are closed, are of extraordinary solidity and dimensions, being 20 to 40 ft. high, or even more, across streams or bayous--formerly outlets--with bases of 8 or 10 ft. to one of height. The task of maintenance consists almost entirely in closing the gaps which occur when the banks on which the levees are built cave into the river. Levee systems on some of the interior or tributary rivers, aggregating some 602 m., are exclusively built and maintained by the state. Louisiana also contributes largely to the 84 m. of levee in Arkansas, necessary to its security from overflow. The improvement of bayous, channels, the construction of canals and the drainage of swamp lands also contribute to the protection of the state. The lakes are mainly in three classes. First come the coast lagoons, many of which are merely landlocked salt-water bays, the waters of which rise and fall with the tides. Of this class are Pontchartrain, Borgne, Maurepas and Sabine. These are simply parts of the sea which have escaped the filling-in process carried on by the great river and the lesser streams. A second class, called "ox-bow" lakes, large in numbers but small in area, includes ordinary cut-off meanders along the Mississippi and Red rivers. A third class, those upon the Red river and its branches, are caused mainly by the partial stoppage of the water above Shreveport by the "raft," a mass of drift such as frequently gathers in western rivers, which for a distance of 45 m. almost completely closed the channel until it was broken up by government engineers. These lakes are much larger at flood season than at other times, and have been much reduced in size by the cutting of a channel through the raft. Lakes of this class are sometimes formed by the choking of the mouth of feeble tributaries by silt deposited by the Red river where the currents meet.