28 



The Great Falls of the Yellowstone. 



Sixteen miles below Yellowstone Lake, at the head of the 

 Grand Canon, are tin 1 (neat Falls of the Yellowstone, the 

 Upper, and the Lower. The two falls are not more than a 

 quarter of a mile apart. Above, the river Hows through a 

 grassy, meadow-like valley, with a calm, steady current, 

 until within about half a mile of the Upper Falls, when 

 the rapids commence hurrying the waters on between low, 

 but narrow and precipitous, walls of massive basalt, when 

 they literally shoot out through a narrow contracted gorge 

 over a precipice 140 feet, striking a slanting shelf below, 

 ricochet ting off into the basin a mass of snow-white foam. 

 The river then spreads out over a wide, gently descending 

 bed of rock, with walls from 200 to 100 feet in height, 

 until it reaches the brink of the Lower Falls, when the 

 stream is contracted to a width of 100 feet, and then 

 plunges over the precipice, a solid, unbroken mass, and falls 

 397 feet into the Spray-tilled Cha8m, enlivened with rainbows 

 and glittering like a shower of diamonds. The walls of the 

 canon immediately above the Lower Falls are about 400 feet in 

 height, or a total depth to the bottom of the falls of about 

 800 feet, and upon each side of the falls are perfectly hori- 

 zontal for nearly the whole height. 



No. 239. The Lower Falls. A near view, not far from the bottom of 

 the canon, and about 800 yards below the falls. 



No. 210. Tin: Lower Falls. Distant view farther down the canon. 



Nos. 241, 242. The Lower Falls. A view from the top of the canon, 

 west side, one mile below the falls, and showing the canou 

 for that distance. 



Xo. 243. The Lower Falls. View from the east side of the canon. 



No. 244. Upper Falls, from the top of the canon, just above the 

 Lower Falls. 



No. 24o, 246. Upper Falls, near view from the east side of the canon. 



No. 247. Upper Falls, near view from the west side. 



The Grand Canon. 



Above the falls, the river flowing over hard, compact, 

 iron-like basalt, makes but little impression upon it, but 

 after its leap it has different material to deal with. In- 

 stead of unyielding rock, there is a vast deposit of soft 

 volcanic ash with harder seams and dike-like eruptions of 

 breccia and basalt. Ages ago this whole region was 

 the basin of an immense lake. Then it became the center of 

 volcanic activity; vast quantities of lava were emptied, which, 

 cooling on the water, took the form of basalt. Volumes of 

 volcanic ash and rock fragments were thrown out from the 

 craters from time to time, forming breccia as they sunk through 

 the water, and mingled with the deposits from silicious 

 springs. Over this were spread the later deposits from the 

 waters of the old lake. 



In time the country was siowly elevated, and the lake was 

 drained away. The easily eroded breccia along the river- 

 channel was cut deeper and deeper as ages passed, while 

 .springs and creeks and the falling rain combined to carve 



