Ground water; population

This paper introduces two maps from the National Atlas of the United States. The first is a groundwater map published in 1967 (scale 1:7,500,000), which uses different colors to indicate unconsolidated and consolidated aquifer rocks and marks springs with an annual yield of 100 million cubic meters, providing a comprehensive overview of the country's hydrogeological conditions and water-supply potential. The second is a population map published in 1968, which, using both county-level and state-level scales, employs multicolored maps and diagrams to illustrate urban and rural population changes between 1950 and 1960, types of population change from 1940 to 1960, and selected socio-economic indicators from the 1960 census. Both maps combine substantial scientific content with excellent cartographic and printing quality.