932  the  geology  oe  the  new  Hebrides.  [May  x893, 
examined  microscopically,  but  lie  suggested  that  they  should  be 
carefully  studied  with  the  view  of  ascertaining  whether  or  not,  like 
the  somewhat  similar  material  of  Port  Darwin,  they  might  show  the 
presence  of  radiolarian  deposits  in  some  of  the  upraised  tracts  on 
which  the  modern  volcanic  cones  stand. 
Dr.  Du  Riche  Preller  observed  that  the  very  fact  mentioned  by 
the  Author,  of  three,  clearly  defined,  successive  coral-walls  or  banks 
having,  in  one  of  the  localities  specified,  been  upheaved  by  volcanic 
action  from  a  depth  of  200  feet  and  more,  tended  to  show  that  these 
banks  marked  three  distinct  phases  of  a  previous  subsidence, 
whether  it  was  due  to  a  gradual  sinking  of  the  bottom  of  the  sea, 
or  to  that  of  a  submarine  volcano.  Thus  the  conflicting  theories  of 
Darwin  and  Dana  on  the  one  hand,  and  of  Murray,  Semper,  and 
Studer  on  the  other,  did  not,  after  all,  appear  to  be  irreconcilable. 
The  occurrence  of  living  coral  at  a  depth  of  240  feet  appeared  to 
upset  existing  views. 
L  Mr.  Teall  said  that  he  had  examined  some  of  the  igneous  rocks 
collected  by  the  Author.  One  was  an  augite-andesite  of  a  type 
common  in  the  volcanic  regions  surrounding  the  Pacific  ,  another 
was  a  fairly  typical  basalt,  and  a  third  a  dolerite.  A  peculiar  rock 
crowded  w'ith  glassy  crystals  of  labradorite,  or  a  moie  basic  felspar, 
must  also  be  referred  to  the  augite- andesites. 
The  Author  observed,  with  reference  to  the  specimens  of  augite- 
andesite  alluded  to  by  Mr.  Teall,  that  one  of  them  was  obtained  at 
the  summit  of  the  crater  on  Tanna  Island,  while  the  other  was 
brought  from  the  c  hot  ground  ’  on  Tongoa  Island.^ 
He  stated  that  the  coral  cliffs  or  terraces  on  Efate  Island  were 
composed  of  coral  from  top  to  bottom,  madrepores  and  many  other 
species  being  most  distinct  among  the  mass  of  coral-detritus  and 
limestone  which  formed  the  cliffs. 
As  regards  the  atoll  called  Cook  Reef,  he  could  only7  suppose 
that  during  some  period  of  great  upheaval  the  floor  of  the  sea 
had  been  elevated  to  within  such  a  distance  of  the  surface  that 
coral  polyps  had  been  able  to  commence  operations,  and  covered  the 
shoal  with  various  forms  of  coral  life. 
The  specimens  of  living  coral  brought  up  from  a  depth  of  200  to 
250  feet  were  not  of  the  reef-building  species,  but  small  branching 
corals  like  the  species  of  Oculina.  . 
He  further  said  that  the  temperature  of  the  surface-water  m  this 
region  was  from  82°  to  84°  Pahr.,  but  no  observations  of  serial 
temperatures  had  been  obtained. 
