After the capture of Port Royal, and the establishment there of the naval base, and until the arrival of monitors a year later, operations of the South Atlantic Blockading Squadron, as it was styled, were confined to blockading. This took two principal forms. The fortifications of Charleston and Savannah being still in the hands of the enemy, and intact, these two chief seaports of that coast were unassailable by our fleet. Even after Fort Sumter had been battered to a shapeless heap of masonry, and Fort Pulaski had surrendered, neither city fell until Sherman's march took it in the rear. But the numerous inlets were substantially undefended against naval attack; and for them the blockade, that tremendously potent instrument of the national pressure, the work of which has been too little commemorated, was instituted almost universally within. Even Fort Pulaski, before its fall, though it sealed the highway to Savannah, could not prevent the Union vessels from occupying the inside anchorage off Tybee Island, completely closing the usual access from the sea to the town. During the ensuing ten months there were very few of these entrances, from Georgetown, the northernmost in South Carolina, down to Fernandina, in Florida, into which the _Pocahontas_ did not penetrate, alone or in company. I do not know whether people in other parts of the country realize that these various inlets are connected by an inside navigation, behind the sea islands, as they are called, the whole making a system of sheltered intercommunication. The usefulness of this was reinforced by the numerous navigable rivers which afford water roads to the interior, and gave a vessel, once entered, refuge beyond the reach of the blockaders' arm, with ready means for distribution. Such a gift of nature to a community, however, has the defects of its qualities. Ease of access, and freedom of movement in all directions, now existed for foe as it had for friend, and the very facility which such surroundings bestow had prevented the timely creation of an alternative. Deprival consequently was doubly severe.