﻿200 
  

  

  PROCEEDINGS 
  OF 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  [Mar. 
  9, 
  

  

  New 
  Mexico 
  * 
  over 
  large 
  spaces 
  ; 
  also 
  in 
  Texas 
  and 
  Tennessee, 
  and 
  

   over 
  great 
  tracts 
  in 
  the 
  valley 
  of 
  the 
  Missouri 
  ; 
  thus 
  indicating 
  

   several 
  extensive 
  blanks. 
  

  

  The 
  " 
  Craie 
  tuffeau," 
  in 
  Westphalia, 
  covers 
  Carboniferous 
  schists 
  

   and 
  limestone 
  f 
  , 
  and 
  we 
  have 
  the 
  same 
  in 
  the 
  Don 
  country 
  of 
  South 
  

   Russia. 
  At 
  Harwich 
  J, 
  Kentish 
  Town 
  §, 
  and 
  Calais, 
  deep 
  borings, 
  

   after 
  having 
  passed 
  through 
  the 
  Cretaceous 
  series, 
  have 
  struck 
  at 
  

   once 
  into 
  rocks 
  apparently 
  Palaeozoic, 
  and 
  which 
  at 
  Calais 
  are 
  true 
  

   Coal-measures. 
  Near 
  Seu 
  d'Urgel, 
  on 
  the 
  River 
  Segra 
  (N. 
  Spain), 
  M. 
  

   Noblemaire 
  || 
  met 
  with 
  Cretaceous 
  rocks 
  resting 
  on 
  Upper 
  Silurian 
  ; 
  

   and 
  M. 
  Delia 
  Marmora 
  ^[ 
  describes 
  them 
  as 
  reposing 
  on 
  Lower 
  Silurian 
  

   in 
  Sardinia. 
  Parts 
  of 
  Scania, 
  in 
  Sweden, 
  exhibit 
  the 
  same 
  kind 
  of 
  

   facts. 
  At 
  and 
  about 
  Segovia 
  **, 
  at 
  Cerada 
  and 
  Lozoya 
  (Spain), 
  beds 
  

   of 
  this 
  formation 
  rest 
  upon 
  ancient 
  schists 
  and 
  granite 
  ; 
  we 
  find 
  

   them 
  also 
  upon 
  the 
  latter, 
  extensively, 
  in 
  Saxony, 
  in 
  Sweden 
  ft, 
  

   in 
  Southern 
  India 
  $i, 
  and 
  (Hippurite 
  limestone) 
  at 
  Tavolara, 
  and 
  

   elsewhere 
  in 
  South-west 
  Sardinia 
  §§. 
  

  

  Fig. 
  5. 
  — 
  Section 
  in 
  the 
  Sierra 
  de 
  Guadarrama 
  , 
  south 
  of 
  Cabanillas, 
  

   showing 
  Chalk 
  resting 
  on 
  Granite 
  of 
  unknown 
  age 
  (after 
  MM. 
  de 
  

   Yerneuil 
  and 
  Collomb). 
  

  

  S. 
  N. 
  

  

  Sierra 
  de 
  

   El 
  Molar. 
  Atalaya. 
  Cabanillas. 
  Guadarrama. 
  

  

  a. 
  Granite. 
  

  

  b. 
  Chalk. 
  

  

  c. 
  Diluvium. 
  

  

  In 
  these 
  twenty-eight 
  instances 
  of 
  blanks, 
  which 
  were 
  taken 
  

   nearly 
  as 
  they 
  came, 
  the 
  Cretaceous 
  beds 
  are 
  found 
  in 
  contact 
  with 
  

   the 
  following 
  rocks 
  (once 
  sea-bottoms). 
  They 
  lie 
  on 
  Jurassic 
  six 
  

   times, 
  Lias 
  once, 
  Trias 
  four 
  times, 
  Carboniferous 
  Limestone 
  or 
  

   schist 
  seven 
  times, 
  on 
  Silurian 
  twice, 
  and 
  on 
  old 
  granite, 
  gneiss, 
  

   and 
  mica- 
  slate 
  eight 
  times. 
  

  

  Why 
  the 
  Chalk 
  is 
  not 
  recorded 
  as 
  lying 
  directly 
  on 
  Permian, 
  Devo- 
  

   nian, 
  <fcc, 
  I 
  cannot 
  tell 
  ; 
  perhaps 
  for 
  want 
  of 
  a 
  more 
  extensive 
  search. 
  

  

  b. 
  Upper 
  Greensand. 
  — 
  Neocomian, 
  Gault, 
  and 
  Lower 
  Greensand 
  

   are 
  missing 
  in 
  Prance, 
  on 
  the 
  west 
  side 
  of 
  the 
  Anglo-Parisian 
  

  

  *' 
  James 
  Hall, 
  ' 
  Boundary 
  Report 
  of 
  Mexico,' 
  vol. 
  i. 
  p. 
  117. 
  

  

  t 
  D'Archiac, 
  ' 
  Histoire 
  des 
  Progres,' 
  vol. 
  v. 
  p. 
  224. 
  

  

  I 
  Austen, 
  Quart. 
  Journ. 
  Geol. 
  Soc. 
  vol. 
  xii. 
  p. 
  41. 
  

  

  § 
  Prestwich, 
  ibid. 
  vol. 
  xii. 
  p. 
  6, 
  vol. 
  xiv. 
  p. 
  249. 
  

  

  || 
  Annales 
  des 
  Mines, 
  5 
  e 
  serie, 
  vol. 
  xiv. 
  p. 
  52. 
  

   ^[ 
  Voyage 
  en 
  Sardaigne, 
  vol. 
  i. 
  p. 
  414. 
  

   ** 
  D'Archiac, 
  'Histoire 
  des 
  Progres,' 
  vol. 
  v. 
  p. 
  49. 
  

   tt 
  Ibid. 
  p. 
  251. 
  

  

  |J 
  Blanford, 
  ' 
  Palaeontologia 
  Indica,' 
  vol. 
  i. 
  p. 
  v. 
  

   §§ 
  Delia 
  Marmora, 
  'Voyage 
  en 
  Sardaigne,' 
  Part 
  3. 
  vol. 
  ii. 
  p. 
  24. 
  

  

  