﻿A. 
  M. 
  Edwards 
  — 
  Infusorial 
  Earths 
  of 
  Pacific 
  Coast. 
  379 
  

  

  Epithemia 
  gibberula. 
  Epithemia 
  granulata. 
  Gomphonema 
  di- 
  

   chotoraum. 
  Odontidium 
  mutabile. 
  Orthosira 
  ?. 
  Pinnularia 
  ?. 
  

   Synedra 
  capitata. 
  Synedra 
  radians. 
  Tabellaria 
  flocculosum. 
  

  

  * 
  Colseed 
  Bay, 
  Hood's 
  Canal, 
  Washington. 
  A 
  lacustrine 
  sedi- 
  

   mentary 
  deposit 
  containing 
  : 
  

  

  Cocconeis 
  placentula. 
  Cyclotella 
  rotula. 
  Epithemia 
  adnata. 
  

   Epithemia 
  luna. 
  Gomphonema 
  vibrio. 
  Melosira?. 
  ISTavicula 
  

   elliptica. 
  Navicula 
  ?. 
  Pinnularia 
  major. 
  Pinnularia 
  ?. 
  Ortho- 
  

   sira 
  orichalea. 
  Odontidium 
  ? 
  Tetracyclus 
  ?. 
  

  

  Pit 
  River, 
  8 
  miles 
  from 
  Fort 
  Crook, 
  Cal. 
  A 
  sub-Plutonic 
  

   deposit. 
  

  

  Amphora 
  ovalis. 
  Cyclotella 
  Astrea. 
  Cyclotella 
  rotula. 
  Cym- 
  

   bella 
  ?. 
  Cymatopleura 
  elliptica. 
  Fragillaria 
  striatula. 
  Gompho- 
  

   nema 
  capitatum. 
  Gomphonema 
  constrictum. 
  Gomphonema 
  ?. 
  

   Epithemia 
  gibba. 
  Epithemia 
  luna. 
  Surirella 
  splendida. 
  Suri- 
  

   rella 
  linearis. 
  Tetracyclus 
  lacustris. 
  Stauroneis 
  punctata. 
  Pin- 
  

   nularia 
  major. 
  Orthosira 
  ?. 
  Navicula 
  cuspidata. 
  

  

  Having 
  now 
  given 
  the 
  results 
  of 
  the 
  examination 
  of 
  the 
  

   first 
  parcel 
  of 
  earths 
  submitted 
  to 
  me 
  by 
  Mr. 
  Gibbs 
  I 
  will 
  

   point 
  out 
  some 
  of 
  the 
  results 
  arrived 
  at. 
  Bailey 
  having 
  had 
  

   sent 
  to 
  him 
  several 
  specimens 
  of 
  so-called 
  ' 
  infusorial 
  earths 
  ' 
  

   as 
  those 
  brought 
  home 
  by 
  Fremont, 
  Blake 
  and 
  others, 
  ascer- 
  

   tained, 
  as 
  he 
  supposed, 
  that 
  all 
  of 
  those 
  collected 
  upon 
  the 
  

   eastern 
  slope 
  of 
  the 
  Sierra 
  Nevada 
  Mountains 
  were 
  of 
  fresh 
  

   water 
  origin, 
  while 
  those 
  from 
  the 
  Coast 
  Range 
  contained 
  the 
  

   remains 
  of 
  Diatomacese 
  only. 
  It 
  became 
  interesting, 
  there- 
  

   fore, 
  in 
  examining 
  the 
  specimens 
  put 
  into 
  my 
  hands 
  to 
  ascer- 
  

   tain 
  if 
  therefrom 
  I 
  was 
  prepared 
  to 
  confirm 
  or 
  refute 
  this 
  

   assertion 
  of 
  Bailey's, 
  upon 
  which, 
  of 
  course, 
  geologists 
  had 
  

   depended 
  for 
  drawing 
  deductions. 
  Up 
  to 
  the 
  time 
  of 
  the 
  pub- 
  

   lication 
  of 
  the 
  paper 
  of 
  Professor 
  Whitney 
  in 
  the 
  Proceed- 
  

   ings 
  of 
  the 
  California 
  Academy, 
  which 
  I 
  have 
  alluded 
  to, 
  the 
  

   true 
  character 
  of 
  these 
  sub-Plutonic 
  deposits 
  was 
  entirely 
  mis- 
  

   understood. 
  And 
  this 
  arose, 
  doubtless, 
  to 
  a 
  certain 
  extent, 
  

   from 
  their 
  occurring 
  only 
  in 
  one 
  portion 
  of 
  the 
  world 
  where 
  

   naturalists 
  have 
  traveled 
  little 
  and 
  where 
  the 
  microscope 
  as 
  

   applied 
  to 
  geology 
  has 
  as 
  yet 
  not 
  made 
  much 
  progress. 
  But 
  

   the 
  lacustrine 
  sedimentary, 
  or 
  sub-Peat, 
  deposits 
  are 
  found 
  

   all 
  over 
  the 
  world 
  and 
  have 
  been 
  much 
  examined 
  by 
  micro- 
  

   scopists. 
  That 
  these 
  and 
  the 
  first 
  mentioned 
  should 
  have 
  been 
  

   classed 
  together 
  and 
  neither 
  of 
  them 
  understood 
  is, 
  perhaps, 
  

   not 
  so 
  surprising 
  when 
  we 
  consider 
  that 
  few 
  microscopists 
  are 
  

   naturalists 
  ; 
  that 
  instrument 
  having 
  been 
  too 
  often 
  used 
  as 
  a 
  

   toy 
  and 
  not 
  employed 
  as 
  an 
  instrument 
  of 
  research. 
  It 
  is 
  not 
  

   to 
  be 
  wondered 
  at 
  perhaps 
  that 
  Bailey 
  did 
  not 
  comprehend 
  the 
  

   origin 
  and 
  geological 
  position 
  of 
  these 
  two 
  classes 
  of 
  strata 
  and 
  

   it 
  is 
  to 
  be 
  hoped 
  that 
  what 
  I 
  have 
  said 
  herein 
  will 
  at 
  least 
  

  

  