A convention, to be composed of delegates from all the States bordering on the Mississippi river, has been called for the purpose ot form ing a company to construct a railroad along the Valley of the Mississippi, from the Falls ofStAnthonyto the Gulf of Mexico. The com ention will assemble at St. Louis on the third Monday of November The Illinois Central Railroad, with its branches, is to be six hundred and ninety-nine "miles long. ItextendsfromChicagoand Galenato Cairo, at the mouth ofthe Ohio. The amount of land which has been appropriated by government for the benefit of the road is 2,681,160 acres. The Mormons are determined to get a footing upon the Pacific. They.have selected a site for a new city near San Bernardino, and erected a grist mill. Their wheat crop this ? year it is expected, will make over thirty-five , thousand barrels of superfine flour.