The Coolidge examiner., 1937-06-03
Prepared by National Geographic Society.


N shore at the full of the tide
I Y and looks out over the swell
ing floods surging in from the
distant horizon, his feet are on the
threshold of an enormous empire,
so vast in extent and population
that the achievements of the haught-
lest rulers of mankind are dWarfed
by comparison.
Though fleets sail over its depth.
they make no significant impress
sion upon this immense realm.
The subjects of this empire
swarm through the waters in my
riads totaling far greater numbers
than all the life of the continental
world. In fact, scientific investiga-
tions indicate that the oceans were
the original abode of life on the
globe, and that the continents were
peopled from that inexhaustible res
ervoir.
Biologists believe that the depres-
sions now occupied by the oceans
have been located in approximately
their present positions during the
entire history of the earth, and that
the foundations of the land masses
likewise have been situated nearly
as they are at the present time.
But during the great geological
periods, the ocean has repeatedly
invaded their edges and even their
interior basins, sometimes to an
enormous extent, forming shallow
epicontinental seas.
Thus, all the continents OF the
world are bordered by strip of
shallow sea, the continental shelf,
which slopes gradually from the
coast to depths varying from 100 to
1000 fathoms at its outer edge. Be-
yond this limit there is usually a
more rapid gradient to the main
floor Of the ocean-the continent
al slope.
This worldwide shallow strip is
of major Importance to the life of
the seas.
North Atlantic Shelf.
This article deals especially with
the mollusks and other small crea-
lures inhabiting the continental
shelf which borders the Atlantic
coast of North America from Nova
Scotia to New York, and includes
the extensive New England fisher
les.
A most remarkable stretch Of
shore this is. It's southern half is
of comparatively even contour, but,
beginning with the region of Cape
Hatteras, the coast to the north
ward has subsidized and is indented
with deep bays and irregularities,
finally terminating in the long curv-
ing and tapering indentation of the
Gulf of Maine.
The latter is the most noteworthy
feature of the coast, its wide mouth
being guarded on either hand by
| Cape Cod and Cape Sable, and its
inner reaches narrowing to double
apex in the Bay of Fundy.
All this northern half of the At
lantic seaboard is succession OF
drowned valleys, and its topography
and geological history indicate that
it has subsidized beneath the waves
of the sea during relatively recent
times. On the other hand, the even
outline of the coast from HatteraS
south to Florida shows no evidence
of such sinking.
The oceanic shelf to the 100-fath-
ON line widens rapidly to the north
ward, reaching it's greatest extent
off the Gulf of Maine, where it is
approximately 400 miles wide.
The central floor of the Gulf of
! Maine is an ancient river valley to
which the river systems, represent
ed by those now existent, contribut-
ed their drainage, to be emptied in
to the prehistoric sea by a single
channel and mouth still traceable
on the sea floor at the edge of the
continental shelf.
Throughout this extensive and
comparatively shallow oceanic
margin, we'll Illuminated by the
SUMS rays, conditions are favorable
for an enormous development of the
marine plants on which sea ami
mails feed: namely, the microscopic
! diatoms, one-celled algae, and the
| larger seaWeeds.
Nursery for Food Fishes.
Here numerous streams empty
their loads of silt, rich in nitrates,
phosphates, and other chemicals
needed for plant food. The strong
tides rushing into the narrowing
channel from the open sea keep
the water stirred with upWelling
currents plentifully supplied with
oxygen.
Hordes of small crustaceans, the
copepods, feed upon this plant life.
At certain seasons they swarm in
these waters in numbers so vast
that they give the sea a reddish
color for miles.
These tiny creatures are rich in
oils and are greedily devoured by
large schools Of mackerel, herring,
aleWives, and shad. Bluefsh, cod,
hake, and haddock pursue and de-
YOUR the smaller fishes, and even
the huge finback and humpback
whales do not disdain to feed upon
the herring,