A major fracture system in indurated sedimentary rocks forms a moderately extensive aquifer yielding 100-300 gallons per minute to wells 160 to 420 feet deep. Pumping-test data show that the fracture system is interconnected to distances more than 1,000 feet from the wells. Recharge occurs through overlying clayey till, and continuous pumping may induce recharge from surface-water sources. Chemical analyses indicate no water-quality problems. Systematic collection of data on pumpage , water level, and chemical quality could help to determine the long-term adequacy of the aquifer system. (Woodard-USGS)