252 C. PARKINSON ON THE DROITWICH 
brine at once flows up with great force. Fourteen feet is the 
deepest part as yet discovered; at either side of the 300 yards 
depression the spring cavity is about 4 feet. Underneath this a 
boring has never yet been made, and we can only judge, from the 
deeper shafts at Stoke works, the probable strata over which the 
brine-cavity exists. The extent of the natural brine-river, or 
reservoir, can hardly be ascertained ; but it cannot be less in breadth 
than 200 yards, and half a mile in length; that other cavities are 
under Yew-tree Hill, Rashwood, and other parts is certain from 
the rapid subsidence. Possibly some communication by a small 
stream exists between each basin, in a line already indicated, viz. 
N.E. to S8.W. What are now empty cavities have, no doubt, 
previously been solid accumulations of rock-salt. 
In the section given by Dr. Nash we find that a brine-spring was 
struck some 80 feet from the surface, a cavity of 22 inches only 
being met with; but the boring was apparently continued another 
80 feet to rock-salt. This was a spring which must have forced its 
way upwards before the more recent borings tapped the deeper 
supply ; no trace of a brine-spring now remains at that depth. I 
am of opinion that some considerable beds of rock-salt exist at a 
greater depth than 210-220 feet, lying more in the N.E. direction 
towards Stoke works. This is somewhat proved by the remarkable 
difference in the wells at Stoke*. 
At first when the salt at Stoke was discovered, it was from the 
rock-salt beds that the salt was extracted, and not from the 
evaporation of brine-springs. In beds of red marl, grey marl, and 
gypsum, of 800 feet (at the least), several bands of excellent rock- 
salt are found. 
270 feet down a bed 15 feet in thickness is passed of intensely 
hard sandstone, which tests the strength of the steel rods and renders 
progress extremely slow. JI think that this is probably the 
immediate base of the brine-cavities at Droitwich (43 miles further 
down the valley), and that the seam of rock-salt above is absolutely 
carried away by brine-springs at Droitwich and remains solid at Stoke. 
Several hundred feet below this hard portion, 25 feet are bored 
through softer marls, sandstones, and rock-salt, till brine-springs ~ 
are tapped at least 800 feet from the surface. Even at this depth 
the salt was formerly got by mining operations, till the brine-springs 
(as Mr. Corbett, M.P., has informed me) suddenly broke through, 
rendering further extraction of rock-salt impossible; this supply of 
brine has never failed. I have remarked on the manner the brine 
wells up with such great force both at Droitwich and Stoke when 
the springs are struck. This leads to the question of the water- 
supply necessary to permeate the rock-salt and produce such a 
remarkable pressure. 
In the first place the supply never varies. On the other hand 
the Droitwich water-works, the supply of water being from the 
Keuper Marlsand surface springs, cannot always keep up their supply. 
* Information of which hasbeen placed at my disposal through the kindness 
of J. Corbett, Esq., M.P., Droitwich. 
