Manchester Memoirs, Vol. Iviii. (19 14), No. 8. 9 



G. W. Ormerod" says : — " The exact northern extent 

 (of the salt deposits) has not been determined. It is 

 probably the line of fault before mentioned which passes 

 from the South Lancashire coal-fields by Warburton and 

 Rostherne in a south-easterly direction to the Rud3/ard 

 fault." He further states that brine was met with at 

 Woolstone, near Warrington, which is west of the fault, 

 but considerably to the north of Rostherne, but the dis- 

 covery of brine within recent years at Warburton proves 

 that there are beds north and east of the fault. We may 

 then admit the probability of salt below the marls in the 

 immediate neighbourhood of Rostherne, a supposition 

 which has considerable bearing upon the possible origin 

 of the mere. 



Hull* says : — " The rather uniform features of the 

 landscape are agreeably varied by the frequent occurrence 

 of little lakes or meres in artificial or natural hollows. 



" The largest and most interesting of those in this 

 district is Rosthern Mere, a natural lake about lOO feet in 

 depth, its bed being about 20 feet below the sea-level, 

 occupying a deep depression excavated in Boulder clay 

 and sand. The other meres, as far as I have been able to 

 ascertain, are situated in the same Post-pliocene formation, 

 as are also those of De la Mere Forest and Ellesmere. 



" It is, however, a remarkable fact, that these natural 

 reservoirs are all (I believe) situated upon the Red Marl, 

 that formation which holds the beds of rock salt. Now 

 this mineral, whenever rainwater has access to it, is liable 

 to be dissolved, the brine being carried away in under- 

 currents. Such a process long continued would probably 

 result in the production of hollows, for wherever the 



*" Outline of the principal Geological features of the Salt-Fields of 

 Cheshire and the adjoining districts." Quart, /ourn. Geol, Soc. of London, 

 IV., 1848, 281. 



* Op. CiL, \-^. I. 



