﻿Hatcher 
  — 
  Sedimentary 
  Rod's 
  of 
  Southern 
  Patagonia. 
  93 
  

  

  the 
  principal 
  and 
  most 
  striking 
  topographic 
  features 
  of 
  the 
  

   region. 
  In 
  the 
  canon 
  of 
  the 
  Rio 
  Tarde 
  they 
  form 
  vertical 
  

   walls 
  that 
  for 
  a 
  considerable 
  distance 
  maintain 
  an 
  average 
  

   height 
  of 
  more 
  than 
  1,000 
  feet. 
  They 
  are 
  referred 
  to 
  the 
  

   Upper 
  Cretaceous 
  entirely 
  upon 
  stratigraphical 
  evidences. 
  

   Since 
  they 
  have 
  been 
  seen 
  to 
  rest 
  unconformably 
  upon 
  the 
  

   330 
  feet 
  of 
  Upper 
  Conglomerates 
  which 
  separate 
  them 
  from 
  

   the 
  underlying 
  Belgrano 
  beds, 
  the 
  latter, 
  according 
  to 
  Stanton 
  

   not 
  older 
  than 
  Gault 
  and 
  perhaps 
  Cenomanian, 
  they 
  must 
  

   therefore 
  be 
  considered 
  as 
  belonging 
  somewhere 
  in 
  the 
  Upper 
  

   Cretaceous. 
  

  

  Lower 
  Lignite 
  beds. 
  — 
  Under 
  this 
  head 
  I 
  include 
  a 
  series 
  of 
  

   beds 
  consisting 
  at 
  the 
  base 
  chiefly 
  of 
  a 
  fine, 
  gray, 
  volcanic 
  ash 
  

   deposit, 
  passing 
  upwards 
  into 
  a 
  series 
  of 
  rather 
  soft 
  red 
  and 
  

   gray 
  sandstones. 
  These 
  beds 
  are 
  entirely 
  wanting 
  in 
  the 
  Lake 
  

   Pueyrredon 
  and 
  Rio 
  Tarde 
  sections, 
  but 
  may 
  be 
  seen 
  in 
  the 
  

   bluffs 
  on 
  the 
  south 
  side 
  of 
  Mayer 
  Basin, 
  and 
  especially 
  on 
  the 
  

   left 
  bank 
  of 
  the 
  south 
  fork 
  of 
  Rio 
  Chico 
  about 
  three 
  miles 
  

   above 
  Shell 
  Gap. 
  At 
  this 
  locality 
  these 
  beds 
  have 
  an 
  esti- 
  

   mated 
  thickness 
  of 
  1,500 
  feet 
  and 
  contain 
  in 
  great 
  abundance 
  

   partially 
  lignitized, 
  partially 
  petrified 
  trunks 
  and 
  branches 
  of 
  

   trees. 
  In 
  several 
  instances 
  vast 
  accumulations 
  of 
  such 
  tree 
  

   trunks 
  were 
  observed, 
  frequently 
  forming 
  the 
  chief 
  constituent 
  

   of 
  beds 
  twenty 
  to 
  thirty 
  feet 
  thick 
  and 
  of 
  unknown 
  lateral 
  

   extent. 
  

  

  I 
  have 
  nowhere 
  observed 
  the 
  Lower 
  Lignite 
  beds, 
  except 
  

   about 
  the 
  headwaters 
  of 
  the 
  south 
  fork 
  of 
  the 
  Rio 
  Chico 
  on 
  

   the 
  south 
  side 
  of 
  Mayer 
  Basin, 
  where 
  they 
  unconformably 
  

   overlie 
  the 
  Variegated 
  Sandstones. 
  Notwithstanding 
  the 
  exceed- 
  

   ingly 
  promising 
  appearance 
  of 
  these 
  lignite 
  beds, 
  an 
  extended 
  

   search 
  in 
  them 
  for 
  fossil 
  remains 
  was 
  not 
  rewarded 
  by 
  the 
  dis- 
  

   covery 
  of 
  any 
  animal 
  remains 
  whatsoever. 
  No 
  definite 
  opinion 
  

   can 
  at 
  present 
  be 
  advanced 
  as 
  to 
  their 
  probable 
  position 
  in 
  the 
  

   Upper 
  Cretaceous. 
  

  

  The 
  Guaraniticbeds. 
  — 
  T\\QG(X\diY&mt\Q, 
  or 
  Dinosaur 
  beds 
  con- 
  

   sist 
  of 
  a 
  series 
  of 
  soft, 
  dark 
  or 
  mottled 
  clays 
  and 
  shales 
  with 
  

   occasional 
  layers 
  of 
  bright 
  red, 
  green 
  and 
  orange-colored 
  mate- 
  

   rials 
  of 
  \ery 
  fine 
  grain. 
  The 
  liner 
  of 
  these 
  colored 
  deposits 
  

   are 
  mixed 
  with 
  grease 
  and 
  successfully 
  used 
  by 
  the 
  Tehuelche 
  

   Indians 
  as 
  mineral 
  paints, 
  in 
  the 
  decoration 
  of 
  their 
  person, 
  

   wearing 
  apparel 
  and 
  other 
  articles. 
  

  

  The 
  Ghiaranitic 
  beds, 
  like 
  the 
  underlying 
  Lower 
  Lignite 
  beds, 
  

   are 
  entirely 
  wanting 
  in 
  the 
  Rio 
  Tarde 
  and 
  Lake 
  Pueyrredon 
  

   sections, 
  but 
  are 
  well 
  represented 
  in 
  the 
  region 
  about 
  the 
  head- 
  

   waters 
  of 
  the 
  south 
  fork 
  of 
  the 
  Rio 
  Chico 
  and 
  in 
  the 
  high 
  

   bluffs 
  on 
  the 
  south 
  side 
  of 
  Mayer 
  Basin 
  between 
  the 
  sources 
  of 
  

   the 
  last 
  named 
  stream 
  and 
  an 
  eastern 
  tributary 
  of 
  Mayer 
  River 
  

  

  