The Mormons. -The St. Louis Republican publishes a communication from a leading Mormon, stating that they have been traduced and slandered, and demanding a full and im-partial investigation of all the charges against them, with the view of counteracting and overcoming the existing prejudices against the sect. The leading men sanguinely expect the admission of the territory in o the Union as a state daring the next session of congress for 1858-59. They claim a population of one hundred thousand, and that the United States has no right to withhold a state government. Mr. Wallace, recently from California via Salt Lake, report having seen on the Plains 1565 vehicles, 8061 yoke of oxen, 704 mules, 46 horses, and 1230 head of loose cattle.
