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 depoisits 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.
 

Negotiating McGee Wash	Jay hooks up for a tug from the Range Rover

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 distancver 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.
 

Top end of McGee Wash. The long flat berm in distance is an  ancient beach barrier 200 feet above the Sehoo Highstand level.	The remote east side of Walker Lake

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.
 

Stranded fishing boat on east side of Walker Lake Now nearly a mile from the receding water	Another casualty of the receding lake, now half  the depth and area it was 100 years ago.

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 4.0’s suspension kept the situation under control until we reached the tire shop in Hawthorne.
 

View from Thorne Bar, looking west across Walker Lake.	Climbing the successive beach levels at Thorne Bar

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. (For the resulting video/DVD, see the Lake Lahontan Expedition Video page). 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 4.0 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!!