
  of 
  Pit 
  River 
  at 
  intervals 
  of 
  

   several 
  miles, 
  being 
  in 
  many 
  places 
  interrupted 
  or 
  covered 
  by 
  

   the 
  beds 
  of 
  clay. 
  They 
  are 
  perhaps 
  best 
  exposed 
  in 
  the 
  canon 
  

   formed 
  by 
  the 
  passage 
  of 
  the 
  river 
  through 
  ' 
  Stoneman's 
  

   Ridge,' 
  the 
  most 
  conspicuous 
  of 
  the 
  lines 
  of 
  upheaval, 
  which 
  

   form 
  what 
  is 
  known 
  as 
  the 
  lower 
  canon 
  of 
  Pit 
  Kiver. 
  They 
  

   here 
  exhibit 
  a 
  thickness 
  of 
  about 
  fifty 
  feet, 
  but 
  are 
  considera- 
  

   bly 
  tilted 
  up, 
  and 
  covered 
  by 
  a 
  thick 
  bed 
  of 
  trap, 
  which 
  has 
  

   been 
  poured 
  out 
  over 
  them. 
  In 
  some 
  places 
  this 
  alternation 
  

   of 
  Diatomaceous 
  deposit 
  and 
  trap 
  is 
  often 
  repeated 
  as, 
  for 
  

   example, 
  on 
  the 
  Psucseeque 
  Creek, 
  a 
  tributary 
  of 
  the 
  Des 
  

   Chutes 
  River 
  ; 
  the 
  bank 
  is 
  capped 
  by 
  hard 
  columnar 
  trap 
  and 
  

   beneath 
  this 
  are 
  successive 
  strata 
  varying 
  in 
  thickness 
  and 
  

   forming 
  steps 
  of 
  thirty 
  to 
  forty 
  feet 
  wide. 
  These 
  steps, 
  which 
  

   at 
  this 
  point 
  number 
  twelve, 
  have 
  been 
  formed 
  by 
  the 
  more 
  

   ready 
  wearing 
  away 
  by 
  weathering 
  of 
  the 
  ' 
  infusorial 
  ' 
  deposits, 
  

   they 
  being 
  protected 
  above 
  and 
  below 
  to 
  a 
  certain 
  extent 
  by 
  

   layers 
  of 
  tufa, 
  concrete 
  or 
  trap. 
  These 
  deposits 
  represent 
  the 
  

   enormous 
  extinct 
  fresh 
  water 
  seas 
  which 
  at 
  one 
  time 
  extended 
  

   over 
  a 
  large 
  part 
  of 
  our 
  continent. 
  Those 
  who 
  are 
  interested 
  

   in 
  the 
  subject 
  will 
  find 
  more 
  particulars 
  in 
  the 
  sixth 
  volume 
  of 
  

   the 
  Pacific 
  Railroad 
  Survey, 
  in 
  the 
  paper 
  by 
  Professor 
  Whit- 
  

   ney 
  I 
  have 
  alluded 
  to 
  above, 
  and 
  in 
  a 
  paper 
  read 
  May 
  16, 
  1870, 
  

   before 
  the 
  New 
  York 
  Lyceum 
  of 
  Natural 
  History 
  by 
  Dr. 
  J. 
  

   S. 
  Newberry 
  and 
  published 
  in 
  the 
  Proceedings 
  for 
  that 
  month. 
  

   I 
  found 
  the 
  following 
  : 
  

  

  Amphora 
  ovalis. 
  Cyclotella 
  operculata. 
  Cyclotella 
  rotula. 
  

   Epithemia 
  granulata. 
  Gomphonema 
  intricata. 
  Orthosira 
  granu- 
  

   lata?. 
  Pinnularia 
  nobilis. 
  

  

  * 
  8. 
  54. 
  Pit 
  River, 
  Lower 
  Canon, 
  Cal. 
  A 
  sub-Plutonic 
  de- 
  

   posit. 
  

  

  Campylodiscus 
  ?. 
  Cocconema 
  lanceolatum. 
  Cocconeis 
  pedicu- 
  

   lus. 
  Cyclotella 
  rotula. 
  Cyclotella 
  operculata. 
  Encyonema 
  

   ccespitosum. 
  Epithemia 
  granulata. 
  Gomphonema 
  coespitosum. 
  

   Gomphonema 
  intricatum. 
  Orthosira 
  punctata. 
  Pinnularia 
  nobilis. 
  

   Surirella?. 
  

  

  This 
  deposit, 
  together 
  with 
  No. 
  5. 
  55. 
  agree 
  in 
  many 
  

   respects 
  with 
  some 
  infusorial 
  earths 
  described 
  by 
  Bailey 
  in 
  

   vol. 
  xvii, 
  of 
  this 
  Journal 
  for 
  March, 
  1854. 
  The 
  earths 
  he 
  

   describes 
  were 
  sent 
  to 
  him 
  by 
  Lieut. 
  Robert 
  Williamson 
  and 
  

   were 
  collected 
  in 
  Oregon 
  and 
  California. 
  In 
  fact 
  one 
  of 
  

   Lieut. 
  Williamson's 
  earths 
  is 
  labelled 
  " 
  Pit 
  River, 
  Washington 
  

   Territory," 
  and 
  agrees 
  with 
  the 
  two 
  deposits 
  described 
  above 
  

   and 
  marked 
  Nos. 
  5. 
  55. 
  and 
  8. 
  54. 
  as 
  I 
  have 
  ascertained 
  from 
  

  

  