Headquarters Army Potomac, July 18.—A flag of truce went up yesterday from Turkey Island Creek, having on board Gen. Dix, who went to meet Gen. Hill for the purpose of making a permanent arrangement for an exchange of prisoners. The interview was highly satisfactory, but no conclusion being arrived at, the flag of truce will return to-day, when Gen. Lee will be present. Richmond papers of to-day contain accounts of the death of Gen. Twiggs at Augusta, .July 15th.
An Englishman, who represented himself as son of the Duke of Somerset, was found at headquarters, a few days since, under suspicious circumstances. He stated that he was with the rebel Gen. Pryor during the recent battle of seven days. He has been sent north.
Worcester Daily Spy, Worcester, MA