﻿

  Geology 
  and 
  Natural 
  History. 
  155 
  

  

  mations 
  in 
  the 
  Carboniferous, 
  nine 
  in 
  the 
  Devonian 
  and 
  Silurian, 
  

   and 
  two 
  in 
  the 
  Cambrian. 
  Those 
  in 
  folio 
  No. 
  27 
  show 
  two 
  in 
  the 
  

   Carboniferous, 
  two 
  in 
  the 
  Devonian, 
  ten 
  in 
  the 
  Silurian, 
  and 
  six 
  in 
  

   the 
  Cambrian. 
  Folio 
  No. 
  29 
  contains 
  the 
  Grass 
  Valley, 
  Nevada 
  

   City 
  and 
  Banner 
  Hill 
  special 
  maps, 
  all 
  upon 
  a 
  scale 
  of 
  y^xw 
  

   This 
  important 
  placer 
  and 
  quartz 
  mining 
  district, 
  which 
  is 
  de- 
  

   scribed 
  in 
  six 
  folio 
  pages 
  of 
  text, 
  has 
  already 
  produced 
  about 
  

   120,000,000 
  of 
  dollars. 
  The 
  maps 
  show 
  Carboniferous, 
  Jura-trias, 
  

   Eocene 
  and 
  Pleistocene 
  formations, 
  besides 
  eleven 
  eruptives, 
  as 
  

   well 
  as 
  many 
  quartz 
  veins 
  and 
  auriferous 
  gravel 
  deposits. 
  

  

  j. 
  s. 
  D. 
  

  

  2. 
  A 
  geological 
  reconnaissance 
  in 
  Northwestern 
  Oregon 
  ; 
  by 
  J. 
  

   S. 
  Dillee. 
  (From 
  the 
  Seventeenth 
  Annual 
  Report 
  of 
  the 
  U. 
  S. 
  

   Geol. 
  Survey. 
  Part 
  I.) 
  — 
  The 
  author 
  has 
  given 
  brief 
  but 
  clear 
  

   accounts 
  of 
  the 
  topography, 
  the 
  features 
  of 
  the 
  coast 
  range 
  and 
  

   of 
  the 
  Oregon 
  coast, 
  and 
  notes 
  of 
  the 
  work 
  reported 
  by 
  previous 
  

   authors. 
  He 
  describes 
  the 
  geological 
  formations 
  met 
  with, 
  con- 
  

   sisting 
  of 
  slight 
  traces 
  of 
  pre-Cretaceous 
  rocks. 
  He 
  concludes 
  that, 
  

   contrary 
  to 
  previous 
  opinions, 
  " 
  it 
  is 
  quite 
  improbable 
  that 
  pre- 
  

   Cretaceous 
  sedimentary 
  rocks 
  form 
  any 
  considerable 
  portion 
  of 
  

   the 
  Coast 
  Range 
  in 
  Oregon 
  north 
  of 
  Coquille." 
  Much 
  the 
  same 
  

   statement 
  may 
  be 
  made 
  regarding 
  the 
  Cretaceous. 
  " 
  No 
  certain 
  

   Cretaceous 
  rocks 
  are 
  known 
  in 
  the 
  [Coast] 
  range, 
  and 
  yet 
  it 
  is 
  

   probable 
  that 
  they 
  do 
  occur 
  where 
  it 
  joins 
  the 
  Klamath 
  moun- 
  

   tains. 
  South 
  of 
  Roseburg 
  a 
  short 
  distance 
  along 
  Myrtle 
  Creek, 
  

   are 
  Cretaceous 
  conglomerate 
  sandstone 
  and 
  shales 
  indi- 
  

   cated 
  by 
  the 
  form 
  of 
  Aucella 
  and 
  other 
  fossils 
  they 
  contain 
  " 
  (p. 
  

   16). 
  

  

  A 
  large 
  tract 
  of 
  Eocene 
  rocks 
  forms 
  the 
  great 
  mass 
  of 
  the 
  coast 
  

   range 
  from 
  near 
  the 
  Columbia 
  to 
  the 
  Coquille. 
  These 
  rocks 
  are 
  

   of 
  both 
  igneous 
  and 
  sedimentary 
  origin. 
  

  

  The 
  tufas 
  in 
  the 
  former 
  contain 
  fossils 
  of 
  Eocene 
  age. 
  The 
  

   shales 
  generally 
  contain 
  marine 
  fossils 
  and 
  in 
  several 
  places 
  coal 
  

   has 
  been 
  discovered 
  in 
  them. 
  They 
  are 
  named 
  the 
  Arago 
  beds 
  

   from 
  Cape 
  Arago, 
  near 
  which 
  the 
  coal-bearing 
  strata 
  have 
  been 
  

   known 
  for 
  several 
  years 
  through 
  the 
  observations 
  of 
  Prof. 
  

   Thomas 
  Condon. 
  The 
  upper 
  part 
  of 
  the 
  series 
  are 
  sandstones 
  

   and 
  have 
  yielded 
  Eocene 
  fossils 
  as 
  determined 
  by 
  Dr. 
  Dall. 
  Oligo- 
  

   cene, 
  Miocene, 
  Pliocene 
  and 
  Pleistocene 
  deposits 
  are 
  distinctly 
  

   recognized; 
  and 
  the 
  author 
  has 
  shown 
  the 
  geological 
  history 
  of 
  

   the 
  region 
  as 
  indicated 
  by 
  evidences 
  of 
  erosion, 
  elevation 
  and 
  

   depression 
  and 
  the 
  relation 
  of 
  the 
  several 
  beds 
  to 
  each 
  other. 
  

   Special 
  tribute 
  is 
  given 
  to 
  the 
  contributions 
  made 
  by 
  Professor 
  

   Condon 
  to 
  the 
  knowledge 
  of 
  the 
  geology 
  of 
  Oregon. 
  

  

  In 
  the 
  second 
  part, 
  on 
  economic 
  geology, 
  account 
  is 
  given 
  of 
  

   the 
  coal 
  fields 
  and 
  a 
  few 
  other 
  mineral 
  products 
  of 
  the 
  region. 
  

  

  The 
  age 
  of 
  the 
  coal 
  is 
  in 
  some 
  cases 
  known 
  to 
  be 
  that 
  of 
  the 
  

   Eocene 
  formation 
  (Pebble 
  Creek, 
  Cape 
  Arago, 
  Callahans, 
  and 
  

   north 
  Fork 
  of 
  the 
  Umpqua). 
  In 
  other 
  places 
  the 
  coal 
  occurs 
  in 
  

   beds 
  known 
  to 
  be 
  older 
  than 
  some 
  Miocene 
  beds. 
  At 
  Coos 
  Bay 
  

  

  