244 FRAGMENTS OF SCIENCE 



sand and gravel. Through this mass of detritus, fortu- 

 nately, a vertical cutting had 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 Yia 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 occasional floods. 

 In reply to this, it may be stated that even the existence 

 of such floods is not well authenticated, and that, if the 

 supposition were true, it would be an additional argument 

 in favor of the cutting power of the river. For if floods 

 operating at rare intervals 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 upward, and from a point near another 

 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 oleft of profound depth, but so narrow 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 unmistakable marks of erosion. This 

 cleft was best seen on looking downward from a point near 



