“ DEGRADATION OF LAND.” 135 
especially of course in winter, has produced some 
erosion of the rock, and a deepening of that most 
romantic and beautiful chasm across which the 
bridge is throwrn, but I can by no means admit as 
some have, and will, that the entire gorge is the 
production of the river, for besides being opposed 
to my conception of the utmost power of a mountain 
torrent, such an idea involves the anomalous con¬ 
clusion of the stream having undergone a general 
sinking from its source onwards, an idea indeed 
which likewise involves the conclusion of a general 
alteration, or sinking in the surrounding tract of 
country, since, the depth of the river’s bed in its 
course, save at this one spot, is not unusually great. 
In my own mind I entertain no doubt that this 
fearful cleft is a disruption of the schistose stratum 
produced during some subterranean igneous action 
on the “ primitive” and internal rocks. 
With greater success however, will the inquirers 
after the influences of modern causes of geological 
change on the very surface of rock appeal to our 
district for corroborative proof. Like the effects 
which the sea produces on every sort of rock, but 
more especially on the schistose strata, there is a 
testimony set up in all directions of the superficial 
destruction of rock which time in his unwearied 
efforts at devastation has ever committed through 
the medium of the disintegrating properties of air 
and water. This lessening or “ degradation of 
land?' may be apparent to a close observer every 
where, but to those who desire decisive evidence 
on the large scale, must be shewn those denuded 
or as it were insulated masses of quartz rock 
appearing through the midst of slate in certain 
spots towards the coast; these doubtlessly were once 
concealed by the same material as they are now 
supported by, but owing to the loosening qualities 
of the elements, bit by bit, atom by atom of the 
