The Appeal. [volume] (Saint Paul, Minn. ;) 1889-19??, 1919-11-01


of New Orleans, with most of it's
transient population, just A years be-
fore Galveston" the bulletin says,
quoting from communication to the
society. - -
Florida Keys Farther Out.
1.-THE student who scans the shores
of Atlantic and gulf, either on the
ground or on the admirable maps of
the coast and geodetic survey and the
photographic Office Of our navy, soon
perceives that the relations between
wave-built bars and wave-cut sea-
cliffs vary from coast stretch to coast
stretch. On the New Jersey coast the
bars are beaten well back to or beyond
the line Of the seacliffs, so that the
ponds or sounds behind the bars are
relatively short and discontinuous
along the Florida coasts the keys
stand farther out to sea and are sepa-
rated from the mainland by great
elongated sounds often affording nav
igable. waterways; while about the
northern shores of the gulf the rela-
tons Of the keys to sounds are more
variable. - -.--,~~- =7@%--7-.~~ - -.7~,
"Closer study serves to interpret
these variable relations. From Florida
westward to Mobile bay the keys are
nearly continuous and the sounds long
and narrow; thence westward to
Lake Borgne the typical keys are lost,
though their lines continue in a series
Of islands-Ship island, Horn island,
Cat island, etc.-separated from the
mainland by the broad Mississippi
sound; still farther westward a new
series of keys, cratic in form and
trend, appears in the Chandelier
islands, and beyond the delta there is
corresponding (and correspondingly
erratic) series Of low keys stretching
westward nearly or. quite to Atcha-
falaya bay.
Keys In Process Of Growth.
"Now the mainland shore Of Mis-
sfssippi sound is marked by a series
of small and narrow keys and sounds
evidently in process Of growth, but
much less advanced than those east of
Mobile bay; and these are among the
evidences that along this stretch Of
shore the gulf has encroached on the
land to such an extent as to leave the
original keys 20 to 40 miles behind.
"Similarly the Chandelier keys and
the corresponding series west Of the
delta are small and new and obviously
connected with the delta building.
"West Of Atchafalaya bay the coast
is characterized by the absence Of
keys and sounds, save Of the infantile
sort, like those of the inland shore Of
Mississippi sound; so that this shore
seems incongruous with the rest until
the student discovers the long line of
completely submerged keys-Sabine
bank, Trinity shoal, Ship shoal, ETC.
in a position precisely corresponding
to the islands south of Mississippi
sound and forming a direct submarine
connection (save as cut off by the
delta) between these islands Of the
eastern gulf and the well-developed
keys Of the southern Texas shore.
''"The position of these banks, like
that of the Horn island and it's fell
lows, is such as to demonstrate that
the waters have invaded the mainland,
and that west of the delta the en-
eroachment has been sufficient not
merely to push back the shore line
30 to 100 miles, but completely to sub
merge the ancient keys.
1.-THE most striking feature Of these
drowned and half-drowned keys is
their symmetric arrangement; except
for the interruption by the delta with
its new and lesser sand banks), the
great bars form sweeping curve reg.
ular as the beach line of a landlocked
bay, and hence afford rough measure
Of the outbuilding of the delta as well
as of the invasion of the gulf on its
tanks.
Hardly less striking than the sym.
metry of the series is the closeness OF
continuity between keys and banks
and it is significant fact that Gal.
weston island is the northwestern
terminus of the west coast system OF
keys, the last stretch Of these sand
banks still rising above the level OF
the tide.
sit is the business Of the geologist to
detect and weigh the evidences Of sub.
sidence or elevation of coasts and te
estimate the rates of movement fol
the guidance of local residents and in