58 DRY RIVER CHANNELS AS ROADS. 



river follows the lowlands, as the divide does the head- 

 lands, yet the river in most cases, by simply winding 

 and turning among the hills, at length finds its way 

 down to the sea, without the necessity of cutting through 

 any considerable gorge, under ordinary circumstances, 

 throughout its whole course. The river channels there- 

 fore furnish another route by following which the hills 

 may be avoided ; river valleys are therefore, as we 

 know, often used by railway engineers for this pur- 

 pose but it is not generally a good line for travellers 

 to follow f through a wild country of a rugged and 

 hilly character, unless there is a dry river bed of sand 

 or gravel, forming a natural road, because the ground 

 alongside of river beds is very often exceedingly broken 

 and obstructed by trees, bushes, swamps, ravines, and 

 other obstacles; and if the river is bordered by cliffs, 

 the stream, by its constant windings from the base of 

 one cliff to the other, renders progress impossible, 

 except at the expense of innumerable crossings, which 

 are almost always dangerous in such places, and often 

 quite impracticable. There is, besides, the risk of sudden 

 floods which, as we shall presently show, may at any 

 moment cause the utter destruction of the wayfarer, 

 overtaken during his passage through these defiles, 

 from which a speedy escape is often impossible. 



Many of these defiles along the courses of great 

 rivers however are grand and impressive beyond de- 

 scription, and frequently present the finest natural scenery 

 in the country. 



But the most wonderful of all these water-channels 

 are the Canons that traverse the highlands of Colorado, 

 and other parts of the south western territories of the 

 United States, which must certainly be ranked among 



