Wauwatosa news. [volume] (Wauwatosa, Wis.) 1900-1948, 1901-04-06
NORTH ATLANTIC SoUNDINGs.
Epitome of the Discoveries of the
British Expedition of 500.

Mr.. Peake's account of deep-sea
sounding expedition in 1899. published hy
John Murray the other day, IS a substan-
tai addition TO our knowledge of the
North Atlantic ocean. The object of this
enterprise was mainly commercial. being
connected with the laying of telegraph
cables. but the author has collated the
resdlts of several other undertakings
which had no purpose but the advance
ment of science, such as the voyage Of
the Challenger, in which Sir John Muir
ray, who contributes notes TO the present
paper, took so active part. These new
sound ngS have enabled Mr.. Peake TO
construct a map of the bed of the North
Atlantic, which is very valuable, especial
ly in regard to the vicinity of the Azores.
1t was known that these islands rise from
Il submarine plateau, generally about
2oOO faJhoms below the surface, and that
between it and the slopes lending up. on
the one side TO the American, on the 9th
er TO the European shores, lie two yet
broader valleys, the beds Of which are
about 500 fathoms deeper. The plateau
itself was an offshoot from that which,
at a less distance from the surface, links
Great Britain with the Shetlands the
FaIoes, Iceland and Greenland, and in.
VIII ch the broad valleys have their heads.
deepening as they proceed southwark:
The Azores are volcanic islands. piled
up masses of lava. But the sea bed
around is now proved to be far more II
regular than was formerly supposed. If
the ocean were lowered by 1000 fathoms,
they would form two distinct groups;
hut q further sinking of 500 fathomS
would unite them into one. The great
island thus revealed, III which the pres
ent Azores are the eliminating submits,
would, however, be largely extended to-
ward the north, and on this mass also
several conspicuous hills would be seen
tn ho IC-
lands the surface is diversified, as the
map shows, by submarine eminenceS and
rather deep basins. But everywhere be-
meath the ocean the process of rock
building ia 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 Atlantic this work is proceed
ing. The large map issued with Mr..
Pcake's paper brings the operation
graphically before our eyes.
A deposit of a bluish-colored clay forms
broad fringe around the margin of the
continental masses, and covers the pla-
teau linking Britain with Greenland. 1t
Is the finer detritus of the land, horne by
the currents into the ocean. To what
depth it extends depends On circumstan-
ces: the zone is broader when the sea bed
sinks gradually, narrower where it steep
ems more quickly. Around the Azores
volcanic mud is found while at the Ber-
mudas the deposit is pounded-up coral
as might be expected. In a few places
green grains are numerous. the casts of
minute Organisms-a material like our
green sands. South of the Azores. and
in one or two isolated spots, is a bed
formed almost entirely of small shells of
mollusks. called pteropods. But beyond
the limit of all these down to 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 so-called
glohigerina OoZe-material similar to that
of the chalk: and this passes at yet great
er depths into a reddish clay. as to the
exact origin of which different opinions
have been observation-disclosures Stand
n ri