14 BULLETIN 54, U. S. DEPARTMENT OF AGRICULTURE. 
recently acquired and is unimportant. Little salt is now visible in the Honey Lake 
Basin. 
On tne northwest slope of Peavine Peak there is a small basin about 30 square miles 
in area which contains a small marsh separated from the headwaters of Long Valley 
Creek only by a low alluvial divide near the station of Purdy, on the Nevada, Cali- 
fornia & Oregon Railway. During Quaternary time this small basin undoubtedly 
drained into Long Valley Creek, and it has therefore no importance to the present 
inquiry. Its area is included in the above figures for the Honey Lake Basin. 
THE TRUCKEE BASIN. 
The Truckee Basin consisted in Quaternary time, as it does now, of the drainage 
basin of the Truckee River heading in the Sierras, notably in Lake Tahoe, and empty- 
ing into the twin lakes Pyramid and Winnemucca. The approach of the river to 
these lakes is over somewhat dissected alluvium, and the river has flowed at times 
into the one lake and at times into the other. At the present time it flows into the 
Pyramid. During the existence of Lake Lahontan the valley of Winnemucca Lake 
contained a long, narrow arm of water connected with the Pyramid Lake body at its 
southern extremity, while the northern end of the latter lake joined the water body 
of the Black Rock Desert. This latter connection was one of the last to be broken 
when Lahontan disappeared, and it is probable that the Truckee Basin continued to 
overfiow into the Black Rock long after the rest of the Lahontan water bodies had 
fully separated. The Truckee River, being headed in a region of higher rainfall in 
the Sierras has suffered less truncation than the other rivers of the Great Basin and 
has been able to keep its channel fairly clear. Several tributary valleys have lost 
their free outward drainage and have become somewhat saline, but they are few and 
insignificant. In the Lahontan period, however, Pyramid Lake received another 
considerable tributary which entered it from the west through a gap in the Virginia 
Range, bringing the drainage of the so-called Winnemucca Valley (which has no rela- 
tion to Lake Winnemucca). 
This drainage line has entirely decayed, and a large area once tributary to it—the 
Lemmon Valley, north of Reno—has been cut off by an alluvial divide and become 
an inclosed basin whose flat bottom carries a group of playas. This basin has an area 
of 90 square miles. Just north of this there is the smaller Warm Springs Basin, with 
an, area of less than 20 square miles and separated from the Hungry Valley and the 
Pyramid Lake drainage by an alluvial divide over 300 feet in height. It is impossible 
to read clearly the history of this basin from data now at hand. It may be that the 
divide between it and the Truckee is quite ancient and that the Lahontan period 
saw it, as now, completely landlocked. However, this question is unimportant, since 
the basin is too small to have accumulated any considerable salt body. Including 
the Lemmon Valley, but not the Warm Springs Basin, the total area of the Truckee 
Basin is 2,975 square miles. 
THE HUMBOLDT-CARSON BASIN. 
The Humboldt-Carson Basin is the core of the Lahontan area. Its present bottom 
is a great playa covering over 500 square miles and containing in its lowest portion the 
Carson Sink, a shallow and variable lake of brackish water. South Carson Lake, also 
on, the main playa, is a shallow lake produced by the meanders of the Carson River. 
A slough connects it with the North Carson Lake, or Carson Sink. The Humboldt 
River enters the playa from the north through a narrow gap near the station of Parran, 
on the Southern Pacific Railway. During high water of Lake Lahontan a sand bar 
was built across this gap, behind which Humboldt Lake has been formed. However, 
overflow has partially cut this bar, and at high-water stages the water of the Humboldt 
Lake now flows through it and into the Carson Sink. 
