170 
ROCK- 
were sent to different por(s in Ireland: the remainder was 
principally exported to Denmark, Russia, Sweden, Prussia, 
and Germany. However, a small quantity went to Guernsey, 
Jersey, and the West Indies. 
This shews, in a striking manner, the great utility and 
advantage of this article in a manufacturing and trading point 
of view, as well as in other ways. 
In regard to the original formation of the beds or strata 
of rock-salt, in this and other countries, different theories, 
opinions, and conjectures, have been formed and proposed; 
but it is one of those geological questions which is extremely 
embarrassing in its nature, and very difficult in its solution. 
Mr. Holland has, however, in the above work, ingeniously 
stated several suppositions on the subject, and the objections 
to which they are exposed. It is remarked, that wherever 
rock-salt is met with, sulphate of lime seems to be very 
generally discovered in mixture with the earthy strata above 
it. And the writer of the “ Memoire sur le Sel Marin,” 
in the 11th volume of the Annals of Chemistry, it is added, 
informs us, that this is the case in Poland, Transylvania, 
and Hungary ; also, that there is commonly a layer of 
gypsum betwixt the strata of stone and the bed of salt. 
This gypseous layer is of different colours, and is found 
crystallized, striated, and mixed with marine shells. The 
gypsum above the beds of rock-salt in Cheshire is, in like 
manner, found crystallized and striated ; but no marine ex¬ 
uviae, or organic remains, it is observed, are ever met with 
in any of the strata. Nor does gypsum accompany it, as is 
usual in other places, as near Cordova, in Spain, where 
rock-salt forms a mountain 500 feet in height, and three 
miles in circumference, as noticed by Kirwan and Towns- 
hend. Jars, the author of the “ Voyages Metallurgies,” 
who it is asserted, has given the most particular account 
we have of the upper stratum of rock-salt about Northwich, 
remarks, that “ it appears to have been deposited by layers 
or beds of several colours;” and that “ these layers of salt 
are in such a position, as to lead us to believe that the de¬ 
position of it was made in waves, similar to those which are 
formed on the sea-coast.” 
This, Mr. Holland says, coincides with an opinion sug¬ 
gested by Mr. Stanley, a friend of his, in regard to the pro¬ 
bable origin of the beds of rock-salt, now in existence in this 
district; who states that rock-salt is there found in several 
strata, one above the other, with intermediate beds of in¬ 
durated clay, in the valleys of the Weaver, and those of the 
other rivers and brooks emptying themselves into it; but 
that it has never been found so near the surface, as to be 
above the level of the sea, or beneath any solid rock. If 
beds of rock-salt are to be considered as so many deposits of 
salt from sea-water, we must suppose the sea, at some former 
period, to have occupied the valleys in this county; and 
that, from time to time, the communications were inter¬ 
rupted between these valleys (then deeper than they are now) 
and the sea. Earthquakes, or accumulations of sand in the 
estuaries of the Mersey and the Dee, might, it is contended, 
have caused the interruptions. Whenever the sea-water in 
the valleys became separated from the sea, t}ie salt contained 
in it would subside, by the natural process of evaporation. 
This, it is supposed, would the more easily have taken place, 
if, by any subterraneous fermentation, the ground below 
the water should have been heated. To account for a 
greater accumulation of salt than the sea-water filling all the 
lowest parts of the district would contain, we must suppose, 
it is said, that the obstruction interposed between the valleys 
and the sea had been repeatedly broken down, and re¬ 
newed again. Tides, unusually high, might occasionally 
overcome the resistance of the accumulated sand; and if the 
intervals between the inundations were only of short dura¬ 
tion, a subsidence of salt might take place, equal to the 
formation of the thickest stratum of the rock-salt now ex¬ 
isting. Long intervals between the inundations would admit 
of an accumulation of clay, and other earthy particles, over 
the salt thus deposited; and in this manner would be formed 
SALT. 
a new basis for another stratum of rock-salt to repose 
upon. 
Thus, it is thought, the regular and astonishing existence of 
the salt strata may be accounted for, without necessarily 
supposing them coeval with the original formation of the 
earth : but to confirm the theory, it is suggested that much 
observation and close inquiry into the natural history of the 
county would be required. 
Mr. Holland, however, justly thinks that there are many 
objections to the theory which supposes the beds of rock- 
salt, in this district, to have been formed by deposition from 
the waters of the sea; some of which he states rather for the 
sake of promoting discussion and inquiry, than of affording 
any very decided opinion on a matter of so much doubt, 
uncertainty, and obscurity. Though on making a per¬ 
pendicular section of the upper bed of rock-salt, an irregular 
stratification, such as noticed by Jars, may, he says, by 
frequent accurate examination, be observed, the general 
appearance of the sides of the openings, whence the rock- 
salt is taken, is that of a confused and irregular red mass; 
in which some portions of salt have a greater, others a less', 
proportionate admixture of earth; while, here and there, 
they may be seen perfectly pure and transparent. He, 
therefore, asks, is it likely that this irregularity and confu¬ 
sion would have existed, had the beds of rock-salt in this 
district been formed by the evaporation of sea-water inun¬ 
dating the land at certain intervals of time, as the above 
theory supposes? On the contrary, says he, would it not 
be natural to expect from reasonings, a priori, that the 
salt, thus deposited from sea-water, would be disposed in 
layers perfectly regular, and differing from one another 
merely in thickness, or a few other circumstances of inferior 
moment ? 
Another fact which, it is supposed, invalidates, in some 
measure, the notion that the rock-salt has been deposited 
from the waters of the sea, is the great disproportion of 
quantity, shewn by analysis to exist, between the earthy 
salts contained in the brine of this district, and those held in 
solution by sea-water; the ratio here being as one to ten, 
or the proportion which the earthy salts bear to the pure 
•muriate of soda in sea-water 'is ten times greater than that 
which prevails in the Cheshire brine. The ascertaining of 
this fact proves, it is supposed, that the rock-salt (from the 
solution of which the brine is formed) is combined with a 
much smaller proportion of earthy salts than exists in sea¬ 
water; a circumstance difficult to be accounted for, on the 
supposition that the beds of this substance were formed by 
the evaporation of the sea-water, occupying the valleys and 
lowest parts of the land. It must be noticed, however, as 
worthy of attention, that the earthy salts, intermixed with 
the rock-salt in the above district, are the same which are 
held in solution by sea-water, being principally muriated 
magnesia and sulphate of lime. 
There is, however, a still stronger proof, it is supposed, 
against the notion that the beds of rock-salt in this county 
are depositions from the sea-water, in the circumstance that 
no marine exuviae have ever been discovered in the strata. 
This, it is imagined, would almost indubitably have been 
the case, had the Jana been covered with sea-water during a 
period of sufficient length for the deposition of beds of salt 
of such prodigious thickness; and the fact, that no such 
exuviae do actually exist, is supposed in itself sufficient to 
induce a suspicion that the theory in question cannot be 
well founded. Other objections too, it is observed, offer 
themselves to its validity; such as the enormous depth of 
sea-water necessary to the production of a body of rock-salt 
forty yards in thickness; the difficulty, if not impossibility, 
on such principles, of accounting for the formation of the 
singular insulated mountain of rock-salt at Cordova, in 
Spain. 
ROCKENHAUSEN, a town of the Bavarian province 
of the Rhine, on the Alsenz, with 1100inhabitants ; 13 miles 
north-by-east of Kaiserslautern. 
RO'CKER, 
