A correspondent writes from Washington, under date of Feb. 1st.- It is reported to me on good authority that Mr. Buchanan con-templates withdrawing the troops from Utah. Dr. Bernheisel, the Mormon delegate, has submitted propositions to the Administration indicating the willingness of the Mormons to vacate Utah and colonise some of the islands of the sea, outside of the jurisdiction of the United States, provided the government will purchase at a fair valuation the Salt Lake city improvements. Dr. B. asks that Commis-sioners be sent out to arrange terms and de-tails. Should these be agreed on Salt Lake city is to become a grand military station or depot for our Western troops.