al
belt has suffered elevation or subsidence. When the inshore sea rests
upon an uplifted bottom, the contour of the coast is smooth and
unbroken, because most of the irregularities of surface have been
overlaid by a deposit of waste from the land; so it offers no harbor
except here and there a silted river mouth, while it shelves off through
a broad amphibian belt of tidal marsh, lagoon, and sand reef to a
shallow sea. Such is the coast of New Jersey, most of the Gulf seaboard
of the United States and Mexico, the Coromandel coast of India, and the
long, low littoral of Upper Guinea. Such coasts harbor a population of
fishermen living along the strands of their placid lagoons,[447] and
stimulate a timid inshore navigation which sometimes develops to
extensive coastwise intercourse, where a network of lagoons and deltaic
channels forms a long inshore passage, as in Upper Guinea, but which
fears the break of the surf outside.[448]

The rivers draining these low uplifted lands are deflected from their
straight path to the sea by coastwise deposits, and idly trail along for
miles just inside the outer beach; or they are split up into numerous
offshoots among the silt beds of a delta, to find their way by shallow,
tortuous channels to the ocean, so that they abate their value as
highways between sea and land. The silted mouths of the Nile excluded
the larger vessels even of Augustus Caesar's time and admitted only their
lighters,[449] just as to-day the lower Rufigi River loses much of its
value to German East Africa because of its scant hospitality to vessels
coming from the sea.

[Sidenote: Embayed coasts.]

The effect of subsidence, even on a low coastal plain, is to increase
accessibility from the sea by flooding the previous river valleys and
transforming them into a succession of long shallow inlets, alternating
with low or hilly tongues of land. Such embayed coasts form our Atlantic
seaboard from Delaware Bay, through Chesapeake Bay to Pamlico Sound, the
North Sea face of England, the funnel-shaped "foerden" or firths on the
eastern side of Jutland and Schleswig-Holstein, and the ragged sounds or
"Bodden" that indent the Baltic shore of Germany from the Bay of Lubeck
to the mouth of the Oder River.[450] Although the shallowness of the
bordering sea and the sand-bars and sand reefs which characterize all
flat coasts here also exclude the largest vessels, such coasts have
nevertheless ample contact with both land and