Established 2004






Lake Lahontan reached its peak known as the "Sehoo Highstand" about 12,700 years ago, as the melting ice, marking the end of the most recent ice age, added to its volume. Then, the waters covered some 8,500 square miles in central Nevada, centered on what is now known as the Carson Sink. Around this time, the first humans made their appearance in North America. As the weather continued to warm and the lake receded, some of the humans gravitated around its shores. "Coincidentally", the woolly mammoths and other large mammals that had populated the area for countless previous ice ages and intervening warm periods, "interglacials", suddenly became extinct. The humans, animals and the lake itself left much evidence of their presence in the now-remote Nevada desert, beckoning to be explored.

At 9:30 am on September 14, 2002, a group of Land Rovers met at the Churchill County Museum, Fallon, Nevada. Their purpose was to explore and film the remains of the vast lake that covered much of Nevada during the Ice Ages (blue area on map below). As befitted a Land Rover expedition, an emphasis was planned on the more remote and difficult-to-reach aspects of the geological and archaeological evidence, inaccessible to the general public. The trip would cover more than 300 miles of desert dirt and 4WD roads in 5 days, with 4 nights camping out on the trail. Our aim was to circle the vast Carson Sink which was the center of the old lake system, then travel south via its connection with the Walker Lake Basin, one of the few remnants that is still filled with water today. We would visit several little known geological and archeological sites, and discover some new ones that have not been previously documented.

Furnishing the necessary Land Rover horsepower were Lynn Helm’s Land Rover Series IIA 88, Marvin Mattson’s Land Rover Series II 109 body with Chevrolet 350 engine, Jay Finklestein’s Series I Discovery, and the author’s Range Rover P38 4.0SE. Equally important was the intellectual horsepower required for the trip’s geological and archaeological theme. The hand-picked team that assembled in Fallon at the start of the trip included my 83-year old Uncle Joe and cousin Sally, both amateur geologists and desert rats of considerable experience. Joe’s lifelong geological interest included studies at UC Berkeley. The scientific team was completed by Jay Finklestein’s nephew David, a cultural anthropology major, also from UC Berkeley.

Participation of Joe and Sally was made possible by a slight dilution of Land Rover purity, they drove Joe’s GMC Jimmy. This was felt to be permissible since the expedition’s 109 was GM-propelled, and the aluminum V8 engines of the Land Rover Discovery and Range Rover both derived originally from the same manufacturer. Thus, the only genuine Land Rover power source present was in Lynn’s 88. In any case, before the trip, Sally diligently did her “homework” by reading a Land Rover book on off-road driving techniques. Also making up for the slight deviations from official Land Rover purity was the custom-made expedition apparel kindly provided by Land Rover Marin, and Land Rover pins supplied by Land Rover of North America. All members also wore Geological Society of America badges to remind them of the serious nature of the task at hand.


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.

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.

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).

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.

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 receded, 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.

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.


Next morning, we were reluctant to leave our spectacular camp spot high on the ancient spit overlooking the Carson Sink. Eventually dragging ourselves away, we descended the steep road back to lakebed level and visited more old beaches along the Stillwater Range, notably at Grimes Canyon, where the road ascended a staircase constructed of old beaches. We then braced ourselves to tackle the sand dune barrier separating us from the vast Carson Sink playa. The road across the dunes was primitive at best, and the GMC got stuck in the sand, but eventually we all made it to the dry lakebed. It was eerie to think of this ground being under 500 feet of water not so very long ago!

Skirting the naval bombing range in the middle of the playa, we had to cross many more miles of bare lake bottom before reaching terra firma at the foot of the West Humboldt Range. I managed to find the 4WD “road” across the playa marked on the map, but it kept disappearing, so we had to take to the bare playa after the style used in modern automobile advertisements. The difference is that this playa was seldom visited by anyone, and was nowhere near as level and predictable as the Black Rock Desert, for example. So, we had to rely on Marvin’s instincts, developed during years of training in the Black Rock, to find us a path where we might not sink in. Those of us who had viewed the video of his daring assaults on the snow-covered road to the viewpoint above Black Rock Point were not reassured that we would again see terra firma, but we stuck together and finally reached the northwest “shore” of the Sink, formed by the lower slopes of the remote West Humboldt Range.

Greeting us here was a spectacular view of the steps cut into the Range by wave action as the ancient lake stabilized at successively lower levels after reaching its peak. An extremely steep and ancient 4WD mining road which had not been used for many years climbed this “staircase” to the top of the range, and several of the vehicles needed a tug to surmount a particularly gnarly “step”. Concern arose about potential damage to the GMC that could result from continuing, so camp was made for the night at an intermediate plateau about halfway up the staircase.

The daily camping routine was now becoming established, with each participant utilizing his own idiosyncratic solution. Jay and David slept in collapsible “tent cots”, which kept out the elements as well as the mosquitoes. Marvin had his classic “Oregon Trail” rooftop tent, while Lynn slept in his permanent bunk in his vehicle. Joe and Sally alternated between a tent and the open air, depending on the weather, while I luxuriated inside my vehicle with one of the back seats folded down. Providing amusement for the gathered throngs was the rest of my Range Rover routine including the evening shower and dressing for dinner before the obligatory round of margaritas and finger snacks. That night a storm appeared, but fortunately held off long enough for dinner to be completed.


