﻿ACADEMY 
  OF 
  SCIENCES. 
  91 
  

  

  I 
  will 
  ennmerate 
  the 
  principal 
  examples 
  which 
  I 
  gathered 
  on 
  my 
  recent 
  trip 
  

   to 
  Mexico, 
  together 
  with 
  those 
  which 
  I 
  have 
  examined 
  in 
  past 
  years, 
  to 
  the 
  

   northward 
  and 
  southward 
  of 
  San 
  Francisco, 
  and 
  offer 
  some 
  examples 
  from 
  my 
  

   sketches 
  and 
  from 
  photographs. 
  

  

  Commencing 
  at 
  the 
  southward 
  I 
  could, 
  in 
  my 
  trip 
  of 
  last 
  March, 
  detect 
  no 
  

   lines 
  of 
  terraces 
  or 
  plateaus 
  whatever 
  at 
  the 
  extremity 
  of 
  the 
  Peninsula 
  of 
  

   Lower 
  California, 
  if 
  we 
  except 
  the 
  peculiar 
  form 
  of 
  the 
  summits 
  of 
  two 
  or 
  three 
  

   mountains 
  to 
  the 
  eastward 
  of 
  San 
  Jose 
  del 
  Cabo. 
  Thence 
  towards 
  Magdalena 
  

   Bay 
  I 
  had 
  no 
  view 
  of 
  the 
  coast 
  ; 
  but 
  on 
  the 
  island 
  of 
  San 
  Margarita, 
  and 
  the 
  

   great 
  headland 
  of 
  Cape 
  Lazaro, 
  forming 
  the 
  ocean 
  bulwark 
  to 
  Magdalena 
  Bay, 
  

   and 
  reaching 
  2,500 
  feet 
  elevation, 
  I 
  discovered 
  no 
  signs 
  of 
  terraces 
  on 
  the 
  

   ocean 
  or 
  bay 
  sides. 
  

  

  Of 
  the 
  coast 
  from 
  Cape 
  Lazaro 
  to 
  Cape 
  Colnett, 
  in 
  latitude 
  319 
  north, 
  I 
  

   cannot 
  speak, 
  except 
  of 
  a 
  long 
  table 
  ridge 
  lying 
  inland 
  from 
  Point 
  Abreojos, 
  in 
  

   about 
  latitude 
  27°. 
  It 
  had 
  the 
  same 
  peculiar 
  features 
  as 
  the 
  mountains 
  referred 
  

   to 
  near 
  San 
  Jose 
  del 
  Cabo. 
  

  

  Northward 
  of 
  Cape 
  Colnett 
  I 
  had 
  very 
  favorable 
  opportunities 
  to 
  study 
  the 
  

   coast 
  line, 
  and 
  made 
  many 
  views 
  to 
  illustrate 
  the 
  numerous 
  and 
  very 
  marked 
  

   examples 
  of 
  terraces 
  that 
  are 
  cut 
  and 
  planed 
  in 
  the 
  flank 
  of 
  the 
  high 
  rocky 
  

   coast 
  barrier. 
  Vancouver 
  has 
  a 
  view 
  of 
  the 
  mesa 
  or 
  table 
  forming 
  Cape 
  Col- 
  

   nett, 
  with 
  the 
  strata 
  inclined 
  at 
  a 
  large 
  angle 
  and 
  the 
  surface 
  cut 
  off 
  quite 
  

   level. 
  

  

  The 
  Point 
  near 
  Solitaries 
  Rocks, 
  in 
  about 
  lat. 
  31° 
  32' 
  is 
  a 
  well 
  marked 
  table 
  

   of 
  about 
  150 
  feet 
  elevation, 
  with 
  a 
  lower 
  table 
  towards 
  the 
  extremity 
  of 
  the 
  

   point, 
  visible 
  when 
  it 
  bears 
  E. 
  S. 
  B. 
  

  

  Five 
  miles 
  southward 
  of 
  Point 
  Grajero, 
  about 
  latitute 
  31° 
  35', 
  a 
  deep, 
  canon- 
  

   like 
  valley 
  opens 
  upon 
  the 
  ocean, 
  and 
  exhibits 
  numerous 
  and 
  very 
  sharply 
  

   marked 
  rock 
  terraces 
  on 
  both 
  sides 
  and 
  at 
  all 
  elevations, 
  reaching 
  nearly 
  a 
  thou- 
  

   sand 
  feet. 
  The 
  canon 
  stretches 
  well 
  back 
  into 
  the 
  mountains. 
  

  

  The 
  northernmost 
  of 
  the 
  Todos 
  Santos 
  Islands, 
  about 
  latitude 
  31° 
  40', 
  and 
  

   not 
  laid 
  down 
  on 
  recent 
  charts, 
  is 
  itself 
  a 
  well 
  marked, 
  rocky, 
  horizontal 
  plateau, 
  

   thinly 
  covered 
  with 
  soil 
  ; 
  whilst 
  the 
  southern 
  island 
  has 
  two 
  terrace 
  marks, 
  the 
  

   lower 
  corresponding 
  to 
  the 
  level 
  of 
  the 
  top 
  of 
  the 
  northern 
  islet, 
  another 
  higher 
  

   one, 
  near 
  the 
  summit 
  of 
  the 
  islet, 
  about 
  twice 
  the 
  height 
  from 
  the 
  sea. 
  Even 
  a 
  

   lower 
  terrace 
  line 
  may 
  be 
  traced 
  about 
  15 
  feet 
  above 
  the 
  present 
  sea 
  level. 
  

  

  When 
  passing 
  abreast 
  the 
  northern 
  point 
  of 
  Todos 
  Santos 
  Bay, 
  no 
  less 
  than 
  

   four 
  well 
  marked 
  terrace 
  rocky 
  points, 
  projecting 
  into 
  the 
  ocean, 
  were 
  sketched 
  

   in 
  the 
  same 
  view. 
  Each 
  point 
  had 
  other 
  terraces 
  of 
  greater 
  elevations 
  rising 
  

   inland 
  ; 
  whilst 
  to 
  the 
  northward 
  stood 
  out 
  the 
  well 
  known 
  Table 
  Mountain 
  with 
  

   its 
  remarkable 
  flat 
  top, 
  2,244 
  feet 
  above 
  the 
  sea, 
  and 
  having 
  a 
  breadth 
  of 
  4.800 
  

   feet. 
  On 
  this 
  single 
  view 
  no 
  less 
  than 
  fourteen 
  terrace 
  markings 
  are 
  exhibited, 
  

   including 
  Table 
  Mountain. 
  The 
  vicinity 
  is 
  the 
  best 
  marked 
  terrace 
  formation 
  

   that 
  I 
  know 
  of 
  on 
  the 
  coast. 
  'I'hey 
  are 
  not 
  made 
  in 
  soft 
  soil, 
  but 
  appear 
  as 
  if 
  

   a 
  planing 
  machine 
  had 
  cut 
  them 
  out 
  of 
  the 
  solid 
  rocks. 
  

  

  