These broad canyons, or canyon valleys, are carved by the streams in obedience to an interesting law of corrasion.
The powers of erosion are far slower than those of corrasion, especially in an arid region, because they are intermittent.
The solution effected by the waters of a stream may also be regarded as a part of corrasion.
Weathering prepares the material for transportation and transportation leads to corrasion.
By this process (corrasion) the rocks are worn and often polished by the materials blown against them.