THE OVEKLAND EOUTE OGDEN TO SAN FRANCISCO. 



187 



volcanic tuff; 



belonging 



succession 



lavas of wliich the 



mainly com 



almost 



and basalti 

 cultivation 



The channel here is 



At low elevations near the river channel the horizontal white lake 

 beds are clearly exposed across the valley. 



Derby was formerly the junction of the oricrlnal route, which nassed 



Wad 



Derby- 



Elevation 4,165 feet. 

 Omaha 1,51S miles. 



' J. / — ^,. — 



the south side of the river has now been taken up and 

 the grade is used as a public road. West of Derby 



alls 



t? 



sisting of continuous bluffs that show the lava flow 



ash 



omaceous 



numb 



The 



successive flo\ys of dark lava show here in the steep bluffs across 

 the river, on the south side of the canyon. 



The line between Storey and "\\ ashoe counties follows the chaimel 

 of Truckee River, and county-line posts are seen at one end or the 

 other of the bridges. 



and IS the point of departure 

 rir2'inia Ranc^e. to the south. 



Clark- 

 Elevation 4,257 feet 

 Omaha 1,520 miles. 



West of Clark the Lake Lahontan clavs are exhibited 

 in cuts along the raih'oad. These extend to a sidins 



Ditho (elevation 4,304 feet), where the last 



named 



remnants of such denosits are 



at this point being ahnost exactly coincident with the uppermost 

 level reached by the waters of the old lake. This is therefore the 

 western hmit of the former Lake Lahontan, whose basin the railroad 

 has been continuously crossing from a point at exactly the same 

 level in the Humboldt Valley near Golconda. 



For several miles beyond Ditho renmants of a very recent though 

 prehistoric lava flow may be seen in the river valley. The flow is a 

 layer, apparently 10 to 20 feet thick, of dense black basalt, which lies 

 chiefly along the very bottom of the valley. It is exposed in cross 

 section at several places by the cutting of the river and along the 



i, which lie slie^htlv above the nresent route. This 



grade 



attained 



form 



^ Ramsay, a town of about 100 inhabit- 

 ants, ia 17 miles south -southeast of Clark 

 station, -with "vrhich it is connected by a 

 good road traversed by a daily stage. The 



country- rock is Tertiary lava (andesite 

 and a little rh}'oUte). Several mines 

 have shipped mme gold ore, but the pro- 

 duction has not been large. 



