A correspondent writes us an interesting account of a recent brilliant exploit of the 21st Battalion Georgia Cavalry, on the 5th instant. He says: ‘The enemy landed on Alston Island fifteen men, who raised a flag and marched across the island with a guide moving some distance in advance. When they discovered our cavalry approaching they retreated to a dense thicket, which skirts the foot of the sand hills on the creek side, and there awaited the charge of our cavalry, which of necessity had to be made under a heavy fire from the enemygunboat, not more than half a mile distant.
The charge also had to be made over a high, bold sand hill. Captain HARRISON, with twenty men of his command (Company B), made the charge. The horses were checked at the crest of the hill by a volley of musketry from the thicket, not more than thirty or forty feet distant. Captain HARRISON gallantly charged down the hill, reiterating the command, ‘, when those of our men who could not force their horses down the hill threw themselves from their saddles and charged on foot. By this impetuous attack the enemy were prevented firing a second volley, although they had re-loaded their rifles, and a moment more might have been fatal to many of our men.
‘Of the enemy, fifteen, including two Lieutenants and a Paymaster, were captured, two of their privates were wounded, one mortally. The loss on our side was one man killed, and one fine horse. Captain BOWEN, Company D, charged the barges in the face of a brisk fire from the blockader, but the sailors, lying in their boats, made off. Captain HARRISON took from the enemy rifles, pistols, cutlasses, and a boat flag. The Yankees threw some of their arms into the creek, and they could not be recovered.