This is Grimes Point Hidden Cave Archaeological Site located in Fallon. This area was underwater millons of years ago covered by Lake Lahontan, that dried up about 8,000 years ago. Native Americans used the caves and you'll find petroglyphs on the rocks. There's a nice hiking trail that loops around the basalt rock formations and caves. They also do tours of the caves a couple times a month. For more information check out: https://www.blm.gov/visit/grimes-pointhidden-cave-archaeological-site | A