THE WM. SANDERSON LOST, WITH ALL HANDS. - The fate of the schooner Wm. Sanderson and that of her entire crew, which for some days past has been a mystery to her owners, has at length been solved by the discovery of the wreck broken up at Sleeping Bear, on the east shore of Lake Michigan, with not a soul left to tell the tale of her sad fate. A letter, which is dated at Empire, a place located between Point Betsie and Sleeping Bear, on November 26th, and signed by George Aylesworth, a wood dealer, directed to a Chicago firm, states that the wreck of the Wm. Sanderson was found broken up on the beach, with her small boat attached and not a trace of the crew, appearances indicating that she went to pieces before reaching the shore. The Chicago firm immediately advised Messr. Scott & Brown, the owners in this city. The Anderson was valued at $22,000, and insured for $15,000. The cargo consisted of 19,500 bushels of wheat consigned to Oswego, and was also insured at the usual proportion. Her freight list was also insured at $1,700. The Sanderson was built at Oswego, by George Goble, and came out in 1853. She had a crew on board of nine persons. Capt. John C. Brown commanded her, and John Woodruff was mate, which are the only names that have thus far been ascertained.