R. H. Chandler — Landslip in the Isle of Wight. 



19 



surface and middle. 1 This I have shown in some detail in a previous 

 communication. Sir Henry Howorth may mean that if my theory 

 were correct the centre would not move more rapidly than the sides 

 and bottom. This would, however, I venture to think, be an erroneous 

 conclusion to draw ; for the rate of distortion would depend upon the 

 magnitude of the stress producing shear and also upon the number 

 of the 'linkages' broken in any given time. The act of breaking 

 a link is equivalent to the liquefaction of the molecule and the 

 reattachment to recongelation. The maximum shearing stress, and, 

 therefore, the maximum rate of distortion, is at the bottom of the 

 glacier, and the force producing it is measured by the total downward 

 component of gravity. Half-way between the base and the summit 

 the shearing stress is one-half that at the base, whilst at the summit, 

 on the surface of the ice, it is nil and there is no differential motion. 



I am sure Sir Henry Howorth will excuse my pointing out that he 

 has been led into a mathematical error by some means or other ; for if 

 he were correct my theory would be discredited. 



IV. — Note on a Landslip in the Isle op "Wight. 

 ' By R. H. Chandler. 



fPHE accompanying sketch is from a photograph taken in April, 

 JL 1906, of a series of landslips just east of Chilton Chine, near 

 Brixton, on the south coast of the Isle of Wight. The cliff, which is 



Fig. 1. Sketch of landslip. Distance from A to B about 50 yards. 



composed of Brick-earth on gravel and this overlying Weald Clay, had 

 fallen away in a series of blocks of triangular section, which were 

 alternately base and apex uppermost ; the apices in places were quite 

 acute, and one could stride from base to base over the sharply defined 

 apex of a clay triangle. The bases of these triangles were the grassed 

 surface, and the apices of toughened and slickensided Brick-earth 



1 Geol. Mag., 1895, p. 408. 



