20 JR. H. Chandler — Landslip in the Isle of Wight. 



which stood up, perhaps, 4 feet beyond the grass ; where the apex 

 would naturally have been higher it was usually broken away and 

 crumbled down. There were spaces between the blocks large enough 

 for a horse to fall down and as much as 15 feet deep, at which depth 

 the talus blocked the view. These spaces were overhung by the 

 triangle that stood on its apex, so that the surface contour of my 

 section is correct. At the time the photograph was taken the landslide 



Gravel 

 Weald Clay %fC. 



Fig. 2. Probable section along tbe line AB showing the relative 

 positions of the beds. No scale. 



was quite new, that is, small pieces of clay were falling from the 

 overhanging faces and the fractures of grass and clay looked perfectly 

 fresh. Possibly it had only occurred a few hours previously. 



The cause of the landslide seems fairly evident, for water percolates 

 through the gravel (on top of the Weald Clay) at a little above the 

 beach level, and this undermines the overlying Brick-earth, besides 

 which the Weald Clay is removed by marine erosion. What appears 

 to have happened in the section here figured may be something like 

 this: for some reason or other the mass of Brick-earth Nos. 1, 2, 3, 

 4, and 5 became undermined and broke away from No. 6 (which is the 

 normal and undisturbed position of the Brick-earth). The shock 

 of this settlement shook off the block No. 1 as a 'free surface'. 

 Block No. 1 settled down and impinged upon the lower corner of 

 No. 2, which caused the separation of 2 from 3. No. 3 was thus left 

 unsupported and undercut, which caused it to separate from No. 4. 

 No. 3 settled down and separated No. 4 from No. 5 (as 1 separated 

 2 from 3). The lower parts of these blocks would settle down into the 

 gravel and water, which would render them more easily movable, 

 and the wedges would gradually tend to drive the detached masses 

 seawards. 



