176
THE SEAS “
manner,
Murray thought that a. fringing reef could be
coverted into a barrier reef.
,
.
This theory has many points in its favour, notably in that
it does not demand any generalsubsidence of the land over
.
the tfopics.
It has been supported by many more recent
investigators of coral reefs, though often with qualifying
statements and additions.
The most important criticisms
are concerned with the formation» of the lagoon, for many
sCientists think that these are at present being lled up with
_
sediment and not, as Murray’s theory demands, graduay
'
increasing by further erosion and solution, and that, in any
case, they
formed by the scouring action of
'
the sea and by the action of boring animals
and plants,
ratherthan by the dissolution on which Murray laid so much
streSs.
It is also very probable that the ring shape of
atolls is dzge to the action of the pœvailing winds. All
atolls lie Within the trade wind areas where the wind
blows from a constant quarter .for the greater part of
the year.
There is actually an atoll ring off Florida which
..
must have been moulded in this manner, it has not been
.
built by living corals but by dèposits of various kinds formed
by submerged _reefs of very mixed origin.
,
"
-
_Clearly ‘a denite proof of. the origin of atolls might be
hoped for if borings were madethrough the coral rock down
into thelower layers.
If the substance of the atoll was
,
found tobe of Coral origin to great depths, then we should
'
have strong evidence in favour of Darwin’s theory, the
,
coral limestone below about thirty fathoms being . that
,_
_
-
which had been Cared down by thesubsidence of the land ;
;
it,
the other hand, a surface layer of coral limestone
—
some thirty fathoms in thickness was found resting on a
-
layer of solidiéd
deposits,’ of volcanic fragments,
‘
__
or similar material, then that would afford— evidence that
7Murray’s views
correct.
With this-end in view ex_
THE SEAS “
manner,
Murray thought that a. fringing reef could be
coverted into a barrier reef.
,
.
This theory has many points in its favour, notably in that
it does not demand any generalsubsidence of the land over
.
the tfopics.
It has been supported by many more recent
investigators of coral reefs, though often with qualifying
statements and additions.
The most important criticisms
are concerned with the formation» of the lagoon, for many
sCientists think that these are at present being lled up with
_
sediment and not, as Murray’s theory demands, graduay
'
increasing by further erosion and solution, and that, in any
case, they
formed by the scouring action of
'
the sea and by the action of boring animals
and plants,
ratherthan by the dissolution on which Murray laid so much
streSs.
It is also very probable that the ring shape of
atolls is dzge to the action of the pœvailing winds. All
atolls lie Within the trade wind areas where the wind
blows from a constant quarter .for the greater part of
the year.
There is actually an atoll ring off Florida which
..
must have been moulded in this manner, it has not been
.
built by living corals but by dèposits of various kinds formed
by submerged _reefs of very mixed origin.
,
"
-
_Clearly ‘a denite proof of. the origin of atolls might be
hoped for if borings were madethrough the coral rock down
into thelower layers.
If the substance of the atoll was
,
found tobe of Coral origin to great depths, then we should
'
have strong evidence in favour of Darwin’s theory, the
,
coral limestone below about thirty fathoms being . that
,_
_
-
which had been Cared down by thesubsidence of the land ;
;
it,
the other hand, a surface layer of coral limestone
—
some thirty fathoms in thickness was found resting on a
-
layer of solidiéd
deposits,’ of volcanic fragments,
‘
__
or similar material, then that would afford— evidence that
7Murray’s views
correct.
With this-end in view ex_