Do not follow the paved road, but go south, across the narrow bridge over the Truckee diversion canal, along the gravel road for 1.9 miles, keeping left and not taking right turns at 0.6, 1.2, and 1.8 miles. Continue 1.2 miles on the dirt road, passing under the power line, to the diatomite mine. Stay away from the high walls. Return to the highway. Continue another 12.4 miles further east on U.S. 50, through Fallon, to Grimes Point.
Signs explain the different designs and likely ages.
Eroded shorelines of Pleistocene Lake Lahontan are easy to see as horizontal benches on the hillsides in the Lahontan Mountains to the east. Follow the gravel road uphill to the east of Grimes Point, 2.1 miles, to a fork in the road. Continue west on U.S. 50, 2.3 miles past Burger King. Some of the bombs have distinct ribs indicating flow of viscous lava. Some bombs are scoria, a type of volcanic rock with numerous holes that formed when gases trapped in the magma tried to escape.