coastlines, active coral reefs are restricted to Southern Florida, Hawaii,
Virgin Islands and Puerto Rico. On Some of the Florida coast, reeflike
structures are produced by sabellariid worms. (Kirtley, 1971.) Organic
reefs stabilize the shoreline and sometimes affect navigation.
4.25 OCCURRENCE OF LITTORAL MATERIALS ON U.S. COASTS
Littoral materials on U.S. coasts vary from Consolidated rock to
clays, but sand with médian diameters between 0.1 and 1.0 millimeters
(3.3 and 0 phi) is most abundant. General information on littoral materials is in the reports of the U.S. Army Corps of Engineers* National
Shoreline Study; information on certain spécifie geological studies is
available in Shepard and Wanless (1971); and information on spécifie
engineering projects is published in Congressional documents and is
available in reports of the Corps of Engineers.
4.251 Atlantic Coast. The New England coast is generally characterized
by rock headlands separating short beaches of sand or gravel. Exceptions
to this dominant condition are the sandy beaches in northeastem Massachusetts, and along Cape Cod, Martha’s Vineyard, and Nantucket.
From the eastem tip of Long Island, New York, to the Southern tip
of Florida, the littoral materials are characteristically sand with médian
diameters in the range of 0.2 to 0.6 millimeter (2.3 to 0.7 phi). This
material is mainly quartz sand. In Florida, the percentage of calcium
carbonate in the sand tends to increase going south until, south of the
Palm Beach area, the sand becomes predominantly calcium carbonate. Size
istributions for the Atlantic coast, compiled from a number of sources,
are s own in Figure 4-9. (Bash, 1972.) Fine sédiments and organic sédiments are common minor constituents of the littoral materials on these
coasts, especially in South Carolina and Georgia. Beach rock and coquina
are common at shallow depths along the Atlantic coast of Florida.
Gulf__Coast
The Gulf of Mexico coasts of Florida, Alabama, and
of cwamnPP1Tkre characterized by fine white sand beaches and by stretches
Cane Sable t e swampy stretches are mainly in Florida, extending from
River rshenardape^ wma?0’
from TarPon Springs to the Ochlockonee
River. (Shepard and Wanless, 1971, p. 163.)
River^hirh^51^ COaSt iS dominated by the influence of the Mississippi
from whï^wave Pt°S1\
°f fine sedi”ænt around the delta
hls bee^ennl
Wlnnowed *nall quantifies of sand. This sand
marshy coîsr Westai?\8?aarier beaCheS offshore of a deeply indented
Ses and beach ridges
" *
tending about 80°mi le^"5»-3 ^OIjlt^nuation of the Louisiana coastal plain
barrier Sds entend. t° S?™ Bayî from there a series of
area are dominantlv fine °M?xJcan border. Littoral materials in th.
millimeter (3.3 and 2 3 phi) ’ Wlt^ median diameters between 0.1 and 0.2
long,
exwide
this
4-22
Virgin Islands and Puerto Rico. On Some of the Florida coast, reeflike
structures are produced by sabellariid worms. (Kirtley, 1971.) Organic
reefs stabilize the shoreline and sometimes affect navigation.
4.25 OCCURRENCE OF LITTORAL MATERIALS ON U.S. COASTS
Littoral materials on U.S. coasts vary from Consolidated rock to
clays, but sand with médian diameters between 0.1 and 1.0 millimeters
(3.3 and 0 phi) is most abundant. General information on littoral materials is in the reports of the U.S. Army Corps of Engineers* National
Shoreline Study; information on certain spécifie geological studies is
available in Shepard and Wanless (1971); and information on spécifie
engineering projects is published in Congressional documents and is
available in reports of the Corps of Engineers.
4.251 Atlantic Coast. The New England coast is generally characterized
by rock headlands separating short beaches of sand or gravel. Exceptions
to this dominant condition are the sandy beaches in northeastem Massachusetts, and along Cape Cod, Martha’s Vineyard, and Nantucket.
From the eastem tip of Long Island, New York, to the Southern tip
of Florida, the littoral materials are characteristically sand with médian
diameters in the range of 0.2 to 0.6 millimeter (2.3 to 0.7 phi). This
material is mainly quartz sand. In Florida, the percentage of calcium
carbonate in the sand tends to increase going south until, south of the
Palm Beach area, the sand becomes predominantly calcium carbonate. Size
istributions for the Atlantic coast, compiled from a number of sources,
are s own in Figure 4-9. (Bash, 1972.) Fine sédiments and organic sédiments are common minor constituents of the littoral materials on these
coasts, especially in South Carolina and Georgia. Beach rock and coquina
are common at shallow depths along the Atlantic coast of Florida.
Gulf__Coast
The Gulf of Mexico coasts of Florida, Alabama, and
of cwamnPP1Tkre characterized by fine white sand beaches and by stretches
Cane Sable t e swampy stretches are mainly in Florida, extending from
River rshenardape^ wma?0’
from TarPon Springs to the Ochlockonee
River. (Shepard and Wanless, 1971, p. 163.)
River^hirh^51^ COaSt iS dominated by the influence of the Mississippi
from whï^wave Pt°S1\
°f fine sedi”ænt around the delta
hls bee^ennl
Wlnnowed *nall quantifies of sand. This sand
marshy coîsr Westai?\8?aarier beaCheS offshore of a deeply indented
Ses and beach ridges
" *
tending about 80°mi le^"5»-3 ^OIjlt^nuation of the Louisiana coastal plain
barrier Sds entend. t° S?™ Bayî from there a series of
area are dominantlv fine °M?xJcan border. Littoral materials in th.
millimeter (3.3 and 2 3 phi) ’ Wlt^ median diameters between 0.1 and 0.2
long,
exwide
this
4-22