First volume of a report documenting a high-sensitivity airborne radiometric and magnetic survey of four quadrangles in Iowa, Nebraska, and Kansas including documentation about data collection and analysis.

Second volume of a report documenting a high-sensitivity airborne radiometric and magnetic survey of the Fremont quadrangle including magnetic, ancillary and radiometric data.

Second volume of a report documenting a high-sensitivity airborne radiometric and magnetic survey of the Fremont quadrangle including maps documenting geophysical and geochemical data.

From abstract: Sedimentary rocks of Cambrian and Ordovician age form a major aquifer system in most of Wisconsin and Iowa, northern Illinois, northwestern Indiana, southeastern Minnesota, and northern Missouri. Many metropolitan areas depend on the aquifer for all or part of their water supplies. Declines in potentiometric head have been large in the most heavily pumped areas, most notably Chicago, Milwaukee-Waukesha, Minneapolis-St. Paul, and Des Moines.

Single record data listings taken during aerial gamma-ray and magnetic surveys of the Fremont Quadrangle in Nebraska and Iowa.

Average record data listings taken during aerial gamma-ray and magnetic surveys of the Fremont Quadrangle in Nebraska and Iowa.

Report discussing the probable impact of urban development on the magnitude and frequency of flooding in the lower reaches of the Walnut Creek basin. (from Abstract)