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THE  GEOLOGY  OE  THE  NEW  HEBRIDES. 
[May  1893,. 
Ngnna,  Pele,  and  Man,  which  are  of  volcanic  origin.  No  coral  was- 
found  on  them  above  sea-level.  On  Mau  and  Nguna  are  the  re¬ 
mains  of  extinct  craters,  hut,  so  far  as  could  he  ascertained,  the 
natives  have  no  traditions  as  to  when  they  were  active.  This 
volcanic  formation  extends  across  to  a  small  part  of  Efate,  where 
there  are  several  hills  on  which  nothing  hut  volcanic  specimens 
were  obtained.  ^ 
The  small  islands  of  Moso,  Protection,  and  Erradaka,  on  the 
western  side  of  Elate,  are  of  coral-formation. 
In  the  vicinity  of  the  volcanic  islands  there  is  very  little  coral- 
reef,  especially  where  the  shores  are  steep.  At  the  western  end. of 
Nguna,  where  the  water  shoals  out  gradually,  and  also  near  its 
south-eastern  end,  coral  has  begun  to  grow  ;  and  there  is  a  fringe 
of  coral-reef  round  the  whole  of  Efate. 
"While  sounding  in  the  vicinity  of  Efate,  live  coral  was  brought 
up  on  the  lead  from  depths  of  28,  89,  ana  42  fathoms  off  Moso, 
37  fathoms  near  Mau,  and  40  fathoms  off  Mataso.  They  were 
generally  a  species  of  small,  delicate  coral  comparable  to  Oculina , 
one  of  them  being  probably  a  Pocilloporid  in  its  flattened  form.. 
3.  Mataso  is  a  small  island,  consisting  of  two  distinct  hills  joined 
by  a  low  beach  of  sand  and  coral,  on  which  cocoanut  palms  and  other 
trees  are  now  growing.  The  higher  of  the  two  hills  is  a  very 
remarkable  peak,  1669  feet  in  height,  and  only  1870  yards  long  b^ 
1000  yards  broad.  Though  so  steep,  its  sides  are  covered  with 
trees  and  grass,  and  the  bare  rock  can  only  be  seen  in  .  one  or 
two  places.  The  lower  hill  is  485  feet  highland  has  a  rich  red 
soil  which  is  very  productive.  The  whole  island  is  of  volcanic 
origin,  and  as  yet  but  little  coral  is  growing  round  the  base  of  the 
steep  hills,  though  on  either  side  of  the  low  beach  there  is  a  narrow 
fringing-reef. 
One  mile  eastward  of  Mataso  rises  a  remarkable  pyramid  ot  bare 
rock,  412  feet  in  height  and  only  130  yards  in  diameter  at  the  base,, 
called  Monument  Eock.  This  rock  is  evidently  volcanic,  but  the 
present  writer  found  it  impossible  to  obtain  any  specimens. 
4.  Mahura  Island ,  lying  6  miles  north  of  Mataso,  is  also  vol¬ 
canic,  nearly  1000  feet  in  height,  and  covered  with  a  coarse  grass. 
At  the  base  of  the  steeper  sides  of  the  island  are  masses  of  volcanic 
boulders,  but  near  the  western  end,  which  is  low,  there  is  a  narrow,- 
fringing  coral-reef.  ......  .,  ,,  ... 
5.  Mai  Island  is  formed  of  three  high,  conical  hills,  evidently  oi 
volcanic  origin,  and  is  surrounded  by  a  fringing-reef.  No.  coral 
was  found  elevated  above  the  sea-level,  but  on  the  flat  portion  of 
the  western  side  of  the  island  it  is  easy  to  trace  howT  the  land  has 
been  extending,  for  there  is  evidence  of  a  beach  some  50  yards  or 
more  inside  the  edge  of  a  belt  of  thickly-growing  trees,  with  coral 
cropping  up  here  and  there  on  the  same  level  as  the  present  beach. 
On  the  eastern  side  of  this  island  a  piece  of  dead  coial,  appa¬ 
rently  the  Alcyonarian  coral  ( Heliopora  ccerulea),  weighing  about 
30  lbs.  was  found.  ,The  bright  blue  colour  extended  light  through 
the  whole  block.  Only  once  before  had  I  seen  a  specimen  of  the 
