MERIWETHER LEWIS AND WILLIAM CLARK-OBSERVATIONS ON NATURAL RESOURCES OF THE GREAT PLAINS, 1804-1806

Among the tasks given to Lewis and Clark to do on their expedition across the Louisiana Territory, President Thomas Jefferson included evaluations of potential uses of the lands and observations of weather, animals, plants, waters and minerals, and other geologic phenomena observed by them along their route. Their journals record their good faith efforts to make these evaluations and observations as they traversed the Great Plains. To aid them in the tasks, they took along reference books including Richard Kirwan's "Elements of Mineralogy", which they used to help them identify minerals and other geologic resources. It seems clear that neither Lewis nor Clark had any formal geological training because they misidentified certain common rocks and minerals. They did collect samples of some of these, a few of which remain in collections today. They appear to have been consistent in both their correct and their incorrect identifications. In the latter case, for example, they were consistent in calling selenite "cabalt" or "quarts" and in calling clinker "pumice stone." They correctly identified such rocks and minerals as pyrite, flint, coal, limestone, sandstone, petrified wood, and granite. Their evaluations of soils varied. Some soils that they reported as good for farming are good while others are not. Given what is known now about the geologic history of the Great Plains, a geologist could plot their sites of geologic observations and the features noted at each on base maps and produce coal resource, clay resource, glacial boundary, landslide and other geologic hazards, and possibly structure maps for the lands they travelled adjacent to the Missouri River across the physiographic province.