Sunday, March 25, 2018

Hidden Cave Tours and Trails east of Fallon, Nevada

Path between boulders and walls with tufa formations, to the left from the Hidden Cave entrance
Hidden Cave is located south of the Stillwater Wildlife Refuge east of Fallon in Churchill County, Nevada. Hidden Cave is not just hidden—it is locked! But entry can be arranged: on the second and fourth Saturdays of each month (with the exception of federally recognized holidays) the BLM offers free public tours. Before going on tour, visitors typically watch a special video at the Churchill County Museum and then caravan out to the cave site. When I visited the cave with a Reno geology group, we were lucky to have—in addition to our knowledgeable group geologist—an enthusiastic and well-versed BLM tour guide, who brought to light the history and archaeological significance of this Ice-Age cave.
Hidden Cave entrance: Bend down and watch your head
Wooden walkways allow access to the archaeological excavation sites. Stratigraphical structures are clearly visible, marked and described. Found items and placed labels have been left for educational and interpretive purpose. Visually, we get an idea of how the history of the cave and the Lake Lahontan area unfolded during the excavation days. For example, a distinct layer of deposited volcanic ash—the Mazama ash layer—indicates the 6,900 BCE eruption of Mount Mazama, resulting in the caldera of Crater Lake, Orgeon.

Distinct layer of Mazama ash
A handout that we received at the Churchill County Museum provides a brief chronology of events in relation to what came to light by studying deposits and items preserved therein. The cave is said to be formed by wave action from Pleistocene Lake Lahontan. Between 21,000 to 10,000 BCE, the cave was alternately submerged beneath and exposed above the fluctuating Ice-Age lake. During the following three millenia, Lake Lahontan was receding and the environment of the cave changed from marsh to a more desert-like land. From 3,800 BCE to the near present, the cave was use as a “cache” site by Native Americans. Archaeologist uncovered both tools and food. We were told it was never used for shelter.
Mustard-colored lichen on red-white scoria
Visitors to Hidden Cave get a lot to explore. Even without joining a scheduled tour, the interpretive trails and views are worth a visit. The system of short trails includes loops and dead-end trails connecting Picnic Cave, Hidden Cave and Burnt Cave. Picnic Cave actually is a rock shelter. Its walls and ceiling feature interesting tufa formations. Alongside a path between the trailhead and the Hidden Cave entrance you will come across scoria, a large mass of reddish gravel from Lake Lahontan's shoreline. These vesicular basal gravels are cemented together with tufa. Often, colorful lichen patterns introduce more structural complexity to the scoria mosaic. Some petroglyph images that you can spot from the trail are assumed to depict the wildlife of the Hidden Cave area. Others look like doodles, but you may wonder if you are standing in front of alien art or ancient cryptography—messages, reminders, pointers or pins on boulders.  

Petroglyphs next to the trail leading to Picnic Cave

Getting to the Cave-Tour Trailhead

Hidden Cave is part of the Grimes Point Archaeological Area. From the Churchill County Museum on 1050 S. Maine St., drive north through the historical downtown district and turn right onto US Highway 50. Follow the highway for approximately twelve miles and turn left, where a sign points to the archaeological site. There are restrooms and picnic tables available at Grimes Point, from where you may explore petroglyph rocks. To continue to Hidden Cave, follow the well-graded dirt road (eastbound for 1.5 miles) and find the signed trailhead on your right.

Hidden Cave Trailhead seen from Picnic Cave

Suggested reading

[1] Hidden Cave, Nevada. Division of Anthropology. Link:
[2] Hidden Cave at Grimes Point. Atlas Oscura. Link:
[3] Grimes Point/Hidden Cave Archaeological Site. BLM. Link:

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