JOINTED STRUCTURE 
305 
The cliffs are divided by vertical and curving joints, separating a long line into blocks of 
ten to twenty feet long and broad. The action of the water is constantly widening these 
joints, and undermining the masses. These fall down, one after the other, and their fragments 
are dispersed by the waters; sometimes a single one of a whole range is left standing alone, 
with a long interval between it and any other, as in the illustration below (fig. 1). In fig. 2, 
the high block is isolated from the cliff behind it, and from the range to which it belongs on 
the left. Its relations to the adjoining cliff may be seen by the range of concretions which 
are thickly dispersed through a certain stratum. Some of these concretions are divided by 
the joint as regularly as if sawn asunder; in other instances they project from the mass, 
having been unaffected by this divisional structure. 
150. 
The process by which these masses arc destroyed, by the undermining action of the waves 
below and the weathering from above, is illustrated in the following woodcut: 
151. 
[Geol. 4th Dist.] 
39 
