...e Fifteenth New York cavalry, returned, having effectually destroyed all the saltpetre works near Franklin, in Pendleton County.--the English steamer Mary Ann, while attempting to run the blockade of Wilmington, N. C. , was captured by the Union steamer Grand Gulf.--the sloop G. Garibaldi was seized at Jupiter Inlet, Florida, while trying to run the blockade with a cargo of cotton. The first negro prison...