would connect the coasts of the United States was Dr. Hartwell Carver, who in 1847 submitted to the U.S. Congress a "Proposal for a Charter to Build a Railroad from Lake Michigan to the Pacific Ocean", seeking a congressional charter to support his idea. Preliminary exploration Congress agreed to support the idea. Under the direction of the Department of War, the Pacific Railroad Surveys were conducted from 1853 through 1855. These included an extensive series of expeditions of the American West seeking possible routes. A report on the explorations described alternative routes and included an immense amount of information about the American West, covering at least . It included the region's natural history and illustrations of reptiles, amphibians, birds, and mammals. The report failed however to include detailed topographic maps of potential routes needed to estimate the feasibility, cost and select the best route. The survey was detailed enough to determine that the best southern route lay south of the Gila River boundary with Mexico in mostly vacant desert, through the future territories of Arizona and New Mexico. This in part motivated the United States to complete the Gadsden Purchase. In 1856 the Select Committee on the Pacific Railroad and Telegraph of the US House of Representatives published a report recommending support for a proposed Pacific railroad bill: Possible routes The U.S. Congress was strongly divided on where the eastern terminus of the railroad should be—in a southern or northern city. Three routes were considered: A northern route roughly along the Missouri River through present-day northern Montana to Oregon Territory. This was considered impractical because of the rough terrain and extensive winter snows. A central route following the Platte River in Nebraska through to the South Pass in Wyoming, following most of the Oregon Trail. Snow on this route remained a concern. A southern route across Texas, New Mexico Territory, the Sonora desert, connecting to Los Angeles, California. Surveyors found during an 1848 survey that the best route lay south of the border between the United States and Mexico. This was resolved by the Gadsden Purchase in 1853. Once the central route was chosen, it was immediately obvious that the western terminus should be Sacramento. But there was considerable difference of opinion about the eastern terminus. Three locations along of Missouri River were considered: St. Joseph, Missouri, accessed via the Hannibal and St. Joseph Railroad. Kansas City, Kansas / Leavenworth,