...th a valuable cargo of dry goods, medicines, and saltpetre — and also two small steamers.--Baltimore American, April 23. This afternoon the National gunboat Anacostia, on her way down the Potomac River , when near Lowry's Point was fired into by a party of rebel infantry, who were dispersed by a couple of shells from the gunboat.--N. Y. Tribune, April 26. Col. Donnelly, of Gen. Banks's forces,...