A thick aquifer of Eocene age underlies the Dover area, Delaware at depths ranging from 250 to 400 feet below the land surface. The aquifer is about 250 feet thick beneath the Dover Air Force Base and is composed of fairly uniform medium to fine glauconitic quartz sand. The static water level in a test well at the base was 18 feet below the land surface, or 5.7 feet above sea level, on April 17, 1957. The yield of the test well was about 300 gpm (gallons per minute), and the specific capacity at the end of a 12-hour pumping period was 8.3 gpm per foot of drawdown.