230 FRAGMENTS OF SCIENCE. 



been made, which exhibited a section showing perfect 

 stratification. There was no agency in the place to roll 

 these stones, and to deposit these alternating layers of 

 sand and pebbles, but the river which now rushes some 

 hundreds of feet below them. At one period of the Via 

 Mala's history the river must have run at this high 

 level. Other evidences of water-action soon revealed 

 themselves. From the parapet of the first bridge I 

 could see the solid rock 200 feet above the bed of the 

 river scooped and eroded. 



It is stated in the guide-books that the river, which 

 usually runs along the bottom of the gorge, has been 

 known almost to fill it during violent thunder-storms; 

 and it may be urged that the marks of erosion which 

 the sides of the chasm exhibit are due to those occa- 

 sional floods. In reply to this, it may be stated that 

 even the existence of such floods is not well authenti- 

 cated, and that if the supposition were true, it would 

 be an additional argument in favour of the cutting 

 power of the river. For if floods operating at rare inter- 

 vals could thus erode the rock, the same agency, acting 

 without ceasing upon the river's bed, must certainly 

 be competent to excavate it. 



I proceeded upwards, and from a point near an- 

 other bridge (which of them I did not note) had a fine 

 view of a portion of the gorge. The river here runs 

 at the bottom of a cleft of profound depth, but so nar- 

 row that it might be leaped across. That this cleft 

 must be a crack is the impression first produced; but 

 a brief inspection suffices to prove that it has been cut 

 by the river. From top to bottom we have the unmis- 

 takable marks of erosion. This cleft was best seen on 

 looking downwards from a point near the bridge; but 

 looking upwards from the bridge itself, the evidence 

 of aqueous erosion was equally convincing. 



