six or seven
inches long and about as thick as a finger, with little rootlets at one
end. Such Mangrove-seedlings, looking more like cigars than anything
else, float in large numbers about the Reef. I have sometimes seen them
in the water about the Florida Reef in such quantities that one would
have said some vessel laden with Havana cigars had been wrecked there,
and its precious cargo scattered in the ocean.

In consequence of their shape and the development of the root, one end
is a little heavier than the other, so that they float unevenly, with
the loaded end a little lower than the lighter one. When they are
brought by the tide against such a cap of soil as I have described,
they become stranded upon it by their heavier end, the rootlets attach
themselves slightly to the soil, the advancing and retreating waves move
the little plant up and down, till it works a hole in the sand, and
having thus established itself more firmly, steadied itself as it were,
it now stands upright, and, as it grows, throws out numerous roots, even
from a height of several feet above the ground, till it has surrounded
the lower part of its stem with a close net-work of roots. Against this
natural trellis or screen all sorts of materials collect; sand, mud,
and shells are caught in it; and as these Mangrove-trees grow in large
numbers and to the height of thirty feet, they contribute greatly to the
solidity and compactness of the shores on which they are stranded.

Such caps of soil on the summit of a Coral Reef are of course very
insecure till they are consolidated by a long period of accumulation,
and they may even be swept completely away by a violent storm. It is
not many years since the light-house built on Sand Key for the greater
security of navigation along the Reef was swept away with the
whole island on which it stood. Thanks to the admirably conducted
Investigations of the Coast-Survey, this part of our seaboard, formerly
so dangerous on account of the Coral Reefs, is now better understood,
and every precaution has been taken to insure the safety of vessels
sailing along the coast of Florida.

I cannot deny myself the pleasure of paying a tribute here to the high
scientific character of the distinguished superintendent of this survey,
who has known so well how to combine the most important scientific aims
with the most valuable practical results in his direction of it. If
some have hitherto doubted the practical value of such