Since our last, we have certain advice that lord Dunmore, with his motley band of pirates and renegadoes, have burnt the elegant brick house of William Brent, esq; at the mouth of Aquia creek, in Stafford county, as also two other houses lower down Potowmack river, the property of widow ladies, with several ferry boats; that on Tuesday se'nnight he relanded on St. George's island, but was beat off by 1200 Marylanders; that he had burnt eight of his vessels, and was seen standing down the. bay the Thursday after with all his fleet.