When the sky cleared the next morning, the fresh air and a hike to the ancient high beach barrier at the top of the mountain (now covered with smooth black “desert pavement”) afforded a breathtaking view of the Carson Sink. The vast extent of the ancient body of water began to “sink in”. The beach barrier, constructed of dark stones of apparently volcanic origin, was almost exactly at the 4,390 ft Sehoo Highstand level, and behind it was a small dry lake. This hitherto undocumented geological feature graphically illustrated the water action on the Weast Humboldt Range when the lake was at its greatest extent. The staggering panorama before us was almost impossible to capture on film; the composite image below is feeble attempt to convey the majesty of the scene.

Descending the treacherous 4WD road back down to the lakebed level (500 feet below), we were more aware than ever of the "stairstep" nature of the hillside, caused by the several ancient beaches formed by wave action as the lake stabilized at successively lower levels after reaching its peak.

The rest of the day was devoted to exploration of the remainder of the West Humboldt Range, which today forms the barrier between the Carson and Humboldt Sinks. It was hard to believe that when the lake was full, only the very highest peaks protruded above the water as a chain of islands in the enormous lake!

On the north side of the range, we visited the Lovelock Indian Cave, where numerous ancient artifacts have been excavated. Indian legend has it that the cave was occupied at one time by a mysterious tribe of red-headed men, who were eventually smoked out by setting fire to brush in front of the cave. Further west, we reached the much less known and visited Ocala Cave. At these two caves we had our only encounters with other human beings while out in the desert. At the Lovelock Cave a pair of dirt bikers were looking for refinements to their annual “border to border” off road route from Mexico to Canada. We caught up with them again near Ocala after a great many miles of rugged and harrowing trail.

Along this rough, remote and obviously hardly ever used 4WD road fringing the north side of the range, we discovered eerie old beaches with the pebbles still piled up undisturbed along the shore. Sitting there, we could really imagine the waves splashing in, and the ancients sitting at the water’s edge, having a barbeque and watching the children swim. Relaxing on the beach, we realized that our time was passing rapidly -- each day packed with geological and archaeological interest. Scientific commentary and debate on the CB was interspersed with Land Rover talk as the route was punctuated by some kind of 4WD challenge (rocks, sand dunes, steep hillclimbs, washouts) -- that sufficed to give pause even to the veteran drivers. Our camp that night was on another bluff with a beautiful view of the Carson Sink.


Leaving camp on Day 4, Lynn's 88 stuck briefly in a steep sandy spot, but soon the convoy continued south through the Hot Springs Mountains, which formed the western shore of the ancient lake. On the sandy dirt roads forming this leg of the journey, Lynn and John (as was their custom at least once on every expedition) swapped vehicles. This enabled John to get grounded again in “real” Land Rover driving and attempt once again to master the numerous transmission levers in the 88, while Lynn glided through the rough and dusty bits in air-cushioned, pollen-filtered Range Rover comfort listening to Mozart on the 11-speaker stereo.

We visited an archaeological site where stone tools and weapons have been found dating from the Clovis period 10 to 12,000 years ago – corresponding to the earliest human migrations to North America. In those days, this spot was right on the lakeshore; an ancient beach appears at this level all along the foot of the Hot Springs Range. The arrival of humans coincided with the extinction of the large mammals that formerly lived here -- including woolly mammoths. Among the remains that cannot be explained today are dozens of mysterious pebble mounds – arranged in geometrical patterns. One theory is that the pebbles were removed from the surrounding terrain to improve water runoff, stimulating the growth of useful plants downhill.

Today, the main transcontinental railroad uses the low-lying route along this western edge of the Carson Sink to ease its passage through the mountains of Nevada. We now followed the railroad (and the former southern branch of Lake Lahontan's waters) south past the once-important junction of Hazen, where trains loaded with all manner of supplies once turned off the main line to reach south to the mining boom towns of Tonopah and Goldfield. Following this now virtually unused southern branch of the railroad, we soon negotiated the only significant paved stretch of the route, alongside the Carson River past Lahontan Reservoir. We stopped in the small village of Silver Springs to renew supplies of ice and fuel.

From Fort Churchill, we left the river and the pavement again (but not the railroad) to turn south through the Adrian Valley, the only low-altitude connection between the Carson and Walker Rivers. In ice age times, this valley joined the Carson and Walker Lake basins to form one vast uninterrupted body of water. At other times (and as recently as 2,000 years ago), the Adrian Valley channeled the Walker River north into the Carson drainage, completely drying up Walker Lake. Today, the Adrian is dry, but evidence abounds of its past vital role in the Lake Lahontan system. A shelf on the hilll sides approximately 100 feet above the valley floor marks the altitude of the Sehoo Highstand, and light-colored lake deposits visible in the picture above right provide further evidence of the onetime lake.

