OVEELAND 



TO 



189 



The largest city in Nevada is RenOj the seat of Washoe County, 



which has long been the principal commercial and 

 industrial center of western Nevada. From this 

 point the Virginia & Truckee Railroad runs south 

 to Carson (31 miles), the State capital, and to Vir- 

 ginia City (52 miles), the locality of the famous Comstock lode, 



Reno. 



Elevation 4,497 feet, 

 ropulation 10,867. 

 Omaha 1,539 miles. 



its course, has undoubtedly been cut by 

 the river. It seems that such a channel 

 may have been developed in one of two 

 ways. Either Truckee River, dammed 

 by the rise of a mountain ridge across its 

 path, formed a lake and, after an outlet 

 had been established by overflow at 

 some low point on the margin, gradually 

 wore this down into a canyon, or else the 

 river, having established its channel 

 across low-lyingplains that existed before 

 the mountains were uplifted, simply 

 maintained its course by cutting down 

 its channel as fast as the mountain bar- 

 rier rose. That the latter hypothesis is 

 the true one appears from the following 

 .considerations. If the site of the Truckee 

 Meadows had ever been dammed to a 

 considerable depth by uplift of the Vir- 

 ginia Range, the lake waters would have 

 soon found an outlet through a low pass 

 to the north, reaching Pyramid Lake by 

 a more direct course than they now take. 

 There is, however, no sign of such a chan- 

 nel nor of traces of shore lines about the 

 valley to indicate that the lake ever rose 

 to this height. 



The uplift of the ranges in the Great 

 Basin and of the Sierra Nevada, which is 

 now near at hand, is a comparatively 

 recent event as reckoned on the geologic 

 time scale. (The term uplift is used 

 only in a relative sense; it does not nec- 

 essarily imply actual uplift. Some ap- 

 parent uplifts may be due to a sinking of 

 adjacent valley areas.) These mountain- 

 building movements began late in the 

 Tertiary period and have continued even 

 down to the present day. Little by 

 nttle blocks of the surface crust readjust 

 themselves, and here and there earth- 

 quakes or the opening of fissures at the 

 surface signify the gradual slipping of one 

 fragment of the earth's crust against 

 another. Probably the movements that 

 iiplifted the higher mountain ranges took 





place in the past in much the same grad- 

 ual manner as to-day. The east front of 



the Sierra is now an earthquake zone, in 

 which are felt occasional shocks and tre- 

 mors due to movements in the earth's 

 crust, and these appear to come perioS- 

 ically. They may be frequent for a 

 period covering several months, which 

 may be followed by a period of relative 



quiescence. 



The Truckee Meadows may have been 

 intermittently a shallow lake and a 

 meadow. At present the river is flowing 

 over volcanic bedrock at the entrance to 

 the canyon, on the east, while the valley 

 above is occupied by alluA'ium and possi- 

 bly some lake beds. The ground water, 

 following the general course of the stream, 

 rises as it encounters the natural rock 

 dam at the entrance to the canyon, mak- 

 ing the lands above the canyon entrance 



marshy. 



mountain 



im 



rocks th at are prob abl y Mesozoic or 

 possibly in part Paleozoic, igneous, and 



afiso- 



Tertiary 



or later age. 



■Tertiary 



exposed for a long period to weathering 



erosion 



down 



lary 



tim 



was poured out, accompanied by showers 

 of volcanic ash and the accumulation of 

 fresh-water lake or marsh deposits. These 



deiKDsits 



streams 



geologic formations here represented. 

 The jreoloric column in the \'icinity of 



Reno is very incomplete— that 



long 



periods of geologic time axe unrepresented 



preserved 



mations. 



depofi I ta 



have been laid down during these periods 

 and later entirely worn away, it may be 



