EMBANKMENTS NEAR BUFFALO SPRINGS. 119 



group, three miles south along the same shore, was constructed almost 

 entirely by currents from the south. 



The manner in which a gravel structure once started on the margin of 

 a lake continues to induce deposition in case the waters rise, is well illus- 

 trated by the group of bars at the right on Plate XXI, which is literally a 

 pile of v-bars, the lowest in the series being the oldest. The thickness of 

 gravel in this compound structure exceeds a hundred feet, and, as shown by 

 the topography, the material composing it was nearly all brought from 

 the south. 



Besides the embankments that have been specially examined, there are 

 many others in the Lahontan basin of equal magnitude and perhaps equally 

 instructive, which illustrate the variety of topographic forms produced by 

 the action of waves and currents. 



On the east shore of Walker Lake are two localities where gravel em- 

 bankments of large size have been built out from the old lake shore and 

 form capes the ends of which are washed by the waves of the present lake. 

 These may be distinguished on Plate XV by the manner in which the rail- 

 road curves about them, close to the water's edge. At each of the localities 

 there are a number of v-shaped gravel deposits that have been built one 

 above another from a common base, so as to produce an exceedingly com- 

 plicated structure. 



In Alkali Valley, about three miles west of Sand Spring Pass, is another 

 locality where the gravel accumulated along the shores of the former lake 

 may be studied to advantage. 



Other deposits of the same character may be seen on the east side of 

 Humboldt Valley, between Rye Patch and Humboldt House, and again at 

 the south end of Winnemucca Lake. A plat of the gravel structure at the 

 last named locality is given below, which will serve as an illustration of the 

 manner in which an embankment of large size may be thrown across a 

 narrow strait so as to obstruct the drainage when the waters retire. 



The deposits at this locality are very similar to the embankment at the 

 west end of Humboldt Lake, represented on Plate XVIII, and find a par- 

 allel in the Bonneville basin in the immense bar at Stockton, Utah. In the 



