﻿Geology 
  and 
  Natural 
  History. 
  223 
  

  

  cies 
  are 
  recognized. 
  The 
  Opuntieae 
  comprise 
  the 
  very 
  large 
  

   genus 
  Opuntia 
  with 
  254 
  species, 
  and 
  the 
  much 
  smaller 
  genera 
  

   Pereskiopsis, 
  Pterocactus, 
  Nopalea, 
  Tacinga, 
  Maihuenia 
  and 
  

   Grusonia, 
  the 
  largest 
  of 
  which 
  has 
  only 
  10 
  species. 
  Each 
  spe- 
  

   cies 
  is 
  described 
  at 
  length 
  and 
  full 
  data 
  are 
  given 
  regarding 
  

   type 
  localities 
  and 
  geographical 
  distribution. 
  In 
  many 
  cases 
  

   interesting 
  notes 
  are 
  added, 
  especially 
  in 
  the 
  case 
  of 
  cultivated 
  

   species 
  and 
  those 
  with 
  a 
  long 
  and 
  involved 
  synonymy. 
  In 
  the 
  

   course 
  of 
  the 
  volume, 
  41 
  new 
  species 
  are 
  described, 
  32 
  belong- 
  

   ing 
  to 
  the 
  genus 
  Opuntia 
  and 
  the 
  others 
  distributed 
  among 
  the 
  

   genera 
  Pereskia, 
  Pterocactus, 
  Nopalea 
  and 
  Tacinga, 
  the 
  last 
  

   being 
  the 
  only 
  new 
  genus 
  proposed. 
  A 
  noteworthy 
  feature 
  of 
  

   the 
  work 
  is 
  the 
  full 
  series 
  of 
  colored 
  illustrations, 
  mostly 
  from 
  

   the 
  brush 
  of 
  Miss 
  M. 
  A. 
  Eaton 
  of 
  the 
  New 
  York 
  Botanical 
  

   Garden. 
  These 
  are 
  supplemented 
  by 
  line 
  drawings 
  and 
  by 
  

   reproductions 
  of 
  photographs 
  showing 
  plants 
  in 
  their 
  natural 
  

   surroundings. 
  a. 
  w. 
  e. 
  

  

  10. 
  Fossil 
  Plants: 
  A 
  text-book 
  for 
  students 
  of 
  Botany 
  and 
  

   Geology; 
  by 
  A. 
  C. 
  Seward. 
  Vol. 
  IV, 
  small 
  8vo, 
  pp. 
  xvi, 
  543, 
  

   with 
  figures 
  630-818 
  in 
  text. 
  Cambridge, 
  1919 
  (Cambridge 
  

   University 
  Press). 
  — 
  Notice 
  of 
  the 
  first 
  volume 
  of 
  this 
  work 
  was 
  

   given 
  by 
  Goodale 
  in 
  this 
  Journal, 
  June, 
  1898 
  (5, 
  472). 
  The 
  

   second 
  and 
  third 
  volumes 
  were 
  reviewed 
  by 
  Wieland, 
  November, 
  

   1910 
  (30, 
  356), 
  and 
  August, 
  1918 
  (46, 
  475). 
  The 
  Ginkgoales, 
  

   Coniferales, 
  and 
  Gnetales 
  are 
  the 
  subjects 
  of 
  this, 
  the 
  concluding 
  

   volume 
  of 
  Professor 
  Seward's 
  great 
  text. 
  It 
  is 
  in 
  completed 
  

   form, 
  primarily 
  an 
  outline 
  of 
  the 
  knowledge 
  of 
  fossil 
  plants, 
  

   excepting 
  the 
  angiosperms, 
  which 
  will 
  be 
  permanently 
  useful 
  

   and 
  usable 
  to 
  the 
  student 
  of 
  structure 
  as 
  well 
  as 
  investigators 
  

   of 
  fossil 
  floras. 
  

  

  As 
  a 
  whole, 
  these 
  volumes 
  have 
  gained 
  from 
  a 
  course 
  of 
  anno- 
  

   tation 
  extending 
  through 
  more 
  than 
  twenty 
  years. 
  In 
  this 
  time 
  

   the 
  subject 
  matter 
  of 
  Paleobotany 
  has 
  at 
  least 
  trebled 
  in 
  bulk, 
  

   and 
  methods 
  have 
  reached 
  a 
  precision 
  not 
  exceeded 
  in 
  either 
  

   branch 
  of 
  Paleozoology. 
  There 
  is 
  observable 
  a 
  distinct 
  advance 
  

   over 
  the 
  texts 
  of 
  Schimper, 
  Solms, 
  and 
  perhaps 
  Zeiller, 
  both 
  in 
  

   amount 
  of 
  detail, 
  and 
  in 
  illustration, 
  along 
  with 
  much 
  of 
  that 
  

   clear 
  discussion 
  which 
  makes 
  the 
  studies 
  of 
  Scott 
  so 
  readable. 
  

   Yet 
  it 
  is 
  in 
  no 
  sense 
  a 
  criticism 
  to 
  say 
  that 
  this 
  new 
  text 
  belongs 
  

   with 
  its 
  prototypes 
  to 
  the 
  formative 
  period 
  of 
  Paleobotany. 
  

   Could 
  any 
  faults 
  or 
  lacks 
  be 
  fairly 
  named, 
  they 
  would 
  only 
  be 
  

   those 
  inherent 
  to 
  all 
  paleobotanic 
  studies 
  thus 
  far. 
  Uneven 
  

   treatment 
  and 
  illustration, 
  with 
  much 
  speculation, 
  have 
  admit- 
  

   tedly 
  characterized 
  much 
  of 
  the 
  work 
  on 
  fossil 
  plants. 
  

  

  But 
  those 
  broader 
  points 
  of 
  view 
  to 
  which 
  Professor 
  Seward's 
  

   text 
  signally 
  contributes, 
  are 
  rapidly 
  clearing. 
  Pitting 
  theory 
  

   against 
  theory 
  is 
  far 
  less 
  in 
  evidence, 
  and 
  determination 
  of 
  the 
  

   time 
  of 
  appearance 
  and 
  range 
  of 
  structures 
  in 
  geologic 
  time 
  is 
  

  

  