36 FAULTS. 



contorted strata ; but it may be shifted to one side or 

 the other, if the line of least resistance in part coin- 

 cides with one of the lines of stratification (fig. 3, 

 PI. I. a, e,f, b). Open fissures forming caves, due 

 to such a cause, are not uncommon in some locali- 

 ties. They were noted in the sea-cliffs of Kerry and 

 Cork, while Kenwood, in his description of the mines 

 of Chili, figures lodes that occur in fissures of this 

 class. 1 



Landslips in recent accumulations have been 

 described, and very similar slips may occur in the 

 older rocks when at the surface. Some of these are 

 due to subordinate beds " running;" others would 

 appear to be caused l>y the subsidence of a tract of 

 country along a line of master joint or into a subter- 

 ranean vacancy, the origin of which we are unac- 

 quainted with, and can only guess at. An example 

 due to the running of a bed is the well-known land- 

 slip in the neighbourhood of Axmouth, Dorsetshire. 

 Here it is quite apparent that the rain water descend- 

 ing through the joints in the chalk and green sand 

 softened the underlying lias clay, which " ran," and 

 this, combined with a slight dip of the strata seaward, 

 induced a large tract of country about a mile long to 

 slip. From an examination of the land margin of the 

 " slip," it is apparent that the first and all subse- 

 quent slips have taken place along joints more or 



1 Ibid., p. 82. 



