Lovelock Cave is a Great Basin archaeological site located in the Humboldt Sink south of Lovelock, Nevada.  There are two entrances w/ a large center boulder chokestone, inside it is 150 feet long & 35 feet wide.  In 1911 the cave was used for bat guano mining & then transferred to the paleotology department at the University of California following the discovery of excess ancient human excrement.  Excavations in the 1910s & 20s revealed a number of prehistoric Indian artifacts including coprolites, a sling, & 11 duck decoys, the dates of early ancient human occupation range from 2580BC to 1500AD, a span of 4,000 years.  Today the Humboldt Sink is relatively dry but during Indian occupation it was part of the ancient Lake Lahontan where fish & wildlife were abundant.  The cave was placed on the national register of historic places in 1984.

Source: https://en.wikipedia.org/wiki/Lovelock_Cave