Natural Resources, School of


Date of this Version



Educational Circular No. 18. December 2003.
Published by Conservation and Survey Division/School of Natural Resources, Institute of Agriculture and Natural Resources/College of Arts and Sciences, University of Nebraska-Lincoln. Copyright (c) 2003 Robert F. Diffendal & Anne P. Diffendal.


Meriwether Lewis and William Clark undertook their journey with the Corps of Discovery in 1804–1806 in order to explore the area that the United States had purchased from France in 1803. Then known as Louisiana, this region included almost everything west of the Mississippi to the continental divide (illustrated below). In order to find the best route across the continent, President Thomas Jefferson charged Lewis to follow the Missouri River to its headwaters and then locate rivers flowing down the west side of the Rocky Mountains to the Columbia River and into the Pacific Ocean. Jefferson's written instructions further specified that the members of the expedition collect and describe plants and animals new to science; enter the latitude and longitude of the rivers, mountains, and other features; and note the land's potential for farming, as well as the climate, timber, and wildlife. They were also to record the occurrences of volcanic features and minerals of all kinds, but especially metals, limestone, coal, and saline and mineral waters. Their journals, notebooks, and maps indicate that the explorers took this charge seriously because they collected a great deal of information on these topics.

General Introduction
Treeless plains (site 1)
Peoria Loess Upper Pleistocene Series; bluff (site 2)
Sandstone in the White Cloud Shale
Upper Pennsylvanian System; bluff (site 3)
Landslide (site 4)
The Loess Hills (site 5)
Plattsmouth Limestone Member Oread Formation
Upper Pennsylvanian System; fossiliferous limestone (site 6)
The mouth of the Platte River (site 7)
River terrace and terrace fill (site 8)
Relief map of Missouri River sites
Bank cutting and landslides (site 9)
Cut off meander and oxbow lake (site 10)
Dakota Group Cretaceous System; bluff (site 11)
Peoria Loess Upper Pleistocene Series; bluff (site 12)
Greenhorn Limestone underlain by Graneros Shale
Upper Cretaceous System; bluff (site 13)
Blowing sand and silt from an exposed sand bar (site 14)
Carlile Shale Upper Cretaceous System; bluffs (site 15)
Erosional remnant (site 16)
Niobrara Formation over Carlile Shale
Upper Cretaceous System; bluffs (site 17)
Niobrara Formation Upper Cretaceous System; bluffs (site 18)
Lower part of Pierre Shale Upper Cretaceous System; bluff (site 19)
Sand bars at the mouth of the Niobrara River (site 20)
Erosional remnant (site 21)
References Cited Appendixes
A. For Further Reading
B. US Geological Survey Topographic Maps