The Washington bee., 1899-07-01
ON THE COAST LINES.
DELAWARE AND CHESAPEAKE BAYS
WERE ONCE VALLEYS.

A Highly Interesting and Inst1 uctiye Talk
on Coastal srsey Coast
Said to BE Sinking-Californis Compara-
lively New Country.
Prof. Oscar c. S. Carter, CT the Gen.
trail High School, Philadelphia, gave an
illustrated talk before the Engineers
Club, recently, on Coastal Topo-
graphy." The subject was treated in
a manner quite new to the older mem
| bers of the club, and illustrated by pho
tographs Of various portions of the
coast line OF North America bordering
on the Atlantic and Pacific Oceans.
Taking up a definite portion Of the
coast line, like that of Mains, or an is
land, like Nantucket, he sh,wed what
forces had been at work, ancient, and
comparatively recent, to produce the
results now seen. The coast line Of
Maine, its rocky character, studded
with islands, is due to the submergence
of the mainland; the islands are simpl!
drowned hills; the valleys that inter-
vened have also been submerged.
The islands of Nantucket and Mar
tha's Vineyard have no bed rock, but
recent formations, some tertiary and
cretaceous. These islands are entirely
distinct in character from the rocky
islands of Maine. and are made up
mostly OF sand, clay and gravel. The
lantern illustrations gave the general
topography Of Nantucket, showing the
coast line and harbor and the jetty
made by the Government, constructed
by bringing powders weighing several
tons each from the coast of Connecticut
and dropping them in parallel lines,
several hundred yards apart. for dis
tance of over a mile out from the har-
bor The wash of the tide was depend
ed upon to scour out the ship channel
thus formed.
Coming down to the coast Of New Jer-
sey, a series of slides showed where
land was being made and where the sea
was cutting it away. This coast also
was shown to be sinking. He regarded
Delaware Bay as a submerged valley,
once high enough to be above the ocean
with the river running through it. In
like manner the sinking Of the coast
had produced the Chesapeake Bay,
Pamlico Sound and the lagoons that
are found along the coast from Norfolk
to Florida, making chain of sounds
which could be used for navigation
with a few short portages.
On the Pacific Coast the illustrations
showed the few harbOrs to be found
there, Santiago, San Dominica, Monter-
ey and San Francisco. in California,
and then few near the Columbia
River. He gave as reasons for this
scarcity that the mountains and valleys
had been lifted up along the shore
line, and there had been very little SUBJ
mergence There were few river val
leys, the rivers being mostly young"
Their valleys had been cut out deep
and the sides were precipitous, whereas
an old, mature valley slOped off in V
shape
Speaking Of the alternate submer-
gence and elevation of the coast. he
said that in the glacial period, when the
ice cap on the entire Northern portion
of the United States was a mile thick,
and when the Adirondacks stood up
as islands and were submerged by the
ice sheet, then the weight of that mass
/ of ice pressed down the earth's crust
and caused it to sink.
! The whole coast line of a continent
was not necessarily involved. and the
| Professor called attention to the fact
! that the nOrthen coast of Norway was
! sinking. while the southern coast was
being elevated.