To-day the noted guerrilla McCown and three of his men were captured by the Forrester New York cavalry regiment, reconnoitring in the direction of Sperryville, Va.--A fight took place in Mobile Bay, between the rebels in Fort Morgan and the National gunboats stationed on the blockade. On the discovery, this morning, of a steamer ashore under the guns of the Fort, all the gunboats of the fleet got under way; and, while some repaired to the flag-ship for instructions, the Octorara steamed in and opened fire on the rebel craft, which speedily drew a reply from the Fort. The rest of the fleet soon steamed in and took up their positions, when the fire became quite spirited. The rebel steamer was struck several times, and abandoned; but she lay so near the Fort, it was impossible to get her out. Finding the efforts to set her on fire were fruitless, the fleet withdrew, after firing two hours.--A squad of rebel cavalry entered Cleveland, Tenn., and conscripted every man able to perform service.