WHICH  HAVE  CONSOLIDATED  ON  STEEP  SLOPES. 
707 
in  1827,  in  which  he  combated  Von  Bitch’s  theory  of  “ Erhebungskratere,”  that  the 
frequent  earthquakes  which  accompany  eruptions  and  are  connected  with  the  injection 
of  lava  from  below,  imply  the  expansion  of  the  solid  framework  of  the  cone,  but  he  still 
insisted  on  the  doctrine  that  “ the  parallel  and  sloping  beds  which  with  a quaquaversal 
dip  compose  every  volcanic  cone,  Avere  not  originally  deposited  horizontally,  or  other- 
•wise  than  at  a high  angle  of  inclination,  and  the  angular  elevation  they  have  since 
sustained  is  in  general  comparatively  trifling*.”  Yet  neither  Mr.  Scrope  nor  I,  when 
we  ascribed  a volcanic  cone  to  the  cumulative  effect  of  reiterated  eruptions,  claimed  any 
originality  for  so  obvious  an  explanation  of  the  phenomena.  For  true  it  is,  as  M.  Elie 
DE  Beaumont  had  remarked,  that  “ Philosophers  and  geologists,  who  from  the  time  of 
the  Greeks  to  our  owm  days  have  seen  Etna  covering  its  flanks  with  new  beds  of  ashes, 
scorise  and  la^a,  have  admitted,  almost  without  examination,  and  as  a self-evident  fact, 
that  the  entu’e  mountain  is  simply  the  result  of  the  gradual  addition  one  over  the  other 
of  elements  mutually  similar,  and  all  resembling  the  products  of  the  eruptions  which 
they  themseh’es  have  Avitnessed”  (ib,  p.  101). 
After  the  publication  of  the  memou's  above  cited  of  MM.  Dufresnoy  and  E.  he  Beau- 
mont, all  geologists  who  implicitly  acquiesced  in  the  doctrine  laid  down  by  them  as  to 
the  law  which  governs  the  consohdation  of  la^n,  became,  almost  unavoidably,  converts 
to  Von  Buch’s  hypothesis ; for  it  was  not  only  necessary  to  admit  a A'ast  amount  of 
upheaval,  but  to  assume  that  the  whole  of  it  had  in  each  volcano  been  posterior  in 
date  to  the  outpouring  of  all,  even  the  latest  of  the  highly-inclined  lavas,  found  in 
each  cone. 
Vrithout  attempting  in  this  place  to  sketch  the  progress  of  a long  controversy  to  which 
this  question  gaA*e  rise,  I may  refer  to  M.  d’xArciiiac’s  able  analysis  of  the  memoirs 
relating  to  it,  in  the  first  volume  of  his  ‘ Histoire  des  progres  de  la  Geologie,’  published 
in  1847,  in  attestation  of  the  deep  impression  Avhich  the  “Elevation-crater”  theory  had 
then  made  on  the  minds  of  not  a few  of  the  most  experienced  geologists  in  Europe.  At 
the  same  time,  it  will  be  seen  in  the  same  chapter  that  some  strong  protests  were  made 
against  it ; one  in  particular  by  my  friend  the  late  M.  Constant  Prevost,  in  his  account 
of  the  new  volcanic  island  Avhich  rose  in  the  Mediterranean  in  1831.  Ascribing  its 
origin  to  eruption  and  not  to  upheaval,  he  took  an  opportunity  in  that  memoir  of 
adducing  arguments  derived  from  the  structure  of  Vesuvius,  Etna  and  other  mountains, 
against  the  theory  of  Von  Bucnf. 
After  I had  given  in  successive  editions  of  my  ‘ Principles  of  Geology,’  from  the  first 
to  the  ninth,  and  in  a paper  on  the  structure  of  volcanos,  published  by  the  Geological 
Society  in  1849J,  my  reasons  for  rejecting  the  “ Crater-of-elevation  ” theory,  I visited 
Madeira  in  1853-54,  and  examined  its  structure,  in  company  with  Mr.  George  Hartung 
of  Konigsberg.  W e went  also  together  to  the  Canaries,  where  Ave  studied  the  island  of 
Palma,  which  had  been  expressly  selected  by  Von  Buck  as  a type  of  what  he  styled  a 
* Trans.  Geol.  Soc.  London,  2 Ser.  vol.  ii.  p.  341,  1827. 
t Mem.  de  la  Societe  Geol  de  Erance,  vol.  ii.  f See  ‘ Proceedings  ’ for  that  year,  p.  207. 
