Description: The final potentiometric map by Downey (1986) and used in this project was the result of a detailed analysis also using the previous potentiometric maps contoured for the Madison Group by Miller and Strausz (1980, in Downey, 1986).
Service Item Id: 98c6cbf9be9342399f24e3cfbeb1f89d
Copyright Text: Downey, J. S., 1986, Geohydrology of bedrock aquifers in the northern Great Plains in parts of Montana, North Dakota, South Dakota and Wyoming: U.S. Geological Survey Professional Paper 1402-E, 87 p.
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Downey, J. S., 1984, Geohydrology of the Madison and associated aquifers in parts of Montana, North Dakota, South Dakota and Wyoming: U.S. Geological Survey Professional Paper 1273-G, 47 p.