Movement of people or materials from one place to another for economic, political, or recreational purposes.
This category is also used for air transportation, aviation, and ground transportation.

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Evolution of the landscape along the Clear Creek Corridor, Colorado--Urbanization, aggregate mining, and reclamation

Prime agricultural land along the Clear Creek floodplain, Colorado, attracted settlement in the 1850's but the demand for sand and gravel for 1900's construction initiated a sequence of events that exceeded previous interests and created the modified land