86 THE DENUDANTS, OR CARVERS OF THE 



above peaty matter, which remains long enough to be 

 enveloped with verdure, the growth and decay of 

 which yearly forms peat, which afterwards creeps 

 downward, till eventually all the shingle is covered. 

 That such must be the process is apparent in various 

 places where, as yet, the work is incomplete.. 



Rain and rivers by themselves seem incapable of 

 doing much work, but when combined with the other 

 denudants, and with cracks or fissures, their effects 

 are considerable. The connection with cracks, joints, 

 and the like, is almost ignored by extreme subserialists, 

 yet they inadvertently admit that there is such. 1 An 

 illustration of the powers of rain and rivers was re- 

 marked near Draperstown, Co. Londonderry. There, 

 one of the streams, a head water of the Moyola river, 

 has its bed partly in drift and partly in a soft friable 

 conglomerate. At first it might be considered that 

 the upper part, in the drift, was solely due to river 

 action ; but on examination it will be found that this 

 is not the case, as there is a break in the drift, 

 immediately north, and partly along which the ravine 

 has been excavated. This stream, during flood, carries 

 down innumerable blocks and pebbles which appa- 

 rently ought to rapidly wear away the conglomerate ; 

 yet this is not the case, for during the ages it has been 

 at work only a few feet in depth have been excavated, 

 except in those places where the bed of the stream and 



1 See page 77. 