At its southern end, Adrian Valley connects with the Walker River, the remote north bank of which we now followed eastwards towards Walker Lake. In this remote area called Sunshine Flat we saw evidence of ancient beach barriers some 200 feet higher than the previously assumed peak of Lake Lahontan. Such evidence occurs in several places in the Walker basin, indicating that sometime since the Bishop eruption of 700,000 years ago, Lake Lahontan reached a staggering size – flooding as far south as Rhodes Salt Marsh, and extending from present day Reno to Battle Mountain.

This perspective was a good reminder that since that time (and for 90% of the past 2.5 million years), the earth has been in an ice age. Roughly every 100,000 years the weather has warmed for a while, but these "interglacials" such as we are now experiencing have usually only lasted for 10,000 years or so before cooling off again. We realized once again that we are overdue for another ice age. Reflecting on this sobering prospect, we located and sampled for analysis another layer of volcanic ash that, with luck, might provide further clues to the lake’s uncertain but checkered chronology.

Late in the day, we made camp beside the Weber Reservoir, a dammed up section of the Walker River, designed to provide water for the Walker River Indian Reservation. Some of the largest and most spectacular formations of ancient lake sediments of the entire trip were apparent here.


Day 5 began with a ride up the bare sandy bottom of McGee Wash, a prominent present-day drainage channel cutting through a bed of ancient lake deposits where strata from the last million years can be studied in the steep, contorted banks on either side. A deep washout half way up prompted us to send Marvin ahead to find a way around. He found a detour track over a sandy hill. As we continued further up the wash, we could see the white tephra layer of the Bishop Tuff, volcanic ash deposited about 650,000 years ago. The deposits above that, which extend far above the Sehoo Highstand level, must have been more recent. Our reward on reaching the head of the wash was a view of a long beach barrier at an altitude of 4,600 feet – far above the 4,390 ft “Sehoo highstand” level.

Returning to the washout, we found that the bypass trail we had used on the way up was too steep to attempt in the reverse direction, so we had to dig our way out with picks and shovels, getting two Land Rovers stuck in the process. We then followed the road skirting the east shore of Walker Lake, where a particularly rocky stretch of trail took us up to an outcropping of tufa-cemented beach gravel far above the Sehoo highstand lake level. Some of the rocks on this road had to be rearranged to allow the passage of the GMC, but all made it to the outcropping, where lunch was served at the ancient shore level with present-day Walker Lake shimmering in the distance 600 feet below us.

Reflecting on the significance of these extremely high lake levels of the distant past, we noted that they provide a possible explanation for the presence of the native Lahontan Cut-throat Trout in Walker and Pyramid Lakes. In the landlocked Great Basin, it is hard to see how such fish could have been introduced naturally. At one time, the lake must have been high enough to break free of the confines of the Great Basin and find a channel to the sea, possibly via the Owyhee and Columbia River system.

All that afternoon, we saw stark evidence of the recent, man-made shrinking of Walker Lake during the past 100 years, due to diversions from the Walker River for irrigation. The water level during that time has dropped by over 120 feet -- so far that ruins of old fishing boats and docks we explored dating from the 1920's are now almost a mile from the shore. As mentioned earlier, this is certainly not the first time Walker Lake has been in danger of extinction, but this time the danger stems from man-made causes.

From Thorne Bar, a curious high sandy spit formation protruding into the lake, we gained a truly panoramic view of the lake and its surroundings. Climbing the sandy road to the top of the Bar, we observed again the characteristic staircase formation on the hillside documenting the successive levels of the lake. On this final stretch, the GMC developed slow leaks in two tires. Considering the very street-oriented nature of the GMC’s rubber and all the rocks we had been over, it was amazing that more trouble had not arisen. Fortunately, air from the p38’s suspension kept the situation under control until we reached the tire shop in Hawthorne.

Finally emerging from hundreds of miles of desert dirt, the participants were sorry to see the trip end, but secretly relished the hot showers, real beds and restaurant food of the awards dinner in Hawthorne. Reflecting on the experience, members of the expedition were well satisfied. Enough evidence had been documented in video footage for the future production of a modest educational documentary about the former lake. To boot, some new sites had been discovered that might shed light on the lake's history.

The vehicles had all performed well with no breakdowns. The customary rude barbs that Range Rover drivers experience from owners of “Real Land Rovers” were attenuated by the fact that the convoy’s p38 was the only vehicle not to get stuck, and was in fact the primary tow truck! All agreed that the GMC had also turned in a creditable performance considering its low clearance and other car-like features. It got its undercarriage scraped, bashed and dented frequently, but had only been actually stuck twice – the same number of times as the Discovery and the 109. However, the experience did turn Joe and Sally into avid Land Rover admirers! 

The expedition experience provided a new way of looking at the desert, and a wider perspective of geologic time and history. In the clamor of today’s news commentary about global warming theories, it is easy to lose sight of the fact that the earth is overdue for another ice age. Who knows, Lake Lahontan may rise again sooner than we think!!