﻿J. 
  S. 
  GAEDXEE, 
  ON 
  THE 
  GEOLOGY 
  OP 
  MADEIRA. 
  279 
  

  

  the 
  sides 
  of 
  the 
  ravine, 
  and 
  dips 
  N.W. 
  towards 
  the 
  sea 
  at 
  a 
  high 
  

   angle, 
  so 
  that 
  it 
  is 
  difficult 
  to 
  estimate 
  its 
  thickness 
  with 
  any 
  

   accuracy. 
  

  

  To 
  the 
  list 
  of 
  species 
  published 
  by 
  Karl 
  Meyer 
  inHartung's 
  ' 
  Geology 
  

   of 
  Madeira,' 
  Mr. 
  Tate 
  Johnson 
  has 
  added 
  Plioladomya, 
  Terebra, 
  and 
  

   Atur'ia 
  zigzag, 
  from 
  the 
  supposed 
  contemporaneous 
  beds 
  of 
  Porto 
  

   Santo. 
  

  

  The 
  far 
  more 
  recent 
  calcareous 
  sand 
  of 
  Canical 
  has 
  been 
  fully 
  

   described 
  by 
  Lyell. 
  All 
  but 
  two, 
  however, 
  of 
  the 
  Pulmonates 
  which 
  

   were 
  then 
  supposed 
  to 
  be 
  extinct 
  have 
  since 
  been 
  found 
  living 
  : 
  and 
  

   the 
  total 
  number 
  for 
  the 
  Madeiras 
  has 
  now 
  risen 
  to 
  at 
  least 
  165, 
  for 
  

   a 
  single 
  collection 
  formed 
  by 
  Mr. 
  Leacock 
  contains 
  this 
  number. 
  

  

  The 
  Fossiliferous 
  Clays 
  and 
  Tuffs 
  of 
  Madeira. 
  

  

  The 
  lignite 
  bed 
  of 
  Sao 
  Jorge, 
  the 
  only 
  one 
  in 
  the 
  island, 
  is 
  

   situated 
  1000 
  feet 
  above 
  the 
  sea-level, 
  in 
  the 
  depths 
  of 
  a 
  wild 
  gorge 
  

   whose 
  almost 
  perpendicular 
  sides 
  of 
  lava 
  and 
  scorice 
  tower 
  to 
  a 
  height 
  

   of 
  2000 
  and 
  3000 
  feet. 
  It 
  is 
  reached 
  by 
  ascending 
  the 
  rocky 
  bed 
  

   of 
  a 
  torrent, 
  overhung 
  by 
  primeval 
  laurel-woods 
  which 
  are 
  carpeted 
  

   with 
  moss 
  and 
  a 
  most 
  luxuriant 
  fern-growth. 
  The 
  spot 
  has 
  been 
  

   visited 
  by 
  Lyell, 
  Bunbury, 
  Conybeare, 
  andHartung 
  ; 
  but 
  at 
  some 
  time 
  

   previous 
  to 
  1865 
  it 
  was 
  buried 
  by 
  a 
  landslip 
  and 
  had 
  not 
  since 
  been 
  

   seen. 
  In 
  my 
  visit 
  during 
  1880 
  I 
  was 
  accompanied 
  by 
  Mr. 
  Charles 
  

   Cossart 
  and 
  a 
  guide 
  who 
  was 
  well 
  acquainted 
  with 
  the 
  spot 
  and 
  had 
  

   formerly 
  collected 
  there 
  ; 
  and 
  with 
  the 
  assistance 
  of 
  our 
  hammock- 
  

   bearers 
  we 
  were 
  able 
  to 
  clear 
  the 
  upper 
  parts 
  of 
  the 
  bed 
  from 
  tangle 
  

   and 
  debris. 
  No 
  lignite, 
  however, 
  was 
  visible, 
  although 
  we 
  apparently 
  

   reached 
  the 
  basalt 
  ; 
  and 
  it 
  is 
  therefore 
  probable 
  that 
  the 
  thin 
  bed 
  of 
  

   upper 
  lignite 
  inHartung's 
  section 
  no 
  longer 
  exists. 
  The 
  beds 
  appeared 
  

   to 
  be 
  lenticular 
  in 
  section 
  and 
  of 
  small 
  extent, 
  made 
  up 
  of 
  compressed, 
  

   light 
  brown, 
  shaly 
  clays 
  between 
  layers 
  of 
  hard 
  stone, 
  and 
  full 
  of 
  

   indistinct 
  vegetable 
  remains. 
  In 
  place 
  of 
  the 
  lignite 
  I 
  saw 
  7 
  feet 
  

   of 
  blackish 
  shales, 
  with 
  well-preserved 
  twigs 
  and 
  branches, 
  and 
  

   resting 
  on 
  basalt. 
  

  

  The 
  section, 
  as 
  given 
  by 
  Hartung, 
  is: 
  — 
  

  

  ft. 
  in. 
  

   Tufaceous 
  breccia, 
  partly 
  concealed, 
  depth 
  unknown. 
  

  

  Hardclay 
  3 
  

  

  Tufaceous 
  breccia 
  with 
  plants, 
  passing 
  right 
  and 
  left 
  to 
  basalt 
  3 
  

  

  Upper 
  lignite 
  4 
  

  

  Underclay 
  10 
  O 
  

  

  Easalt 
  , 
  15 
  O 
  

  

  Lignite 
  — 
  ? 
  

  

  ]>o 
  distinct 
  remains 
  of 
  plants 
  are 
  now 
  found, 
  though 
  they 
  were 
  

   formerly 
  met 
  with 
  abundantly. 
  Sir 
  Charles 
  Bunbury 
  recognized 
  

   Woodivardia, 
  DavaJlia, 
  Nephrodium, 
  and 
  other 
  common 
  Madeira 
  

   ferns, 
  and 
  laid 
  stress 
  on 
  the 
  myrtle- 
  and 
  laurel-like 
  character 
  of 
  the 
  

   dicotyledons, 
  which 
  he 
  considered 
  all 
  to 
  belong 
  to 
  the 
  existing 
  flora 
  

   of 
  the 
  island. 
  Heer, 
  however, 
  in 
  describing 
  a 
  collection 
  made 
  by 
  

   Hartung, 
  comprising 
  27 
  supposed 
  species, 
  referred 
  many 
  of 
  them 
  to 
  

  

  tj2 
  

  

  