﻿THE 
  

  

  AMERICAN 
  JOURNAL 
  OF 
  SCIENCE 
  

  

  [FOURTH 
  SERIES.] 
  

  

  Art. 
  L. 
  — 
  Some 
  Lavas 
  of 
  Monte 
  Arci, 
  Sardinia 
  ; 
  by 
  Henry 
  

   S. 
  Washington. 
  

  

  Introduction. 
  — 
  It 
  is 
  not 
  generally 
  known 
  that 
  near 
  Monte 
  

   Ferru, 
  the 
  well-known 
  volcano 
  of 
  Sardinia, 
  there 
  is 
  another, 
  

   Monte 
  Arci, 
  not 
  far 
  distant, 
  of 
  only 
  slightly 
  smaller 
  size, 
  and 
  

   yielding 
  somewhat 
  similar 
  rocks. 
  During 
  a 
  visit 
  to 
  Sardinia, 
  

   undertaken 
  in 
  1905 
  for 
  the 
  Carnegie 
  Institution 
  of 
  Washington, 
  

   two 
  days 
  were 
  spent 
  in 
  examining 
  part 
  of 
  the 
  western 
  flank 
  of 
  

   this 
  volcano. 
  As 
  only 
  a 
  very 
  small 
  part 
  of 
  the 
  volcanic 
  mass 
  

   was 
  studied, 
  the 
  present 
  paper 
  is 
  to 
  be 
  regarded 
  as 
  a 
  prelimi- 
  

   nary 
  one 
  based 
  on 
  a 
  hasty 
  reconnoissance, 
  and 
  it 
  is 
  hoped 
  to 
  

   complete 
  the 
  study 
  by 
  a 
  visit 
  in 
  the 
  near 
  future.* 
  All 
  the 
  

   analyses 
  in 
  this 
  paper 
  were 
  made 
  by 
  me, 
  with 
  the 
  exception 
  of 
  

   a 
  few 
  quoted 
  ones. 
  

  

  Our 
  present 
  knowledge 
  of 
  Monte 
  Arci 
  is 
  due 
  wholly 
  to 
  

   Count 
  Alberto 
  della 
  Marmora, 
  f 
  the 
  pioneer 
  explorer 
  and 
  inves- 
  

   tigator 
  of 
  the 
  island, 
  whose 
  many 
  years 
  of 
  indefatigable 
  labor 
  

   have 
  served 
  as 
  the 
  foundation 
  for 
  most 
  of 
  our 
  knowledge 
  of 
  its 
  

   geology. 
  So 
  far 
  as 
  I 
  know, 
  there 
  is 
  no 
  other 
  description 
  of 
  the 
  

   volcano, 
  and 
  it 
  is 
  not 
  even 
  mentioned 
  in 
  Cossu's^; 
  monograph 
  

   on 
  the 
  island 
  or 
  in 
  Tennant's§ 
  book. 
  The 
  area 
  of 
  Monte 
  Arci 
  

   is 
  embraced 
  in 
  Folio 
  217, 
  I, 
  II, 
  III 
  of 
  the 
  maps 
  of 
  the 
  Insti- 
  

   tuto 
  Geografico 
  Militare 
  (scale 
  = 
  1 
  : 
  50,000). 
  

  

  Topography 
  and 
  Geology. 
  

  

  Monte 
  Arci 
  is 
  situated 
  about 
  20 
  km. 
  southeast 
  of 
  the 
  towu 
  of 
  

   Oristano, 
  near 
  the 
  center 
  of 
  the 
  west 
  coast 
  of 
  Sardinia 
  and 
  some 
  

  

  * 
  My 
  thanks 
  are 
  due 
  Mr. 
  C. 
  W. 
  Wright 
  of 
  Ingurtosu, 
  Sardinia, 
  for 
  collect- 
  

   ing 
  additional 
  specimens 
  of 
  rhyolite 
  at 
  Capanna. 
  

  

  f 
  A. 
  della 
  Marmora, 
  Vovage 
  en 
  Sardaigne, 
  Part 
  3, 
  Geologie, 
  Vol. 
  I, 
  

   Turin, 
  1857. 
  

  

  X 
  A. 
  Cossu, 
  L'Isola 
  di 
  Sardegna, 
  Rome, 
  1900. 
  

  

  §R. 
  Tennant, 
  Sardinia 
  and 
  its 
  Eesources, 
  London, 
  1885. 
  

  

  Am. 
  Jour. 
  Sci. 
  — 
  Fourth 
  Series, 
  Vol. 
  XXXVI, 
  No. 
  216. 
  — 
  December, 
  1913. 
  

   39 
  

  

  