﻿Geology 
  and 
  Mineralogy. 
  173 
  

  

  4. 
  The 
  Fundamental 
  Principles 
  of 
  Petrology, 
  translated 
  from 
  

   the 
  German 
  of 
  E. 
  Weinschenk 
  by 
  A. 
  Johannsen. 
  8vo. 
  Pp. 
  

   214 
  ; 
  13V 
  figs, 
  in 
  text, 
  VI 
  pis. 
  New 
  York, 
  1916 
  (McGraw-Hill 
  

   Book 
  Co.). 
  — 
  This 
  translation 
  of 
  Grundzuge 
  der 
  Gesteinskunde 
  

   has 
  been 
  well 
  carried 
  out 
  by 
  Professor 
  Johannsen, 
  and 
  in 
  several 
  

   ways 
  the 
  book 
  is 
  an 
  improvement 
  on 
  the 
  original 
  work. 
  As 
  its 
  

   name 
  implies, 
  it 
  is 
  not 
  in 
  its 
  nature 
  descriptive 
  of 
  the 
  different 
  

   kinds 
  of 
  rocks, 
  but 
  treats 
  of 
  such 
  subjects 
  as 
  volcanism 
  and 
  the 
  

   origin 
  of 
  igneous 
  rocks, 
  differentiation, 
  rock-weathering, 
  the 
  

   nature 
  of 
  sediments, 
  contact 
  metamorphism, 
  post-volcanic 
  pro- 
  

   cesses, 
  regional 
  metamorphism 
  and 
  jointing 
  and 
  rock-textures. 
  

   These 
  subjects 
  are 
  treated 
  in 
  a 
  simple 
  and 
  yet 
  condensed 
  way 
  so 
  

   that 
  the 
  work, 
  as 
  intended, 
  is 
  suitable 
  for 
  students 
  commencing 
  

   work 
  in 
  petrology. 
  Regarding 
  matters 
  concerning 
  which 
  there 
  is 
  

   yet 
  no 
  agreement 
  it 
  naturally, 
  for 
  the 
  most 
  part, 
  presents 
  the 
  views 
  

   of 
  the 
  German 
  school 
  of 
  geologists. 
  Professor 
  Weinschenk 
  him- 
  

   self 
  has 
  worked 
  largely 
  in 
  areas 
  of 
  regionally 
  metamorphosed 
  

   rocks, 
  and 
  thus 
  in 
  the 
  subject 
  of 
  metamorphism 
  he 
  speaks 
  with 
  

   a 
  certain 
  authority 
  and 
  presents 
  views 
  of 
  his 
  own. 
  The 
  book 
  

   may 
  be 
  usefully 
  read 
  by 
  teachers 
  and 
  students 
  who 
  are 
  not 
  

   acquainted 
  with 
  it 
  in 
  the 
  original 
  text 
  and 
  in 
  giving 
  them 
  this 
  

   opportunity 
  the 
  translator 
  has 
  performed 
  a 
  commendable 
  task. 
  

   The 
  volume 
  is 
  well 
  printed 
  and 
  handsomely 
  illustrated, 
  l. 
  v. 
  p. 
  

  

  5. 
  IJ 
  Oural 
  du 
  Nord 
  ; 
  Le 
  Bassin 
  des 
  Rivieres 
  Wagran 
  et 
  

   Kakwa, 
  par 
  Louis 
  Duparc 
  et 
  Marguerite 
  Tikanowitch, 
  (Mem. 
  

   Soc. 
  de 
  Phys. 
  et 
  d'Hist. 
  Nat. 
  de 
  Geneve, 
  vol. 
  xxxviii, 
  fasc. 
  2, 
  pp. 
  

   69-166. 
  Pis. 
  6-7, 
  1914). 
  — 
  In 
  continuation 
  of 
  the 
  geologica 
  land 
  

   petrographical 
  researches 
  being 
  carried 
  out 
  on 
  the 
  northern 
  part 
  

   of 
  the 
  chain 
  of 
  the 
  Ural 
  Mts., 
  by 
  Professor 
  Duparc 
  and 
  his 
  stu- 
  

   dent 
  assistants, 
  the 
  present 
  work 
  is 
  an 
  interesting 
  addition. 
  There 
  

   is 
  no 
  topographic 
  map 
  of 
  this 
  region 
  and 
  the 
  field 
  work 
  is 
  mostly 
  

   of 
  the 
  nature 
  of 
  a 
  reconnaissance, 
  but 
  the 
  exploration 
  of 
  the 
  area 
  

   derives 
  importance 
  in 
  connection 
  with 
  the 
  occurrence 
  of 
  plati- 
  

   num. 
  Here 
  a^ain, 
  as 
  elsewhere 
  in 
  the 
  Urals, 
  occur 
  great 
  masses 
  

   of 
  gabbros 
  associated 
  with 
  olivine 
  and 
  pyroxene 
  rocks, 
  similar 
  

   types 
  to 
  those 
  described 
  in 
  former 
  publications 
  by 
  the 
  senior 
  

   author. 
  The 
  main 
  part 
  of 
  the 
  work 
  is 
  devoted 
  to 
  a 
  detailed 
  

   petrographic 
  and 
  chemical 
  study 
  of 
  the 
  rock 
  types 
  collected. 
  

  

  l. 
  v. 
  P. 
  

  

  6. 
  Etude 
  comparee 
  des 
  Gites 
  Platiniflres 
  de 
  la 
  Sierra 
  de 
  

   Honda 
  et 
  de 
  V 
  Oural; 
  by 
  Louis 
  Duparc 
  and 
  Augustin 
  Grosset. 
  

   Mem. 
  Soc. 
  Phys. 
  et 
  Hist. 
  Nat. 
  de 
  Geneve, 
  xxxviii, 
  253, 
  1916. 
  — 
  

   Platinum 
  has 
  recently 
  been 
  found 
  in 
  connection 
  with 
  peridotite 
  

   rocks 
  that 
  occur 
  in 
  the 
  Sierra 
  de 
  Honda, 
  Province 
  of 
  Malaga, 
  

   Spain. 
  A 
  petrographic 
  study 
  of 
  the 
  rocks 
  of 
  this 
  locality 
  shows, 
  

   however, 
  that 
  the 
  character 
  of 
  this 
  occurrence 
  is 
  quite 
  distinct 
  

   from 
  that 
  of 
  the 
  classic 
  locality 
  in 
  the 
  Ural 
  Mts. 
  The 
  conclusion 
  

   is 
  reached 
  that 
  the 
  primary 
  occurrences 
  of 
  platinum 
  may 
  be 
  of 
  

   the 
  following 
  three 
  types 
  : 
  (1) 
  In 
  dunite 
  rocks. 
  Occurrences 
  of 
  

   this 
  kind 
  are 
  the 
  most 
  common 
  and 
  richest 
  ; 
  this 
  type 
  is 
  found 
  

   in 
  the 
  Urals 
  Mts. 
  (2) 
  In 
  pyroxenites 
  which 
  are 
  composed 
  of 
  a 
  

  

  