26 THE FOREST LANDS OF FINLAND. 



fort. High above the bed of the present rapids immense 

 caverns have been hollowed in the adjoining rock, indica- 

 tive of the tunnelling of the river in byegone times. At 

 a distance of about fifteen miles below Lake Saima the 

 Wuoksi is navigable. Before falling into Lake Ladoga at 

 Kexholm it spreads out into two large lakes, but through- 

 out the greater part of its length, according to Murray, it 

 winds between high banks formed of granite, with layers 

 of clay and sand. The total length of the river is 170 

 versts, 113 miles. Geological data prove that the river is 

 decreasing in volume, the ancient breadth of its course 

 being in many places marked by round, kettle-shaped 

 holes, in which boulders no longer gyrate. The limits of 

 the old bed may be clearly seen in the vicinity of the 

 Falls. 



The Falls of Wallin-Koski and Kuri-Koski, a short 

 distance beyond those of Imatra, are inferior in grandeur, 

 but far more picturesque. The Falls of Imatra may be 

 taken as a type of many of the waterfalls met with in 

 Finland, in Sweden, in Norway, and in the same latitudes 

 in Russia. 



It is easy to imagine the phenomena accompanying the 

 gradual advance of a waterfall upwards in the water course 

 of a river. In many books on geology the process is 

 described. To meet a popular opinion that rivers flowing 

 through ravines found these ravines existing as rents in the 

 mountain chain, and availed themselves of them to escape 

 to a lower level, Professor Geikie has given in a volume 

 entitled " The Scenery of Scotland, viewed in connection 

 with its Physical Geology " a volume I may afterwards 

 have occasion to cite at greater length a graphic account 

 (p. 18-34) of the action of a river in forming for itself a bed 

 and a valley in which this bed seems to lie at rest. More 

 briefly, the action of a waterfall may be described thus : 

 Where the current below the fall is not so strong as to roll 

 away the fallen rocks, where it is such as to sap the 



