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XIY.— ON THE RECENT REMAHKABLE SUBSIDENCES OF 

 THE GROUND IN THE SALT DISTRICTS OF CHESHIRE, 

 BY Professor EDWARD HULL, ll.d., f.r.s., Director of the 

 Geological Survey op Ireland. 



[Read, 21st March, 1881.] 



The author referred to the recent remarkable subsidences which 

 had taken place in the neighbourhood of North wich, in Cheshire, 

 accounts of which had appeared in the newspapers, and the 

 causes of which were little understood. Having become well 

 acquainted with that part of England some years since, when 

 connected with the Geological Survey of Great Britain, he 

 ventured to offer some explanation of these locally alarming 

 occurrences, which he hoped might not prove unacceptable. 



The district where the subsidences had occurred is a nearly 

 flat plain, from ] 00 to 200 feet above the sea level, traversed by 

 the valley of the Weaver and other streams, composed of the 

 formation known as the New Red Marl, and overlaid at the 

 surface by a few feet of Drift sand or clay. The Red Marl 

 formation is the well known depository of beds of rock-salt in 

 the British Isles, owing to which it had once been called " The 

 Saliferous Marl," and it was owing to the dissolving away of the 

 surfaces of the beds of salt-rock by underground waters, in the 

 manner presently to be described, that the subsidences of the 

 ground had taken place. 



There was reason to believe that rock-salt underlies nearly the 

 whole plain of Cheshire formed of the New Red Marl, occupying 

 an area of about 500 square miles. The occurrence of the salt beds 

 had been proved at Northwich, Winsford, Dunham, Anderton, 

 Moulton, Middlewich, AVheelock, Roughwood, Lawton, Baddiley, 

 Dirtwich, Audlem, Nantwich, and Combermere Abbey, all in 

 Cheshire ; and Mr. Ormerod liad some years ago endeavoured to 

 trace the lines of faulting, or dislocation, traversing the country, 

 according to the different levels at which the beds of salt had 

 been proved. (Quart. Jour. Geol. Soc, Yol. IV.) 



