Y.

The naval operations described in the following pages extended, on the
seaboard, over the Gulf of Mexico from Key West to the mouth of the
Rio Grande; and inland over the course of the Mississippi, and its
affluents, from Cairo, at the southern extremity of the State of
Illinois, to the mouths of the river.

Key West is one of the low coral islands, or keys, which stretch out,
in a southwesterly direction, into the Gulf from the southern
extremity of the Florida peninsula. It has a good harbor, and was used
during, as since, the war as a naval station. From Key West to the
mouth of the Rio Grande, the river forming the boundary between Mexico
and the State of Texas, the distance in a straight line is about eight
hundred and forty miles. The line joining the two points departs but
little from an east and west direction, the mouth of the river, in 25 deg.
26' N., being eighty-three miles north of the island; but the shore
line is over sixteen hundred miles, measuring from the southern
extremity of Florida. Beginning at that point, the west side of the
peninsula runs north-northwest till it reaches the 30th degree of
latitude; turning then, the coast follows that parallel approximately
till it reaches the delta of the Mississippi. That delta, situated
about midway between the east and west ends of the line, projects
southward into the Gulf of Mexico as far as parallel 29 deg. N.,
terminating in a long, narrow arm, through which the river enters the
Gulf by three principal branches, or passes. From the delta the shore
sweeps gently round, inclining first a little to the north of west,
until near the boundary between the States of Louisiana and Texas;
then it curves to the southwest until a point is reached about one
hundred miles north of the mouth of the Rio Grande, whence it turns
abruptly south. Five States, Florida, Alabama, Mississippi, Louisiana,
and Texas, in the order named, touch the waters bounded by this long,
irregular line; but the shore of two of them, Alabama and Mississippi,
taken together, extends over little more than one hundred miles. All
five joined at an early date in the secession movement.

The character of the coast, from one end to the other, varies but
slightly in appearance. It is everywhere low, and either sandy or
marshy. An occasional bluff of moderate height is to be seen. A large
proportion of the line is skirted by low sandy islands, sometimes
joined by narrow necks to the mainland