immediately after the louisiana wentase, lewis and clarke on their famous journey of exploration out to the west and they opened a new era in american history, where there was an idea that the government -- had explorers, mostly people who were in the military, go into the west and tried to identify important things that were located in that area. it was something that the 18th mind of thomas jefferson felt was important. it became a legacy so even after jefferson was long gone, there were still groups of explorers who were officially going into the west. there was a whole section of the army, the topographical core, that was founded in the 1830's with the specific goal of trying describe the entire geographical area of what the united states considered to be its territory. the exploration just kept going on right up through the 1870's and 1880's. there were still explorers going out and trying to quantify and qualify everything that they were seeing. happen that needed to before people went out to settle or before some of the exploitation of the west for commercial purposes took pla