Detailed and reconnaissance mapping of the Devils Hole, Nevada, area has improved definition of the local geologic structure within a regional carbonate aquifer near its primary discharge points -- the springs of Ash Meadows. Several formerly unmapped calcite veins, and other young calcite-lined paleo-spring feeder zones were found, as well as a number of previously unknown small collapse areas in the limestone. Although the predominant structural grain of the area is oriented northwest, the importance of the very subordinate northeast-striking faults and fractures is underscored by their association with Devils Hole itself, with most of the collapse depressions, and with many of the calcite veins in ' lake beds ' and alluvium. Probable channeling of groundwater flow may occur along one important northeast-striking fault zone. The persistent tendency for openings may have been facilitated by underlying low-angle faults that separate brittle carbonate rocks from underlying, less-competent clastic rocks.
