Evening star., 1952-12-22
Great Canyon Is Found
On Mid-AtIuntic Floor
Its Significance Unknown;
Continental Link Studied
By Thomos R. Henry


Finding of great canyon in the floor
Of the mid-Atlantic. roughly 300 feet
deep and three miles wide, has been
reported to the National Research Coun-
Gil here by DR.. Maurice Ewing, of Co
lumbia University.
The canyon already has been traced
for about 800 miles. 1t runs approxi-
mately north and south about half
way between Newfoundland and the
Azores. DR.. Ewing believes from theo-
retical considerations that it forks
around Greenland to the north and
may extend far to the south of the
area which has been explored. Buried
hundreds of fathoms deep under the
Atlantic waves, if laid bare it would
constitute one of the most prominent
features of the surface of the Western
Hemisphere.
It cuts through an ancient mountain
range running between Newfoundland
and the Azores which cons ago may
have been land bridge between Europe
and North America but which presun-
ably has been submerged for several
million years. This is in much the same
fashion, DR.. Ewing believes, as the Della
ware River cuts through the Delaware
water gap in Pennsylvania.
No Adequate Explanation Found.
The implications of the discovery may
be quite significant although no ade-
quate explanation has been advanced.
The canyon might be likened, one scien-
tist who listened to DR.. Ewing report
commented, Ito part of guttering
around the roof of the world"-the
worlds roof being considered the crustal
layers of the continents.
Submarine canyons running east from
the North American coast are we'll
known. Most conspicuous is the Hudson
River canyon which can be traced out
to sea for several hundred miles. There
are several smaller ones scattered up
and down the coast. These may be the
remains of buried river basins of mil
leniums ago. The longitudinal canyon.
however, is a quite new phenomenon.
This canyon was discovered after re-
peated ship crossings by means OF depth
sounding records. These have been piling
up for some years but there was no
reason to connect the many slight de-
presSions recorded. Only recently was
it possible to make a co-ordinated study
of the phenomenon which resulted in
the present picture of this great natural
feature.
For the most part. DR.. Ewing said,
floor of the Atlantic is fiat plain with
mountain ranges and isolated mountains
rising from it. The ascent is always
abrupt. There is little transition between
plain and mountain.
The accessible sea floor is composed
of layers of sand and clay two or three
miles deep. This has been deposited
through all the milleniums since the
seas existed in their present form. Up
to now, it has been supposed, the accu-
mutation has been quite even over the
whole surface and very slow. This might
be compared with the light layer OF soil
which covers the continents.
Underneath this light surface. how
ever, the picture is quite different from
that of continental surface. The silt
accumulation, it is shown by the speed
of sound waves, rests upon rock OF
type which, on the continents, is en-
countered only at depths of 25 to 80
miles.
Explaining the West Indies.
They are obviously, DR.. Ewing says.
different kind of rocks than ever were
Immediately under the surface of a
continent. This is of particular sig
nificance in explaining the West Indies.
1t has been postulated that islands like
Cuba, Puerto Rico and the Bahamas may
be the remnants of an ancient, vanished
Sub-continent But his experiments show.
Dr. Ewing reported, that the sea bottom
around them is precisely the same as
that of the rest of the ocean. These
rocks never could have been part of a
continent
A better hypothesis. he said. is that
the West Indian islands may be part
of new continent rising from the sea
bottom and that eventually the frag-
ments will be fitted together.
The existence of such canyons, he said.
may ultimately be tied up with continent
formation although the connection still
is quite obscure.