Day 1: Southeast Carson Sink

Departing from Fallon, we started with an official BLM tour of nearby Hidden Cave – the premier archaeological site of the Great Basin. In the dank interior of this cavern, open to visitors for only half an hour twice a month, we were able to observe layered strata spanning over 10,000 years, including ancient buried cache baskets and atlatl (throwing stick) arrows. This cave was formed by wave action of the ancient lake, and appears to have been used by humans since about 3-4,000 years ago when the waters were much lower. A layer of ash from the Mt Mazama (Crater Lake, Oregon) eruption 6,700 years ago helped confirm the time scale.

Hidden Cave Interior showing archaeological  record going back 10,000 years.	Petroglyphs near Hidden Cave

After the official tour, we began our own, less civilized, agenda. After a brief stop at Grimes Point to view the petroglyphs (too near the main road – and with its own parking lot -- to be considered serious exploration), our first destination was a nondescript- looking site off Highway 50, recently discovered by University of Nevada, Reno, geologist Ken Adams. Here, ash from the Mono Craters eruption was buried in a mile long sand barrier, providing evidence of an old beach dating from as recently as 600 years ago. This was a graphic illustration of how the lake basin has periodically filled and emptied over the years since the peak 12,700 years ago, known to geologists as the “Sehoo Highstand”. In fact, the recent nature of this high lake level upsets prior theories of Lake Lahontan chronology.
 

Rocky Road to Fish Cave	Tufa Lining Fish Cave

From here, in order to reach the blessed shade of our lunch stop at Fish Cave, we had to cross the Lahontan Mts and descend a very rocky 4WD trail. To avoid damage, the GMC bypassed the rocky section on a longer but easier road. In the cave itself, formed by the wave action of the lake, spectacular tufa deposits lined the roof (evidence of underground springs bubbling up and precipitating their mineral load).  

View from Fish Cave.  Note beach-like shorelines center right.	Convoy Crossing to Stillwater Marsh

The cave has natural fortifications at its entrance, and it was easy to see it being used as a holdout against rival tribes. Looking out over the Carson Sink, an idea could be gained of the vast size of the former lake -- the mountains forming the other side were barely visible. To our right we could see the faint horizontal lines carved in the hillside by the waves as the lake stabilized at various intermediate levels.  

Stillwater Mash	3,800 year old habitation sites in Stillwater Marsh

After lunch, we traversed many miles of undulating primitive dirt tracks to inspect a recently discovered 3,800-year-old habitation site in the Stillwater Marsh area. In the 1980's, when a series of wet years had climatologists talking of an imminent return to the Ice Age, this area was inundated once again. When the waters recceded, a number of sites were exposed containing many interesting artifacts of prior occupation dating back to several thousand years ago. Locating several of these sites, we were able to film a number of arrowheads, shells, bones, and other remnants on the surface. The mysterious circles on the ground (Photo above) at first appear natural, but are actually archaeological features including dwellings and shell middens.  

Shells from fresh water shellfish  indicating the entire area has been underwater	Climbing 4WD road to ancient beach at Cox Benchmark

As evening approached, we left the marsh area and headed east to the foot of the mountains. We climbed a steep 4WD trail up the face of the Stillwater Range to reach a spectacular ancient spit known as Cox Benchmark, now 500 feet above the dry floor of the Carson Sink. Camping here, we could see the old beaches, cut into the sides of the Range, stretching for miles north and south.