The Grit-advocate., 1901-04-26
DISCOVERIES OF THE BRITISH
EXPEDITION OF 1909.
Beneath the Ocean Nature Ii Sowing
the Dust of Continents to Be''-The
Azores Are Said to he Volcanic
Islands.

by John Murray the other day, is a
substantial addition to our knowledge
of the North Atlantic ocean. The OBJ
ject of this enterprise was mainly COM
mercial, being connected with the lay
ing Of telegraph cables, but the author
has cOllated the results OF several
other undertakings which had no pur-
pose but the advancement of science,
such as the voyage of the Challenger,
in which Sir John Murray who con-
tributes notes to the present paper,
took SO active part. These new
soundings have enabled Mr.. Peake to
construct a map Of the bed of the
North Atlantic which is very valu-
able especially in regard to the vicin-
ity of the Azores. 1t was known that
these islands rise from a submarine
plateau. generally about 1000 fathoms
below the surface, and that between it
and the slopes leading up, on the one
side to the American, Oh the other to
the European Shores lie two yet broad
er valleys. the beds of which are about
500 fathoms deeper. The plateau it.
self was an offshoot from that which,
at less distance from the surface,
links Great Britain with the ShetlOnds.
the Faroes, Iceland and Greenland,
and in which the broad valleys have
their heads, deepening as they proceed
southwark. The Azores are volcanic
islands. piled up moses Of lava. But
the sea led around is now proved to
be far more irregular than was for
merly supposed If the ocean were
lowered by 1000 fathoms, they would
form two distinct groups; but a fur
ther sinking of 500 fathoms would
unite them into one. The great islands
thus revealed, of which the present
Azores ore the eliminating submits.
would however, be largely extended
toward the north, and on this mass
also several conspicuous hills would
be seen to rise. Even among the exist
ing islands the surface is diversified,
as the map shows. by submarine emf
nences and rather deer bosns. But
everywhere beneath the ocean the pro-
cess Of rock building is going on.
Slowly but surely nature is sowing
the dust of continents to be- not only
with the material of Aeonian hills. but
also with that which has once been
alive. In every part of the North At
,lantic this work Is proceeding. The
large map issued with Mr.. Peake's pa
per brings the operation graphically
before our eyes. A deposit of blush
colored clay forms a broad fringe
around the margin of the continental
masses, and covers the plateau linking
Britain with Greenland. 1t is the finer
detritus of the land, borne by the cur
rents into the ocean. To what depth
it extends depends on circumstances:
the zone is broader when the sea bed
sinks gradually. narrower where 1t
steepens more quickly. Around the
Azores a volcanic mud is found, while
at the Bermudas, the deposit is pound
ed-up coral-as might be expected. In a
few places green grains are numerous,
the casts of minute urGanisms-a ma
teral like our green sands South Of
the Azores, and il one or two isolated
spots. is a bed formed almost entirely
of small shc)ls CT molusks, called
pteropods. But beyond the limit OF all
these, down to the depths Of $500
fathoms, the ocean floor is covered
with calcareous mud. composed of the
relics of minute living creatures, such
as algae and foraminifera-the social
bed globigerina ooze-material similar
= to that of the chalk and this passes
at yet greater depths into reddish
t-t~