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assumed that the subsidence is due to an outflow towards the 

 deeper parts of the lake of this oozy substratum — that under 

 ordinary circumstances the waters of the lake give to this ooze 

 sufficient support to maintain it in its normal position. But if 

 by any means that support were withdrawn, or the superin- 

 cumbent pressure increased, the equilibrium would cease to be 

 maintained, the oozy matter would be pressed outward and the 

 upper crust would be broken up. In the present case there had 

 been no lowering of the level of the water — but a considerable 

 amount of pile driving had been going on which very possibly 

 had disturbed the superficial arrangement of the soil below the 

 surface of the water — and the gradual accumulation of buildings 

 on the surface had gone on adding from time to time to the 

 weight that pressed more and more heavily on the soft matter 

 below. If this be the explanation of the event it comes to very 

 much the same as in the cases of the Eigi and the Eossberg, viz., 

 superincumbent pressure and withdrawal of supports. The moving 

 bogs of Ireland appear to be phenomena of an analogous kind. 



To come still nearer home, we have a series of subsidences 

 taking place in Cheshire and "Worcestershire in consequence of 

 the abstraction of the salt. In Cheshire these are in some places 

 altering the face of the country, producing depressions of the 

 surface, that fill up with water, forming large pools, where only a 

 few years ago was dry ground. Almost any person who passes along 

 the railway through Droitwich must have noticed how the retain- 

 ing walls of the railway are fissured by the sinking of the ground. 



Similiar operations have been going on on a large scale in 

 limestone districts — water charged with carbonic acid, percolating 

 through beds of limestone, dissolves it, making caverns and 

 galleries — and these from time to time fall in, forming cliffs and 

 ravines. The gorge in the cHSs at Cheddar is assigned by many 

 geologists to this cause. 



But at our own doors we have a neat little landslip and we 

 find it a rather troublesome neighbour. So far as I have been 



