Washington, March 1, 1843. To Colonel J.J. Abert, Chief of the Corps of Top. Eng. Sir: Agreeably to your orders to explore and report upon the country between the frontiers of Missouri and the South Pass in the Rocky Mountains, and on the line of the Kansas and Great Platte rivers, I set out from Washington city on the 2d day of May, 1842, and arrived at St. Louis by way of New York, the 22d of May, where the necessary preparations were... more...