16 
Lawton in the south-east comer of the basin beds of rock 
salt have been found at a considerable height above sea 
level. At Nortliwich and Winsford the rock salt lies below 
the level of the sea. The Keuper marls of Cheshire are 
covered by drift. The clays, gravels, and sands of the drift 
are very much mixed up, and the clay is full of boulders 
of granite, and various kinds of stone, many of the softer 
kinds being deeply ice-marked or scratched. 
In the early history of the salt trade, when but a very 
small quantity of salt was made, the springs at North wich, 
Middlewich, and Nantwich either gently ran away into the 
rivers or rose nearly to the surface. When the rock salt 
was discovered near to North wich in 1670, a strong brine 
was found running upon the surface of the salt. This brine 
was utilised at once, being stronger than that of the natural 
springs. On the banks of the Weaver many brine wells 
were sunk, and since that time all the white salt manufac- 
tured has been made from the brine thus discovered. Neg- 
lecting minor thin seams of salt which are met with either 
above or below the main beds, we may say there are two 
thick beds of rock salt known locally as Top Rock salt and 
Bottom Rock salt. These two beds are separated by a layer 
of marl much indurated and containing veins of salt run- 
ning nearly vertically, as if occupying rifts, or cracks, or 
crevices in the hardened marl. This layer is about 30 feet 
thick. The first bed of rock salt, or the “ Top Rock,” is at 
Northwich from 40 to 80 yards from the surface, varying 
with the different surface levels and dipping from the 
N.E. to S.W. The surface of this salt bed is very 
irregular, being water-worn and channeled as if by minia- 
ture streams. In most cases immediately before reaching 
the salt a much indurated marl is found, locally termed 
“ flag.” On piercing this flag brine was met with in the 
first instance, and continues so to be to the present day.*' 
* At Nantwich this <c flag” has been met with in a boring for brine 
now being carried on. 
