﻿Geology 
  and 
  Mineralogy. 
  301 
  

  

  This 
  volume 
  is 
  of 
  more 
  than 
  ordinary 
  interest, 
  and 
  worthily 
  

   stands 
  as 
  the 
  first 
  of 
  a 
  new 
  series 
  of 
  publications, 
  the 
  Monographs 
  

   of 
  the 
  Geological 
  Survey. 
  The 
  researches 
  reported 
  in 
  it 
  combine 
  

   stratigraphical, 
  petrographical 
  and 
  paleontological 
  studies 
  of 
  the 
  

   most 
  thorough 
  kind, 
  of 
  a 
  very 
  complex 
  series 
  of 
  rocks 
  much 
  dis- 
  

   turbed 
  by 
  folding 
  and 
  faulting 
  and 
  with 
  igneous 
  intrusions. 
  

   Messrs. 
  Peach 
  and 
  Home, 
  the 
  chief 
  authors 
  of 
  the 
  volume, 
  began 
  

   the 
  study 
  of 
  the 
  southern 
  uplands 
  geology 
  in 
  1888, 
  having 
  as 
  a 
  

   clue 
  for 
  the 
  interpretation 
  of 
  the 
  stratigraphy 
  the 
  results 
  of 
  

   Professor 
  Lap 
  worth's 
  studies, 
  particularly 
  the 
  carefully 
  estab- 
  

   lished 
  succession 
  of 
  graptolites. 
  They 
  make 
  special 
  reference 
  to 
  

   the 
  value 
  of 
  Professor 
  Lapworth's 
  results 
  as 
  well 
  as 
  his 
  method 
  

   of 
  investigation, 
  at 
  the 
  close 
  of 
  the 
  second 
  chapter. 
  Mr. 
  J. 
  J. 
  H. 
  

   Teall 
  contributes 
  valuable 
  chapters 
  on 
  the 
  petrography 
  of 
  the 
  

   igneous 
  rocks, 
  the 
  granite 
  masses, 
  and 
  on 
  contact 
  metamorphism. 
  

   Several 
  specialists, 
  both 
  within 
  and 
  outside 
  the 
  Survey, 
  contribute 
  

   both 
  assistance 
  and 
  advice. 
  Not 
  least 
  among 
  these 
  is 
  Mrs. 
  

   Robert 
  Gray, 
  whose 
  superb 
  collection 
  of 
  30,000 
  specimens 
  of 
  the 
  

   Silurian 
  fossils 
  of 
  the 
  Girvan 
  district 
  was 
  first 
  placed 
  at 
  the 
  

   service 
  of 
  Messrs. 
  Nicholson, 
  Etheridge 
  and 
  Lapworth 
  ; 
  it 
  was 
  

   again 
  at 
  the 
  disposal 
  of 
  the 
  Survey 
  ; 
  and 
  in 
  the 
  Appendix 
  is 
  pub- 
  

   lished 
  a 
  list 
  of 
  the 
  fossils 
  with 
  their 
  range 
  and 
  distribution, 
  pre- 
  

   pared 
  by 
  Mrs. 
  Gray. 
  

  

  The 
  value 
  of 
  the 
  report 
  is 
  heightened 
  for 
  the 
  general 
  reader 
  by 
  

   the 
  chapter 
  (n) 
  giving 
  a 
  concise, 
  but 
  full, 
  history 
  of 
  previous 
  

   researches 
  among 
  the 
  Silurian 
  rocks 
  of 
  the 
  south 
  of 
  Scotland, 
  

   beginning 
  with 
  Hutton 
  in 
  1795. 
  The 
  recapitulation 
  of 
  the 
  results 
  

   of 
  the 
  investigations 
  of 
  the 
  Geological 
  Survey 
  in 
  the 
  southern 
  

   uplands 
  will 
  indicate 
  some 
  of 
  the 
  more 
  important 
  problems 
  here 
  

   discussed 
  in 
  detail 
  : 
  

  

  " 
  1. 
  The 
  occurrence 
  of 
  a 
  series 
  of 
  Arenig 
  volcanic 
  and 
  plutonic 
  

   rocks 
  on 
  various 
  anticlines 
  over 
  an 
  area 
  of 
  about 
  1500 
  square 
  

   miles. 
  

  

  " 
  2. 
  The 
  existence 
  of 
  a 
  well-marked 
  band 
  of 
  radiolarian 
  cherts 
  

   and 
  mudstones, 
  overlying 
  the 
  foregoing 
  volcanic 
  series, 
  which 
  has 
  

   been 
  traced 
  over 
  a 
  part 
  of 
  the 
  uplands 
  measuring 
  about 
  2000 
  

   square 
  miles. 
  

  

  " 
  3. 
  The 
  main 
  band 
  of 
  radiolarian 
  chert 
  and 
  mudstone, 
  though 
  

   about 
  70 
  feet 
  thick, 
  represents 
  the 
  succession 
  of 
  deposits 
  which, 
  

   elsewhere 
  in 
  Britain, 
  intervene 
  between 
  the 
  Middle 
  Arenig 
  and 
  

   uppermost 
  Llandeilo 
  strata. 
  

  

  "4. 
  The 
  occurrence 
  at 
  various 
  localities 
  over 
  a 
  limited 
  area 
  of 
  

   volcanic 
  rocks 
  of 
  Llandeilo 
  and 
  Caradoc 
  age. 
  

  

  "5. 
  During 
  the 
  examination 
  of 
  the 
  various 
  black 
  shale 
  out- 
  

   crops 
  throughout 
  the 
  uplands, 
  a 
  great 
  amount 
  of 
  detailed 
  evidence 
  

   has 
  been 
  obtained, 
  confirming 
  the 
  order 
  of 
  succession 
  established 
  

   by 
  Professor 
  Lapworth, 
  and 
  the 
  lateral 
  variation 
  of 
  the 
  strata 
  

   between 
  Moffat 
  and 
  Girvan. 
  

  

  "6. 
  The 
  inclusion 
  of 
  the 
  Downtonian 
  strata 
  of 
  Lanarkshire 
  and 
  

   the 
  Pentland 
  Hills 
  in 
  the 
  Silurian 
  system, 
  owing 
  to 
  the 
  discovery 
  

  

  Am. 
  Jour. 
  Sci. 
  — 
  Fourth 
  Series, 
  Vol 
  IX, 
  No. 
  52. 
  — 
  April, 
  1900. 
  

   21 
  

  

  