GAXNETT.] TOPOGEAPHY THE GRAND CANON. 477 



slope. The measurement vrhicTi I published in 1872, which was so wide 

 of the mark, was made by a comparison of the vertical angles subtended 

 by a tree at the head of the fall, whose height had been measured, and 

 by the fall. Probably here the source of error was in sighting at the 

 base of the fall, which was very ill-defined, owing to the immense amount 

 of spray and vapor. 



I measured the volume of water in the river just at the head of the 

 rapids above the Upper Fall, at the end of August. The amount of 

 water carried by the stream was found to be 1,200 cubic feet per second. 

 This result is little, if any, below the average of the year. 



A marked feature of this stream is certain to strike the observer; that 

 is, that it shows no signs of floods. The river flows very nearly bank- 

 full all the year and this although most of its water comes from high 

 mountains. There is no broad flood-plain of bare gravel and bowlders 

 strewn with wrecks of forests. The explanation is as simple and appar- 

 ent as the phenomenon. The river has a balance-wheel in the form of 

 the lake, by which inequalities of supply are leveled down. It is 

 probable that the river, from the foot of the hike to the mouth of its 

 East Fork, does not vary in level a foot between its highest and lowest 

 stages. Tlie case of Lewis Fork of the Snake is similar, and there we 

 find a similar absence of evidences of floods. Were this idea, thus given 

 to us by nature, carried out on all these mountain streams, the sources 

 of the Missouri, Platte, and Arkansas, the question of controlling the 

 Mississippi in its lower course would be vastly simplified, while the 

 water would be stored for use in reclaiming great areas of land, other- 

 wise arid and desert. 



About half way between the two falls. Cascade Creek, a small stream 

 which heads in the southern slopes of the Washburn Eange, falls into 

 the river. A few hundreds of yards above its mouth this little stream 

 makes a succession of beautiful cascades, to which the name Crystal 

 Falls has been given. They are three in number, and placed so closely 

 together that they almost form a continuous fall. The total height is 

 129. Though the amount of water in the stream is small, still from its 

 graceful form this little fall is well worthy a visit. 



THE GRAND CANON. 



This feature, too, has been so frequently described that anything 

 further concerning it is almost superfluous. Commencing at the Falls 

 it extends down nearly to the mouth of the East Fork, a distance, as 

 the river flows, of 21 miles. Indeed, from the falls to the mouth of 

 Gardiner's Eiver the Yellowstone is in a continuous canon, but the par- 

 tial break at the mouth of the East Fork separates it into two parts, 

 known as the Grand and the Third Cafions. The former occupies the 

 line of greatest depression in a volcanic plateau, which slopes to the 

 northward and southward from the Washburn group < f mountains, and 

 to the westward from the Amethyst Eidge of the Yellowstone Eange. 

 Its course is northeast as far as the extremity of the Washburn group, 

 and, after passing that, it tarns north with a very slight inclination west. 

 The height of the plateau at the falls is about 7,800 feet. It increases 

 slightly northeastward, until, in passing the mountains, it has an eleva- 

 tion of about 8,000 feet. Thence northward it decreases in height rap- 

 idly, and at the mouth of Tower Creek it reaches but 7,200 feet. At the 

 head of the Upper Fall the river level is but a few feet below the ton of 

 the plateau. This fall adds 1 12 and the Lower Fall 300 feet to the depth 

 of the chasm. From the foot of this fall to the mouth of East Fork 



