The Coolidge examiner., 1937-06-03

Browns Banks, at the entrance to
the Gulf of Maine, as well as the
Grand Banks of Newfoundland, far
ther away, form a veritable nurs-
cry for the important food fishes of
our coasts, and thus connect man.
kind by an interlacing food chain
with the microscopic plant life of
these shallow waters.
The evolution of the animal world,
as we know it, would have been
impossible had these primitive
plants not come into existence.
From such forms, also, all the high
er land plants of the world origi-
nate.
The Intertidal Zone.
AS the open seas were peopled
from the oceanic shelf, so the fresh
water streams and swamps received
parts of the overflow. Countless spe-
cies found food and a measure of
safety from enemies by creeping
into the area between the tides,
where they acquired resistance to
exposure to the open air at the in
tervals of low water. Here a rapid
evolution took place, so that the
intertidal zone became densely pop
ulated with life.
Finally, from fresh-water swamps
on the one hand and from the upper
parts of the marine tidal zone on
the other, first plants and then ami
mails invaded the land itself and
produced the highly specialized
types that now reign over it.
North of Cape Cod, the coast of
New England is predominantly high
and rocky. Beginning with the head
lands of Nahant, Marblehead, and
Cape Ann, north of Boston, the cliffs
are at first isolated to local regions,
with intervening stretches of sandy
beaches and flats. But from Port
land, in Casco Bay, northWard, the
coast is an almost unbroken sue
cession of granite cliffs, sloping
rock-ribbed promontories, and re-
entrant bays and harbors, with oc-
casional beaches.
The tidal waters flowing from the
open sea are gradually confined by
the narrowing outline of the Gulf of
Maine, which forces them to pro-
gressively increasing height, and
reach climax in the Bay of Fundy.
From Massachusetts, Bay north to
Portland, the tide rises nine feet.
1t continues to increase northward,
until it becomes 18 feet at Eastport
and 81 to 48 feet at the ends of the
two tapering horns which terminate
the Bay of Fundy.
Here, too, there are interpolated
stretches of beaches, fiat points, and
swampy meadows, and these are
entirely covered at high tide. Ma
turally the width of the tidal zone
on the side of vertical cliff is
| measured exactly by the vertical
| rise and fall of the water. For ex-
ample, the cliffs that surround Bliss
island, at the entrance of Passa-
maquoddy bay, are exposed for %
feet from the top Of the barnacle
frieze that marks the high-tide limit
| to the water level at low tide.
Crowded With Life.
This region between the tides is
teeming with life, both plant and
animal, in crowded array. On the
| vertical granite walls of Bliss island,
the various species are arranged in
overlapping zones, with the conspic-
uous white band of rock barnacles.
Below this, the rockweeds hang in
thick, gracefully festooned clusters
| down to the low water-mark.
Concealed beneath the rockweed,
and succeeding the base of the
barnacle zone, the rocks are
covered with dense layer of young
| black mussels.
Among them are closely crowded
groups of the common dog whelk,
feeding upon the mussels, and lay
ing their graceful vase-shaped egg
cases, tinted rose and yellow, in
mosaiclike patches in the crevices.
| The latter mollusks secrete a pur-
pie dye, formerly used by the In
dians for coloring their deerskin
garments. They are related to the
murex of the Phoenicians, from
which that people derived the IA
nous royal purple, later arrogated
by the Roman emperors for their
personal use.
The dog whelk has a thick shell
with characteristic spindle-shaped
opening. 1t is extremely variable in
color, size, and sculpture along the
New England shore
The common periWinkle creeps
everywhere over the rockweed from
the loW-Water mark to the highest
part of the barnacle zone and even
| upon the bare rocks far above it..
| This remarkable sea snail can stand
exposure to the open air longer than
any other marine creature of the
| northern coast.
1t is in a transitional state of
evolution toward terrestrial life,
| for its gill seems to be on the point
of being replaced by lung. 1t has
very wide range, being found on
both sides Of the Atlantic. In Eng
land it is the common "winkle"
! sold in markets.